NTIA Report 99-367

Broadband Spectrum Survey

at San Francisco, California

May-June 1995

Frank H. Sanders

Bradley J. Ramsey

Vincent S. Lawrence

U.S. DEPARTMENT OF COMMERCE

William M. Daley, Secretary

Larry Irving, Assistant Secretary

for Communications and Information

July 1999
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PREFACE

A spectrum survey often depends upon significant efforts by personnel not directly involved in

the measurements. We wish to thank the following people and organizations who made the

spectrum survey at San Francisco, California, a success: Watson Communications, who allowed

us to use their site on Grizzly Peak as a measurement location; the U.S. Coast Guard, who

allowed us to use their facilities on Yerba Buena Island as a measurement location; and the

California State Parks Department, and Mr. James Burke of that Department, who allowed us to

use the summit of Angel Island as a measurement location.

Certain commercial equipment and software are identified in this report to adequately describe

the measurements. In no case does such identification imply recommendation or endorsement

by the National Telecommunications and Information Administration (NTIA), nor does it imply

that the equipment or software identified are necessarily the best available for the application.

This report is available on the World Wide Web through the Institute for Telecommunication

Sciences (ITS) home page. The ITS home page address is: http://www.its.bldrdoc.gov.

Descriptions and availability of other NTIA reports are found on the ITS publications page. The

publications page address is: http://www.its.bldrdoc.gov/pub/pubs.html.

iii
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CONTENTS

Page

PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii

FIGURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi

ABSTRACT ..................................................... 1

1. INTRODUCTION ............................................. 1

1.1 Background .............................................. 1

1.2 Authority ................................................ 2

1.3 Purpose ................................................. 2

1.4 Extrapolation of Spectrum Occupancy Data ........................ 2

2. SAN FRANCISCO SPECTRUM SURVEY ............................ 3

2.1 Introduction .............................................. 3

2.2 Measurement Site Description ................................. 3

2.3 Data Considerations ........................................ 5

2.4 Measured Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2.5 Band-by-Band Evaluation of San Francisco Spectrum Survey Results . . . . . . 82

3. CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92

4. REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94

APPENDIX A: OVERVIEW OF BROADBAND SPECTRUM SURVEYS . . . . . . . . . 95

APPENDIX B: INTERPRETATION OF SPECTRUM SURVEY DATA . . . . . . . . . . . 105

APPENDIX C: RADIO SPECTRUM MEASUREMENT SYSTEM . . . . . . . . . . . . . . 119

APPENDIX D: DATA ACQUISITION SOFTWARE . . . . . . . . . . . . . . . . . . . . . . . . 131

v
FIGURES

Page

Figure 1. Regional map of San Francisco, California showing the location of

all three RSMS measurement sites ............................. 6

Figure 2. Regional map of San Francisco, California showing areas that are

line-of-sight from the measurement site at Grizzly Peak .............. 7

Figure 3. Regional map of San Francisco, California showing areas that are

line-of-sight from the measurement site at Yerba Buena .............. 8

Figure 4. Regional map of San Francisco, California showing areas that are

line-of-sight from the measurement site at Angel Island .............. 9

Figure 5. Summary graph of 108-138 MHz measurements at Grizzly Peak . . . . . . . 11

Figure 6. Summary graph of 108-138 MHz measurements at Yerba Buena . . . . . . . 12

Figure 7. Summary graph of 138-162 MHz measurements at Grizzly Peak . . . . . . . 13

Figure 8. Summary graph of 138-162 MHz measurements at Yerba Buena . . . . . . . 14

Figure 9. Summary graph of 162-174 MHz measurements at Grizzly Peak . . . . . . . 15

Figure 10. Summary graph of 162-174 MHz measurements at Yerba Buena . . . . . . . 16

Figure 11. Summary graph of 174-216 MHz measurements at Grizzly Peak . . . . . . . 17

Figure 12. Summary graph of 174-216 MHz measurements at Yerba Buena . . . . . . . 18

Figure 13. Summary graph of 216-225 MHz measurements at Grizzly Peak . . . . . . . 19

Figure 14. Summary graph of 216-225 MHz measurements at Yerba Buena . . . . . . . 20

Figure 15. Summary graph of 225-400 MHz measurements at Grizzly Peak . . . . . . . 21

Figure 16. Summary graph of 225-400 MHz measurements at Yerba Buena . . . . . . . 22

Figure 17. Summary graph of 400-406 MHz measurements at Grizzly Peak . . . . . . . 23

Figure 18. Summary graph of 400-406 MHz measurements at Yerba Buena . . . . . . . 24

Figure 19. Summary graph of 406-420 MHz measurements at Grizzly Peak . . . . . . . 25

vi
FIGURES (Continued)

Page

Figure 20. Summary graph of 406-420 MHz measurements at Yerba Buena . . . . . . . 26

Figure 21. Summary graph of 420-450 MHz measurements at Grizzly Peak . . . . . . . 27

Figure 22. Summary graph of 420-450 MHz measurements at Yerba Buena . . . . . . . 28

Figure 23. Summary graph of 450-470 MHz measurements at Grizzly Peak . . . . . . . 29

Figure 24. Summary graph of 450-470 MHz measurements at Yerba Buena . . . . . . . 30

Figure 25. Summary graph of 470-512 MHz measurements at Grizzly Peak . . . . . . . 31

Figure 26. Summary graph of 470-512 MHz measurements at Yerba Buena . . . . . . . 32

Figure 27. Summary graph of 512-806 MHz measurements at Grizzly Peak . . . . . . . 33

Figure 28. Summary graph of 512-806 MHz measurements at Yerba Buena . . . . . . . 34

Figure 29. Summary graph of 806-902 MHz measurements at Grizzly Peak . . . . . . . 35

Figure 30. Summary graph of 806-902 MHz measurements at Yerba Buena . . . . . . . 36

Figure 31. Summary graph of 902-928 MHz swept measurements at Grizzly Peak . . . 37

Figure 32. Summary graph of 902-928 MHz swept measurements at Yerba Buena . . . 38

Figure 33. Summary graph of 902-928 MHz stepped measurements at Grizzly Peak . . 39

Figure 34. Summary graph of 902-928 MHz stepped measurements at Yerba Buena . . 40

Figure 35. Summary graph of 928-960 MHz measurements at Grizzly Peak . . . . . . . 41

Figure 36. Summary graph of 928-960 MHz measurements at Yerba Buena . . . . . . . 42

Figure 37. Summary graph of 960-1215 MHz measurements at Grizzly Peak . . . . . . . 43

Figure 38. Summary graph of 960-1215 MHz measurements at Yerba Buena . . . . . . . 44

Figure 39. Summary graph of 1215-1400 MHz measurements at Grizzly Peak . . . . . . 45

Figure 40. Summary graph of 1215-1400 MHz measurements at Yerba Buena . . . . . . 46

vii
FIGURES (Continued)

Page

Figure 41. Summary graph of 1350-1400 MHz measurements at Grizzly Peak . . . . . . 47

Figure 42. Summary graph of 1350-1400 MHz measurements at Yerba Buena . . . . . . 48

Figure 43. Summary graph of 1400-1530 MHz measurements at Grizzly Peak . . . . . . 49

Figure 44. Summary graph of 1400-1530 MHz measurements at Yerba Buena . . . . . . 50

Figure 45. Summary graph of 1530-1710 MHz measurements at Grizzly Peak . . . . . . 51

Figure 46. Summary graph of 1530-1710 MHz measurements at Yerba Buena . . . . . . 52

Figure 47. Azimuth-scan graph of 1710-2300 MHz measurements at Angel Island . . . 53

Figure 48. Summary graph of 2300-2500 MHz measurements at Grizzly Peak . . . . . . 54

Figure 49. Summary graph of 2300-2500 MHz measurements at Yerba Buena . . . . . . 55

Figure 50. Azimuth-scan graph of 2500-2700 MHz measurements at Angel Island . . . 56

Figure 51. Summary graph of 2700-2900 MHz measurements at Grizzly Peak . . . . . . 57

Figure 52. Summary graph of 2700-2900 MHz measurements at Yerba Buena . . . . . . 58

Figure 53. Summary graph of 2900-3100 MHz measurements at Grizzly Peak . . . . . . 59

Figure 54. Summary graph of 2900-3100 MHz measurements at Yerba Buena . . . . . . 60

Figure 55. Summary graph of 3100-3700 MHz measurements at Grizzly Peak . . . . . . 61

Figure 56. Summary graph of 3100-3700 MHz measurements at Yerba Buena . . . . . . 62

Figure 57. Azimuth-scan graph of 3700-4200 MHz measurements at Angel Island . . . 63

Figure 58. Summary graph of 4200-4400 MHz measurements at Grizzly Peak . . . . . . 64

Figure 59. Summary graph of 4200-4400 MHz measurements at Yerba Buena . . . . . . 65

Figure 60. Azimuth-scan graph of 4400-5000 MHz measurements at Angel Island . . . 66

Figure 61. Summary graph of 5000-5250 MHz measurements at Grizzly Peak . . . . . . 67

viii
FIGURES (Continued)

Page

Figure 62. Summary graph of 5000-5250 MHz measurements at Yerba Buena . . . . . . 68

Figure 63. Summary graph of 5250-5925 MHz measurements at Grizzly Peak . . . . . . 69

Figure 64. Summary graph of 5250-5925 MHz measurements at Yerba Buena . . . . . . 70

Figure 65. Azimuth-scan graph of 5925-7125 MHz measurements at Angel Island . . . 71

Figure 66. Azimuth-scan graph of 7125-8500 MHz measurements at Angel Island . . . 72

Figure 67. Summary graph of 8500-10550 MHz measurements at Grizzly Peak . . . . . 73

Figure 68. Summary graph of 8500-10550 MHz measurements at Yerba Buena . . . . . 74

Figure 69. Azimuth-scan graph of 10550-13250 MHz measurements at Angel Island . 75

Figure 70. Summary graph of 13250-14200 MHz measurements at Grizzly Peak . . . . 76

Figure 71. Summary graph of 13250-14200 MHz measurements at Yerba Buena . . . . 77

Figure 72. Azimuth-scan graph of 14200-15700 MHz measurements at Angel Island . 78

Figure 73. Summary graph of 15700-17700 MHz measurements at Grizzly Peak . . . . 79

Figure 74. Summary graph of 15700-17700 MHz measurements at Yerba Buena . . . . 80

Figure 75. Azimuth-scan graph of 17700-19700 MHz measurements at Angel Island . 81

Figure B-1. Functional diagram of the RSMS signal-processing path for

measured data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109

Figure C-1. ITS radio spectrum measurement system with antennas mounted for

a broadband spectrum survey at a remote field site . . . . . . . . . . . . . . . . . 120

Figure C-2. Top and side view drawings of the RSMS . . . . . . . . . . . . . . . . . . . . . . . 121

Figure C-3. Front panel of the RSMS instrument racks . . . . . . . . . . . . . . . . . . . . . . . 122

Figure C-4. Block diagram of the RSMS receiver . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

Figure C-5. Example calibration graph of noise figure and correction factor curves . . . 128

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BROADBAND SPECTRUM SURVEY AT

SAN FRANCISCO, CALIFORNIA

MAY-JUNE 1995

Frank H. Sanders, Bradley J. Ramsey, and Vincent S. Lawrence1

The National Telecommunications and Information Administration (NTIA) is

responsible for managing the Federal Government’s use of the radio spectrum. In

discharging this responsibility, NTIA funds the Institute for Telecommunication

Sciences (ITS) radio spectrum measurement system to collect data for spectrum

utilization assessments. This report details such a data collection effort spanning all

of the spectrum from 108 MHz to 19.7 GHz in the metropolitan area of San Francisco,

California, during May and June 1995.

Key words: land mobile radio (LMR); radar emission spectrum; radio frequency environment;

radio spectrum measurement system (RSMS); spectrum resource assessment;

spectrum survey.

1. INTRODUCTION

1.1 Background

The National Telecommunications and Information Administration (NTIA) is responsible for

managing the Federal Government’s use of the radio spectrum. Part of this responsibility is to

establish policies concerning spectrum assignment, allocation, and use; and to provide the various

departments and agencies with guidance to ensure that their conduct of telecommunications

activities is consistent with these policies [1, part 8.3]. In discharging this responsibility, NTIA

(1) assesses spectrum utilization, (2) identifies existing and/or potential compatibility problems

among the telecommunication systems that belong to various departments and agencies,

(3) provides recommendations for resolving any compatibility conflicts that may exist in the use

of the frequency spectrum, and (4) recommends changes to promote spectrum efficiency and

improve spectrum management procedures.

Since 1973, NTIA has been collecting data on Federal use of the radio frequency spectrum in

support of the NTIA Spectrum Analysis Program. The radio spectrum measurement system

(RSMS) is used by NTIA to provide technical support for several programs, such as,

(1) Spectrum Resource Assessments (SRAs), (2) U.S. participation in the International

Telecommunication Union (ITU) conferences and ITU Radiocommunication Sector (ITU-R)

activities, (3) analysis of electromagnetic compatibility (EMC) conflicts, (4) interference

resolution, and (5) systems review activity related to new Federal Government systems.

1

The authors are with the Institute for Telecommunication Sciences, National Telecommunications

and Information Administration, U.S. Department of Commerce, Boulder, CO 80303-3328.
1.2 Authority

The RSMS is under the administrative control of the Director of ITS. The Deputy Associate

Administrator of the Office of Spectrum Management (OSM) is responsible for meeting the

spectrum management requirements of NTIA, as transmitted to him by the Associate

Administrator of OSM. RSMS measurement activities are authorized by the Deputy Associate

Administrator of OSM in consultation with the Director of ITS. Federal agencies with spectrum

management needs can request support of the RSMS through the Deputy Associate Administrator

of OSM.

1.3 Purpose

Under Departmental Organizational Order 25-7, issued October 5, 1992, and amended

December 3, 1993, the Office of Spectrum Management is responsible for identifying and

conducting measurements necessary to provide NTIA and the various departments and agencies

with information to ensure effective and efficient use of the spectrum. As part of this NTIA

measurement program, spectrum occupancy measurements are conducted using the RSMS. The

spectrum occupancy data presented in this report do not include identification of specific emitters.

The measured data are provided for the spectrum management community to:

enable a better understanding of how telecommunication systems use the allocated

spectrum;

provide timely information on variations in frequency band usage, e.g., identify

frequency bands becoming heavily used;

support the NTIA system review process by providing information on the

availability of spectrum for new systems; and

assess the feasibility of promoting alternative types of services or systems that

result in more effective and efficient use of the spectrum.

1.4 Extrapolation of Spectrum Occupancy Data

The spectrum survey measurements contained in this report cannot be used solely to assess the

feasibility of using alternate services or systems in a band. Extrapolation of data in this report

to general spectrum occupancy for alternative spectrum uses requires consideration of additional

factors. These include spectrum management procedures, types of missions performed in the

bands, and new spectrum requirements in the development and procurement stages. (See

Appendix A for a broader discussion of systems that are not normally expected to appear in

RSMS measurement data.) Also, measurement area, measurement site, and measurement system

parameters should be considered.

2
The area chosen for a spectrum survey will affect measured spectrum occupancy. For example,

measurements made in Denver, Colorado [2] are probably representative of metropolitan areas

that do not have any maritime radionavigation or extensive military activity. A coastal city, such

as San Diego, California [3] with major naval installations, will show higher levels of usage in

bands that support such activities.

Choice of measurement site within an area also can affect measured spectrum occupancy. An

area such as Seattle-Tacoma, Washington (rough terrain, heavy forestation, and widely dispersed

transmitters) may require multiple measurement sites to adequately characterize usage.

Spectrum management procedures (such as band allotments for functions and missions) also

affect spectrum utilization. For example, channels used for taxi dispatch might show heavy use

whereas channels allocated for law enforcement or public safety may show less use. Regardless

of usage, dedicated channels for these safety-of-life functions remain a spectrum requirement.

Special events such as natural disasters, Olympic games, and Presidential inaugurations may also

create unique spectrum requirements.

Spectrum measurements provide data on expected signal levels and probability of occurrences

that are essential for assessing alternate uses of the spectrum. Such information is difficult to

obtain from band allocation databases or an understanding of spectrum management procedures.

2. SAN FRANCISCO SPECTRUM SURVEY

2.1 Introduction

This section (1) describes the measurement sites selected for the San Francisco, California,

spectrum survey, (2) briefly describes the data processing used to characterize spectrum

occupancy across the 108-MHz to 19.7-GHz frequency range, (3) presents the measured data, and

(4) provides band-by-band commentary on the survey results. Appendix A contains a thorough

description of the spectrum survey measurement procedure. Appendix B provides details for

interpretation of data presented in this report. Appendices C and D provide descriptions of the

RSMS hardware and software used to make the measurements.

2.2 Measurement Site Description

The San Francisco metropolitan area is centered on, and largely surrounds, the San Francisco

Bay, an estuarine body of water, measuring about 100 km north-to-south and about 30 km eastto-west, that is almost completely land-locked. A high ridge separates the west side of the bay

from the ocean, and another high ridge occurs on the east side of the bay. The land around the

south part of the bay is low-lying. Urban development in the area is especially dense on the

west, south, and east sides of the bay, and it is this area that is targeted by the RSMS spectrum

survey effort.

3
If topology were the only concern, the most desirable measurement location for the survey would

be a high point on the west ridge, such as Mt. Sutro. Unfortunately, all topologically desirable

measurement locations on the west ridge are already occupied by high-power transmitters, such

as for television broadcast services, rendering these locations unusable for the purposes of RSMS

broadband spectrum survey measurements. (See section A.2 for detailed requirements of RSMS

spectrum survey measurement locations.) On the east side of the bay, the high ground affords

excellent line-of-sight coverage of the bay area, but again the topologically desirable locations

tend to already be occupied by high-power transmitters. A third possibility for RSMS

measurement location would be an island in the bay, preferably one with a high summit not

already occupied by high-power transmitters.

A detailed area reconnaissance suggested three strong candidates for measurement locations:

Grizzly Peak, on the east ridge, Yerba Buena Island, in the middle of the bay, and Angel Island,

about 32 km northwest of Yerba Buena Island. All three locations presented advantages and

disadvantages for RSMS measurements, as shown in Table 1.

Table 1. Factors Considered in the Selection of Measurement Locations for the San Francisco

Broadband Spectrum Survey.

Location Advantages Disadvantages

Grizzly Peak Excellent line-of-sight coverage of the

metropolitan area

Some nearby land mobile radio base

stations present potential for overload of

the RSMS receiver in some bands

Yerba Buena Island

(summit)

Moderately good line-of-sight coverage

of the metropolitan area; no land mobile

radio base station overload potential

X-band surface search radar at the summit

might mask other x-band emissions;

heavy vehicular traffic in the vicinity

might generate substantial radio noise in

VHF-UHF bands

Angel Island

(summit)

Moderately good line-of-sight coverage;

only one low-power UHF transmitter on

the summit

More logistical problems, such as limited

access to adequate commercial power;

State Parks Department prefers that

RSMS not stay on the summit for more

than a few days

Because each of the three candidate measurement locations presented possible problems that

would make spectrum measurements difficult in one or more bands, a final determination was

made to perform measurements in most bands at more than one site. The data could be

subsequently analyzed to extract usable data for every band from at least one measurement

location. Except for fixed-terrestrial point-to-point microwave band measurements, all bands

between 108 MHz and 19.7 GHz were measured at both Grizzly Peak and Yerba Buena Island.

The measurements of the fixed point-to-point microwave bands were reserved for Angel Island,

because that location provided the least-obstructed horizon (crucial for good azimuth-scan

measurements), and the measurements could be done within the time constraints imposed for that

location.

4
When all data were collected and analyzed, it became apparent that, although some overload had

occurred in some bands, all three sites had yielded measurements that were presentable as final

data. Additionally, it became apparent that the duplication of measurements at the Grizzly Peak

and Yerba Buena Island locations had provided necessary data for determining the answer to a

persistent question regarding the validity of RSMS broadband spectrum survey data: To what

extent are measurement results for a given band at a given location representative of the spectrum

occupancy in that band for an entire metropolitan area? The results of this spectrum survey, as

described at length in the conclusions (Section 3), indicate in general that measured usage

patterns were representative of the entire metropolitan area.

It was also apparent by the end of the measurements that the Angel Island location was probably

the best location for a San Francisco broadband spectrum occupancy measurement survey,

because of the lack of transmitters on the summit and the relatively good line-of-sight coverage

of the metropolitan area. If future spectrum surveys are performed in San Francisco, it would

be worth extraordinary effort to overcome the logistic problems and to obtain permission to keep

the RSMS on the Angel Island summit long enough to complete a broadband spectrum survey.

The three San Francisco measurement locations are shown in Figure 1. The Grizzly Peak

location was a fenced enclosure at 707 Sky Valley Drive in Berkeley, California. The property

was owned by Watson Communications. Measurement site coordinates were 37.8822° N,

122.2328° W, and the site base altitude was 527 m MSL. Figure 2 shows areas that were line-ofsight (white areas) to the RSMS from 2 m above ground (typical mobile antenna height) and

those areas that were obstructed (shaded with plus (+) signs in the Figure) from the RSMS due

to terrain. The Grizzly Peak measurement location afforded the most extensive line-of-sight

coverage of the San Francisco area.

The Yerba Buena Island location was at the summit of the island, within a Coast Guard

communications facility. The site coordinates were 37.8101° N, 122.3650° W, and the site base

altitude was 104 m MSL. Figure 3 shows areas that were line-of-sight to the RSMS and those

areas that were obstructed from the RSMS due to terrain, in the same manner as Figure 2. The

Yerba Buena Island measurement location afforded moderately good line-of-sight coverage of

the San Francisco area.

The Angel Island location was at the summit of Mt. Caroline Livermore, part of the Angel Island

State Park facility. The site coordinates were 37.8617° N, 122.4296° W, and the site base

altitude was 238 m MSL. Figure 4 shows line-of-sight coverage for this site. This location

afforded good coverage of the San Francisco area.

2.3 Data Considerations

The San Francisco spectrum survey, with the following few exceptions, was performed as

described in Appendix A. For spectrum surveys, the RSMS is configured as two measurement

systems operating simultaneously: one, identified as "System-1," for frequency measurements

below 1 GHz; and the other, "System-2" for measurements above 1 GHz. All System-1

frequency bands were measured with a 100-MHz to 1-GHz log-periodic antenna (LPA) mounted

5
Figure 1. Regional map of San Francisco, California, showing the location of all three RSMS

measurement sites. Map produced with MapExpertTM software from DeLorme

Mapping, Freeport, Maine.

6
Figure 2. Regional map of San Francisco, California, showing areas that are line-of-sight

(white) and terrain nonline-of-site (plus-sign shaded) from the measurement site at

Grizzly Peak.

7
Figure 3. Regional map of San Francisco, California, showing areas that are line-of-sight

(white) and terrain nonline-of-site (plus-sign shaded) from the measurement site at

Yerba Buena.

8
Figure 4. Regional map of San Francisco, California, showing areas that are line-of-sight

(white) and terrain nonline-of-site (plus-sign shaded) from the measurement site at

Angel Island.

9
at a 45° angle for slant polarization and aimed toward the downtown San Francisco area. This

improved RSMS detection of emissions from the most densely developed part of San Francisco.

The System-2 frequencies were measured with a 500-MHz to 18-GHz slant polarized biconical

omni antenna, except for azimuth-scanned2 bands that were measured with a rotating dish

antenna (1-m parabolic reflector with dual horizontal and vertical feeds).

As detailed in Section 2.5 and Section 3, most bands were measured at two locations to

determine the extent to which measured usage patterns were representative of usage patterns

across the entire metropolitan area.

Some broadcast signals were received at sufficiently high levels at both the Grizzly Peak and

Yerba Buena Island measurement locations to cause some frontend overload in the RSMS

receiver. For the most part, these overload effects were mitigated by the use of rf attenuation

in the bands occupied by these signals. Band-by-band comments on measurement results

(Section 2.5.1) include discussion of overload effects in the three bands (108 to 114, 174 to 216,

and 490 to 612 MHz) where rf attenuation was used.

All measured data, except the azimuth-scanning measurements, underwent a postmeasurement

cumulative processing (cuming) step before being displayed. Every frequency data point

recorded was cumulated (cumed) according to the measurement algorithm3 used to collect the

data. Swept and stepped measurements were cumed such that the graphed data points (received

signal levels; RSLs) showed the maximum, mean, and minimum RSLs of all scans. Swept/m3

data already contained this information, so cuming resulted in graphs showing maximum of

maximum RSLs, mean of mean RSLs, and minimum of minimum RSLs. Azimuth-scan data

were not cumed, but horizontally and vertically polarized scans were combined in postmeasurement processing so the graphed data show only one resultant single-line curve.

2.4 Measured Data

Each survey band of measured data is displayed graphically on a single page along with

corresponding frequency allocation information (Figures 5-75). Each survey band figure has an

identical format. The survey band graph in the middle of the page shows frequency in megahertz

on the x-axis vs. received signal level marked at 5-dBm increments on the y-axis. Noise level

tick marks on the y-axis of some graphs (e.g., "max sample noise," "mean sample noise" and

"min sample noise" on Figure 5) show measurement system noise limits. Measurement system

response to different types of signals and system noise limits are described in Appendix B. The

figure caption includes the survey location and principle measurement parameters.

2

The azimuth-scanning measurement routine is an operator-interactive technique using a rotating

dish antenna with a swept measurement algorithm. See Section B.8 in Appendix B for more

information about azimuth-scanning.

3

Appendix B contains operational descriptions of the RSMS measurement algorithms, including

swept, stepped, and swept/m3.

10
11

20 dB added attenuation

(see note below)

GOVERNMENT AERONAUTICAL RADIONAVIGATION. AERONAUTICAL AERONAUTICAL MOBILE. AERALLOCATIONS: MOBILE. MONON-GOVERNMENT AERONAUTICAL RADIONAVIGATION. AERONAUTICAL 1. AERONAUTICAL MOBILE. 3. AERALLOCATIONS: MOBILE. MOGENERAL VHF Omnidirectional Range (VOR). Differential-Global- Air Traffic Control. 1. Air Traffic Control (ATC). 2. Air UTILIZATION: Positioning-System (DGPS), government only.

108 117.975 121.9375-123.0875 128.8125 132.0125 

max sample noise

mean sample noise

min sample noise

Note: Concerning 108-114 MHz attenuated data, see comments in Table 2 of Section 2.5.1. AERONAUTICAL MOBILE. Private aircraft.2. 123.1 MHz: SAR (search and rescue) scene-of-action communications.3. AERONAUTICAL MOBILE.

4. SPACE OPERATION (space-to-Earth), METEOROLOGICAL-S

RESEARCH (space-to-Earth), 137-137.025 MHz and 137.175-13137.025-137.175 MHz and 137.825-138: Mobile-Satellite.

5. Government use includes TIROS downlinks; non-Government inclu

satellite systems (Little LEOS).

Figure 5. NTIA spectrum survey graph summarizing 4,600 sweeps across the 108-138 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
12

20 dB added attenuation

(see note below)

GOVERNMENT AERONAUTICAL RADIONAVIGATION. AERONAUTICAL AERONAUTICAL MOBILE. AERALLOCATIONS: MOBILE. MONON-GOVERNMENT AERONAUTICAL RADIONAVIGATION. AERONAUTICAL 1. AERONAUTICAL MOBILE. 3. AERALLOCATIONS: MOBILE. MOGENERAL VHF Omnidirectional Range (VOR). Differential-Global- Air Traffic Control. 1. Air Traffic Control (ATC). 2. Air UTILIZATION: Positioning-System (DGPS), government only.

108 117.975 121.9375-123.0875 128.8125 132.0125 

mean sample noise

min sample noise

Note: Concerning 108-114 MHz attenuated data, see comments in Table 2 of Section 2.5.1. AERONAUTICAL MOBILE. Private aircraft.2. 123.1 MHz: SAR (search and rescue) operations.3. AERONAUTICAL MOBILE.

4. SPACE OPERATION (space-to-Earth), METEOROLOGICAL-S

RESEARCH (space-to-Earth), 137-137.025 MHz and 137.175-13137.025-137.175 MHz and 137.825-138: Mobile-Satellite.

5. Government use includes TIROS downlinks; non-Government inclu

satellite systems (Little LEOS).

Figure 6. NTIA spectrum survey graph summarizing 5,800 sweeps across the 108-138 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
13

GOVERNMENT FIXED, MOBILE. FIXED, 5,6. 8.ALLOCATIONS: MOBILE, 3.NON-GOVERNMENT AMATEUR, AMATEUR. 3. 5. LAND MOBILE. 9. LAALLOCATIONS: 2.GENERAL Non-tactical military land mobile 4. 7. Land transportation, public safety, LanUTILIZATION: communications. 1. industrial, Earth telecommand, etc. safe

138 144 146 148 149.9 150.8 156.2475-157.1875 

mean sample noise

min sample noise

1. 143.75 MHz and 143.9 MHz: Civil Air Patrol.2. AMATEUR-SATELLITE.3. MOBILE-SATELLITE (Earth-to-space).4. Nontactical military land mobile communications. 148.15 MHz: Civil Air Patrol. Government use

includes TIROS command links and NASA satellite operations. Non-Government use includesnongeostationary nonvoice mobile satellite systems (Little LEOS).

5. 149.9-150.05 MHz: RADIONAVIGATION-SATELLITE, MOBILE-SATELLITE (Earth-to-space).

6. 150.05-150.8 MHz: FIXED, MOBILE.7. Government use includes military nontactical mobile and fixed 

downlinks. Non-Government use includes "Little LEOS."

8. 157.0375-157.1875 MHz: MARITIME MOBILE, VHF distress s9. 156.2475-157.0375 MHz: MARITIME MOBILE.10. 157.1875-157.45 MHz, 161.575-161.625 MHz, and 161.775-162.0

Figure 7. NTIA spectrum survey graph summarizing 4,600 sweeps across the 138-162 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
14

GOVERNMENT FIXED, MOBILE. FIXED, 5,6. 8.ALLOCATIONS: MOBILE, 3.NON-GOVERNMENT AMATEUR, AMATEUR. 3. 5. LAND MOBILE. 9. LAALLOCATIONS: 2.GENERAL Non-tactical military land mobile 4. 7. Land transportation, public safety, LanUTILIZATION: communications. 1. industrial, Earth telecommand, etc. safe

138 144 146 148 149.9 150.8 156.2475-157.1875 

mean sample noise

min sample noise

1. 143.75 MHz and 143.9 MHz: Civil Air Patrol.2. AMATEUR-SATELLITE.3. MOBILE-SATELLITE (Earth-to-space).4. Nontactical military land mobile communications. 148.15 MHz: Civil Air Patrol. Government use

includes TIROS command links and NASA satellite operations. Non-Government use includesnongeostationary nonvoice mobile satellite systems (Little LEOS).

5. 149.9-150.05 MHz: RADIONAVIGATION-SATELLITE, MOBILE-SATELLITE (Earth-to-space).

6. 150.05-150.8 MHz: FIXED, MOBILE.7. Government use includes military nontactical mobile and fixed 

downlinks. Non-Government use includes "Little LEOS."

8. 157.0375-157.1875 MHz: MARITIME MOBILE, VHF distress s9. 156.2475-157.0375 MHz: MARITIME MOBILE.10. 157.1875-157.45 MHz, 161.575-161.625 MHz, and 161.775-162.0

Figure 8. NTIA spectrum survey graph summarizing 5,700 sweeps across the 138-162 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
15

GOVERNMENT FIXED, MOBILE ALLOCATIONS:NON-GOVERNMENT ALLOCATIONS:GENERAL Land Mobile Radio (LMR) including weather radio, public safety, and law enforcement. UTILIZATION:

162.0125 

mean sample noise

min sample noise

1. FIXED, Land Mobile.2. Industrial, public safety.

3. FIXED, MOBILE.

Figure 9. NTIA spectrum survey graph summarizing 37,000 sweeps across the 162-174 MHz range (Syste

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
16

GOVERNMENT FIXED, MOBILE ALLOCATIONS:NON-GOVERNMENT ALLOCATIONS:GENERAL Land Mobile Radio (LMR) including weather radio, public safety, and law enforcement. UTILIZATION:

162.0125 

min sample noise

1. FIXED, Land Mobile.2. Industrial, public safety.

3. FIXED, MOBILE.

Figure 10. NTIA spectrum survey graph summarizing 44,000 sweeps across the 162-174 MHz range (Syste

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
17

20 dB added attenuation (see note below)

GOVERNMENTALLOCATIONS:NON-GOVERNMENT BROADCASTING (television broadcasting), 1, 2.ALLOCATIONS:GENERAL Channel 7 Channel 8 Channel 9 Channel 10 Channel 11 Channel 12 UTILIZATION:

174 180 186 192 198 204 

mean sample noise

min sample noise

Note: Concerning 174-216 MHz attenuated data, see comments in Table 2 of Section 2.5.1. Subscription television services and limited wireless microphone operations also are permitted in this band.

2. TV broadcast licencees are permitted to use subcarriers on a secon

broadcast purposes.

Figure 11. NTIA spectrum survey graph summarizing 13,000 sweeps across the 174-216 MHz range (Syst

swept/m3 algorithm, sample detector, 100-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 
18

20 dB added attenuation (see note below)

GOVERNMENTALLOCATIONS:NON-GOVERNMENT BROADCASTING (television broadcasting), 1, 2.ALLOCATIONS:GENERAL Channel 7 Channel 8 Channel 9 Channel 10 Channel 11 Channel 12 UTILIZATION:

174 180 186 192 198 204 

mean sample noise

min sample noise

Note: Concerning 174-216 MHz attenuated data, see comments in Table 2 of Section 2.5.1. Subscription television services and limited wireless microphone operations also are permitted in this band.

2. TV broadcast licencees are permitted to use subcarriers on a secon

broadcast purposes.

Figure 12. NTIA spectrum survey graph summarizing 15,000 sweeps across the 174-216 MHz range (Syst

swept/m3 algorithm, sample detector, 100-kHz bandwidth) at San Francisco (Yerba Buena), CA, 
19

GOVERNMENT MARITIME MOBILE, Radiolocation, Fixed, Aeronautical Mobile, 1, 2. LAND MOBILE, Radiolocation, 1. Radiolocation, 1.ALLOCATIONS:NON-GOVERNMENT MARITIME MOBILE, Fixed, Radiolocation, Aeronautical Mobile, 2. LAND MOBILE. AMATEUR.ALLOCATIONS:GENERAL Automated maritime telecommunications systems. Trunked and conventional systems. Amateur (1.25 meters).UTILIZATION:

216 220 222 

mean sample noise

min sample noise

1. Radiolocation is limited to the military services. 2. Secondary services, other than radiolocation, generally are lim

telecommand operations.

Figure 13. NTIA spectrum survey graph summarizing 2,880 sweeps across the 216-225 MHz range (Syst

swept/m3 algorithm, sample detector, 3-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 19
20

GOVERNMENT MARITIME MOBILE, Radiolocation, Fixed, Aeronautical Mobile, 1, 2. LAND MOBILE, Radiolocation, 1. Radiolocation, 1.ALLOCATIONS:NON-GOVERNMENT MARITIME MOBILE, Fixed, Radiolocation, Aeronautical Mobile, 2. LAND MOBILE. AMATEUR.ALLOCATIONS:GENERAL Automated maritime telecommunications systems. Trunked and conventional systems. Amateur (1.25 meters).UTILIZATION:

216 220 222 

mean sample noise

min sample noise

1. Radiolocation is limited to the military services. 2. Secondary services, other than radiolocation, generally are lim

telecommand operations.

Figure 14. NTIA spectrum survey graph summarizing 3,420 sweeps across the 216-225 MHz range (Syst

swept/m3 algorithm, sample detector, 3-kHz bandwidth) at San Francisco (Yerba Buena), CA, 19
21

GOVERNMENT FIXED, MOBILE, 1. 2. FIXED, MOBILE, 3.ALLOCATIONS:NON-GOVERNMENT 2. 3.ALLOCATIONS:GENERAL Military tactical and training communications including air traffic control (ATC).UTILIZATION: 2.

225 328.6-335.4 

mean sample noise

min sample noise

1. Government usage is limited to military services; additionally, 235-322 MHz is allocated on a primary

basis to the mobile-satellite service. 242.95-243.05 MHz is used for search and rescue operationsincluding position-indicating radiobeacons.

2. AERONAUTICAL RADIONAVIGATION, instrument landing sy3. 399.9-400.05 MHz: RADIONAVIGATION-SATELLITE, MOBI

Figure 15. NTIA spectrum survey graph summarizing 1,900 sweeps across the 225-400 MHz range (Syst

swept/m3 algorithm, sample detector, 30-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
22

GOVERNMENT FIXED, MOBILE, 1. 2. FIXED, MOBILE, 3.ALLOCATIONS:NON-GOVERNMENT 2. 3.ALLOCATIONS:GENERAL Military tactical and training communications including air traffic control (ATC).UTILIZATION: 2.

225 328.6-335.4 

max sample noise

mean sample noisemin sample noise

1. Government usage is limited to military services; additionally, 235-322 MHz is allocated on a primary

basis to the mobile-satellite service. 242.95-243.05 MHz is used for search and rescue operationsincluding position-indicating radiobeacons.

2. AERONAUTICAL RADIONAVIGATION, instrument landing sy3. 399.9-400.05 MHz: RADIONAVIGATION-SATELLITE, MOBI

Figure 16. NTIA spectrum survey graph summarizing 2,500 sweeps across the 225-400 MHz range (Syst

swept/m3 algorithm, sample detector, 30-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
23

RSMS not configured to receive sp

GOVERNMENT 1. METEOROLOGICAL AIDS (Radiosonde), 2, 3, 4, 5.ALLOCATIONS:NON-GOVERNMENT 1. METEOROLOGICAL AIDS (Radiosonde), 3, 4, 5.ALLOCATIONS:GENERAL 1. Meteorological radiosondes and satellite communication including GOES and TIROS-N.UTILIZATION:

400.05-400.15 

max sample noise

mean sample noise

min sample noise

1. STANDARD FREQUENCY AND TIME SIGNAL-SATELLITE (400.1 MHz ±25 kHz).2. 400.15-401 MHz: METEOROLOGICAL-SATELLITE (space-to-Earth).3. 400.15-401 MHz: SPACE RESEARCH (space-to-Earth), MOBILE-SATELLITE (space-to-Earth), Space

Operation (space-to-Earth).

4. 401-402 MHz: SPACE OPERATION (space-to-Earth), Earth 

Meteorological-Satellite. (Earth-to-space).

5. 402-403 MHz: Earth Exploration-Satellite (Earth-to-space), Mete

Figure 17. NTIA spectrum survey graph summarizing 1,320 sweeps across the 400-406 MHz range (Syst

swept/m3 algorithm, sample detector, 3-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 19
24

RSMS not configured to receive sp

GOVERNMENT 1. METEOROLOGICAL AIDS (Radiosonde), 2, 3, 4, 5.ALLOCATIONS:NON-GOVERNMENT 1. METEOROLOGICAL AIDS (Radiosonde), 3, 4, 5.ALLOCATIONS:GENERAL 1. Meteorological radiosondes and satellite communication including GOES and TIROS-N.UTILIZATION:

400.05-400.15 

max sample noise

mean sample noise

min sample noise

1. STANDARD FREQUENCY AND TIME SIGNAL-SATELLITE (400.1 MHz ±25 kHz).2. 400.15-401 MHz: METEOROLOGICAL-SATELLITE (space-to-Earth).3. 400.15-401 MHz: SPACE RESEARCH (space-to-Earth), MOBILE-SATELLITE (space-to-Earth), Space

Operation (space-to-Earth).

4. 401-402 MHz: SPACE OPERATION (space-to-Earth), Earth 

Meteorological-Satellite. (Earth-to-space).

5. 402-403 MHz: Earth Exploration-Satellite (Earth-to-space), Mete

Figure 18. NTIA spectrum survey graph summarizing 1,740 sweeps across the 400-406 MHz range (Syst

swept/m3 algorithm, sample detector, 3-kHz bandwidth) at San Francisco (Yerba Buena), CA, 19
25

GOVERNMENT FIXED, MOBILE, RADIO ASTRONOMY, 1. FIXED, MOBILE, Space Research (space-to-space).ALLOCATIONS:NON-GOVERNMENT RADIO ASTRONOMY, 1.ALLOCATIONS:GENERALUTILIZATION: LMR, 2. LMR, 2.

406 410 

mean sample noise

min sample noise

1. 406-406.1 MHz: MOBILE-SATELLITE (Earth-to-space). Satellite emergency position-indicating

radiobeacons (EPIRB) only. Supported by the joint U.S. SARSAT/Russian COSPAS satellite network.

2. Fixed and mobile services are allocated for Government nonmi

authorized on a local-coordinated, secondary, noninterfering basi

Figure 19. NTIA spectrum survey graph summarizing 14,000 sweeps across the 406-420 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
26

GOVERNMENT FIXED, MOBILE, RADIO ASTRONOMY, 1. FIXED, MOBILE, Space Research (space-to-space).ALLOCATIONS:NON-GOVERNMENT RADIO ASTRONOMY, 1.ALLOCATIONS:GENERALUTILIZATION: LMR, 2. LMR, 2.

406 410 

mean sample noise

min sample noise

1. 406-406.1 MHz: MOBILE-SATELLITE (Earth-to-space). Satellite emergency position-indicating

radiobeacons (EPIRB) only. Supported by the joint U.S. SARSAT/Russian COSPAS satellite network.

2. Fixed and mobile services are allocated for Government nonmi

authorized on a local-coordinated, secondary, noninterfering basi

Figure 20. NTIA spectrum survey graph summarizing 17,400 sweeps across the 406-420 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
27

GOVERNMENT RADIOLOCATION.ALLOCATIONS:NON-GOVERNMENT Amateur.ALLOCATIONS:GENERAL Long-range surveillance radars, 1, 2.UTILIZATION:

420 

min +peak noise

1. Radiolocation is limited to military services. Primarily, long-range radar systems essential to the nations

early warning capability, law enforcement, and tracking objects in space. These systems use very highpower and wide bandwidths. Low power radio control operations are permitted in the band. NASA andmilitary use of telemetry and telecommand is also extensive.

2. There is some non-Government use of spread spectrum modes; a

433 MHz), television (420-432 & 438-444 MHz), repeaters (435 MHz), and amateur satellite (435-438 MHz).

Figure 21. NTIA spectrum survey graph summarizing 46 scans across the 420-450 MHz range (System-1, b

algorithm, +peak detector, 1000-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1995.
28

GOVERNMENT RADIOLOCATION.ALLOCATIONS:NON-GOVERNMENT Amateur.ALLOCATIONS:GENERAL Long-range surveillance radars, 1, 2.UTILIZATION:

420 

min +peak noise

1. Radiolocation is limited to military services. Primarily, long-range radar systems essential to the nations

early warning capability, law enforcement, and tracking objects in space. These systems use very highpower and wide bandwidths. Low power radio control operations are permitted in the band. NASA andmilitary use of telemetry and telecommand is also extensive.

2. There is some non-Government use of spread spectrum modes; a

433 MHz), television (420-432 & 438-444 MHz), repeaters (435 MHz), and amateur satellite (435-438 MHz).

Figure 22. NTIA spectrum survey graph summarizing 55 scans across the 420-450 MHz range (System-1, b

algorithm, +peak detector, 1000-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1995.
29

RSMS rece

(see no

GOVERNMENT Meteorological-Satellite (space-to-Earth).ALLOCATIONS:NON-GOVERNMENT LAND MOBILE. LAND MOBILE.ALLOCATIONS:GENERAL LMR, 1, 2, 3. LMR, 1, 2, 3. LMR, 2, 4, 5. LMR, 2, 4, 5.UTILIZATION: (base or mobile) (mobile only) (base or mobile) 

450 455 460 465 

mean sample noise

min sample noise

Note: Signal at 466.8 MHz results from receiver intermodulation with TV channel 14.1. 450-451 MHz and 455-456 MHz: Remote pickup broadcast.2. 451-454 MHz, 456-459 MHz, 460-462.5375 MHz, 462.7375-467.5375 MHz, and

467.7375-470 MHz: Public Safety, Industrial, Land Transportation.

3. 454-455 MHz and 459-460 MHz: Domestic Public.4. 462.5375-462.7375 MHz and 467.5375-467.7375 MHz: Personal5. 460-470 MHz: GOES and TIROS satellite downlinks.

Figure 23. NTIA spectrum survey graph summarizing 6,900 sweeps across the 450-470 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
30

RSMS rece

(see no

GOVERNMENT Meteorological-Satellite (space-to-Earth).ALLOCATIONS:NON-GOVERNMENT LAND MOBILE. LAND MOBILE.ALLOCATIONS:GENERAL LMR, 1, 2, 3. LMR, 1, 2, 3. LMR, 2, 4, 5. LMR, 2, 4, 5.UTILIZATION: (base or mobile) (mobile only) (base or mobile) 

450 455 460 465 

mean sample noise

min sample noise

Note: Signal at 466.8 MHz results from receiver intermodulation with TV channel 14.1. 450-451 MHz and 455-456 MHz: Remote pickup broadcast.2. 451-454 MHz, 456-459 MHz, 460-462.5375 MHz, 462.7375-467.5375 MHz, and

467.7375-470 MHz: Public Safety, Industrial, Land Transportation.

3. 454-455 MHz and 459-460 MHz: Domestic Public.4. 462.5375-462.7375 MHz and 467.5375-467.7375 MHz: Personal5. 460-470 MHz: GOES and TIROS satellite downlinks.

Figure 24. NTIA spectrum survey graph summarizing 8,300 sweeps across the 450-470 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
31

Peak RSL @ 507.2 MHz: −17 

20 dB added attenuation (see note b

Signal saturation

(see note below)

GOVERNMENTALLOCATIONS:NON-GOVERNMENT BROADCASTING, LAND MOBILE, 1.ALLOCATIONS:GENERAL Channel 14 Channel 15 Channel 16 Channel 17 Channel 18 Channel 19 UTILIZATION:

470 476 482 488 494 500 

mean sample noise

min sample noise

Note: Strong RSL of TV channel 14 caused receiver saturation and compressed peak measurements, added

attenuation (490 to 612 MHz corrected similar problems, see comments in Table 2 of Section 2.5.

1. Land Mobile Radio Services include Public Safety, Domestic Pub

assignments in specific urban areas. The band also is allocated to television operations.

Figure 25. NTIA spectrum survey graph summarizing 6,900 sweeps across the 470-512 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
32

Peak RSL @ 507.2 MHz: −16.

20 dB added attenuation (see note b

Signal saturation

(see note below)

GOVERNMENTALLOCATIONS:NON-GOVERNMENT BROADCASTING, LAND MOBILE, 1.ALLOCATIONS:GENERAL Channel 14 Channel 15 Channel 16 Channel 17 Channel 18 Channel 19 UTILIZATION:

470 476 482 488 494 500 

mean sample noise

min sample noise

Note: Strong RSL of TV channel 14 caused receiver saturation and compressed peak measurements, added

attenuation (490 to 512 MHz) corrected similar problems, see comments in Table 2 of Section 2.5.

1. Land Mobile Radio Services include Public Safety, Domestic Pub

assignments in specific urban areas. The band also is allocated to television operations.

Figure 26. NTIA spectrum survey graph summarizing 8,200 sweeps across the 470-512 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
33

20 dB added attenuation (see note below)

GOVERNMENT 1.ALLOCATIONS:NON-GOVERNMENT BROADCASTING. 1. BROADCASTING.ALLOCATIONS:GENERAL Television broadcasting (channels 21-36). Television broadcasting (channels 38-69).UTILIZATION:

512 608-614 

mean sample noise

min sample noise

Note: Concerning 512-612 MHz attenuated data, see comments in Table 2 of Section 2.5. 1. RADIO ASTRONOMY. No stations are authorized to transmit iFigure 27. NTIA spectrum survey graph summarizing 5,000 sweeps across the 512-806 MHz range (Syst

swept/m3 algorithm, sample detector, 100-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 
34

20 dB added attenuation (see note below)

GOVERNMENT 1.ALLOCATIONS:NON-GOVERNMENT BROADCASTING. 1. BROADCASTING.ALLOCATIONS:GENERAL Television broadcasting (channels 21-36). Television broadcasting (channels 38-69).UTILIZATION:

512 608-614 

mean sample noise

min sample noise

Note: Concerning 512-612 MHz attenuated data, see comments in Table 2 of Section 2.5. 1. RADIO ASTRONOMY. No stations are authorized to transmit iFigure 28. NTIA spectrum survey graph summarizing 5,200 sweeps across the 512-806 MHz range (Syst

swept/m3 algorithm, sample detector, 100-kHz bandwidth) at San Francisco (Yerba Buena), CA, 
35

GOVERNMENTALLOCATIONS:NON-GOVERNMENT LAND MOBILE, 1.ALLOCATIONS:GENERAL Conventional and 2. Cellular Systems (Public Mobile). 4. Conventional and 3. Cellular Systems (Public Base). UTILIZATION: Trunked (mobile). Trunked (base).

806 821 824 849-851 866 869 

max sample noise

mean sample noise

min sample noise

1. 806-890 MHz: Limited allocation is available for television Channels 70-83.2. Public Safety (mobile).3. Public Safety (base).4. Aeronautical Mobile (ground-to-air).

5. Aeronautical Mobile (air-to-ground).6. 896-901 MHz: Private Land Mobile (paired with 935-940 MHz)7. 901-902 MHz: General Mobile.

Figure 29. NTIA spectrum survey graph summarizing 2,880 sweeps across the 806-902 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
36

GOVERNMENTALLOCATIONS:NON-GOVERNMENT LAND MOBILE, 1.ALLOCATIONS:GENERAL Conventional and 2. Cellular Systems (Public Mobile). 4. Conventional and 3. Cellular Systems (Public Base). UTILIZATION: Trunked (mobile). Trunked (base).

806 821 824 849-851 866 869 

max sample noise

mean sample noise

min sample noise

1. 806-890 MHz: Limited allocation is available for television Channels 70-83.2. Public Safety (mobile).3. Public Safety (base).4. Aeronautical Mobile (ground-to-air).

5. Aeronautical Mobile (air-to-ground).6. 896-901 MHz: Private Land Mobile (paired with 935-940 MHz)7. 901-902 MHz: General Mobile.

Figure 30. NTIA spectrum survey graph summarizing 3,300 sweeps across the 806-902 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
37

GOVERNMENT RADIOLOCATION.ALLOCATIONS:NON-GOVERNMENTALLOCATIONS:GENERAL Military radiolocation systems; Industrial scientific and medical (ISM); Automatic Vehicle Monitoring (AVM); spread spectrum devices; microwave ovens; digital UTILIZATION: Fixed and mobile radio services are permitted on a secondary basis. Band utilization is increasing for non-Government ISM, spread spectrum and other modes, 1, 

902 

min maxhold noise

1. Location and Monitoring Service (LMS) systems are authorized subject to not causing harmful interference

to Government stations and must tolerate interference from ISM devices and all authorized stations.

2. Emissions from microwave ovens manufactured after December 31

be confined within the band 902-928 MHz.

Figure 31. NTIA spectrum survey graph summarizing 28,800 sweeps across the 902-928 MHz range (System-1

algorithm, maximum-hold detector, 10-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 199
38

GOVERNMENT RADIOLOCATION.ALLOCATIONS:NON-GOVERNMENTALLOCATIONS:GENERAL Military radiolocation systems; Industrial scientific and medical (ISM); Automatic Vehicle Monitoring (AVM); spread spectrum devices; microwave ovens; digital UTILIZATION: Fixed and mobile radio services are permitted on a secondary basis. Band utilization is increasing for non-Government ISM, spread spectrum and other modes, 1, 

902 

min maxhold noise

1. Location and Monitoring Service (LMS) systems are authorized subject to not causing harmful interference

to Government stations and must tolerate interference from ISM devices and all authorized stations.

2. Emissions from microwave ovens manufactured after December 31

be confined within the band 902-928 MHz.

Figure 32. NTIA spectrum survey graph summarizing 34,200 sweeps across the 902-928 MHz range (System-1

algorithm, maximum-hold detector, 10-kHz bandwidth) at San Francisco (Yerba Buena), CA, 199
39

GOVERNMENT RADIOLOCATION.ALLOCATIONS:NON-GOVERNMENTALLOCATIONS:GENERAL Military radiolocation systems; Industrial scientific and medical (ISM); Automatic Vehicle Monitoring (AVM); spread spectrum devices; microwave ovens; digital UTILIZATION: Fixed and mobile radio services are permitted on a secondary basis. Band utilization is increasing for non-Government ISM, spread spectrum and other modes, 1, 

902 

1. Location and Monitoring Service (LMS) systems are authorized subject to not causing harmful interference

to Government stations and must tolerate interference from ISM devices and all authorized stations.

2. Emissions from microwave ovens manufactured after December 31

be confined within the band 902-928 MHz.

Figure 33. NTIA spectrum survey graph summarizing 45 scans across the 902-928 MHz range (System-1, b

algorithm, +peak detector, 1000-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1995.
40

GOVERNMENT RADIOLOCATION.ALLOCATIONS:NON-GOVERNMENTALLOCATIONS:GENERAL Military radiolocation systems; Industrial scientific and medical (ISM); Automatic Vehicle Monitoring (AVM); spread spectrum devices; microwave ovens; digital UTILIZATION: Fixed and mobile radio services are permitted on a secondary basis. Band utilization is increasing for non-Government ISM, spread spectrum and other modes, 1, 

902 

1. Location and Monitoring Service (LMS) systems are authorized subject to not causing harmful interference

to Government stations and must tolerate interference from ISM devices and all authorized stations.

2. Emissions from microwave ovens manufactured after December 31

be confined within the band 902-928 MHz.

Figure 34. NTIA spectrum survey graph summarizing 54 scans across the 902-928 MHz range (System-1, b

algorithm, +peak detector, 1000-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1995.
41

GOVERNMENT FIXED. FIXED.ALLOCATIONS:NON-GOVERNMENT 1. LAND FIXED. LAND MOBILE. 5. FIXED. FIXED.ALLOCATIONS: MOBILEGENERAL 1. 2. 3. Private land mobile (base), 3. Auxiliary broadcasting, private fixed microwave, studio-to-transUTILIZATION: 4.

928 929 932 935 940 941 944 

max sample noise

mean sample noise

min sample noise

1. FIXED. Private fixed microwave, public and private land mobile, telemetry applications. Two-way

services paired with 952-953 MHz.

2. Public and private land mobile.3. Paired band for point-to-point and point-to-multipoint communications.

4. Trunked and conventional systems in 12.5 kHz channels (paired w5. MOBILE.6. 944-952 MHz: Primarily, studio-to-transmitter links. 952-953 M

960 MHz: Primarily, fixed point-to-point communications.

Figure 35. NTIA spectrum survey graph summarizing 21,000 sweeps across the 928-960 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
42

GOVERNMENT FIXED. FIXED.ALLOCATIONS:NON-GOVERNMENT 1. LAND FIXED. LAND MOBILE. 5. FIXED. FIXED.ALLOCATIONS: MOBILEGENERAL 1. 2. 3. Private land mobile (base), 3. Auxiliary broadcasting, private fixed microwave, studio-to-transUTILIZATION: 4.

928 929 932 935 940 941 944 

max sample noise

mean sample noise

min sample noise

1. FIXED. Private fixed microwave, public and private land mobile, telemetry applications. Two-way

services paired with 952-953 MHz.

2. Public and private land mobile.3. Paired band for point-to-point and point-to-multipoint communications.

4. Trunked and conventional systems in 12.5 kHz channels (paired w5. MOBILE.6. 944-952 MHz: Primarily, studio-to-transmitter links. 952-953 M

960 MHz: Primarily, fixed point-to-point communications.

Figure 36. NTIA spectrum survey graph summarizing 22,200 sweeps across the 928-960 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
43

GOVERNMENT AERONAUTICAL RADIONAVIGATION, 1.ALLOCATIONS:NON-GOVERNMENT AERONAUTICAL RADIONAVIGATION, 1.ALLOCATIONS:GENERAL TACAN, DME, MLS, ATCRBS, MODE-S, T-CAS, JTIDS, 2.UTILIZATION:

960 

mean +peak noise

min +peak noise

1. The 960-1215 MHz band is reserved on a worldwide basis for the use and development of electronic aids

to air navigation. On a case-by-case basis, Government systems utilizing spread spectrum techniques forterrestrial communication, navigation, and identification may be authorized on condition that aeronauticalradionavigation services not experience harmful interference.

2. Tactical Air Navigation (TACAN). Distance Metering Equipmen

(MLS). Air Traffic Control Radar Beacon system (ATCRBS, MOSystem (T-CAS). Joint Tactical Information Distribution System 

Figure 37. NTIA spectrum survey graph summarizing 18,500 sweeps across the 960-1215 MHz range (Syst

swept/m3 algorithm, +peak detector, 300-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
44

GOVERNMENT AERONAUTICAL RADIONAVIGATION, 1.ALLOCATIONS:NON-GOVERNMENT AERONAUTICAL RADIONAVIGATION, 1.ALLOCATIONS:GENERAL TACAN, DME, MLS, ATCRBS, MODE-S, T-CAS, JTIDS, 2.UTILIZATION:

960 

mean +peak noise

min +peak noise

1. The 960-1215 MHz band is reserved on a worldwide basis for the use and development of electronic aids

to air navigation. On a case-by-case basis, Government systems utilizing spread spectrum techniques forterrestrial communication, navigation, and identification may be authorized on condition that aeronauticalradionavigation services not experience harmful interference.

2. Tactical Air Navigation (TACAN). Distance Metering Equipmen

(MLS). Air Traffic Control Radar Beacon system (ATCRBS, MOSystem (T-CAS). Joint Tactical Information Distribution System 

Figure 38. NTIA spectrum survey graph summarizing 17,500 sweeps across the 960-1215 MHz range (Syst

swept/m3 algorithm, +peak detector, 300-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
45

GOVERNMENT RADIOLOCATION, RADIOLOCATION. AERONAUTICAL RADIONAVIGATION, FIXED, MOBALLOCATIONS: 1. Radiolocation.NON-GOVERNMENT Amateur. AERONAUTICAL RADIONAVIGATION.ALLOCATIONS:GENERAL 2, 3, 4. 3, 4, 5. 3, 4. 3, 6, Fixed anUTILIZATION:

1215 1240 1300 1350 

min +peak noise

1. RADIONAVIGATION-SATELLITE (space-to-Earth).2. 1227.6 MHz: Global Positioning System (GPS).3. High-power long-range surveillance radars including FAA Air-Route Surveillance Radar (ARSR).

4. Tethered balloon-mounted radar for drug interdiction.5. Amateur television. Amateur weak signal modes and other mode6. 1381.05 MHz: GPS data relay.

Figure 39. NTIA spectrum survey graph summarizing 14 scans across the 1215-1400 MHz range (System-2, b

algorithm, +peak detector, 1000-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1995.
46

GOVERNMENT RADIOLOCATION, RADIOLOCATION. AERONAUTICAL RADIONAVIGATION, FIXED, MOBALLOCATIONS: 1. Radiolocation.NON-GOVERNMENT Amateur. AERONAUTICAL RADIONAVIGATION.ALLOCATIONS:GENERAL 2, 3, 4. 3, 4, 5. 3, 4. 3, 6, Fixed anUTILIZATION:

1215 1240 1300 1350 

min +peak noise

1. RADIONAVIGATION-SATELLITE (space-to-Earth).2. 1227.6 MHz: Global Positioning System (GPS).3. High-power long-range surveillance radars including FAA Air-Route Surveillance Radar (ARSR).

4. Tethered balloon-mounted radar for drug interdiction.5. Amateur television. Amateur weak signal modes and other mode6. 1381.05 MHz: GPS data relay.

Figure 40. NTIA spectrum survey graph summarizing 12 scans across the 1215-1400 MHz range (System-2, b

algorithm, +peak detector, 1000-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1995.
47

GOVERNMENT FIXED, MOBILE, RADIOLOCATION, 1.ALLOCATIONS:NON-GOVERNMENT 1.ALLOCATIONS:GENERAL Military radiolocation, fixed and mobile links, GPS, aeronautical radionavigation, 2, 3.UTILIZATION:

1350 

max sample noise

mean sample noise

min sample noise

1. 1350-1370 MHz: AERONAUTICAL RADIONAVIGATION (allocation is for the United States and

Canada only).

2. Military radiolocation applications are primarily high-power long-range surveillance radars.

3. 1369.05-1393.05 MHz: Fixed and mobile satellite services (space

data. GPS operates at 1381.05 MHz to relay data detected by orb

Figure 41. NTIA spectrum survey graph summarizing 2,300 sweeps across the 1350-1400 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
48

GOVERNMENT FIXED, MOBILE, RADIOLOCATION, 1.ALLOCATIONS:NON-GOVERNMENT 1.ALLOCATIONS:GENERAL Military radiolocation, fixed and mobile links, GPS, aeronautical radionavigation, 2, 3.UTILIZATION:

1350 

max sample noise

mean sample noise

min sample noise

1. 1350-1370 MHz: AERONAUTICAL RADIONAVIGATION (allocation is for the United States and

Canada only).

2. Military radiolocation applications are primarily high-power long-range surveillance radars.

3. 1369.05-1393.05 MHz: Fixed and mobile satellite services (space

data. GPS operates at 1381.05 MHz to relay data detected by orb

Figure 42. NTIA spectrum survey graph summarizing 2,300 sweeps across the 1350-1400 MHz range (Syst

swept/m3 algorithm, sample detector, 10-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
49

GOVERNMENT EARTH EXPLORATION- FIXED, MOBILE (Aeronautical telemetering). ALLOCATIONS: SATELLITE (Passive), 1. 2.NON-GOVERNMENT EARTH EXPLORATION- 3, 4. MOBILE (Aeronautical telemetering). ALLOCATIONS: SATELLITE (Passive), 1.GENERAL Passive. Aeronautical telemetry and telecommand.UTILIZATION:

1400 1427 1435 

max sample noise

mean sample noise

min sample noise

1. RADIO ASTRONOMY, SPACE RESEARCH (Passive).2. MOBILE. 1427-1429 MHz: MOBILE except aeronautical mobile, SPACE OPERATION

(Earth-to-space).

3. Land Mobile (Telemetering and telecommand), Fixed (Telemeteri4. 1427-1429 MHz: SPACE OPERATION (Earth-to-space).5. MOBILE-SATELLITE (space-to-Earth), Mobile (Aeronautical tel

Figure 43. NTIA spectrum survey graph summarizing 4,800 sweeps across the 1400-1530 MHz range (Syst

swept/m3 algorithm, sample detector, 30-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
50

GOVERNMENT EARTH EXPLORATION- FIXED, MOBILE (Aeronautical telemetering). ALLOCATIONS: SATELLITE (Passive), 1. 2.NON-GOVERNMENT EARTH EXPLORATION- 3, 4. MOBILE (Aeronautical telemetering). ALLOCATIONS: SATELLITE (Passive), 1.GENERAL Passive. Aeronautical telemetry and telecommand.UTILIZATION:

1400 1427 1435 

max sample noise

mean sample noise

min sample noise

1. RADIO ASTRONOMY, SPACE RESEARCH (Passive).2. MOBILE. 1427-1429 MHz: MOBILE except aeronautical mobile, SPACE OPERATION

(Earth-to-space).

3. Land Mobile (Telemetering and telecommand), Fixed (Telemeteri4. 1427-1429 MHz: SPACE OPERATION (Earth-to-space).5. MOBILE-SATELLITE (space-to-Earth), Mobile (Aeronautical tel

Figure 44. NTIA spectrum survey graph summarizing 4,600 sweeps across the 1400-1530 MHz range (Syst

swept/m3 algorithm, sample detector, 30-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
51

RSMS not configured to receive sp

GOVERNMENT 1. 2. RADIONAVIGATION-SATELLITE (space-to- 3. 4. 5. 6. METEORALLOCATIONS: Earth), AERONAUTICAL RADIONAVIGATION. (RadiosonNON-GOVERNMENT 1. 2. RADIONAVIGATION-SATELLITE (space-to- 3. 4. 5. 6. METEORALLOCATIONS: Earth), AERONAUTICAL RADIONAVIGATION. (RadiosonGENERAL INMARSAT, AMS(R)S. GPS, GLONASS. Aids to air INMARSAT. AMS(R)S. RadiosondUTILIZATION: SARSAT. navigation imagery.

1530 1545 1559 1610 1626.5 1646.5 1660 1668.4 

max sample noise

mean sample noise

min sample noise

1. MOBILE-SATELLITE (space-to-Earth). 1530-1544 MHz: MARITIME MOBILE-SATELLITE (space-toEarth). 1530-1535 MHz: Mobile (Aeronautical telemetering).2. AERONAUTICAL MOBILE-SATELLITE (space-to-Earth). 1545-1549.5 MHz: Mobile-Satellite (spaceto-Earth). 1549.5-1558.5 MHz: MOBILE-SATELLITE (space-to-Earth).3. AERONAUTICAL RADIONAVIGATION, RADIODETERMINATION-SATELLITE (Earth-to-space),

MOBILE-SATELLITE (Earth-to-space). 1610.6-1613.8 MHz: RADIO ASTRONOMY. 1613.8-1626.5:Mobile-Satellite (space-to-Earth).

4. 1626.5-1645.5 MHz: MARITIME MOBILE-SATELLITE (Earth-to-space). 1645.5-1646.5 MHz:

MOBILE-SATELLITE (Earth-to-space, distress and safety only).

5. AERONAUTICAL MOBILE-SATELLITE (Earth-to-space). 1646

to-space). 1651-1660 MHz: MOBILE-SATELLITE (Earth-to-sp

6. RADIO ASTRONOMY. 1660-1660.5 MHz: AERONAUTICAL M

1660.5-1668.4 MHz: SPACE RESEARCH (Passive).

7. 1668.4-1670 MHz: RADIO ASTRONOMY. 1670-1700 MHz: 

(space-to-Earth).

8. METEOROLOGICAL-SATELLITE (space-to-Earth).9. GOES, TIROS-N.

Figure 45. NTIA spectrum survey graph summarizing 18,000 sweeps across the 1530-1710 MHz range (Sys

swept/m3 algorithm, sample detector, 30-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
52

RSMS not configured to receive sp

GOVERNMENT 1. 2. RADIONAVIGATION-SATELLITE (space-to- 3. 4. 5. 6. METEORALLOCATIONS: Earth), AERONAUTICAL RADIONAVIGATION. (RadiosonNON-GOVERNMENT 1. 2. RADIONAVIGATION-SATELLITE (space-to- 3. 4. 5. 6. METEORALLOCATIONS: Earth), AERONAUTICAL RADIONAVIGATION. (RadiosonGENERAL INMARSAT, AMS(R)S. GPS, GLONASS. Aids to air INMARSAT. AMS(R)S. RadiosondUTILIZATION: SARSAT. navigation imagery.

1530 1545 1559 1610 1626.5 1646.5 1660 1668.4 

max sample noise

mean sample noise

min sample noise

1. MOBILE-SATELLITE (space-to-Earth). 1530-1544 MHz: MARITIME MOBILE-SATELLITE (space-toEarth). 1530-1535 MHz: Mobile (Aeronautical telemetering).2. AERONAUTICAL MOBILE-SATELLITE (space-to-Earth). 1545-1549.5 MHz: Mobile-Satellite (spaceto-Earth). 1549.5-1558.5 MHz: MOBILE-SATELLITE (space-to-Earth).3. AERONAUTICAL RADIONAVIGATION, RADIODETERMINATION-SATELLITE (Earth-to-space),

MOBILE-SATELLITE (Earth-to-space). 1610.6-1613.8 MHz: RADIO ASTRONOMY. 1613.8-1626.5:Mobile-Satellite (space-to-Earth).

4. 1626.5-1645.5 MHz: MARITIME MOBILE-SATELLITE (Earth-to-space). 1645.5-1646.5 MHz:

MOBILE-SATELLITE (Earth-to-space, distress and safety only).

5. AERONAUTICAL MOBILE-SATELLITE (Earth-to-space). 1646

to-space). 1651-1660 MHz: MOBILE-SATELLITE (Earth-to-sp

6. RADIO ASTRONOMY. 1660-1660.5 MHz: AERONAUTICAL M

1660.5-1668.4 MHz: SPACE RESEARCH (Passive).

7. 1668.4-1670 MHz: RADIO ASTRONOMY. 1670-1700 MHz: 

(space-to-Earth).

8. METEOROLOGICAL-SATELLITE (space-to-Earth).9. GOES, TIROS-N.

Figure 46. NTIA spectrum survey graph summarizing 16,500 sweeps across the 1530-1710 MHz range (Sys

swept/m3 algorithm, sample detector, 30-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
53

RSMS not configured to receive sp

GOVERNMENT FIXED, MOBILE. ALLOCATIONS: NON-GOVERNMENT FIXED. MOBILE, Fixed. ALLOCATIONS:GENERAL Federal fixed microwave, telemetry, Private fixed microwave. Auxiliary broadcasting, domestic public fixed, cable TV, control UTILIZATION: telecommand, 1. Future PCS. and repeater links, point to multipoint video, cellular, 2.

1710 1850 1990 22

minimum maxhold noise

1. Predominantly federal medium-capacity line of sight (LOS) fixed service band.2. 1990-2110 MHz: Electronic news gathering (ENG). GOES uplink, NASA’s global ground network and

TDRSS (2025-2110 MHz). 2110-2200 MHz: NASA space and Earth to space command links supportPioneers, Voyagers, MAGELLAN, GALILEO, and ULYSSES (2110-2120 MHz). Paired fixed links(2110-2130 MHz with 2160-2180 MHz; 2130-2150 MHz with 2180-2200 MHz). Point-to-point and pointto multipoint links (2150-2160 MHz).

3. SPACE RESEARCH (space-to-Earth)(space-to-space), SPACE O

space), EARTH EXPLORATION-SATELLITE space-to-Earth)(sp

4. Space telemetry, telecommand and control systems. Fixed micro5. FIXED, MOBILE except aeronautical mobile, SPACE RESEARC6. SPACE RESEARCH (space-to-Earth)(Deep Space only).7. NASA deep space network space-to-Earth telemetry. Radio astro

Figure 47. NTIA spectrum survey azimuth-scan graph of the 1710-2300 MHz range (System-2, band event 

maximum-hold detector, 100-kHz bandwidth) at San Francisco (Angel Island), CA, 1995.
54

ISM band

GOVERNMENT 1. RADIOLOCATION, MOBILE, Fixed. RADIOLOCATION, 5.ALLOCATIONS:NON-GOVERNMENT 2. MOBILE. 6. Amateur. FIXED, MOALLOCATIONS: RadiolocatioGENERAL 3. Telemetry, telemetry communications, aeronautical telemetry, 4. Amateur Satellite (space-to-Earth). 7. UTILIZATION: Amateur mixed modes, 7.

2300 2310 2390 2400 2450 

minimum maxhold noise

1. RADIOLOCATION, Fixed, Mobile.2. Amateur.3. Amateur weak signal modes and other modes.4. AF high-power long-range surveillance radar and air traffic control radar. Venus Radar Mapper (VRM)

synthetic aperture radar.

5. No Government allocations in this band after August 1995.

6. AMATEUR.7. 2400-2500 MHz: This spectrum is used increasingly for ind

applications including microwave ovens, spread spectrum cordles

8. RADIODETERMINATION-SATELLITE (space-to-Earth).9. Satellite downlinks and multichannel fixed and portable video tra

Figure 48. NTIA spectrum survey graph summarizing 13,200 sweeps across the 2300-2500 MHz range (Sys

swept algorithm, maximum-hold detector, 100-kHz bandwidth) at San Francisco (Grizzly Peak), C
55

ISM band

GOVERNMENT 1. RADIOLOCATION, MOBILE, Fixed. RADIOLOCATION, 5.ALLOCATIONS:NON-GOVERNMENT 2. MOBILE. 6. Amateur. FIXED, MOALLOCATIONS: RadiolocatioGENERAL 3. Telemetry, telemetry communications, aeronautical telemetry, 4. Amateur Satellite (space-to-Earth). 7. UTILIZATION: Amateur mixed modes, 7.

2300 2310 2390 2400 2450 

minimum maxhold noise

1. RADIOLOCATION, Fixed, Mobile.2. Amateur.3. Amateur weak signal modes and other modes.4. AF high-power long-range surveillance radar and air traffic control radar. Venus Radar Mapper (VRM)

synthetic aperture radar.

5. No Government allocations in this band after August 1995.

6. AMATEUR.7. 2400-2500 MHz: This spectrum is used increasingly for ind

applications including microwave ovens, spread spectrum cordles

8. RADIODETERMINATION-SATELLITE (space-to-Earth).9. Satellite downlinks and multichannel fixed and portable video tra

Figure 49. NTIA spectrum survey graph summarizing 13,200 sweeps across the 2300-2500 MHz range (Sys

swept algorithm, maximum-hold detector, 100-kHz bandwidth) at San Francisco (Yerba Buena), C
56

RSMS not configured to receive sp

GOVERNMENT 3. ALLOCATIONS:NON-GOVERNMENT BROADCASTING-SATELLITE, FIXED, 1. FIXED, ALLOCATIONS: SATELLGENERAL Auxiliary broadcasting, pay television distribution, private video teleconferences, educational television (ITSF), 2. Private fUTILIZATION:

2500 2655 

minimum maxhold noise

1. Broadcasting-satellite service is limited to community reception of educational and public service

television programming.

2. 2500-2686 MHz: Omnidirectional multichannel multipoint distribution service (MMDS) transmissions

that can be contained within 6-MHz channel bandwidths.

3. Earth Exploration-Satellite (Passive), Radio Astronomy, Space Re4. EARTH EXPLORATION-SATELLITE (Passive), RADIO ASTRON

Figure 50. NTIA spectrum survey azimuth-scan graph of the 2500-2700 MHz range (System-2, band event 

maximum-hold detector, 10-kHz bandwidth) at San Francisco (Angel Island), CA, 1995.
57

GOVERNMENT AERONAUTICAL RADIONAVIGATION, METEOROLOGICAL AIDS, Radiolocation, 1, 2.ALLOCATIONS:NON-GOVERNMENTALLOCATIONS:GENERAL Airport surveillance radars (ASRs), military ground control approach radars (GCAs), NWS weather radars (NEXRAD, etc.), long-range surveillance radars and air UTILIZATION:

2700 

min +peak noise

1. The aeronautical radionavigation service is restricted to ground-based radars and associated airborne

transponders that transmit only in this band when actuated by these radars.

2. The secondary radiolocation service is limited to the military an

primary services.

Figure 51. NTIA spectrum survey graph summarizing 15 scans across the 2700-2900 MHz range (System-2, b

algorithm, +peak detector, 1000-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1995.
58

GOVERNMENT AERONAUTICAL RADIONAVIGATION, METEOROLOGICAL AIDS, Radiolocation, 1, 2.ALLOCATIONS:NON-GOVERNMENTALLOCATIONS:GENERAL Airport surveillance radars (ASRs), military ground control approach radars (GCAs), NWS weather radars (NEXRAD, etc.), long-range surveillance radars and air UTILIZATION:

2700 

1. The aeronautical radionavigation service is restricted to ground-based radars and associated airborne

transponders that transmit only in this band when actuated by these radars.

2. The secondary radiolocation service is limited to the military an

primary services.

Figure 52. NTIA spectrum survey graph summarizing 12 scans across the 2700-2900 MHz range (System-2, b

algorithm, +peak detector, 1000-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1995.
59

GOVERNMENT MARITIME RADIONAVIGATION, Radiolocation, 1, 2.ALLOCATIONS:NON-GOVERNMENT MARITIME RADIONAVIGATION, Radiolocation, 1, 2.ALLOCATIONS:GENERAL Maritime radars and radar beacons (racons), military high-power three-dimensional long-range surveillance radars and air traffic control radars.UTILIZATION:

2900 

min +peak noise

1. Radiolocation assignments are primarily for the military; however, other agency use is permitted for

experimentation, research, and survey operations, if no harmful interference occurs.

2. 2900-3000 MHz: Also, allocated for next generation weather rad

Figure 53. NTIA spectrum survey graph summarizing 25 scans across the 2900-3100 MHz range (System-2, b

algorithm, +peak detector, 1000-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1995.
60

GOVERNMENT MARITIME RADIONAVIGATION, Radiolocation, 1, 2.ALLOCATIONS:NON-GOVERNMENT MARITIME RADIONAVIGATION, Radiolocation, 1, 2.ALLOCATIONS:GENERAL Maritime radars and radar beacons (racons), military high-power three-dimensional long-range surveillance radars and air traffic control radars.UTILIZATION:

2900 

1. Radiolocation assignments are primarily for the military; however, other agency use is permitted for

experimentation, research, and survey operations, if no harmful interference occurs.

2. 2900-3000 MHz: Also, allocated for next generation weather rad

Figure 54. NTIA spectrum survey graph summarizing 22 scans across the 2900-3100 MHz range (System-2, b

algorithm, +peak detector, 1000-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1995.
61

GOVERNMENT RADIOLOCATION. RADIOLOCATION. RADIOLOCATION, 1. ALLOCATIONS:NON-GOVERNMENT Radiolocation. Amateur, Radiolocation. Radiolocation. ALLOCATIONS: GENERAL 3. 3. 3. UTILIZATION:

3100 3300 3500 36

min +peak noise

1. AERONAUTICAL RADIONAVIGATION (Ground-based).2. Radiolocation.

3. Primarily, military airborne, land-based, and shipborne defense ra

Figure 55. NTIA spectrum survey graph summarizing 23 scans across the 3100-3700 MHz range (System-2, b

algorithm, +peak detector, 3000-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1995.
62

GOVERNMENT RADIOLOCATION. RADIOLOCATION. RADIOLOCATION, 1. ALLOCATIONS:NON-GOVERNMENT Radiolocation. Amateur, Radiolocation. Radiolocation. ALLOCATIONS: GENERAL 3. 3. 3. UTILIZATION:

3100 3300 3500 36

min +peak noise

1. AERONAUTICAL RADIONAVIGATION (Ground-based).2. Radiolocation.

3. Primarily, military airborne, land-based, and shipborne defense ra

Figure 56. NTIA spectrum survey graph summarizing 21 scans across the 3100-3700 MHz range (System-2, b

algorithm, +peak detector, 3000-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1995.
63

RSMS not configured to receive sp

Noise floor rise caused by front-end amplifier variation

GOVERNMENTALLOCATIONS:NON-GOVERNMENT FIXED, FIXED-SATELLITE (space-to-Earth).ALLOCATIONS:GENERAL Domestic public fixed, satellite communications.UTILIZATION:

3700 

minimum maxhold noise

Figure 57. NTIA spectrum survey azimuth-scan graph of the 3700-4200 MHz range (System-2, band event 

maximum-hold detector, 100-kHz bandwidth) at San Francisco (Angel Island), CA, 1995.
64

GOVERNMENT AERONAUTICAL RADIONAVIGATION, 1.ALLOCATIONS:NON-GOVERNMENT AERONAUTICAL RADIONAVIGATION, 1.ALLOCATIONS:GENERAL Airborne radio altimeters.UTILIZATION:

4200 

max +peak noise

mean +peak noise

min +peak noise

1. 4202 ±12 MHz: Standard frequency and time satellite service (space-to-Earth), permitted.Figure 58. NTIA spectrum survey graph summarizing 17,500 sweeps across the 4200-4400 MHz range (Sys

swept/m3 algorithm, +peak detector, 300-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
65

GOVERNMENT AERONAUTICAL RADIONAVIGATION, 1.ALLOCATIONS:NON-GOVERNMENT AERONAUTICAL RADIONAVIGATION, 1.ALLOCATIONS:GENERAL Airborne radio altimeters.UTILIZATION:

4200 

max +peak noise

mean +peak noise

min +peak noise

1. 4202 ±12 MHz: Standard frequency and time satellite service (space-to-Earth), permitted.Figure 59. NTIA spectrum survey graph summarizing 16,500 sweeps across the 4200-4400 MHz range (Sys

swept/m3 algorithm, +peak detector, 300-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
66

RSMS not configured to receive sp

GOVERNMENT FIXED, MOBILE. FIXED, MOBILE. FIXED, MOBILE. FIXED, MOBILE. ALLOCATIONS:NON-GOVERNMENT FIXED-SATELLITE (space-to-Earth). 1. 1, 2. FIXED-SATELLITE ALLOCATIONS: (space-to-Earth).GENERAL Military tactical Military tactical communications. Military tactical communications. Military tactical communicationUTILIZATION: communications. spread spectrum.

4400 4500 4635 4660 4685 4800 

minimum maxhold noise

1. FIXED-SATELLITE (space-to-Earth). 3. RADIO ASTRONOMY, Space Research (Passive).2. FIXED, MOBILE.Figure 60. NTIA spectrum survey azimuth-scan graph of the 4400-5000 MHz range (System-2, band event 

maximum-hold detector, 100-kHz bandwidth) at San Francisco (Angel Island), CA, 1995.
67

GOVERNMENT AERONAUTICAL RADIONAVIGATION.ALLOCATIONS:NON-GOVERNMENT AERONAUTICAL RADIONAVIGATION.ALLOCATIONS:GENERAL Microwave landing systems. Differential Global-Positioning System (DGPS) for aircraft navigation (5000-5150 MHz).UTILIZATION:

5000 

max +peak noise

mean +peak noise

min +peak noise

Figure 61. NTIA spectrum survey graph summarizing 17,000 sweeps across the 5000-5250 MHz range (Sys

swept/m3 algorithm, +peak detector, 300-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1
68

GOVERNMENT AERONAUTICAL RADIONAVIGATION.ALLOCATIONS:NON-GOVERNMENT AERONAUTICAL RADIONAVIGATION.ALLOCATIONS:GENERAL Microwave landing systems. Differential Global-Positioning System (DGPS) for aircraft navigation (5000-5150 MHz).UTILIZATION:

5000 

max +peak noise

mean +peak noise

min +peak noise

Figure 62. NTIA spectrum survey graph summarizing 16,500 sweeps across the 5000-5250 MHz range (Sys

swept/m3 algorithm, +peak detector, 300-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1
69

GOVERNMENT RADIOLOCATION. AERONAUTICAL 3. MARITIME RADIONAVIGA- 4. RADIOLOCATION.ALLOCATIONS: RADIONAVIGATION, 1. TION, Radiolocation.NON-GOVERNMENT Radiolocation. AERONAUTICAL 3. MARITIME RADIONAVIGA- 4. Amateur. ALLOCATIONS: RADIONAVIGATION, 2. TION, Radiolocation.GENERAL Weather radars. 5. Military radars, 7. UTILIZATION:

5250 5350 5460-5470 5600 5650 

min +peak noise

1. RADIOLOCATION.2. Radiolocation.3. RADIONAVIGATION, Radiolocation.4. MARITIME RADIONAVIGATION, METEOROLOGICAL AIDS, Radiolocation.

5. Government weather radars, e.g., Terminal Doppler Weather Rad6. FIXED-SATELLITE (Earth-to-space), Amateur.7. 5725-5875 MHz: Industrial, scientific, and medical (ISM).

Figure 63. NTIA spectrum survey graph summarizing 13 scans across the 5250-5925 MHz range (System-2, b

algorithm, +peak detector, 3000-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1995.
70

GOVERNMENT RADIOLOCATION. AERONAUTICAL 3. MARITIME RADIONAVIGA- 4. RADIOLOCATION.ALLOCATIONS: RADIONAVIGATION, 1. TION, Radiolocation.NON-GOVERNMENT Radiolocation. AERONAUTICAL 3. MARITIME RADIONAVIGA- 4. Amateur. ALLOCATIONS: RADIONAVIGATION, 2. TION, Radiolocation.GENERAL Weather radars. 5. Military radars, 7. UTILIZATION:

5250 5350 5460-5470 5600 5650 

min +peak noise

1. RADIOLOCATION.2. Radiolocation.3. RADIONAVIGATION, Radiolocation.4. MARITIME RADIONAVIGATION, METEOROLOGICAL AIDS, Radiolocation.

5. Government weather radars, e.g., Terminal Doppler Weather Rad6. FIXED-SATELLITE (Earth-to-space), Amateur.7. 5725-5875 MHz: Industrial, scientific, and medical (ISM).

Figure 64. NTIA spectrum survey graph summarizing 12 scans across the 5250-5925 MHz range (System-2, b

algorithm, +peak detector, 3000-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1995.
71

GOVERNMENTALLOCATIONS:NON-GOVERNMENT FIXED, FIXED-SATELLITE (Earth-to-space). 1. FIXED, FIXED-SATELLITE (Earth-to-space). FIXEDALLOCATIONS: (EarthGENERAL Common carrier fixed links. Common carrier fixed links. CommUTILIZATION:

5925 6425 6525 6875 

minimum maxhold noise

1. FIXED-SATELLITE (Earth-to-space), MOBILE. 2. FIXED, MOBILE.Figure 65. NTIA spectrum survey azimuth-scan graph of the 5925-7125 MHz range (System-2, band event 

maximum-hold detector, 300-kHz bandwidth) at San Francisco (Angel Island), CA, 1995.
72

RSMS not configured to receive sp

Noise floor fall caused by froamplifier variation

GOVERNMENT FIXED, 1. 3. FIXED, FIXED-SATELLITE (space-to-Earth), FIXED. FIXED-SATELLITE (Earth-to-space), 5, 6, 7. ALLOCATIONS: Mobile-Satellite (space-to-Earth), 4.NON-GOVERNMENT ALLOCATIONS:GENERAL 2. 2. 2. 2. 2. UTILIZATION:

7125 7250 7300 7750 7900 

minimum maxhold noise

1. 7190-7235 MHz: SPACE RESEARCH (Earth-to-space).2. Point-to-point microwave voice/data links, defense satellite communications systems (DSCS).3. FIXED-SATELLITE (space-to-Earth), MOBILE-SATELLITE (space-to-Earth), Fixed.4. 7450-7550 MHz: METEOROLOGICAL-SATELLITE (space-to-Earth).5. 7900-8025 MHz: MOBILE-SATELLITE (Earth-to-space), fixed.

6. 8025-8400 MHz: EARTH EXPLORATION-SATELLITE (spa

(Earth-to-space) (no airborne transmissions).

7. 8175-8215 MHz: METEOROLOGICAL-SATELLITE (Earth-to-8. SPACE RESEARCH (space-to-Earth) (Government: 8400-8450 

Figure 66. NTIA spectrum survey azimuth-scan graph of the 7125-8500 MHz range (System-2, band event 

maximum-hold detector, 300-kHz bandwidth) at San Francisco (Angel Island), CA, 1995.
73

GOVERNMENT RADIOLOCATION. 1. 2. 3. RADIOLOCATION.ALLOCATIONS:NON-GOVERNMENT Radiolocation. 1. 2. 3. Radiolocation. Amateur, RadiolocatioALLOCATIONS:GENERAL Military use is primary. 4. 5.UTILIZATION:

8500 9000 9200 9300 9500 10000 

minimum +peak noise

1. AERONAUTICAL RADIONAVIGATION, Radiolocation.2. MARITIME RADIONAVIGATION, Radiolocation.3. RADIONAVIGATION, Meteorological Aids, Radiolocation.

4. Maritime radionavigation radar, airborne weather radar, radar tran5. Military airborne radar.6. RADIOLOCATION. 10450-10500 MHz: Amateur, Amateur-Sa

Figure 67. NTIA spectrum survey graph summarizing 13 scans across the 8500-10550 MHz range (System-2, b

algorithm, +peak detector, 3000-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 1995.
74

GOVERNMENT RADIOLOCATION. 1. 2. 3. RADIOLOCATION.ALLOCATIONS:NON-GOVERNMENT Radiolocation. 1. 2. 3. Radiolocation. Amateur, RadiolocatioALLOCATIONS:GENERAL Military use is primary. 4. 5.UTILIZATION:

8500 9000 9200 9300 9500 10000 

minimum +peak noise

1. AERONAUTICAL RADIONAVIGATION, Radiolocation.2. MARITIME RADIONAVIGATION, Radiolocation.3. RADIONAVIGATION, Meteorological Aids, Radiolocation.

4. Maritime radionavigation radar, airborne weather radar, radar tran5. Military airborne radar.6. RADIOLOCATION. 10450-10500 MHz: Amateur, Amateur-Sa

Figure 68. NTIA spectrum survey graph summarizing 12 scans across the 8500-10550 MHz range (System-2, b

algorithm, +peak detector, 3000-kHz bandwidth) at San Francisco (Yerba Buena), CA, 1995.
75

RSMS not configured to receive sp

GOVERNMENT 1.ALLOCATIONS:NON-GOVERNMENT 2. FIXED, FIXED-SATELLITE (space-to-Earth). FIXED-SATELLITE FIXED, BROADCASTING- FIXEDALLOCATIONS: (space-to-Earth), 3. SATELLITE. (EarthGENERAL Common carrier point-to-point microwave links, television Direct broadcast Cable UTILIZATION: studio-to-transmitter links. satellite services (DBS).

10550 10700 11700 12200 12700 

minimum maxhold noise

1. 10600-10700 MHz: EARTH EXPLORATION-SATELLITE (Passive), SPACE RESEARCH (Passive).

10680-10700 MHz: RADIO ASTRONOMY.

2. 10550-10680 MHz: FIXED. 10600-10700 MHz: EARTH EXPLORATION-SATELLITE (Passive),

SPACE RESEARCH (Passive). 10680-10700 MHz: RADIO ASTRONOMY.

3. Mobile except aeronautical mobile.4. Television auxiliary broadcasting (includes: SHL, STL, ENG, an

Figure 69. NTIA spectrum survey azimuth-scan graph of the 10550-13250 MHz range (System-2, band even

maximum-hold detector, 3000-kHz bandwidth) at San Francisco (Angel Island), CA, 1995.
76

GOVERNMENT AERONAUTICAL RADIOLOCATION, Space Research, Standard Frequency and Time Signal-Satellite (Earth-to-space). RADIONAVIGALLOCATIONS: RADIONAVIGATION, 1. Space ResearchNON-GOVERNMENT AERONAUTICAL Radiolocation, Space Research, Standard Frequency and Time Signal-Satellite (Earth-to-space). RADIONAVIGALLOCATIONS: RADIONAVIGATION, 1. Space ResearchGENERAL Military airborne radars.UTILIZATION:

13250 13400 14000 

min +peaknoise

1. Space Research (Earth-to-space). 2. FIXED-SATELLITE (Earth-to-space).Figure 70. NTIA spectrum survey graph summarizing 25 scans across the 13250-14200 MHz range (Syst

stepped algorithm, +peak detector, 3000-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 19
77

GOVERNMENT AERONAUTICAL RADIOLOCATION, Space Research, Standard Frequency and Time Signal-Satellite (Earth-to-space). RADIONAVIGALLOCATIONS: RADIONAVIGATION, 1. Space ResearchNON-GOVERNMENT AERONAUTICAL Radiolocation, Space Research, Standard Frequency and Time Signal-Satellite (Earth-to-space). RADIONAVIGALLOCATIONS: RADIONAVIGATION, 1. Space ResearchGENERAL Military airborne radars.UTILIZATION:

13250 13400 14000 

min +peaknoise

1. Space Research (Earth-to-space). 2. FIXED-SATELLITE (Earth-to-space).Figure 71. NTIA spectrum survey graph summarizing 23 scans across the 13250-14200 MHz range (Syst

stepped algorithm, +peak detector, 3000-kHz bandwidth) at San Francisco (Yerba Buena), CA, 19
78

GOVERNMENT Fixed, FIXED, Mobile, MOBILE, Fixed, Space Research. FIXED, Mobile, 3. AERALLOCATIONS: Mobile. Space Research. Space Research. RADNON-GOVERNMENT FIXED-SATELLITE 1. 3. AERALLOCATIONS: (Earth-to-space). RADGENERAL 2. 2.UTILIZATION:

14200 14400 14500 14714.5 15136.5 15350-15400 

minimum maxhold noise

1. FIXED-SATELLITE (Earth-to-space).2. Military communication links and microwave links. Air traffic control links, including video data.

3. EARTH EXPLORATION-SATELLITE (Passive), RADIO ASTRON

Figure 72. NTIA spectrum survey azimuth-scan graph of the 14200-15700 MHz range (System-2, band even

maximum-hold detector, 3000-kHz bandwidth) at San Francisco (Angel Island), CA, 1995.
79

GOVERNMENT RADIOLOCATION. RADIOLOCATION, Space Research 1. 3. RadiALLOCATIONS: (Deep Space) (Earth-to-space).NON-GOVERNMENT Radiolocation. Radiolocation. 2. 4. FIXEALLOCATIONS: (EarGENERAL Military airborne radars. Military airborne radars.UTILIZATION:

15700 16600 17100 17200 17300 

min +peak noise

1. RADIOLOCATION.2. Radiolocation.

3. RADIOLOCATION, Earth Exploration-Satellite (Active), Space R4. Earth Exploration-Satellite (Active), Radiolocation, Space Researc

Figure 73. NTIA spectrum survey graph summarizing 25 scans across the 15700-17700 MHz range (Syst

stepped algorithm, +peak detector, 3000-kHz bandwidth) at San Francisco (Grizzly Peak), CA, 19
80

GOVERNMENT RADIOLOCATION. RADIOLOCATION, Space Research 1. 3. RadiALLOCATIONS: (Deep Space) (Earth-to-space).NON-GOVERNMENT Radiolocation. Radiolocation. 2. 4. FIXEALLOCATIONS: (EarGENERAL Military airborne radars. Military airborne radars.UTILIZATION:

15700 16600 17100 17200 17300 

min +peak noise

1. RADIOLOCATION.2. Radiolocation.

3. RADIOLOCATION, Earth Exploration-Satellite (Active), Space R4. Earth Exploration-Satellite (Active), Radiolocation, Space Researc

Figure 74. NTIA spectrum survey graph summarizing 23 scans across the 15700-17700 MHz range (Syst

stepped algorithm, +peak detector, 3000-kHz bandwidth) at San Francisco (Yerba Buena), CA, 19
81

RSMS not configured to receive sp

GOVERNMENT 2.ALLOCATIONS:NON-GOVERNMENT FIXED, MOBILE, FIXED-SATELLITE (space-to-Earth), 1. 3. FIXED, FIXED-SATELLITE (space-to-Earth), MOBILALLOCATIONS:GENERAL General purpose point-to-point microwave band including private, common carrier, cable television relay systems (CARS), studio-to-transmitter (STL) television linUTILIZATION: Digital Electronic Message Services (DEMS), etc.

17700 18600 18800 

minimum maxhold noise

1. 17700-17800 MHz: FIXED-SATELLITE (Earth-to-space).2. EARTH EXPLORATION-SATELLITE (Passive), SPACE RESEARCH (Passive).

3. FIXED, FIXED-SATELLITE (space-to-Earth), EARTH EXPLORA

(except aeronautical mobile), SPACE RESEARCH (Passive).

Figure 75. NTIA spectrum survey aximuth-scan graph of the 17700-19700 MHz range (System-2, band even

maximum-hold detector, 3000-kHz bandwidth) at San Francisco (Angel Island), CA, 1995.
The text above each graph (delimited by horizontal and vertical lines) shows the applicable U.S.

Government and non-Government frequency allocations and corresponding typical user

information (general utilization) for the survey band. The vertical lines delimit, by frequency,

both the allocations and the measured survey band graph on the same page.

The frequency allocations (services) are entered according to convention just as they appear in

the "U.S. Government Table of Frequency Allocations" [1, part 4.1.3]. Briefly summarized: the

names of primary services are printed in capital letters; secondary services are printed in upper

and lower case; and where the allocated service is followed by a function in parentheses, the

allocation is limited to the function shown. Frequency allocations are continuously updated and

some assignment information on the graphs may be out of date; however, the allocations shown

were current at the time the measurements were performed.

The vertical lines are placed according to frequency separations in the allocation tables. The

frequencies (in megahertz) are written at the lower end of the vertical lines. Any service entry

that does not fit within the line-delimited space above the graph is given a number referencing

the complete allocation text below the graph on the same page. If there is additional information

pertinent to a specific Government or non-Government allocation, it is indicated by a number

referencing a note below the graph. General utilization (i.e., a description of how the frequency

allotment is typically used) also will show a reference number if insufficient space is available

within the vertical line delimiters. All notes are written in simple text format distinguishable

from the allocated service entries that are entered according to convention, as previously

explained.

It should be noted that the appearance of survey band graphed data is affected substantially by

the measurement parameters and the analysis techniques employed. For example, data in

Figures 7 and 9 were measured with similar techniques; however, Figure 7 appears to show a

denser signal population than Figure 9. Closer examination shows that Figure 7 covers twice the

frequency range of Figure 9 and this may be a primary reason for the apparently denser signal

environment of Figure 7. Similarly, various survey bands may be plotted with different graph

scales or measured with different bandwidths and algorithms. This is the case for Figures 31

and 33. Both figures cover the same frequency range, but the bandwidths and measurement

algorithms are completely different.

The previous two examples are given as a caution to the reader that each survey band is intended

to best describe the signal environment within its frequency range and is not, generally

comparable to other survey bands. The band-by-band summary observations of Section 2.5

should help in interpreting the data graphs.

2.5 Band-by-Band Evaluation of San Francisco Spectrum Survey Results

It is important to understand those aspects of spectrum use that can be extrapolated from the

RSMS data presented in this report, and also those aspects of spectrum use that cannot be

inferred from these data. Most bands were surveyed at two separate locations in the San

Francisco area during two weeks of May, 1995. This was effectively a double survey, intended

82
to determine the extent to which RSMS occupancy data from any given site are indicative of

usage patterns across an entire metropolitan area. As described more fully in Table 2 and in

Section 3, comparisons of survey results between the two sites show measured usage patterns that

were truly indicative of overall spectrum occupancy across the metropolitan area for most bands,

the major exception being the 902 to 928 MHz Industrial, Scientific, and Medical (ISM) band.

In most measured bands, the RSMS data presented in this report show maximum, minimum, and

mean power levels of received signals. In these bands, the accumulative measurement time

during the survey typically was several hours, spread uniformly over the diurnal cycle.

Nondynamic bands that were measured with the azimuth-scanning technique show only a single

occupancy curve representing a few minutes of sampling time. Appendix B details the sampling

techniques and probability-of-intercept factors for RSMS spectrum surveys.

Based on the measurement and sampling techniques used, we believe that these data represent

a good statistical sampling of the activity in the radio spectrum in the San Francisco metropolitan

area. Maximum and minimum activity levels measured in the spectrum probably are

representative of actual activity levels. The mean curves provide a qualitative estimate of the

typical received power as a function of frequency. The maximum, minimum, and mean curves

also can be used to qualitatively assess the relative density of channel occupancy on a band-byband basis. Likewise in the azimuth-scan bands, the single plotted curve provides a density

estimate of spectrum occupancy in the survey area.

However, while the data presented here can be used to infer the density of frequency occupancy,

these data cannot be used to infer the statistical percentage of time that channels are occupied.

A good analogy is to imagine counting houses while driving along a street: one can easily count

the number of houses that have been built on each block (analogous to counting the number of

frequencies that show activity in each band in the RSMS survey), but one cannot tell, on the

basis of that count, what percentage of time the houses are occupied. Signals that are observed

in 100% of the scans can be determined, because the minimum curve will show such activity.

Other than 100% signals, the mean curves provide a qualitative, not quantitative, measure of

occupancy for the measured frequencies.

There is an RSMS measurement technique for obtaining absolute channel occupancy statistics.

Measurements of this type were performed (in mobile radio bands) in conjunction with the RSMS

occupancy survey in San Francisco. Results of those measurements will be published separately.

Table 2 contains a band-by-band evaluation of spectrum occupancy in the San Francisco area.

Comments and observations are based on examination of the RSMS data collected during the

spectrum survey and frequency allocation information in the NTIA Manual of Regulations and

Procedures for Federal Radio Frequency Management [1, Chapter 4].

83
Table 2. Comments on San Francisco Spectrum Survey Results

Survey Band

(MHz)

Figures Comments

108-138 5, 6 For measurements below 114 MHz, 20-dB rf attenuation was added at the RSMS

frontend to prevent overload by signals in the adjacent 88 to 108 MHz commercial

FM radio broadcast band. This raised the RSMS noise floor in this range by

20 dB relative to the rest of the band, and reduced RSMS sensitivity to signals in

the 108 to 114 MHz range by the same amount.

Instrument landing system (ILS) localizers transmit in the 108 to 112 MHz range,

so detection of ILS localizers was degraded by the high RSMS noise figure in this

range. Some ILS localizers, including San Francisco (SFO) airport, are nevertheless observed. Across 108 to 118 MHz, very-high frequency omnidirectional

range (VOR) aeronautical navigation beacons are observed as 100% emitters.

These are seen as vertical lines coming up from the minimum curve. Also, in the

air traffic control (ATC) band across 118 to 136 MHz, automated terminal

information service transmissions appear as high-average or 100% signals.

Frequently used ATC frequencies also appear as high points on the mean curve.

Air mobile frequencies that were used at least once during the survey are observed

on the maximum curve. A large number of the available channels in the ATC

band were used during the survey period.

In the 137 to 138 MHz band, television infrared observation satellite (TIROS)

signals are not usually receivable by the RSMS. However, three signals were

received in this band, from either satellites or other meteorological-aids transmitters.

138-162 7, 8 A large number of mobile signals are observed in the 138 to 144 MHz portion of

the spectrum, especially as measured from Grizzly Peak. The mean curve is

significantly raised across the 144 to 148 MHz range, used by amateurs. From

148 to 162 MHz, a large percentage of available channels also show use. Transmitters between 152 MHz and 153 MHz were in operation continuously during the

survey period.

Maritime mobile signals occur between 156.2475 MHz and 162.025 MHz. All of

these channels show some occupancy, consistent with expectations for the RSMS

coverage of the San Francisco Bay area from the measurement locations.

162-174 9, 10 A variety of fixed and mobile signals are observed. The signal at 162.4 MHz is a

public broadcast weather information channel. Approximately half of the channels

in this band show some occupancy during the survey period, although most

channels were not occupied often enough to affect the mean curve. Measured

occupancy is similar for the Grizzly Peak and Yerba Buena Island locations.

174-216 11, 12 Television broadcast channels 7, 9, 11, and 13 are occupied by San Francisco

stations. Channels 8, 10, and 12 are occupied by San Diego stations. 20-dB rf

attenuation was used to prevent frontend overload in the RSMS. Measured occupancy is similar for the Grizzly Peak and Yerba Buena Island locations.

84
Table 2. Comments on San Francisco Spectrum Survey Results (Continued)

Survey Band

(MHz)

Figures Comments

216-225 13, 14 Maritime mobile signals and Government seismic stations are observed between

216 MHz and 220 MHz. A trunked-system base station occupies the spectrum

between 220.0 MHz and 220.75 MHz. Amateur signals are observed above

222 MHz, and the relative density of channel occupancy slightly increases above

223.25 MHz. No military radiolocation occurs in this spectral range in the San

Francisco area. Measured occupancy data were similar for the Grizzly Peak and

Yerba Buena Island locations.

225-400 15, 16 Military ATC and other communications are observed at high density. Many of

these signals are 100% transmissions from fixed locations, as is especially evident

in the Yerba Buena data. Even signals that are less than 100% often are used

enough of the time to significantly affect the mean curve. ILS glideslope signals

from San Francisco and Oakland airports are observed. Measured occupancy is

similar for the Grizzly Peak and Yerba Buena Island locations.

400-406 17, 18 Occupancy is dominated by non-Government meteorological-aids systems that

show peaks that are each 50 to 100 kHz wide and 800 kHz apart. One such

system was observed from Yerba Buena Island, and the same system and an

additional system were observed from Grizzly Peak. Radiosonde signals were also

observed at 401.9 and 404.02 MHz.

406-420 19, 20 Occupancy in this band appears to be relatively heavy in San Francisco as

compared to San Diego [3] and Los Angeles [4], and the band shows more use

than in Denver [2]. Not only do most of the channels show occupancy on at least

one occasion during the survey, but the mean curve shows that many of those

channels were in use for an appreciable fraction of the time during the survey. A

number of trunked-radio systems are operative in this band in the San Francisco

area, and this may partly explain why the measured occupancy in this band is

relatively high.

The emission spectra also show that many of the channels were carrying fm

traffic. The channel at 412.8 MHz measured at Yerba Buena shows a possible

digital signal.

In addition to trunked-radio transmissions, this band also supports such dedicatedchannel systems as the National Weather Service Automated Surface Observation

System (constant-use signal at 410.075 MHz), Government scientific systems such

as seismic sensors, and various law enforcement and military activities. Measured

occupancy patterns are similar for the Grizzly Peak and Yerba Buena Island

locations.

420-450 21, 22 High-power air search radar signals produced all usage observed in this band.

Some of these radar signal amplitudes, in excess of −30 dBm in 50 ohms, were

near RSMS receiver saturation levels. The radars are mostly long-range, on naval

ships and aircraft. Comparison of the high level of activity in this band in the San

Francisco area and other coastal cities (San Diego and Los Angeles [3,4]) with

practically nonexistent activity at a continental interior location (Denver, Colorado

[2]) implies that this may be a nationwide pattern.

85
Table 2. Comments on San Francisco Spectrum Survey Results (Continued)

Survey Band

(MHz)

Figures Comments

450-470 23, 24 A large number of land mobile signals are observed, and many of them sufficiently often to affect the mean curve. The band edges of the 460 to 465 MHz

base station allocation are very distinct. The 454 to 455 MHz domestic public

base stations are also distinctly observed. Much of the measured activity between

466 MHz and 470 MHz was due to overload in the RSMS receiver from television

channel 14 transmissions (470 to 476 MHz), and does not represent true occupancy. Measured occupancy patterns are similar for the Grizzly Peak and Yerba

Buena Island locations.

470-512 25, 26 Television channels 14 and 20 are broadcast in San Francisco. Channel 14

overloaded the RSMS receiver system, and consequently an intermodulation

product occurs at 480.3 MHz. The other occupancy observed in this band,

(allocation for television channels 16 and 17) is generated by land mobile radio

transmitters.

Spectrum nominally allocated for television broadcast channels 16 and 17 shows

use by the San Francisco T-band land-mobile-radio allocation, as defined in [5,

Part 90.311], for ten major urban areas in the United States. Base stations operate

in the lower half of each channel, and mobile stations operate in the upper half of

each channel. Occupancy is a combination of Public Safety, Domestic Public,

Industrial, and Land Transportation assignments. Measured occupancy patterns are

similar for the Grizzly Peak and Yerba Buena Island locations.

512-806 27, 28 All of the signals observed in this band are San Francisco-area UHF television

broadcast. 20-dB rf attenuation was added between 512 MHz and 612 MHz to

prevent overload of the RSMS receiver by particularly high-amplitude signals in

this part of the band. Measured occupancy patterns are similar for the Grizzly

Peak and Yerba Buena Island locations.

806-902 29, 30 Cellular, trunked, and public safety portions of this part of the spectrum are clearly

delineated. Mobile and base parts of the band are also easy to identify.

The 806 to 821 MHz (mobile conventional and trunked) band segment is heavily

occupied, as is the 821 to 824 MHz mobile public safety band and its base station

counterpart between 866 MHz and 869 MHz. The 824 to 849 MHz cellular

mobile band shows enough use by mobile units to affect the mean curve slightly.

The 849 to 851 MHz ground-to-air allocation shows lower usage, but the

probability-of-intercept for such signals by the RSMS is low. The 851 to

866 MHz base conventional and trunked band shows usage that significantly raises

the mean curve. The 866 to 869 MHz base public safety shows usage on most

channels, and the mean curve is affected. The 869 to 894 MHz band, occupied by

cellular base stations, is distinctly observed. The 100% occupancy channels

(879 to 881 MHz and 891 to 892 MHz) are probably system control channels.

Air-to-ground signals between 894 MHz and 896 MHz are observed, confirming

that low probability-of-intercept may prevent the RSMS from measuring corresponding ground-to-air signals. Many signals are observed in the 896 to

901 MHz private land mobile band, and a few signals (901 to 902 MHz general

mobile allocation) are seen in the Grizzly Peak data. In this band overall,

measured occupancy patterns are similar for the Grizzly Peak and Yerba Buena

Island locations.

86
Table 2. Comments on San Francisco Spectrum Survey Results (Continued)

Survey Band

(MHz)

Figures Comments

902-928 31, 32

33, 34

This band is measured in two ways: with the positive peak detector in maximum

hold mode and 10-kHz IF bandwidth, as shown in Figures 31 and 32, and with the

positive peak detector in stepped mode and 1-MHz bandwidth, as shown in

Figures 33 and 34. The narrow-IF bandwidth, maximum-hold measurement is

intended to show industrial, scientific and medical (ISM), and Part 15 device

operations, while the wide-IF bandwidth, stepped algorithm is intended to optimize

the RSMS for measurement of radar signals in the band. For the San Francisco

area, both algorithms produced band usage data that show occupancy levels only

slightly higher than were measured in the Denver, Colorado, survey [2], and not as

high as measured in San Diego and Los Angeles, California [3, 4].

A wide variety of systems operate in this band. These include, but are not limited

to, high-power naval radars (primary allocation in the band), ISM devices, Part 15

devices, wireless local area networks (required to either use spread spectrum or

frequency-hopping transmitters), automatic vehicle monitoring, highway toll tag

readers, location and monitoring service (LMS) systems (for commercial vehicle

tracking), digital communication systems, and amateur radio (allocated on a

secondary, non-interference basis). A number of assignments for railroads exist in

this band for the San Francisco area. Figures 31 and 32 show the cumulative

effect of nonradar devices on spectrum usage in this band. Radar emissions tend

to be discriminated out of these data by the narrowband (10-kHz) IF. Maximum

observed signal amplitude in this bandwidth is about −55 dBm on an omni

antenna. Note that many of the signals are observed in 100% of RSMS data

scans. The measured occupancy patterns, as measured with maximum-hold mode,

differed substantially between the Grizzly Peak and Yerba Buena Island locations,

implying that the patterns measured with this algorithm and bandwidth are

probably highly dependent upon local ISM systems. This is consistent with the

low-power emissions from these systems.

Figures 33 and 34 show spectrum occupancy by high-power naval radars. These

are long-range radars that were receivable at the measurement locations from ships

in San Francisco Bay and ships on the open waters beyond the Golden Gate. The

difference in measured occupancy, as measured from Grizzly Peak and Yerba

Buena Island, probably represents the vagaries of transit by various military ships

during different measurement periods.

928-960 35, 36 Paging systems are observed between 929 MHz and 932 MHz.

No signals are observed in the paired 932 to 935 MHz and 941 to 944 MHz pointto-point and point-to-multipoint bands, and this could be due to low probability-ofintercept for such signals by the RSMS, but signals have been measured in this

band in other localities, such as Los Angeles [4]. Base stations in the 935 to

940 MHz land mobile band show substantial occupancy. Most signals in the

944 to 960 MHz fixed band (auxiliary broadcasting, fixed private microwave, and

studio-to-transmitter links) were present in 100% of RSMS data scans, a pattern

that has been observed in Denver, San Diego, and Los Angeles [2, 3, 4]. Overall,

measured occupancy patterns are similar for the Grizzly Peak and Yerba Buena

Island locations.

87
Table 2. Comments on San Francisco Spectrum Survey Results (Continued)

Survey Band

(MHz)

Figures Comments

960-1215 37, 38 Activity in this band is produced entirely by aeronautical navigation aids. These

include tactical air navigation beacons (TACAN), distance-measuring equipment

(DME), and air traffic control radar beacon system (ATCRBS) interrogators and

transponders. Probable TACAN signals appear as bumps in the mean curve at

(approximately) 961, 987, 1018, 1119, 1131, 1157, 1165, 1171, 1173, 1192, 1196,

and 1202 MHz. DME airborne interrogations occur from 1025 to 1150 MHz;

DME ground beacon replies occur between 962 MHz and 1025 MHz, and between

1150 MHz and 1213 MHz. Note the delineation that is visible at 1150 MHz.

ATCRBS ground-based interrogations occur at 1030 MHz, and airborne replies

occur at 1090 MHz. Both of these peaks are clearly visible in the data. Because

the emissions in this band are primarily pulsed, the mean curve is essentially

unaffected by all signals except TACAN. Overall, measured occupancy patterns

are similar for the Grizzly Peak and Yerba Buena Island locations.

1215-1400 39, 40 This band shows occupancy by high-power, long-range air search radars.

Frequencies occupied by distinctly identifiable radar signals are 1310 MHz and

1345 MHz. Emission parameters for this type of radar vary, but values measured

by the RSMS crew are typically as follows: mechanical beam rotation, 9 to 12 s

rotation time, 1 to 6 μs pulse widths, and 300 to 600 pps transmitted. These

radars usually are observed to emit staggered pulse trains to enhance doppler

processing of target returns. Overall, measured occupancy patterns are similar for

the Grizzly Peak and Yerba Buena Island locations; although measured amplitudes

in Grizzly Peak data are typically higher than at Yerba Buena Island.

1350-1400 41, 42 Unlike the measurements made in the 1215 to 1400 MHz band, measurements in

this band are optimized to observe nonradar emissions. Nevertheless, much of the

activity observed in this band is from radars. The prominent features observed in

Grizzly Peak data are spurious emissions from the radars between 1215 MHz and

1400 MHz. At Yerba Buena Island, where the radars were received at lower

amplitudes, the spurious emissions are below the measurement system noise floor,

and consequently are not seen.

1400-1530 43, 44 No activity is observed in this band in the San Francisco area. But note that this

band is heavily used by telemetry systems at test ranges, and measurement sites

near such facilities, such as Los Angeles [4], do show activity in this band.

1530-1710 45, 46 Numerous signals are observed in the maritime mobile satellite earth-to-space band

of 1626.5 to 1646.5 MHz. Some radiosonde signals are observed in the 1668.4 to

1700 MHz band. Overall, measured occupancy patterns are similar for the Grizzly

Peak and Yerba Buena Island locations.

1710-2300 47 All signals observed in this band are terrestrial point-to-point communications, as

measured with the RSMS azimuth-scanning technique. The measurement system

noise floor varies across this frequency range, as evidenced by the dip centered at

2000 MHz. Note that all signals observed in this band in San Francisco are

analog; in some other measurement locations, such as Los Angeles [4], some

digital signals are observed.

88
Table 2. Comments on San Francisco Spectrum Survey Results (Continued)

Survey Band

(MHz)

Figures Comments

2300-2500 48, 49 Some observed signals (2305 to 2310 MHz, and 2355 MHz) were present for only

brief periods; indicated by the lack of impact on the mean curve. Other than those

signals, all of the observed activity is background radiation generated by ISM

devices, and especially by aggregate emissions from microwave ovens in the San

Francisco area. This background is observed at other RSMS spectrum survey

locations [2], [3], [4]. See also Gawthrop, et al. [6], for further information on

emission characteristics of microwave ovens.

2500-2700 50 At least 22 fixed transmitters are observed in this band. The individual signal

spectra are standard NTSC television broadcast, indicating that these are multichannel multipoint distribution system (MMDS, also called wireless cable

television) transmitters. Fixed microwave links in this band, if any, are probably

hidden by the more powerful MMDS transmitters. There is some variation in the

RSMS system noise floor across this frequency range.

2700-2900 51, 52 All signals in this band are generated by high-power air-search radars. Nine

frequencies (2705, 2745, 2765, 2790, 2825, 2835, 2850, 2885, and 2895 MHz) are

easily discernable. Because automatic attenuation was not yet implemented in the

RSMS, these radars saturated the RSMS frontend at their center frequencies during

most of the measurements. However, a few manually attenuated scans were

recorded to document the peak received power, and are shown as the maximum

curve. So, the mean curve reflects the maximum, positive-peak detected amplitudes of the majority of scans (which were unattenuated), while the maximum

curve shows the true envelope of radar emissions in this band. Radars in this

band as measured by RSMS crew, typically have the following characteristics:

mechanical rotation, no elevation scanning, 4.7 to 5.0 s rotation time, about 1 μs

pulse width, and about 1000 pps emitted at a high-order stagger, presumably for

doppler processing of target returns.

2900-3100 53, 54 In contrast to the spectrum survey measurements in San Diego and Los Angeles

[3,4], no high-power air-search radars are observed in this band. This apparently

reflects a relative paucity of activity by naval vessels in the vicinity of San

Francisco during the measurement period. The high level of occupancy between

3000 MHz and 3100 MHz is generated by maritime and naval surface-search and

navigation radars in the San Francisco Bay area. Most large vessels, both military

and civilian, carry a surface-search radar that operates at or near 3050 MHz.

3100-3700 55, 56 In contrast to the spectrum survey measurements in San Diego and Los Angeles

[3,4], very little spectrum occupancy is observed in the San Francisco area during

the spectrum survey period. Occupancy observed between 3100 MHz and

3220 MHz is spurious emission activity from the 3050-MHz surface-search radars.

One or two radar signals occur sporadically between 3220 MHz and 3500 MHz.

Radar signals observed between 3500 MHz and 3600 MHz are generated by naval

air-traffic control radars.

89
Table 2. Comments on San Francisco Spectrum Survey Results (Continued)

Survey Band

(MHz)

Figures Comments

3700-4200 57 RSMS azimuth scans show only a single, fixed, point-to-point microwave link in

this band. The link’s spectrum shows that it is analog. The low level of

occupancy by fixed terrestrial links in this band in the San Francisco area

correlates well with measurement results in Denver, San Diego, and Los Angeles

[2,3,4]. Demand for fixed link assignments in this band is decreasing,4 and

results of this survey, as well as the RSMS spectrum surveys in Denver, San

Diego, and Los Angeles [2,3,4] (which consistently show almost no terrestrial

signals in this band), raise the question of whether there are nearly as many

operational terrestrial links as are indicated by the number of existing licenses.

The RSMS noise floor shows variation between 3860 MHz and 4000 MHz.

4200-4400 58, 59 Airborne radio altimeter signals, transmitted by aircraft on approach and departure

from nearby airfields, are clearly observed between 4225 MHz and 4350 MHz in

the Yerba Buena Island data. Observation of these signals depends upon location

of the measurement system below aircraft flight patterns; the Grizzly Peak site

was not under such flight patterns, and these signals were not recorded.

Two signal modulations predominate: pulsed and FM/CW. Because the signals

occur very intermittently, and some are pulsed, the mean and minimum curves are

not affected.

4400-5000 60 Only a single fixed, point-to-point microwave link is observed in this band at

4681 MHz, as measured with the RSMS azimuth-scanning technique. Low

observed occupancy in this band is consistent with the measured results from

Denver and Los Angeles [2,4]. The band exhibited considerably more occupancy

in San Diego [3].

4

Most terrestrial point-to-point links in this band carry long-distance telephone traffic. These

links are gradually being replaced by fiber-optic technology; as indicated by this graph showing

the number of transmitter licenses issued, in the U.S., for the years 1987 through 1996.

90
Table 2. Comments on San Francisco Spectrum Survey Results (Continued)

Survey Band

(MHz)

Figures Comments

5000-5250 61, 62 No signals are observed in this band during the period of the San Francisco

spectrum survey. There is no microwave landing system (MLS) deployed in the

San Francisco area. The small peaks that appear in the occupancy graph for

Yerba Buena Island are noise, generated by adjacent-band maritime surface-search

radars operating between 5250 MHz and 5925 MHz. This band was similarly

measured with no signal occupancy in Denver, San Diego, and Los Angeles

[2,3,4]. This lack of observed occupancy is expected, since until recently MLS

has been virtually the only system assigned to this band, and MLS is deployed at

a very limited number of locations in the United States.

Differential global-positioning system (DGPS) services for aircraft navigation are

currently being activated between 5000 MHz and 5150 MHz, but such service was

not yet active at the time of this spectrum survey.

5250-5925 63, 64 Occupancy by maritime surface-search and navigation radars is observed between

5250 MHz and 5350 MHz. Weather radar emissions occupy the band between

5400 MHz and 5650 MHz. A military navigation radar is observed between

5650 MHz and 5675 MHz. Radar spurious emissions from the aggregate occupancy are observed up to 5800 MHz.

5925-7125 65 Numerous fixed links, both analog and digital, are observed in the San Francisco

area. The digital links occupy spectrum between 5925 MHz and 6370 MHz, and

other digital links occur at 6680 MHz and 7020 MHz. Measurement of significant

occupancy by fixed-terrestrial and earth-to-space links in this band demonstrates

the ability to observe such signals with the RSMS, and indicates that lack of

observed occupancy in other bands, such as 3700 to 4200 MHz, probably indicates

that such bands are, in fact, not occupied in the metropolitan area.

7125-8500 66 Only a few fixed links, all of them analog, are observed in the RSMS azimuthscan measurement. Substantially less occupancy is observed in this band in San

Francisco than in either the Denver or San Diego surveys [2,3]. The dip between

7850 MHz and 8000 MHz is due to a decrease in the RSMS noise floor across

that range.

8500-10550 67, 68 All signals observed in this band are generated by maritime surface-search radars

and airborne radars. The observed occupancy at Yerba Buena Island is higher

than that observed at Grizzly Peak because the surface-search radars are in closer

proximity to Yerba Buena Island, and their main-beam antenna patterns illuminate

the island more effectively than they illuminate the high peak.

Essentially all surface-search radars carried by small vessels operate in this band;

larger vessels also frequently carry radars that operate in this band. Typical

operational parameters of the surface search radars, as measured by RSMS, are:

mechanical rotation, 2 to 4 s rotation, less than 300 ns pulse width, pulse

repetition rates of several thousand pps, no pulse staggering present. Airborne

radars have similar pulse characteristics, but employ mechanical sector scans.

10550-13250 69 No signals are observed in this band in San Francisco. Observed occupancy is

similar to San Diego and Los Angeles [3,4], and lower than was observed in

Denver [2].

91
Table 2. Comments on San Francisco Spectrum Survey Results (Continued)

Survey Band

(MHz)

Figures Comments

13250-14200 70, 71 A single radar is observed at 13450 MHz in only one RSMS measurement scan.

Radars in this band are short-range, often used for fire control.

14200-15700 72 One signal, an earth-to-space link, is observed at 17350 MHz. In general, the

probability-of-intercept by the RSMS for signals in this band is low. See

Appendix B.

15700-17700 73, 74 No signals are observed in the RSMS azimuth scan. In general, the probabilityof-intercept by the RSMS for signals in this band is low. See Appendix B.

17700-19700 75 A few signals are observed near 19450 MHz. These are terrestrial links. The

change in the RSMS noise floor at 19300 MHz is due to a band edge in the

spectrum analyzer. In general, the probability-of-intercept by the RSMS for

signals in this band is low. See Appendix B.

3. CONCLUSIONS

RSMS spectrum survey measurements are intended to provide spectrum engineers and spectrum

managers with data that show patterns of spectrum occupancy at selected metropolitan locations

across the United States. It has been implicitly assumed during previous RSMS spectrum surveys

that the occupancy patterns observed at a well-chosen measurement location in a metropolitan

area are indicative of the overall occupancy patterns for the entire area. In San Francisco, that

assumption was tested by performing most of the spectrum survey measurements at two

measurement locations. To the extent that spectrum occupancy results are replicated at the two

locations for any given band, the assumption is considered to be true for this metropolitan area.

Table 3 summarizes the comparison between measured band occupancy for all survey bands

measured at the two locations in the San Francisco area.

Table 3. Comparison of Measured Spectrum Occupancy at Two Locations

Survey Band

(MHz)

Qualitative degree

of similarity

Comments on any observed occupancy pattern variation between

the two measurement locations

108-138 High

138-162 High

162-174 High

174-216 High

216-225 High

225-400 High

400-406 High

406-420 High

92
Table 3. Comparison of Measured Spectrum Occupancy at Two Locations (Continued).

Survey Band

(MHz)

Qualitative degree

of similarity

Comments on any observed occupancy pattern variation between

the two measurement locations

420-450 Moderate Transitory nature of naval high-power radars in this band significantly changes occupancy as a function of time.

450-470 High

470-512 High

512-812 High

806-902 High

902-928

(nonradar)

Low Prevalent use of low-powered devices in this band causes measured

occupancy to be dominated by nearby devices.

902-928

(radar)

High

928-960 High

960-1220 High

1200-1400 High

1350-1400 High

1400-1530 High

1530-1710 High

2300-2500 High

2700-2900 Moderate Reduced line-of-sight coverage for these radars at one measurement

location.

2900-3100 High

3100-3700 High

4200-4400 Low Reception of directive, low-power airborne radio altimeters dependent

upon location of measurement system relative to local flight paths.

5000-5250 High

5250-5925 Moderate Line-of-sight coverage for these radars significantly better at one

measurement location.

8500-10600 High

13250-14250 High

15700-17700 High

As shown in Table 3, almost every measured band shows highly similar occupancy patterns

between the two measurement locations, with some microwave bands showing only moderate

similarity in measured occupancy. Variation between the measured occupancy in the microwave

bands is believed to be due to the criticality of line-of-sight coverage at those frequencies, and

generally the location with the largest line-of-sight coverage area shows higher measured

occupancy levels.

93
The two bands that show low correlation in measured occupancy between the two measurement

sites (902 to 928 MHz, nonradar, and 4200 to 4400 MHz) may do so because their use is

dominated by devices that are only receivable for short distances. In the case of the 902 to

928 MHz nonradar occupancy, this results from prevalent use of low-power devices in the band.

In the case of 4200 to 4400 MHz, this results from the low power and high directivity of airborne

radio altimeter signals.

The results of the multiple-location measurements in San Francisco provide proof that the

occupancy patterns measured by the RSMS at any well-selected measurement location are, for

the most part, accurate representations of the spectrum occupancy for the entire metropolitan area

(assuming, of course, that the measurement location is selected with due regard for the criteria

presented in Section A.2 of Appendix A). The only significant exception to this generalization

seems to be in the ISM band (902 to 928 MHz), where usage is dominated by low-power

transmitters of limited signal intercept range.

The dependence of measured occupancy data on line-of-sight coverage in the microwave bands

does suggest that future RSMS spectrum surveys should perform the azimuth-scan measurements

for the point-to-point bands at multiple locations, as well.

4. REFERENCES

[1] Manual of Regulations and Procedures for Federal Radio Frequency Management, revised

Jan. and May. 1996, NTIA Office of Spectrum Management, U.S. Government Printing

Office, Stock No. 903-008-00000-8.

[2] F.H. Sanders and V.S. Lawrence, "Broadband spectrum survey at Denver, Colorado," NTIA

Report 95-321, Sep. 1995.

[3] F.H. Sanders, B.J. Ramsey, and V.S. Lawrence, "Broadband spectrum survey at San Diego,

California," NTIA Report 97-334, Dec. 1996.

[4] F.H. Sanders, B.J. Ramsey, and V.S. Lawrence, "Broadband spectrum survey at Los

Angeles, California," NTIA Report 97-336, May 1997.

[5] Title 47 Code of Federal Regulations, Telecommunications, Part 80 to End, revised Oct.

1994, (U.S. Government Printing Office, Superintendent of Documents, Mailstop: SSOP,

Washington, DC 20402-9328).

[6] P.E. Gawthrop, F.H. Sanders, K.B. Nebbia, and J.J. Sell, "Radio Spectrum Measurements

of Individual Microwave Ovens," NTIA Report 94-303, Vol 1 & 2, Mar. 1994.

94
APPENDIX A: OVERVIEW OF BROADBAND SPECTRUM SURVEYS

A.1 INTRODUCTION

Procedures for conducting a broadband spectrum survey using the Institute for Telecommunication Sciences (ITS) radio spectrum measurement system (RSMS) are outlined in this Appendix.

Site selection factors, significant measurement system parameters, and hardware and software

configurations developed for the surveys are described. Measurement system response to various

types of signals is described in Appendix B. Detailed information on the system hardware

(including the vehicle, instrumentation, antennas, and receiver frontend), calibration procedures,

and other measurement capabilities are provided in Appendix C. Measurement system software

is described in Appendix D.

A.2 SURVEY SITE SELECTION

A successful spectrum survey (also called a site survey) requires careful selection of a

measurement site. Maximum signal intercept probability and minimum logistics problems are

the first considerations when locating a site for an RSMS spectrum survey.

The primary signal intercept factors are (1) maximum line-of-sight coverage to increase the

probability of weak signal reception, such as transmissions from mobile units; (2) limited

numbers of nearby transmitters to prevent intermodulation or saturation problems that can arise

even though preselection and/or filtering is used for survey measurements; and (3) limited manmade noise such as impulsive noise from automobile ignition systems, electrical machinery, and

power lines that can add to the received signals of interest and give misleading results.

The primary logistics factors are (1) commercial power to increase the probability of completing

the spectrum survey (typically two weeks of 24-hr operation) without power interruptions;

(2) commercial telephone for relatively inexpensive reliable communications, compared to the

RSMS cellular telephone that possibly could contaminate the measurements when transmitting;

and (3) security of personnel, vehicle, and electronic hardware.

The ideal site is a well-illuminated, fenced, and patrolled area that satisfies all of the primary site

selection factors above and has reasonable access to lodging for the operating personnel.

A.3 SPECTRUM SURVEY MEASUREMENTS

Spectrum surveys are normally conducted for two weeks using the RSMS in an automatic mode.

The measurement system is preprogrammed to continuously run software algorithms tailored to

the characteristics of the radio emitters that typically occupy measured frequency sub-bands.

Two decades of making such measurements in cities across the United States suggest that general

patterns of spectrum occupancy tend to be repeated from site to site. Emissions from the

following sources commonly are observed during RSMS spectrum surveys:

95
land-mobile, marine-mobile, and air-mobile communication radios;

terrestrial, marine and airborne radars, and airborne radio altimeters;

radionavigation emitters, such as TACAN and VOR;

cellular and trunked communication systems;

broadcasting transmitters such as UHF and VHF television, and multipoint

distribution systems (wireless cable TV);

industrial, scientific and medical (ISM) sources, including vehicular tracking

systems, welders, and microwave ovens; and

common carrier (point-to-point) microwave signals.

Emissions that are not normally receivable during spectrum surveys are:

satellite downlink emissions;

galactic and solar noise;

some types of spread spectrum signals; and

radio transmitters that are turned off.

Although the last category is self-evident, questions exist regarding the extent to which users who

have assignments in the radio spectrum either do not operate, or operate very rarely. Appendix B

discusses factors related to probability of intercept and addresses matters of measurement time

vs. statistical significance of data.

As mentioned above, there are many different types of radio signals within the measurement

frequency range. Each is measured with a hardware configuration and measurement algorithm

specifically selected to give the most useful description of the particular type of signal(s)

expected in a frequency sub-band. The measurement system parameters specially configured for

each signal type include: antennas, signal conditioning, tuning speed, measurement bandwidth,

detector mode, and measurement repetitions. The RSMS measurement software automatically

switches the measurement system to the proper configuration for each sub-band. The measurements are repeated in various sub-bands according to specifications established by consideration

of signal intercept probability, signal variability, measurement significance, current need for data,

and expenditure of system resources.

For spectrum surveys, the RSMS normally performs measurements of general spectrum

occupancy across a frequency range of 108 MHz to 19.7 GHz. To accomplish this task,

measurements are conducted in an automatic mode with the RSMS configured as two measure96
ment systems, identified as "System-1" for frequency measurements below 1 GHz, and

"System-2" for simultaneous measurements above 1 GHz.

The RSMS data acquisition (DA) measurement control software1 provides automated instructions

to configure the receiver system, execute measurement routines, record measured data, and

maintain a real-time log of the measurements. The measurement system configuration parameters

used by the software are called "band events" and the automated band event execution procedures

are called "band event schedules." Unattended operation of the measurement system for extended

periods of time is made possible through this use of computer control. Remote monitoring and

control of the RSMS is possible via a telephone modem linked to the computer. Standardized

measurement band event schedules are used for each spectrum survey, and the measured data are

stored for postmeasurement processing.

A.3.1 Survey Band Events

The spectrum measured by the RSMS is divided into selected frequency ranges (survey bands)

that are measured according to a computer-stored list of measurement parameters and instrument

settings called a band event. Each band event combines a measurement algorithm with an

antenna, a particular signal input port, frontend configuration, receiver settings, spectrum analyzer

mode, and data-recording options. Band event parameters and options are detailed in

Appendix D. The factors considered when selecting frequency sub-bands, receiver algorithms,

and other parameters for the band events are discussed in Appendix B.

Spectrum survey "standard" band events for System-1 and System-2 are shown in Tables A-1

and A-2, respectively. Each row in the survey band-event tables, beginning with an event

number, shows the measurement parameters for a specific receiver configuration in the RSMS.

Instruction to run the event is entered by an operator or comes from a computer-loaded band

event schedule, as explained in the following Section. The DA software, when instructed, sends

the command parameters for an event to the system hardware and initiates measurements for the

event.

Tables A-1 and A-2 are subdivided into four parts: (1) "Standard Events" identifies the event

number and exact frequency range of interest, (2) "DA Receiver Parameters" shows input values

for receiver configuration subroutines, (3) "DA Spectrum Analyzer Parameters" lists configuration

command values sent to the spectrum analyzer, and (4) "Antenna" identifies the type and gain

of the antenna selected for the event. Appendix D contains operational descriptions for all of the

table parameters found under (2) and (3) above.

1

All automated measurements are accomplished through computer software control of the

measurement hardware. Appendix D contains a complete description of the RSMS data

acquisition software.

97
Table A-1. Standard Spectrum Survey Band Events for RSMS System-1

98

Standard Events DA Receiver Parameters DA Spectrum Analyzer Parameters* 

Event

Number

Freq. Band

(MHz)

Algorithm Start (MHz) End (MHz) Scans (# of) Sweeps (# of) Steps (# of) IFBW (kHz) Detector Type VBW (kHz) RL (dBm) MH/VA (#swps) S

11 108-162 sw/m3 104 164 6 100 1 10 sample 10 -20 1 12 162-174 sw/m3 160 180 2 500 1 10 sample 10 -20 1 13 174-216 sw/m3 170 220 1 500 1 100 sample 100 -10 1 14 216-225 sw/m3 216 225 3 60 1 3 sample 3 -30 1 15 225-400 sw/m3 225 405 6 100 1 30 sample 30 -10 1 16 400-406 sw/m3 400 406 2 60 1 3 sample 3 -10 1 17 406-420 sw/m3 400 420 2 200 1 10 sample 10 -20 1 18 420-450 stepped 420 450 1 1 30 1000 +peak 3000 -10 1 19 450-470 sw/m3 450 470 2 200 1 10 sample 10 -20 1 20 470-512 sw/m3 470 520 5 100 1 10 sample 10 -20 1 21 512-806 sw/m3 512 812 3 200 1 100 sample 100 -10 1 22 806-902 sw/m3 806 906 10 60 1 10 sample 10 -20 1 23 902-928 swept 900 930 3 1 1 10 MXMH 10 -10 600 24 902-928 stepped 900 930 1 1 30 1000 +peak 3000 -10 1 25 928-960 sw/m3 920 960 4 300 1 10 sample 10 -20 1 

* For spectrum surveys, attenuation is set to 0 (default), display to 10 dB/div, and the spectrum analyzer in use must measure at l** A 100-MHz to 1-GHz omnidirectional antenna is used for spectrum surveys. For the San Francisco survey, however, a 100-M

antenna (LPA) with 5.5-dBi to 6.1-dBi gain was used. The LPA was mounted at a 45° angle to emulate slant polarization (see 
Table A-2. Standard Spectrum Survey Band Events for RSMS System-2

99

Standard Events DA Receiver Parameters DA Spectrum Analyzer Parameters* 

Event

Number

Freq. Band

(MHz)

Algorithm Start (MHz) End (MHz) Scans (# of) Sweeps (# of) Steps (# of) IFBW (kHz) Detector Type VBW (kHz) RL (dBm) MH/VA (#swps) 

05 960-1215 sw/m3 950 1250 1 500 1 300 +peak 3000 -10 1 06 1215-1400 stepped 1200 1400 1 1 200 1000 +peak 3000 -10 1 07 1350-1400 sw/m3 1350 1400 5 100 1 10 sample 10 -20 1 08 1400-1530 sw/m3 1400 1550 5 200 1 30 sample 30 -10 1 09 1530-1710 sw/m3 1530 1710 6 500 1 30 sample 30 -10 1 10 1710-2300 swept 1700 2300 6 1 1 100 MXMH 100 -10 600 11 2300-2500 swept 2300 2500 2 1 1 100 MXMH 100 -10 600 12 2500-2700 swept 2500 2700 2 1 1 100 MXMH 100 -10 600 13 2700-2900 stepped 2700 2900 1 1 200 1000 +peak 3000 -10 1 14 2900-3100 stepped 2900 3100 1 1 200 1000 +peak 3000 -10 1 15 3100-3700 stepped 3100 3700 1 1 200 3000 +peak 3000 -10 1 16 3700-4200 swept 3700 4200 5 1 1 100 MXMH 100 -10 600 17 4200-4400 sw/m3 4200 4400 1 500 1 300 +peak 3000 -10 1 18 4400-5000 swept 4400 5000 6 1 1 100 MXMH 100 -10 600 19 5000-5250 sw/m3 5000 5300 1 500 1 300 +peak 3000 -10 1 20 5250-5925 stepped 5250 5950 1 1 240 3000 +peak 3000 -10 1 
Table A-2. Standard Spectrum Survey Band Events for RSMS System-2 (Continued)

100

Standard Events DA Receiver Parameters DA Spectrum Analyzer Parameters* 

Event

Number

Freq. Band

(MHz)

Algorithm Start (MHz) End (MHz) Scans (# of) Sweeps (# of) Steps (# of) IFBW (kHz) Detector Type VBW (kHz) RL (dBm) MH/VA (#swps) 

21 5925-7125 swept 5925 7125 4 1 1 300 MXMH 1000 -10 600 22 7125-8500 swept 7100 8600 5 1 1 300 MXMH 1000 -10 600 23 8500-10550 stepped 8500 10600 1 1 720 3000 +peak 3000 -10 1 24 10550-13250 swept 10550 13250 1 1 1 3000 MXMH 3000 -10 600 25 13250-14200 stepped 13250 14250 1 1 340 3000 +peak 3000 -10 1 26 14200-15700 swept 14200 15700 1 1 1 3000 MXMH 3000 -10 600 27 15700-17700 stepped 15700 17700 1 1 700 3000 +peak 3000 -10 1 28 17700-19700 swept 17700 19700 1 1 1 3000 MXMH 3000 -10 600 

* For spectrum surveys, attenuation is set to 0 (default), display to 10 dB/div, and the spectrum analyzer in use must measure at l** A 500-MHz to 18-GHz slant polarized biconical omnidirectional antenna is used for spectrum survey measurements. A parabo

is used for azimuth-scanning. See Sections C.4 and D.2 of Appendices C and D, respectively, for descriptions of the antennas and thalgorithm used with the dish antenna.

+ If slow-rotation emitters (e.g., weather radars) contribute significantly to the measured occupancy in a survey band, an increased 

used to better characterize their peak power envelope (see Section B.7.2 in Appendix B).
A.3.2 Band Event Schedules

Using RSMS measurement control software, any band event can be executed by an operator at

any time. For spectrum surveys, many band events are used to span several gigahertz of

spectrum, and each event requires a different amount of time to execute. DA software includes

an automated band event execution mode where any of the band events may be programmed

(scheduled) to execute in any sequence for any amount of time (within hardware limits on

continuous operation of the measurement system).

There are two types of schedules used for spectrum surveys with the RSMS: a standard band

event schedule of all the survey bands, or a special band event schedule for a few selected survey

bands. For example, if a survey were conducted in a port city, a special schedule might include

only survey bands with assignments for maritime communications (this was not, however, the

case for San Francisco). Any number of special schedules can be run during a survey.

Tables A-3 and A-4 show the standard band event schedules for RSMS System-1 and System-2,

respectively. Tables A-5 and A-6 show special band event schedules for measurements in survey

bands expected to show altered usage during adverse weather. The tables include: (1) schedule

number;2 (2) band event number (specifies which band event to execute in the sequence);

(3) priority number (value assigned to the band event data, with "1" being the highest priority);

(4) event time (approximate time in minutes needed to run the event); and (5) accumulative time

(approximate time in hours that the schedule has run).

Band event priority is an important consideration when scheduling standard band events; i.e.,

some frequency bands in a spectrum survey are of more interest to spectrum managers than

others. In fact, an important part of the preparation for a spectrum survey is a review of local

frequency assignments and allocations. From this preliminary information, measurement

parameters may be modified and band event priority numbers (1, 2, or 3, with 1 being highest

priority) adjusted to optimize survey data.

Highly dynamic bands (where occupancy changes rapidly) include those used by mobile radios

(land, marine, and airborne) and airborne radars. These bands are assigned a high priority and

are measured often during a spectrum survey in order to maximize opportunities for signal

detection. Bands that are not very dynamic in their occupancy (such as those occupied by

commercial radio and television signals or fixed emitters such as air traffic control radars) need

not be observed as often, because the same basic occupancy picture will be generated every time.

Such bands are given a low priority and less measurement time. An extreme case is that of the

common carrier microwave bands, which are essentially nondynamic. Generally, these are only

measured once during a survey and are not included in the band event automatic measurement

schedules.

2

Schedule numbers are assigned sequentially from 1 to 64. The system software supports only

64 band events in a schedule; however, there is no limit on how many times the schedule

executes during a survey.

101
Table A-3. Standard Band Event Schedule for RSMS System-1

Schedule

Number

Band Event

Number

Priority

Number

Event Time

(minutes)

Accumulative

Time (hours)

1 12 1 16.3 0.27

2 11 2 10.3 0.44

3 17 1 10.8 0.62

4 14 2 5.1 0.71

5 13 3 5.8 0.81

6 19 1 10.8 0.99

7 22 2 10.8 1.17

8 20 1 13.8 1.40

9 23 2 5.3 1.48

10 25 1 20.0 1.82

11 18 2 6.7 1.93

12 12 1 16.3 2.20

13 16 3 3.4 2.26

14 17 1 10.8 2.44

15 24 2 6.7 2.55

16 19 1 10.8 2.73

17 11 2 10.3 2.90

18 20 1 13.8 3.13

19 14 2 5.1 3.22

20 25 1 20.0 3.55

21 21 3 7.3 3.67

22 12 1 16.3 3.94

23 22 2 10.8 4.12

24 17 1 10.8 4.30

25 23 2 5.3 4.39

26 15 3 8.3 4.53

27 19 1 10.8 4.71

28 18 2 6.7 4.82

29 20 1 13.8 5.05

30 24 2 6.7 5.16

31 25 1 20.0 5.50

102
Table A-4. Standard Band Event Schedule for RSMS System-2

Schedule

Number

Band Event

Number

Priority

Number

Event Time

(minutes)

Accumulative

Time (hours)

1 05 3 5.6 0.09

2 06 3 42.0 0.79

3 07 2 8.6 0.94

4 08 2 12.7 1.15

5 09 1 37.2 1.77

6 11 3 3.0 1.82

7 13 3 18.0 2.12

8 14 2 42.0 2.82

9 15 2 42.0 3.52

10 17 3 5.6 3.61

11 19 3 5.6 3.71

12 20 2 49.0 4.52

13 23 2 49.0 5.34

14 25 1 25.0 5.76

15 27 1 52.0 6.62

16 05 3 5.6 6.72

17 09 1 37.2 7.34

18 17 3 5.6 7.43

19 19 3 5.6 7.52

20 25 1 25.0 7.94

21 27 1 52.0 8.81

22 05 3 5.6 8.90

23 07 2 8.6 9.04

24 08 2 12.7 9.25

25 09 1 37.2 9.87

26 11 3 3.0 9.92

27 14 2 42.0 10.62

28 15 2 42.0 11.32

29 17 3 5.6 11.42

30 19 3 5.6 11.51

103
The standard band event schedules are arranged to execute priority 1 events three times more

Table A-5. Adverse Weather Band Event Schedule for RSMS System-1

Schedule

Number

Band Event

Number

Priority

Number

Event Time

(minutes)

Accumulative

Time (hours)

1 12 1 16.3 0.27

2 11 2 10.3 0.44

3 12 1 16.3 0.72

4 14 2 5.1 0.80

Table A-6. Adverse Weather Band Event Schedule for RSMS System-2

Schedule

Number

Band Event

Number

Priority

Number

Event Time

(minutes)

Accumulative

Time (hours)

1 09 1 37.2 0.62

2 23 2 49.0 1.44

3 05 3 5.6 1.53

4 17 3 5.6 1.62

5 20 2 49.0 2.44

6 14 2 42.0 3.14

7 13 3 18.0 3.44

often than priority 3 events. However, some adjustment to this arrangement is necessary to

accommodate total time required to complete the sequenced band event schedule. For example,

if less than two weeks of measurement time is available, a time-consuming priority 1 event (such

as Band Event 27 in Table A-4) cannot be run three times more often than priority 3 events if

all bands are to be measured adequately.

Because of the many land mobile radio (LMR) bands below 1 GHz, System-1 scheduling reflects

some preplanning for time-of-day analysis. The sequenced schedule is prepared so that all events

will be run within an 8-hr period; such that, after a few days of 24-hr data collection certain

LMR bands will be measured at least once during each hour.

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APPENDIX B: INTERPRETATION OF SPECTRUM SURVEY DATA

B.1 INTRODUCTION

Institute for Telecommunication Sciences (ITS) radio spectrum measurement system (RSMS)

spectrum survey measurements are performed with a variety of receiver algorithms (see Section

D.2 of Appendix D). These algorithms provide various combinations of frequency-sweeping or

frequency-stepping, positive-peak or sample detection, and data-processing capabilities during the

data acquisition phase of the spectrum survey. Additional processing is performed on the data

after the acquisition phase. Measurement algorithms are assigned on an individual basis to

optimally measure spectrum use in each band.

Each algorithm has a particular response to noise and signal activity. It is critical to understand

the noise and signal response of each algorithm if the RSMS data are to be used accurately. This

appendix describes the algorithms currently used for RSMS spectrum surveys. The noise and

signal response of each algorithm is described, along with the types of spectrum occupancy it is

best suited to measure. Some of the data-processing techniques also are discussed to fully

explain the measurement algorithms.

B.2 SIGNAL PROBABILITY-OF-INTERCEPT FACTORS

RSMS measurements are intended to achieve a high probability of intercept for the types of

signal activity occurring in each spectral band. Factors that are considered include:

the types of emitters allocated to the band (e.g., land mobile radio, radiolocation,

or broadcasting);

the percentage of time individual transmitters in the band typically operate (e.g.,

100% on-air time by broadcasters vs. intermittent radio dispatch messages);

the dependence (or nondependence) of band activity on diurnal and other cyclic

occurrences (e.g., radionavigation beacons with no time dependence vs. marine

mobile activity which varies as a function of time of day, day of week, and

weather conditions);

the time interval that individual transmissions usually occupy (e.g., air traffic

control communications vs. cellular telephone communications);

the periodicity, if any, of individual transmissions (e.g., a highly periodic search

radar beam that completes a rotation every 4 s vs. mobile communications that

occur in a random distribution over time);

the directional gain, if any, of antennas used by the transmitters (e.g., an omnidirectional navigation beacon vs. a point-to-point microwave link);

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the typical peak and average power outputs of transmitters in the band (e.g,

4-MW peak power from a radar vs. a fraction of a watt from a personal cellular

telephone);

the signal amplitude duty cycle (e.g., a 30-dB duty cycle for a typical radar vs.

a near 0-dB duty cycle for a two-way radio transmission);

the relative abundance or paucity of systems using the band (e.g., a band used

largely by airborne fire-control radars vs. a band used by thousands of local

voice-communication radios); and

the polarization of typical transmitted signals in the band.

These factors are used to optimize the receiver parameters for the selected band, to select the

measurement algorithm, and to determine how measurement time should be allocated. The

relative amount of time devoted to measure each band is roughly proportional to the dynamics

of band usage. For example, point-to-point microwave bands are not very dynamic because the

transmitters in these bands normally operate 24 hrs/day, 365 days/year, at uniform power levels,

fixed modulations, and fixed beam directions. Their operations are not normally affected by

external factors, such as weather or local emergencies. Consequently, these bands are measured

only once during a spectrum survey. In contrast, activity in land mobile radio bands is highly

dynamic, varying significantly with time of day, day of week, and other factors such as local

emergency conditions. Consequently, these bands are measured frequently throughout a site

survey, so that a maximal number of time-dependent signals will be intercepted. Slightly less

dynamic bands, such as those used by tactical radars, are measured less frequently than the

mobile bands, but more frequently than the point-to-point microwave bands. Bands whose use

varies with local weather, such as those used by weather radars, may be measured on different

clear-weather and foul-weather schedules.

Swept-spectrum measurement techniques are used in highly dynamic bands. Stepped-spectrum

techniques are used in bands occupied by periodic emitters, such as radars. A slow-rotating dish

antenna sweep of the horizon coupled with simultaneous swept-spectrum measurements is used

in point-to-point microwave bands. These measurement techniques are detailed in the following

subsections.

A parabolic antenna is used to measure signals from fixed-beam, highly directional transmitters

in the point-to-point microwave bands (see the description of azimuth scanning in Section B.8).

For bands in which signals are expected to originate primarily from a single quadrant as seen

from the RSMS location, a moderately directional antenna (such as a cavity-backed spiral or a

log-periodic antenna) is used. For bands in which signals are expected to originate from any

direction with an approximately constant probability, such as bands used by airborne beacon

transponders and air-search radars, the RSMS uses omnidirectional antennas.

Slant polarized antennas are used for all RSMS measurements except those in the point-to-point

microwave bands. Slant-polarized biconical omnidirectional antennas are usually used for

measurements at frequencies above 1 GHz, and slant-oriented log-periodic or conical

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omnidirectional antennas are usually used below 1 GHz. Slant polarization provides adequate

response to all signals except those having a slant direction orthogonal to the RSMS antennas.

Orthogonally oriented slant-polarized signals are rare. In the point-to-point microwave bands,

the transmitted signals are always vertically or horizontally polarized, and thus RSMS receive

polarization in those bands is alternately vertical and horizontal, with the results being combined

into a composite scan.

The end result of these selections (number of measurements made in each band, selection of

antenna type and polarization, and selection of measurement algorithm) is to optimize the

probability of intercept for signals present during the course of the RSMS site survey. Inevitably,

some signals will be missed; however, the standard RSMS spectrum survey data set should

provide a statistically useful measure of the relative number, levels, and types of signals in each

of the bands between 108 MHz and 19.7 GHz.

B.3 OVERVIEW OF SWEPT MEASUREMENT TECHNIQUES

The HP-8566B spectrum analyzers1 used in the RSMS sweep across the spectrum in individual

segments that are called spans. The frequency range of each span is in turn broken into 1001

individual frequency bins. When the spectrum analyzers perform sweeps across a selected span,

they spend a finite amount of time measuring received power in each of the 1001 bins. For

example, a 20-ms sweep time divided by 1001 measurement bins per sweep yields a 20-μs

measurement time in each frequency bin. Within each bin measurement interval (in this example,

20 μs), the power measured in the waveform may take on multiple values. However, the

spectrum analyzer can only provide a single power measurement per bin.

The single value derived from the multiple values occurring within each bin-sampling interval

depends upon the particular spectrum analyzer detector mode selected. The modes available in

the RSMS spectrum analyzers are positive peak, negative peak, sample, and "normal." (Note:

positive peak detection is different from the maximum-hold display mode discussed in

Section B.6.) Positive peak detector mode will latch to the highest power value attained by the

measured waveform during the sampling interval (continuing the example above, this would be

20 μs) for each bin. Similarly, the negative peak detector mode latches to and displays the

lowest power level measured during each bin interval. In sample detector mode, the value

displayed is the power level that the input waveform has assumed at the end of the bin

measurement interval. If the bin sampling interval is uncorrelated with respect to the input

waveform, this value can be considered to be randomly selected from the input waveform.

Finally, in "normal" detection mode, alternate bins use positive peak and negative peak detection.

If the analyzer’s video bandwidth is substantially narrower than the IF bandwidth, and if a white

noise source (such as thermal electron noise in a circuit or a noise diode) is being measured, then

1

Commercial equipment is identified to accurately describe the RSMS measurements. Such

identification implies neither an endorsement by NTIA nor a recommendation that the equipment

is best for the application.

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an average value of the noise will be displayed irrespective of the detector mode that has been

selected.

If the analyzer’s video bandwidth is equal to or greater than the IF bandwidth, and if a white

noise source is being measured, then the displayed power level will vary as a function of the

detector mode. Positive peak detection will display noise values approximately 10 to 12 dB

higher than the RMS noise level, and negative peak will display values about 10 to 20 dB below

the RMS noise level. "Normal" detection used on such a noise source will display an illuminated

band about 20 to 30 dB wide, with an average value approximately equal to the RMS level of

the noise. Normal detection mode is useful for estimating the variability of a signal.

B.3.1 Description of the Swept/m3 Measurement Algorithm

The swept/m3 algorithm, developed by ITS, is an extension to the swept measurements just

described. In swept/m3 mode, frequency-domain data traces are measured repeatedly across a

band on the spectrum analyzer. Each sweep is returned individually to the control computer, but

the data traces are not individually recorded. Instead, for each of the 1001 frequency bins that

the analyzer returns in each sweep, the computer sorts the returned values as follows: the value

in each bin is compared to the highest and lowest values so far observed in that bin, and if the

new value represents a new maximum or minimum in that bin, then it is saved as such. (This

is, in effect, a software-implemented version of maximum-hold and minimum-hold trace mode.)

Also, the current value of each bin is included in a running average of all the values returned for

that bin in previous sweeps. This is an average of measured power in the selected detector mode

(i.e., the decibel values are averaged). Thus, the maximum, minimum, and mean (m3) signal

levels in a band are simultaneously obtained over the time interval (typically several minutes) that

the spectrum analyzer continues sweeping. This real-time cumulative (cuming) process

compresses data volume by several orders of magnitude, but the compression causes loss of the

original data sweeps, and thus precludes the possibility of processing the original data sweeps

with different algorithms during postmeasurement analysis. Figure B-1 shows how the swept/m3

cumulative processing is integrated with the normal RSMS processing path. All other cumulative

processing is accomplished during postmeasurement analysis.2 In the diagram, all measured data

identified as "RSMS data output for lab analysis" is considered to be postmeasurement data.

B.4 DESCRIPTION OF SWEPT/M3/SAMPLE DATA COLLECTION

If the swept/m3 algorithm (described in Subsection B.3.1) is performed using the sample detector

(see Section B.3 for a description of the sample detector in the RSMS analyzers), then the data

are referred to as "swept/m3/sample."

2

All band events measured more than once during the same survey are cumulated (cumed) as

explained in this appendix. Stepped and swept data records are cumed for maximum, mean, and

minimum received signal levels. Swept/m3 data already contains this information, so a maximum

of maximums, mean of means, and minimum of minimums is extracted for survey graphs.

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Figure B-1. Functional diagram of the RSMS signal-processing path for measured data.

B.4.1 Interpretation of Noise Responses in Swept/m3/Sample Data

The noise level displayed by a measurement system using the sample detector will be equal to

[kTB + (measurement system noise figure)].3 With a 1-MHz IF bandwidth and a 10-dB

measurement system noise figure, for example, the average noise level would occur at −104 dBm.

3

kTB is derived from the Nyquist Theorem for electron thermal noise, where: k is Boltzmann’s

constant (1.38 × 10-20 mW × s/K), T is system temperature (290 K for these measurements), and

B is measurement IF bandwidth in Hz. For B = 1 Hz, at room temperature: kTB = −174 dBm.

In a 1-MHz IF bandwidth, kTB = −174 + 10log(106) = −114 dBm.

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If the video bandwidth (that is, the postenvelope detector, low-pass filtering bandwidth) is

significantly narrower than the IF bandwidth, then the variance in the measured average noise

will be very small (approximately 1 dB). This mode normally is used only for calibrations in

the RSMS.

However, if the video bandwidth is set to a value equal to or greater than the IF bandwidth

(which is the case for RSMS spectrum survey measurements), then the maximum level sampled

on thermal noise will be about 10 to 12 dB above the average, and the minimum level sampled

on thermal noise will be about 10 to 20 dB below the average.

B.4.2 Interpretation of Signal Responses in Swept/m3/Sample Data

Because the sample detector value displayed for each bin is the value of the waveform at the end

of each bin interval, the value displayed for a signal with a duty cycle of 100% will be equal to

the peak power of the signal (if the signal was present for the entire bin interval). However, if

a signal has less than a 100% duty cycle (and is not present during the entire bin interval), then

the probability that the signal will be sampled is less than 1. For example, if the signal is only

present for half of the bin interval, there is only a 50% chance that the sample detector will

capture the value of the signal (and a 50% chance that the measurement system’s thermal noise

will be displayed). For typical radar signals, which operate with a duty cycle of about 1:1000,

the probability that a bin will display the radar signal value is only about 1/1000 (0.1%). The

same rationale holds for impulsive noise; sample detection mode tends to display high-duty cycle

signals, but not low-duty cycle signals such as radars and impulsive noise. This makes sample

detection a desirable option for measurements in bands handling mobile communications, where

the signals of interest have high duty cycles, and where measurement of impulsive noise is not

desirable for the purposes of the RSMS project.

For swept/m3/sample data, the highest curve shows the maximum signal ever captured by the

sample detector on any trace at each measured frequency. This represents the highest value ever

attained by high-duty cycle signals at each measured frequency; impulsive energy could have

been present at even higher values, but would have been discriminated against by the sample

detector. At frequencies where no signal was ever measured, the maximum curve will have a

value of kTB + measurement system noise figure + (typically)10 dB. This value will be 10 dB

higher than the average noise (middle) curve. Since a signal displayed on the maximum curve

can occur with different amplitudes at different times, there is no way to determine, solely from

examination of the maximum curve, how frequently the displayed signals were measured.

The middle curve of swept/m3/sample data shows the power average (average of the measured

decibel values) of all of the raw data traces gathered in the band. Qualitatively, the closer this

curve comes to the maximum curve at any given frequency, the higher the percentage of scans

in which the signal was observed. Quantitatively, it is not possible to derive an actual percentage

of scans in which the signal was present. This is because the signal may not always have been

received at the same level, and the level received on raw scans is not recorded. If, however, the

average curve comes close to touching the maximum curve, then the signal must have been

present in nearly 100% of the raw data traces. Conversely, if the maximum and mean curves are

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far apart, then the signal probably was observed in a lower percentage of raw data scans. If no

signals were ever measured at any given frequency, then the middle curve will show

measurement system noise at a value of kTB + measurement system noise figure (about 10 dB

below the maximum noise curve).

Finally, the lowest curve shows the minimum power level measured in any raw data trace, at

each measured frequency bin. If no signal is measured in a bin during any sweep, then this

curve will have a value of: kTB + measurement system noise figure − (10 to 20 dB). This is

10 to 20 dB lower than the average curve. If a signal is present in 100% of the measurement

sweeps, then a bump will occur in the minimum curve at that frequency. The amplitude of the

bump will be equal to the minimum power measured for the signal. Thus, this curve serves the

purpose of showing signals that are continuously present during the spectrum survey.

In this report, the nominal levels of the measurement system noise for the maximum, minimum,

and mean curves are indicated by labeled tick marks on the y-axis of each swept/m3/sample

graph. The tick marks, labeled "max sample noise," "mean sample noise," and "min sample

noise," are intended to assist report users in determining which graphed features are signal

responses and which graphed features are measurement system noise.

B.5 DESCRIPTION OF SWEPT/M3/+PEAK DATA COLLECTION

If the swept/m3 algorithm is performed using the positive peak (+peak) detector (see Section B.3

for a description of the +peak detector in the RSMS spectrum analyzers), then the data are called

"swept/m3/+peak."

B.5.1 Interpretation of Noise Responses in Swept/m3/+Peak Data

The average noise level displayed by a measurement system using a +peak detector will be equal

to kTB + measurement system noise figure + approximately 10-12 dB. With a 1-MHz IF

bandwidth and a 10-dB measurement system noise figure, for example, the average +peak noise

level would occur at −174 dBm/Hz + 10log(106 Hz) + 10-dB noise figure + 10-dB peak detector

offset = −94 dBm.

If the video bandwidth (the postenvelope detector, low-pass filtering bandwidth) is equal to or

greater than the IF bandwidth (which is the case for RSMS site survey measurements), and if the

sweep time is short (a few tens of microseconds per bin), then the maximum level sampled on

thermal noise will be about 10 dB above the average; the minimum level of thermal noise will

be about 10 dB below the average. Note that this ±10-dB value for maximum and minimum

levels of +peak noise is the same as the ±10-dB offset levels for sample detection; however the

maximum, mean, and minimum peak-detected levels are 10 dB higher than the corresponding

sample-detected levels.

Positive peak detection shows less than a ±10-dB difference between the maximum, mean, and

minimum as sample times increase (i.e., as sweep times become longer). This is because the

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positive peak detector will have a higher probability of latching to a high noise level if it samples

the noise for a relatively long interval. In this case, the minimum and average noise levels will

approach the maximum noise level to within a few decibels. The maximum will be 2 to 3 dB

higher than the short sweep-time values.

B.5.2 Interpretation of Signal Responses in Swept/m3/+Peak Data

Because the +peak detector latches to the highest value that the waveform assumes during each

bin interval, the value displayed for a signal will be equal to the peak power of the signal

(assuming that the measurement system is not bandwidth-limited in its response) regardless of

the signal’s duty cycle. This makes +peak detection mode useful for measuring impulsive

activity such as radar signals. (This means that +peak detection also will record impulsive noise

in the spectrum.) Thus, the +peak detector is used in RSMS spectrum surveys to measure

radiolocation bands and other bands where activity is dominated by impulsive (low-duty cycle)

transmissions.

For swept/m3/+peak data, the highest curve shows the maximum signal ever captured by the

+peak detector on any trace in each measured frequency bin. At frequencies at which no signal

was ever measured, the maximum curve will have a value of kTB + measurement system noise

figure + about 10-dB peak detector offset + 10 dB. If the sweep time is short (a few tens of

microseconds per bin), this will be about 10 dB higher than the average peak detector response.

If the sweep time is much longer, the average will be higher, coming to within a few dB of the

maximum. There is no way to determine, solely from examination of the maximum curve, how

frequently the displayed signals were observed.

The middle curve of swept/m3/+peak data shows the power average (average of the antilogs of

1/10 the measured decibel values) of all the data traces that were gathered in the band.

Qualitatively, the closer this curve comes to the maximum curve at any frequency, the higher the

percentage of scans in which the signal was observed. Quantitatively, it is not possible to derive

a percentage of time the signal was present, because the signal may not always be received at

the same level. If, however, the average curve nearly touches the maximum curve, then the

signal must have been present in nearly all of the raw data traces. Conversely, if the maximum

and mean curves are far apart, then the signal was probably observed in a low percentage of

scans. If no signals were measured at a frequency, and if sweep time is a few tens of

milliseconds, the middle curve will show measurement system noise at a value of kTB +

measurement system noise figure + about 10-dB peak detector offset. This value will be nearly

10 dB higher if the sweep time is appreciably longer.

Finally, the lowest curve shows the minimum power level measured with the +peak detector in

any sweep, in each frequency bin. If no signal is measured at a frequency, and if the sweep time

is a few tens of milliseconds, this curve will have a value of: kTB + measurement system noise

figure + about 10-dB peak detector offset - 10 dB, which is 10 dB lower than the mean peak

detector curve. If the sweep time is longer, the minimum curve will approach the maximum and

mean curves. If a signal is observed at a frequency in every data sweep, then a bump will occur

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in the minimum curve at that frequency. Thus, this curve shows signals that are present

continuously during the spectrum survey.

In this report, the nominal levels of the measurement system noise for the maximum, minimum,

and mean curves are indicated by tick marks on the y-axis of each swept/m3/+peak graph. The

tick marks, labeled "max +peak noise," "mean +peak noise," and "min +peak noise," are intended

to assist report users in determining which graphed features are detected signals and which

graphed features are measurement system noise.

B.6 DESCRIPTION OF SWEPT/MAX-HOLD DATA COLLECTION

If a frequency-sweeping algorithm is performed using the +peak detector (see Section B.3 for a

description of the +peak detector in the RSMS spectrum analyzers) while the spectrum analyzer

display is being operated in the Maximum-Hold mode,4 then the data are referred to as

"swept/max-hold."

The measured data are peak-detected, maximum-hold scans. Each scan represents an interval of

a few minutes of maximum-hold running on the measurement system. The scans do not contain

mean or minimum information. They are intended only to show the presence of intermittent,

low-duty cycle signals, and therefore no additional information is obtained.

The individual scans are cumed for the site survey report, and as a result, the final graphs show

maximum, minimum, and mean curves. However, the distribution of maximum-hold data is

narrow when noise is being measured, and so the difference between these curves is only about

±3 dB on noise, instead of the ±10 dB difference which usually characterizes swept/m3 data.

B.6.1 Interpretation of Noise Responses in Swept/Max-Hold Data

The maximum, mean, and minimum curves displayed by a measurement system will be nearly

identical if the hold time is more than a few tens of microseconds per bin. If white noise is

measured, the three curves will all have a value of about kTB (at room temperature) +

measurement system noise figure + about 10-dB peak detector offset + 10 dB. With a 1-MHz

IF bandwidth and a 10-dB measurement system noise figure, for example, the noise level is about

-174 dBm/Hz + 10log(106 Hz) + 10-dB noise figure + 10-dB peak detector offset + 10 dB =

-84 dBm.

If the video bandwidth is equal to or greater than the IF bandwidth, then the maximum level

sampled on thermal noise in maximum-hold mode is empirically observed to limit at about 2 dB

4

In Maximum-Hold mode, the spectrum analyzer repeatedly sweeps a portion of spectrum, and

saves the highest value measured in any sweep in each screen display bin. Thus, Maximum-Hold

mode generates a maximum-level trace which is analogous to the maximum-level trace generated

by RSMS software in the Swept/m3/+peak mode.

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above the mean of the maximum, and the minimum level sampled on thermal noise is about 2 dB

below the mean of the maximum.

B.6.2 Interpretation of Signal Responses in Swept/Max-Hold Data

Swept/max-hold measurement mode is ideal for capturing low-duty cycle signals from

intermittently operating systems. It can be used in bands occupied by impulsive emitters that

operate intermittently (e.g., airborne radars). A swept/max-hold measurement displays the

maximum activity observed in a band for an interval of a few minutes. No information is

collected to indicate mean or minimum activity during that interval.

For cumed swept/max-hold data, the highest curve shows the maximum signal ever captured by

the +peak detector on any maximum-hold trace at each measured frequency. Since a signal

displayed on the maximum curve could have occurred with different amplitudes at different

times, there is no way to determine, solely from examination of the maximum curve, how

frequently the displayed signals were actually observed.

The middle curve of cumed swept/max-hold data shows the power-average (average of the

antilogs of 1/10 the measured decibel values) of all individual maximum-hold data traces that

were measured in the band. Qualitatively, the closer this curve comes to the maximum curve at

a frequency, the higher the percentage of scans in which the signal was observed. Quantitatively,

it is not possible to derive an actual percentage of time that the signal was present, because the

signal may not have always been received at the same level. If the mean curve nearly touches

the maximum curve, then the signal must have been present in most of the raw data traces. If

no signals were ever measured at any given frequency, then the middle curve will be about 3 dB

lower than the maximum curve.

Finally, the lowest curve shows the minimum power level ever measured with the +peak detector

in any maximum-hold data trace, at each measured frequency. If a signal was present in every

scan, then the curve shows a bump at that frequency. Otherwise, the curve will show noise 3 dB

below the mean curve. Thus, this curve shows signals that were present in all of the scans.

B.7 DESCRIPTION OF STEPPED/+PEAK DATA COLLECTION

Although most spectrum analyzers routinely are operated by sweeping in the frequency domain,

this is not the most efficient method for measuring spectral emissions from pulsed emitters like

radars. An alternative method, called stepping, is usually faster and can provide measurement

results with wider dynamic range than is possible with sweeping.

Stepping is performed by tuning the measurement system to a frequency and then performing a

time-scan at that frequency over a span of zero hertz. In this mode, the spectrum analyzer makes

1001 measurements at equally spaced time intervals during the selected scan time. Positive peak

detection is always used. For rotating radars, the interval (called dwell time) for a single timescan is set equal to or greater than the radar rotation time. (For electronically beam-scanning

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radars, this interval is selected on the basis of the typical recurrence of the radar beam at the

measurement site.) For example, if a radar has a 10-s rotation time, then the dwell time at each

measured frequency might be set to 12 s. Thus, the emitter’s rotating main beam certainly would

be aimed in the direction of the measurement system at some moment during the 12-s time scan.

At the end of the dwell period, the highest-amplitude point that was measured is retrieved,

corrected for calibration factors, and stored. This process of waiting at a frequency in a 0-Hz

span and recording the highest point measured during a radar rotation (or beam-scanning) interval

is called a "step." When each step is completed, the measurement system is tuned to another,

higher frequency, and the process is repeated. Attenuation can be added or subtracted at the

RSMS signal input at each measurement step. Thus, the instantaneous dynamic range of the

RSMS, (normally about 60 dB) can be augmented by the amount of input attenuation that is

selected. Maximum available attenuation is 50-70 dB (depending upon which frontend is

selected), giving a total RSMS measurement range of about 110-130 dB.

The spectrum interval between adjacent measured frequencies is approximately equal to the IF

bandwidth of the measurement system. For example, if a 1-MHz IF bandwidth is being used,

then the frequency interval between steps will be about 1 MHz. The IF bandwidth is determined

from the inverse of the emitter pulse width. For example, if 1 μs is the shortest pulse width

expected from emitters in a band, then a 1-MHz measurement (IF) bandwidth is used. In this

manner, the measurement system progressively tunes across the band of interest.

Stepped measurements are used for all dominantly radiolocation (radar) bands. IF bandwidth and

dwell times are optimized for typical radars in the band. The individual stepped measurement

scans are cumed for spectrum surveys and the final graphs show a maximum, minimum, and

mean value for each dwell time at each measured frequency during the entire survey.

B.7.1 Interpretation of Noise Responses in Stepped/+Peak Data

The mean noise level displayed by the measurement system in the +peak detector stepped mode

will be equal to kTB (at room temperature) + measurement system noise figure + 10-dB peak

detector offset. With a 1-MHz IF bandwidth and a 10-dB measurement system noise figure, for

example, the mean +peak noise level is -174 dBm/Hz + 10log(106 Hz) + 10-dB noise figure +

10-dB peak detector offset = -94 dBm.

The difference between the maximum and minimum levels measured for noise in the stepped

mode is small; the maximum and minimum curves will be about ±2 dB relative to the mean

curve.

B.7.2 Interpretation of Signal Responses in Stepped/+Peak Data

Stepped/+peak measurement mode is ideal for capturing low-duty cycle signals from systems that

direct energy at the measurement site at regular intervals (e.g., rotating radars). If the dwell time

is greater than or equal to the rotation time of the radar, then the stepped algorithm will fill the

emission envelope completely.

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The maximum curve on each site survey graph for stepped measurements depicts the maximum

envelope of the spectral emissions of the emitters observed in the band. The result is a

representation of the spectrum occupancy when emissions (usually radar beams) are directed at

the measurement site.

The minimum curve represents the lowest signal ever measured at each frequency step during

the survey. If an emitter is turned off during a single scan, then this curve will be at the system

noise level for that emitter. At frequencies where this curve is above the noise level, but well

below the maximum curve, the difference represents either varying emitter power output levels,

varying emitter-scanning modes, varying propagation between the emitter and the measurement

site, or a combination of these factors.

The mean curve represents the mean power (the average of the antilogs of 1/10 the decibel values

of received signal level) for each frequency step in the band of interest during the site survey.

This is not necessarily the same as the mean signal level transmitted by a radar to the measurement location. For example, a radar that was turned on during half the stepped scans, and turned

off during the other half would appear, after cuming, with a maximum curve that is its emission

envelope, a minimum curve that is the measurement system noise floor, and a mean curve

roughly 3 dB below the radar envelope. However, the radar might never have been measured

at the amplitudes shown on the mean curve.

B.8 DESCRIPTION OF SWEPT/AZ-SCAN DATA COLLECTION

In bands dominated by point-to-point fixed microwave communication systems, the transmitter

main beams are seldom pointed towards the RSMS. To enhance the probability of intercepting

low-level sidelobe and backlobe signals from these sources, a high-gain parabolic reflector with

a linear horizontal and vertical cross-polarized feed antenna is used. However, the site survey

data must include signals received from all points on the horizon; so, azimuth-scanning with the

parabolic reflector (dish) antenna is performed. The RSMS dish is pointed at the horizon and

slowly rotated through 360°. Simultaneously, a spectrum analyzer sweeps the band of interest

with positive peak detection and maximum-hold scan mode. Such measurements are called

"swept/az-scan."

The dish antenna is rotated at approximately 6°/s (1 rpm), while the sweep time across the band

is set at 20 ms. At the highest frequencies, where the dish beamwidth is about 1°, the dish

rotates through one beamwidth in 1/6 s (170 ms). This is long enough for 7 or 8 sweeps

(170 ms/20 ms) within the beam width. Thus, every point on the horizon is sampled at least 7 or

8 times across the entire band of interest. Maximum-hold mode and positive peak detection

ensure that any signal that arrives at the RSMS site is retained on the scan.

The dish is rotated twice around the horizon: once with horizontal polarization and once with

vertical polarization. The purpose is to observe point-to-point linked signals of either

polarization. The two polarization scans are combined to show the maximum envelope of both

scans on a single data curve.

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The single data curve is corrected for noise diode calibration factors and recorded. Unlike other

RSMS site survey measurements, this measurement is performed only once at each survey

location and no cuming is performed on this data. Activity in these bands does not vary much

with time and little information is gained by measuring these bands repetitively.

B.8.1 Interpretation of Signal Responses in Swept/Az-Scan Data

Swept/az-scan data show the presence of a signal at some point or points on the horizon. The

data curve does not reveal the direction of any signals, but does show the aggregate occupancy

of the spectrum by all point-to-point signals detected omnidirectionally on the horizon.

Generally, two types of signals will be noted in the az-scan graphs: those having narrow

emission spectra, and those having wider emissions. The narrow signals are analog links, and

the wider signals are digital links. Because a single transmitting tower (a single point on the

horizon) may have many channels in operation (often located next to each other in the spectrum),

clusters of signals with uniform amplitudes will be observed. Space-to-earth and earth-to-space

links in these bands normally are not detected by the RSMS.

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APPENDIX C: RADIO SPECTRUM MEASUREMENT SYSTEM

C.1 INTRODUCTION

The NTIA/ITS radio spectrum measurement system (RSMS) is a mobile, self-contained

computer-controlled radio-receiving system capable of many measurement scenarios over a

frequency range of 30 MHz to 22 GHz. Figure C-1 is a view of the RSMS with telescoping

masts raised and antennas mounted for a broadband spectrum survey at a remote field site. This

appendix contains particulars on the vehicle, instrumentation, and operation of the RSMS when

it is deployed for broadband spectrum survey measurements.

C.2 VEHICLE

For maximum effectiveness, a spectrum measurement system must be readily transported to field

locations that may lack sheltering structures or commercial power. In such cases, the

measurement system must be deployed with its own shelter and its own power source. To meet

this need, the measurement system, including antennas and support hardware, is carried in a

shielded, insulated, climate-controlled shell mounted on a Chevrolet truck cab and chassis. The

RSMS is the assembled measurement system and vehicle unit. The vehicle has four-wheel drive,

and a low-geared transmission for use on rough terrain and steep grades. The RSMS is

sufficiently small and light enough to fit on C-130 or larger aircraft for rapid transport over long

distances.

Figure C-2 shows the internal layout of the RSMS. Four 5 ft-2 in high equipment racks are

located transversely above the rear axle. These racks divide the box-like equipment compartment

into two parts: one in front and one behind the racks. The forward area comprises the operator’s

compartment with access to the equipment front panels, the main power panel and breaker box,

work counters, two chairs, telephone, fax machine, and a cellular fax/modem. A built-in safe

below the equipment racks provides storage for classified materials. A full-height cabinet in the

forward driver’s side corner provides for storage of small, frequently used items. A compartment

for the smaller of two telescoping masts is located behind this cabinet, and is accessed from

outside the van.

Additional storage cabinets are available to the rear of the racks for larger and less-used items.

Compartments for the large mast and the external-tap power cable and its electrically driven reel

are located behind these cabinets, with outside access. The weight of the mast-rotator, power

cable, and reel is counterbalanced on the driver’s side by the 10-kW generator and two air

conditioners. The rear area provides access to the back of the equipment racks. The generator

compartment is serviceable via an outside lift-up panel. The air conditioners are not operator

accessible.

The shielded, windowless measurement compartment provides radio frequency (rf) isolation

between the measurement system and the outside environment. This shields equipment and

personnel from high-level fields, as well as preventing internal computer noise from contaminating the measurements. The small working compartment also reduces requirements for air119
Figure C-1. ITS radio spectrum measurement system with telescoping masts raised and antennas

mounted for a broadband spectrum survey at a remote field site.

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Figure C-2. Top and side view drawings of the RSMS.

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conditioning and heating. Both of the telescoping masts are installed on rotators (at their bases)

and will raise the antennas to a little over 8 m above ground.

C.3 INSTRUMENTATION

The RSMS normally is configured as two independent spectrum measurement systems: one

optimized to measure lower frequency portions of the spectrum (System-1), and the other to

measure higher frequencies (System-2), with some frequency overlap between the two systems.

Figure C-3 is a fish-eye front panel view of the rack mounted instrumentation. Measurement and

control instruments for System-1 are in the two racks on the right of center; and for System-2,

they are in the two racks left of center. Both systems use rf frontends that incorporate dynamic

rf attenuation, low-noise preamplification and tunable frequency preselection. These features

allow the RSMS to achieve the best possible combination of dynamic range, sensitivity, and offtuned signal rejection in its measurements.

Figure C-3. Front panel of the ITS radio spectrum measurement system instrument racks.

For spectrum surveys, the low-frequency system usually is operated between 100 MHz and

1 GHz, with its antenna(s) mounted on the smaller forward mast and its rf frontend located inside

the operator’s compartment. The high-frequency system is used for the remaining survey

frequencies from 1 to 19.7 GHz, with its antenna(s) mounted on the larger mast and its rf

frontend located at the top of that mast to overdrive the higher line losses that occur above

1 GHz. The RSMS receiver is depicted as a block diagram in Figure C-4. As the diagram

shows, both the high and low frequency systems are designed around a Hewlett-Packard 8566B

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spectrum analyzer (0 to 22 GHz), although the RSMS software will control other spectrum

Figure C-4. Block diagram of the RSMS receiver.

analyzers, such as the HP-70000 series. The selection of 1 GHz as the break point between the

two systems in a site survey mode is determined primarily by the availability of antennas, which

often begin or end their frequency response around 1 GHz.

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Each of the measurement systems can be controlled in fully automatic, semiautomatic, and fully

manual modes. In fully automatic operation, each system is controlled by ITS-written software

(named DA, for Data Acquisition) that runs under Microsoft-DOS on 80486-based computers.

Spectrum surveys normally are conducted in the fully automatic mode. RSMS operators are able

to interrupt automatic measurements to perform work in semiautomatic and manual modes.

These modes allow special measurements with varying degrees of automated assistance.

Each of the two measurement systems have independent antennas, rf frontends, masts, spectrum

analyzers and computers, but share the use of auxiliary equipment for special measurements,

analysis, and troubleshooting. Support equipment includes a digital oscilloscope, pulse train

analyzer, demodulator, modulation domain analyzer, rotator controllers, signal generators

(frequencies range from a few kilohertz to 18 GHz), power supplies, low-noise amplifiers, cables,

connectors, and hand tools. Data from the oscilloscope can be downloaded to the controller

computers. Data from the auxiliary devices often are used to determine specific characteristics

of selected emitters during the course of a spectrum survey or other measurement.

The rf operational characteristics of the two measurement systems are shown as a function of

frequency in the Table. The lower frequency system can be operated across a frequency range

of 100 Hz to 2 GHz, with fixed bandpass and varactor preselection at frequencies below

500 MHz and tracking yttrium-iron-garnet (YIG) preselection from 0.5 to 2 GHz. This system

includes 0 to 50 dB of dynamically selectable rf attenuation in the frontend, and achieves a

typical overall noise figure of 10 dB across its entire frequency range. The higher frequency

system can be operated across the 0.5 to 22 GHz range, with YIG preselection from 2 to 20 GHz.

This system incorporates 0 to 70 dB of dynamically selectable rf attenuation in the frontend, and

uses low-noise preamplifiers to achieve a typical noise figure of 10 to 15 dB up to about 10 GHz,

and a noise figure that increases from 15 to 25 dB at frequencies from 10 to 20 GHz. Better

noise figures can be obtained by using the fixed bandpass filters for preselection instead of the

YIG, but that arrangement is tenable only if there are no in-band signals strong enough to

overload the preamplifiers.

C.4 ANTENNAS

The RSMS normally carries a complement of broadband antennas that cover a 0.1 to 20 GHz

frequency range. Other antennas necessary for measurements at higher or lower frequencies are

stored at the ITS laboratory. Omnidirectional, slant-polarized, biconical antennas are most

frequently used for site surveys. These antennas provide a good response to circular, vertical,

and horizontal signal polarizations. At frequencies from 0.1 to 1 GHz, a slant-polarized log

periodic antenna (LPA) may be used if (as in the San Francisco survey) most of the radio activity

in the area is confined to an area subtending 180° or less, relative to the RSMS. Besides the

100-MHz to 1-GHz LPA, the following omnidirectional slant-polarized biconical antennas also

are carried: 0.1 to 1 GHz, 0.5 to 20 GHz, 1 to 12 GHz, 2 to 8 GHz, and 8 to 20 GHz.

In addition to the LPA and omnidirectional antennas, a variety of broadband cavity-backed spiral

(CBS) antennas are carried. These have antenna patterns that are most useful for directionfinding using differential methods at relative observation angles of 60° or 90°. They also are

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useful as auxiliary antennas for manual monitoring of emitters or spectrum of special interest and

Available RSMS RF Signal-processing Paths

Frequency Range RSMS

System

Dynamic

RF Atten.

(dB)

Type of Preselection and

Low-noise Preamplification

Noise

Fig.*

(dB)

100 Hz - 2 MHz** 1 0-50 Fixed bandpass; HP-85685A preamps+ 10

2 MHz - 20 MHz** 1 0-50 5% Varactor; HP-85685A preamps+ 10

20 MHz - 100 MHz** 1 0-50 5% Varactor; HP-85685A preamps 10

100 MHz - 500 MHz 1 0-50 5% Varactor; HP-85685A preamps 10

500 MHz - 2 GHz 1 0-50 Tracking YIG; HP-85685A preamps 10

500 MHz - 2 GHz 2 0-70 Fixed bandpass; 0.5-2 GHz preamp± 10

2 GHz - 4 GHz 2 0-70 Fixed bandpass; 2-4 GHz preamp± 10

4 GHz - 8 GHz 2 0-70 Fixed bandpass; 4-8 GHz preamp± 10-15

8 GHz - 18 GHz 2 0-70 Fixed bandpass; 8-18 GHz preamp± 15-25

2 GHz - 20 GHz 2 0-70 Tracking YIG; 1-20 GHz preamp§ 15-25

* Noise figure is measured using a noise diode (+25-dB excess noise ratio) and variant Y-factor calibration

performed at the antenna terminals.

** Due to the shortage of storage space for large antennas, this frequency range is not normally measured as

part of an RSMS spectrum survey.

+ The low-frequency input on the HP-85685A preselector must be used.

± Generally, this path is only used to perform azimuth-scans or special measurements during an RSMS

spectrum survey, but may be used for normal survey bands if no high-amplitude signals are anticipated

in the measured frequency range.

§ This path normally is used for all spectrum survey bands (except azimuth-scans, see note ± above) in the

1- to 19.7-GHz frequency range. The YIG and preamplifier nominally operate in the 2- to 18-GHz

frequency range, but have demonstrated adequate performance across a 1- to 20-GHz range.

for use on side excursions to measure specific emitters of interest in the area of a site survey.

The frequency ranges of these CBS antennas are 1 to 12 GHz, 8 to 18 GHz, and 400 MHz to

2 GHz. The latter normally is not carried due to its size.

A 1-m parabolic reflector antenna with a choice of feeds (linear cross-polarized and circular)

normally is carried. This antenna is used to perform the azimuth-scanning measurements in the

common carrier (point-to-point microwave) spectrum survey bands, and is used for measurements

on specific emitters (e.g., selected radars).

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The receiving antennas are the only components of the RSMS that are not calibrated in the field.

Because most RSMS measurements are performed to acquire relative emission levels, rather than

absolute incident field-strength values, the main requirement for RSMS antennas is that they have

a fairly flat gain response as a function of measured frequency. If absolute incident field

strengths must be known for received signals, then the gain factors (or, equivalently, the antenna

correction factors) for the applicable antennas are determined from manufacturer-generated tables

and curves, and the RSMS measurements are corrected in a post-acquisition analysis phase.

C.5 ATTENUATORS, PRESELECTORS, AND PREAMPLIFIERS

All RSMS measurements are made using the rf frontends shown in Figure C-4. These frontends

incorporate dynamically switched rf attenuation, preselection, and preamplification. The HewlettPackard 85685A is used for frequencies below 2 GHz, and a unit designed and fabricated by ITS

is used at frequencies between 2 and 20 GHz. The two boxes (HP 85685A and ITS designed

unit) are functionally similar, but differ in significant details. For example, the 85685A provides

0 to 50 dB of rf attenuation, and the ITS box provides 0 to 70 dB of rf attenuation. This active

attenuation allows the total dynamic range of the RSMS to be extended to as much as 130 dB.

Effective bandpass preselection is required if low-noise preamplifiers (LNAs) are used; this is

the case for essentially all RSMS measurements. Preselection prevents strong off-tuned signals

from overloading the frontend LNAs. Preselection in the HP-85685A is provided by fixed

filtering (up to 2 MHz) and by 5% tracking varactors from 2 to 500 MHz. Tracking YIG filters

are used in the frequency ranges of 500 MHz to 2 GHz and 2 GHz to 20 GHz. YIG filters

provide the narrowest preselection (15 MHz wide at 500 MHz to about 25 MHz wide at

20 GHz), but at a cost of about 6 dB of insertion loss. Using fixed bandpass filters can reduce

the preselection insertion loss to about 1 dB; fixed bandpass filters in an approximately octave

progression are available in the ITS frontend (see Figure C-4). These can only be used if no

signals are present in the band that are strong enough to overload the LNAs.

LNAs are used to achieve the best possible sensitivity, coupled with (ideally) just enough gain

to overdrive the noise figure of the rest of the measurement system. Operationally, at frequencies

below 1 GHz, line losses are sufficiently low to allow placement of the rf frontend inside the

operator’s compartment with an rf line to the antenna mounted on the mast. At frequencies

above 1 GHz, however, the line loss is 10 dB or more, and thus the LNAs (and the rest of the

rf frontend) must be positioned at the top of the mast. (Consequently, the mast must be sturdier

than the lower frequency system mast.) If a single LNA at the top of the mast were used, it

would have to produce at least 41 dB of excess noise to overdrive system noise (6 dB of

insertion loss, 10 dB of rf line loss, and at least 25 dB of spectrum analyzer noise figure). Thus,

to achieve an overall noise figure of 10 dB, a single LNA would have to have a noise figure of

about 8 dB, and a gain of at least 33 dB. Because LNAs to accomplish this would overload at

relatively low levels, low-noise preamplification is provided by cascaded preamplifiers located

at two points in the high-frequency system: one at the top of the mast (overdriving YIG insertion

loss, mast line loss, and the 4-dB noise figure of the second LNA) and one at the input to the

spectrum analyzer (to overdrive the analyzer noise figure).

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C.6 CALIBRATION

RSMS calibrations are performed prior to and during every RSMS measurement scenario, such

as a spectrum survey. Typically, a noise diode excess noise ratio (ENR) source is used to

calibrate an entire signal path for measurements about to be performed. Resultant frequencydependent noise figure and gain calibration curves are used to automatically correct the measured

amplitudes of all received signals. As measurements are performed, gain corrections are added

automatically to every sampled data point. Gain and noise figure curves are used by RSMS

operators to determine the relative health of the measurement system, and to pinpoint locations

in the measurement system rf path that are operating suboptimally.

Excluding the receiving antenna, the entire signal path within the RSMS is calibrated with a noise

diode source connected at the point where the rf line attaches to the receiving antenna. The

connection may be accomplished manually or via an automatic relay, depending upon the

measurement scenario. The noise level in the system is measured at 128 points across a selected

frequency range with the noise diode turned on (ON) and turned off (OFF). The RSMS control

computer stores all of the ON vs. OFF noise diode values, then uses the measured difference

between ON and OFF at each of the 128 calibration points to solve calibration equations for gain

and noise figure. The gain values are inverted in sign to become correction values. The

resulting set of 128 noise figure and gain correction values are stored as a function of system

frequency in look-up tables on the computer disk. Calibration curves, as in Figure C-5, showing

system noise figure and gain corrections as a function of frequency across a selected range are

generated. The frequency-dependent gain-correction curve is used to automatically correct the

measured amplitudes of all received signals in subsequent measurements.

RSMS calibrations are implemented as a variant of the Y-factor calibration method [1]. The

Y-factor method of amplitude calibration provides for a simple, yet accurate characterization of

the amplitude response and noise figure of an rf receiver system. At frequencies below 12 GHz,

accuracy of noise diode calibration with spectrum analyzers installed in the RSMS is good to

within a decibel. At frequencies from 12 to 18 GHz, accuracy falls to about ±2.5 dB due to a

higher system noise figure. For noise diodes producing an excess noise ratio of about +25 dB,

as are used for RSMS measurements, gain and noise figure calibrations cannot be performed in

a practical sense if the system noise figure is more than about 30 dB or is less than about 1 dB.

This is because the difference between Pon and Poff becomes too small to measure reliably in the

first case, and too near the rated excess noise ratio of the noise diode to measure reliably in the

second case. Noise diode calibrations will not provide information on phase shift as a function

of frequency; if the measurement system must be calibrated for phase shift, then alternative

calibration methods must be used. Appendix E of the Los Angeles spectrum survey report [2]

provides a detailed description of RSMS noise diode calibration theory.

The RSMS calibration technique has proven very successful for field-deployed radio spectrum

measurement systems. It is a fast way to determine sensitivity and gain-correction values for a

measurement system, and it also is very useful for isolating the gains and losses through

individual components of the measurement system, such as rf lines and amplifiers. Moreover,

the relatively low cost and small size, weight, and power requirements of noise diodes make it

possible to locate several of them at various places in the measurement system to diagnose where

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system losses are occurring; and to carry spares in the event that one fails. Noise diodes can

Figure C-5. RSMS System-1 calibration graph showing noise figure (upper, dashed curve) and

gain correction values (lower, solid curve) as a function of frequency.

themselves be calibrated by such entities as the National Institute of Standards and Technology.

C.7 ADDITIONAL MEASUREMENT CAPABILITIES

When deployed for general spectrum occupancy measurements (broadband spectrum surveys),

the RSMS also is equipped to perform other measurements. Following are brief descriptions of

other measurement capabilities currently available.

Extended Emission Spectra: Measurements of radiated and in-guide emission spectra of

individual radio transmitters, particularly radars, are a major capability of the RSMS program.

A combination of high sensitivity and interactive frontend rf attenuation make it possible to

measure routinely the emission spectra of radio emitters across several gigahertz of spectrum.

Specialized RSMS measurement techniques and algorithms support spectrum measurements of

intermittently received emitters, such as scanning radars, without the need to interrupt or interfere

with their operations. The RSMS uses a stepped measurement routine that allows for measurements that are faster, have more dynamic range, and are more repeatable than swept measurements. Accurately tracked YIG and varactor-tuned preselection make stepped measurements

highly resistant to problems of overload from strong center-frequency signals while measuring

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low-amplitude emissions in adjacent parts of the spectrum. A dynamic range of 110 to 130 dB

is achievable through the use of switched attenuation (invoked as a function of input signal level).

Azimuth Scan: This special measurement routine is used to determine the receivability of

selected signals at particular locations, even if those signals propagate via unconventional

(nonline-of-sight) routes. The RSMS parabolic dish antenna is rotated through 360° on the

horizon while recording received signal strength. This results in data showing the receivability

of signals at all azimuths, and reveals nonline-of-sight propagation routes, if any exist. Azimuth

scanning may be used to support spectrum surveys.

Transmitter Equipment Characteristics: The RSMS is capable of measuring and recording

signal characteristics of multiple transmitter types. As part of any measurement scenario, certain

received signals may be singled out for monitoring and detailed analysis. These special

measurements may be used to determine radiated emission characteristics of known transmitters

or identify the source of unknown transmissions. Measured transmitter (signal) characteristics

include: tuned frequency or frequencies, beam-scanning method (regular rotation, sector scan,

etc.), beam-scan interval, radiated antenna pattern, modulation type (AM, chirped, etc.), pulse

width, pulse repetition rate, pulse jitter, pulse stagger, and intrapulse modulation. Although the

RSMS can observe the presence of phase coding in pulsed signals, no phase measurement

capability is included explicitly in RSMS capabilities.

C.8 REFERENCES

[1] S. Adam, Microwave Theory and Applications, Englewood Cliffs, NJ: Prentice-Hall, Inc.,

1969, pp. 490-502.

[2] F.H. Sanders, B.J. Ramsey, and V.S. Lawrence, "Broadband spectrum survey at Los

Angeles, California," NTIA Report 97-336, May 1997.

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APPENDIX D: DATA ACQUISITION SOFTWARE

D.1 INTRODUCTION

The RSMS is designed to identify and characterize spectrum usage at certain frequencies or in

selected bands, and to perform in-depth analysis of factors such as system compatibilities with

each other or with spectrum assignments. Because of the diverse signal types encountered when

measuring an extended spectrum, the measurement system must be able to detect all or at least

most of the signals and to display or record as much information about them as possible.

Obviously, a general-purpose measurement system cannot receive every signal type; however,

the RSMS receiver detects almost every signal type encountered. As shown in Appendix C, the

RSMS hardware can be configured as a receiver for practically all signal types occurring within

an extended frequency range spanning 100 Hz to 19.7 GHz.

The key to efficient use of this extended measurement capability is rapid reconfiguration. The

RSMS uses software developed by ITS to control all measurement system functions via

computer. This control program, called "DA" (for Data Acquisition), runs on any DOS-based

computer with sufficient memory. It interfaces via general-purpose interface bus (GPIB) with

the measurement system at rates limited only by the computer’s operating speed and functional

speed of the managed hardware (interfaces, switches, components, etc.). DA will support many

combinations of rf frontends, spectrum analyzers, and auxiliary analysis equipment. DA also

controls noise diode calibration of the RSMS and characterizes the noise figure and gain for

individual components and entire measurement signal paths.

The DA program is basically four control subroutines that direct operation of multiple subroutine

kernels that in turn control every function of the measurement system. This appendix includes

descriptions of the four control subroutines (receiver algorithm, spectrum analyzer, rf frontend,

and calibration) and the resultant system functions. As DA program development continues to

meet new measurement demands, these functional descriptions may change with time.

D.2 RECEIVER ALGORITHM SUBROUTINE

The DA receiver algorithm subroutine provides software management for up to 32 measurement

algorithms (called band events for RSMS operations; see Section A.3.1 in Appendix A). Any

one of these algorithms, when coupled with spectrum analyzer and frontend selections (described

later in this appendix), becomes a customized measurement system for receiving certain signals

or signal types. Because the characteristics of emitters and the requirements for data on those

emitters vary considerably, many different algorithms have been developed. However, all of the

algorithms are based upon either a frequency sweep across the spectrum of interest, or a series

of discrete steps across that spectrum.

For spectrum surveys, sweeping algorithms generally are used to examine spectral bands occupied

by high duty-cycle emitters such as mobile radios and television transmitters; stepping algorithms

are used to monitor spectral bands occupied by low duty cycle emitters such as radiolocation

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equipment (radars). Following are brief descriptions of the algorithms used during a spectrum

survey.

Swept: This algorithm controls a conventional spectrum analyzer1 sweep across a

selected portion of spectrum. Any type of detection available in the analyzer (i.e.,

positive peak, sample, etc.) can be used. Repeated sweeps may be programmed, and

multiple sweeps incorporating the maximum-hold spectrum analyzer mode also may

be performed. This algorithm also allows for sweeping a spectral band in several subbands (scans). This feature is important if a narrow bandwidth (e.g., 10 kHz) must be

used to measure a spectral band that is more than 1000 times the width of the

measurement bandwidth; e.g., measuring 900 to 930 MHz with a 10-kHz bandwidth

requires at least three scans to ensure no loss of data.

Swept/m3: This is a swept measurement (as described above) that produces three data

traces across a measurement range. At each of the 1000 frequencies measured on each

individual spectrum analyzer sweep, the maximum, minimum, and (log) mean received

signal levels are measured. Repeated sweeps are made across the spectrum of interest,

and for each of the measurement points returned from each sweep, the three registers

for current maximum, minimum, and mean are updated. This process continues until

it is halted programmatically. The total amount of time for each sweep, and the total

number of sweeps to be performed, are specified in advance by the operator. The

duration of each individual sweep may be a few milliseconds, with a typical swept/m3

measurement (hundreds of sweeps) lasting a total of several minutes. These

cumulative three-trace swept/m3 measurements are saved on magnetic media, and may

themselves be cumed (see Section 2.3) in the analysis phase of a site survey to yield

long-term swept/m3 curves. Typical RSMS site surveys use swept/m3 measurements

for mobile radio bands.

Stepped: Stepping measurements consist of a series of individual amplitude measurements made at predetermined (fixed-tuned) frequencies across a spectrum band of

interest. The measurement system remains tuned to each frequency for a specified

measurement interval. This interval is called step-time, or dwell. The frequency

interval for each step is specified by an operator, and is usually about equal to the IF

bandwidth of the measurement system. For example, measurements across 200 MHz

might use 200 steps at a 1-MHz step interval and a 1-MHz IF bandwidth. Computer

control of the measurement system is needed for this (step, tune, and measure) process

to be performed at maximum speed.

Stepped measurements usually are performed to capture peak signals occurring on an

intermittent basis. A prime example is a periodically scanning radar. If the step-time

(dwell) is set slightly longer than the rotation or scanning interval of the radar beam,

then the maximum receivable level from the beam will illuminate the RSMS at some

1

For most RSMS operations with DA software control, any GPIB-interfaced spectrum analyzer

that processes at least 1000 points (frequencies) per display sweep may be used.

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time during that interval. The RSMS, which is fixed-tuned for the entire dwell period,

records each peak-detected point during that interval and the maximum amplitude

recorded is saved for that frequency. The RSMS then tunes to the next frequency (one

step), and repeats the process until the entire specified spectrum has been measured.

For intermittently received signals, such as scanned-beam radars, the stepped algorithm

has advantages over swept measurements. Stepping is faster, allows more dynamic

range (attenuation can be added and subtracted as a function of measured frequency

to extend the total available dynamic range of the measurement system), and has better

repeatability than swept measurements.

The RSMS uses stepped measurements to gather data in radiolocation bands where

measurements can be tailored to transmitter characteristics; i.e., dwell times, IF bandwidths, and step widths are determined as a function of the parameters of the

radiolocation equipment which normally operates in the band.

Swept/az-scan: This is not currently a selectable algorithm in DA, but is a hybrid

routine using the swept algorithm (above) with a rotating dish antenna. The dish is

targeted on the horizon, then rotated 360° while the swept algorithm is running with

positive peak detection and Maximum-Hold screen mode on the spectrum analyzer.

The result is an analyzer display that shows the maximum activity across a band in an

omnidirectional receiver sense, but with the effective gain of a dish antenna. This

routine is most useful for nondynamic bands where received signal levels tend to be

weak. Good examples are the common carrier (point-to-point) microwave bands; their

transmitters are fixed-tuned, operate continuously, and do not move. The transmitters

also are low powered, and use high-gain antennas, which further reduce their

probability of intercept.

D.2.1 Receiver Parameters

Following are brief descriptions of the DA program input parameters needed to run the above

subroutines (algorithms). Brackets identify the corresponding column headings as they appear

in the band event tables (Section A.3.1 of Appendix A). For example, [algorithm] in the tables

shows which of the above described subroutines is controlling the band event.

Start and Stop Frequencies [start (MHz)] [end (MHz)]: The value in megahertz of

the first and last frequency point to be measured. These numbers must be equal to or

fall outside the event frequency band range.

Passes: The number of times the algorithm iterates for each run command. This

value is always "1" for spectrum surveys.

Scans [scans (# of)]: The number of measurement sub-bands to occur between the

start and stop frequencies. This value usually is determined by comparing measurement bandwidth and frequency range. For example, a 30-MHz frequency range

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measured with a 100-kHz IF bandwidth would ensure sampling of all frequencies

(1001 points) in one scan. However, if a 10-kHz IF bandwidth were used in the above

example, three scans would be required to ensure sampling of all frequencies.

Sweeps [sweeps (# of)]: The number of sweeps in each scan. The DA program

processes each sweep, so increasing this number can add greatly to measurement time;

however, increasing this value also increases the probability of intercept for

intermittent signals.

Steps [steps (# of)]: The number of frequency steps to occur between the start and

stop frequencies. This parameter is used only with stepped algorithms.

Graph Min and Graph Max: The minimum and maximum values in dBm for the

graphical display of measured amplitude data.

D.3 SPECTRUM ANALYZER SUBROUTINE

The DA spectrum analyzer subroutine manages configuration control strings (via GPIB) for the

spectrum analyzer. The operator selects spectrum analyzer parameters (listed in the following

subsection) from menus in the DA program. Generally, parameters are selected that will

configure the analyzer to run with a receiver algorithm for a desired measurement scenario. The

software protects against out-of-range and nonfunctional configurations but the operator can

control the analyzer manually for unusual situations.

D.3.1 Spectrum Analyzer Parameters

When the DA program sends command strings to the analyzer, all signal-path parameters are

reset according to the operator selections for the measurement scenario. Following are brief

descriptions of the analyzer parameter choices controlled by DA. Brackets identify the

corresponding column headings as they appear in the band-event tables in Section A.3.1 of

Appendix A.

Attenuation: May be adjusted from 0 to 70 dB in 10-dB increments. The spectrum

analyzer subroutine determines whether or not RSMS frontend attenuators are

available, and if so, will set them to the selected value. Spectrum analyzer attenuation

is set to zero when RSMS attenuation is active; if however, RSMS attenuators are not

available, the spectrum analyzer attenuation will be set to the selected value.

IF Bandwidth [IFBW (kHz)]: May be selected from 0.01 to 3000 kHz in a 1, 3, 10

progression.

Detector [detector type]: ±peak, positive peak, negative peak, sample, maximum hold,

and video average modes are available. See Appendix B for discussions on detector

selection for receiver algorithms.

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Video Bandwidth [VBW (kHz)]: May be selected from 0.01 to 3000 kHz in a 1, 3,

10 progression.

Display: Amplitude graticule choices in dB/division are: 1, 2, 5, and 10. This

parameter selection applies to both the analyzer and the system console displays.

Reference Level [RL (dBm)]: May be adjusted from −10 to −70 dBm in 10-dB

increments.

Sweeps [MH/VA (#swps)]: Number of analyzer-processed sweeps per scan. This

parameter is used only with maximum hold or video-averaged detection.

Sweep Time [swp/stp (sec)]: This parameter (entered in seconds) specifies sweep

(trace) time if used with swept algorithms, or specifies step time (dwell) if used with

a stepped algorithm.

D.4 RF FRONTEND SUBROUTINE

The DA software handles the rf frontend path selection differently from other routines. Most of

the rf-path parameters are predetermined by the measurement algorithm so operators need only

select an antenna and choose whether preamplifiers are turned on or off. Preselection also is

controlled by the antenna selection.

The antenna selection is made from a list of antenna choices that is stored in a separately

maintained library file called by the rf frontend subroutine. Antenna information stored in the

file includes:

antenna type (omni, cavity-backed, etc.);

manufacturer (may include identification or model number);

port (tells the computer where signals enter the RSMS and includes particulars on

any external signal conditioning such as special mounting, additional amplifiers,

or extra path gain or loss);

frequency range;

vertical and horizontal beam widths;

gain relative to an isotropic antenna;

front-to-back gain ratio; and

side-lobe gain levels.

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D.5 CALIBRATION SUBROUTINE

The calibration subroutine may be run at any time the operator chooses, but measurements must

be interrupted. The software is interactive and flexible, allowing the operator to choose any

calibration path and frequency range desired. RSMS calibrations are performed with noise diodes

using techniques described in Section C.6 of Appendix C.

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