NTIA Technical Report TR-11-478

Wideband Man-Made Radio Noise 

Measurements in the VHF and 

Low UHF Bands

Jeffery A. Wepman

Geoffrey A. Sanders

NTIA Technical Report TR-11-478

Wideband Man-Made Radio Noise 

Measurements in the VHF and 

Low UHF Bands

Jeffery A. Wepman

Geoffrey A. Sanders

U.S. DEPARTMENT OF COMMERCE

July 2011

iii

DISCLAIMER

Certain commercial equipment and materials are identified in this report to specify adequately 

the technical aspects of the reported results. In no case does such identification imply 

recommendation or endorsement by the National Telecommunications and Information 

Administration, nor does it imply that the material or equipment identified is the best available 

for this purpose.

v

CONTENTS

Page

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

TABLES..................................................................................................................................xiv

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

2 BACKGROUND .....................................................................................................................3

2.1 Description of Noise Parameters........................................................................................3

2.2 Man-Made Noise Models...................................................................................................5

2.3 Previous Noise Measurements ...........................................................................................6

3 NOISE MEASUREMENT LOCATION SELECTION.............................................................8

4 NOISE MEASUREMENT FREQUENCY AND BANDWIDTH SELECTION .....................14

4.1 Noise Measurement Bandwidth Selection ........................................................................14

4.2 Noise Measurement Frequency Selection .........................................................................14

5 NOISE MEASUREMENTS...................................................................................................19

5.1 Noise Measurement System.............................................................................................19

5.2 Noise Measurement System Optimization and Verification..............................................22

5.3 Noise Measurement Procedure.........................................................................................23

6 DATA ANALYSIS................................................................................................................26

6.1 Time Domain Characteristics and APDs of Individual Noise Data Records......................26

6.2 Median, Mean, and Peak Noise Power Analysis...............................................................30

6.3 Complementary Cumulative Distributions of Hourly Median Noise Power ......................37

6.4 Statistics of the Hourly Medians of Mean Noise Power....................................................37

6.5 Comparison of Measured Results with Models.................................................................41

7 SUMMARY AND CONCLUSIONS......................................................................................46

8 ACKNOWLEDGEMENTS....................................................................................................48

9 REFERENCES ......................................................................................................................49

APPENDIX: SPECTRUM SURVEY MEASUREMENTS .......................................................51

A.1 Spectrum Survey Measurement System...........................................................................51

A.2 Spectrum Survey Measurement Procedure ......................................................................52

A.3 Spectrum Survey Measurement Results...........................................................................54
vi

FIGURES

Page

Figure 1. Model of an RF receiving system. ..........................................................................3

Figure 2. Predicted Fam values versus frequency for both the ITU and Hagn models..............6

Figure 3. Photograph of the RSMS-4G measurement vehicle. ...............................................8

Figure 4. Aerial photograph of residential measurement location in Boulder (courtesy 

of the U.S. Geological Survey). The marker near the bottom of the 

photograph shows the location of the residential Boulder spectrum survey 

measurements discussed in Section 4 and described in the Appendix....................10

Figure 5. Aerial photograph of business measurement location in Boulder (courtesy 

of the U.S. Geological Survey). ............................................................................11

Figure 6. Aerial photograph of residential measurement location in Denver (courtesy 

of the U.S. Geological Survey). ............................................................................12

Figure 7. Aerial photograph of business measurement location in Denver (courtesy of 

the U.S. Geological Survey). ................................................................................13

Figure 8. Maximum, mean, and median received signal power at all measurement 

locations for 110–115 MHz (RBW = 10 kHz, 100 sweeps, sweep time = 

300 ms). ...............................................................................................................16

Figure 9. Maximum, mean, and median received signal power at all measurement 

locations for 219–224 MHz (RBW = 3 kHz, 60 sweeps, sweep time = 900 

ms). ......................................................................................................................17

Figure 10. Maximum, mean, and median received signal power at all measurement 

locations for 400–404 MHz (RBW = 3 kHz, 60 sweeps, sweep time = 900 

ms). ......................................................................................................................18

Figure 11. Block diagram of the noise measurement system installed in the RSMS-4G 

measurement vehicle. ...........................................................................................19

Figure 12. VSWR versus normalized frequency for the quarter-wave monopole 

antennas. ..............................................................................................................20

Figure 13. Photograph of the noise measurement system installed in the RSMS-4G 

measurement vehicle. ...........................................................................................22

Figure 14. Example time domain plot showing 60 ms of a noise data record from the 

residential Boulder location at 0349 on September 1, 2009 with a 112.5-

MHz center frequency and 1.16-MHz span...........................................................27
vii

Figure 15. Example APD from the residential Boulder location at 0349 on September 

1, 2009 with a 112.5-MHz center frequency and 1.16-MHz span..........................28

Figure 16. Example APD from the Denver business location at 0723 on August 19, 

2009 with a 221.5-MHz center frequency and 1.16-MHz span..............................28

Figure 17. Example APD from the Boulder business location at 1211 on July 22, 2009 

with a 401-MHz center frequency and 1.16-MHz span. ........................................29

Figure 18. Example APD from the Denver residential location at 2319 on July 29, 

2009 with a 112.5-MHz center frequency and 1.16-MHz span..............................29

Figure 19. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 112.5 MHz at the Boulder residential location (August 

31–September 1, 2009).........................................................................................31

Figure 20. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 221.5 MHz at the Boulder residential location 

(September 3–4, 2009). ........................................................................................31

Figure 21. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 401 MHz at the Boulder residential location (September 

2–3, 2009). ...........................................................................................................32

Figure 22. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 112.5 MHz at the Boulder business location (July 21–

22, 2009)..............................................................................................................32

Figure 23. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 221.5 MHz at the Boulder business location (July 20–

21, 2009)..............................................................................................................33

Figure 24. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 401 MHz at the Boulder business location (July 22–23, 

2009)....................................................................................................................33

Figure 25. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 112.5 MHz at the Denver residential location (July 29–

30, 2009)..............................................................................................................34

Figure 26. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 221.5 MHz at the Denver residential location (July 28–

29, 2009)..............................................................................................................34

Figure 27. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 401 MHz at the Denver residential location (July 27–

28, 2009)..............................................................................................................35
viii

Figure 28. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 112.5 MHz at the Denver business location (August 17–

18, 2009)..............................................................................................................35

Figure 29. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 221.5 MHz at the Denver business location (August 18–

19, 2009)..............................................................................................................36

Figure 30. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a 

center frequency of 401 MHz at the Denver business location (August 19–

20, 2009)..............................................................................................................36

Figure 31. Complementary cumulative distribution of the hourly median values of the 

median, mean, and peak powers in a 1-MHz bandwidth at a center 

frequency of approximately 112.5 MHz over both residential locations. ...............38

Figure 32. Complementary cumulative distribution of the hourly median values of the 

median, mean, and peak powers in a 1-MHz bandwidth at a center 

frequency of approximately 221.5 MHz over both residential locations. ...............38

Figure 33. Complementary cumulative distribution of the hourly median values of the 

median, mean, and peak powers in a 1-MHz bandwidth at a center 

frequency of 401 MHz over both residential locations. .........................................39

Figure 34. Complementary cumulative distribution of the hourly median values of the 

median, mean, and peak powers in a 1-MHz bandwidth at a center 

frequency of approximately 112.5 MHz over both business locations. ..................39

Figure 35. Complementary cumulative distribution of the hourly median values of the 

median, mean, and peak powers in a 1-MHz bandwidth at a center 

frequency of approximately 221.5 MHz over both business locations. ..................40

Figure 36. Complementary cumulative distribution of the hourly median values of the 

median, mean, and peak powers in a 1-MHz bandwidth at a center 

frequency of 401 MHz over both business locations. ............................................40

Figure 37. Comparison of measured and predicted values of Fam and standard deviation 

of Fam for residential locations.14..........................................................................44

Figure 38. Comparison of measured and predicted values of Fam and standard deviation 

of Fam for business locations.................................................................................44

Figure A-1. Block diagram of the spectrum survey measurement system. ................................51

Figure A-2. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 1 (104–164 MHz, RBW = 10 kHz, 100 

sweeps, sweep time = 300 ms)..............................................................................55
ix

Figure A-3. Maximum, mean, and median received signal power at the Denver 

residential location for Event 1 (104–164 MHz, RBW = 10 kHz, 100 

sweeps, sweep time = 300 ms)..............................................................................56

Figure A-4. Maximum, mean, and median received signal power at the Boulder business 

location for Event 1 (104–164 MHz, RBW = 10 kHz, 100 sweeps, sweep 

time = 300 ms). ....................................................................................................57

Figure A-5. Maximum, mean, and median received signal power at the Denver business 

location for Event 1 (104–164 MHz, RBW = 10 kHz, 100 sweeps, sweep 

time = 300 ms). ....................................................................................................58

Figure A-6. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 2 (160–180 MHz, RBW = 10 kHz, 500 

sweeps, sweep time = 300 ms)..............................................................................59

Figure A-7. Maximum, mean, and median received signal power at the Denver 

residential location for Event 2 (160–180 MHz, RBW = 10 kHz, 500 

sweeps, sweep time = 300 ms)..............................................................................60

Figure A-8. Maximum, mean, and median received signal power at the Boulder business 

location for Event 2 (160–180 MHz, RBW = 10 kHz, 500 sweeps, sweep 

time = 300 ms). ....................................................................................................61

Figure A-9. Maximum, mean, and median received signal power at the Denver business 

location for Event 2 (160–180 MHz, RBW = 10 kHz, 500 sweeps, sweep 

time = 300 ms). ....................................................................................................62

Figure A-10. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 3 (170–220 MHz, RBW = 100 kHz, 500 

sweeps, sweep time = 100 ms)..............................................................................63

Figure A-11. Maximum, mean, and median received signal power at the Denver 

residential location for Event 3 (170–220 MHz, RBW = 100 kHz, 500 

sweeps, sweep time = 100 ms)..............................................................................64

Figure A-12. Maximum, mean, and median received signal power at the Boulder business 

location for Event 3 (170–220 MHz, RBW = 100 kHz, 500 sweeps, sweep 

time = 100 ms). ....................................................................................................65

Figure A-13. Maximum, mean, and median received signal power at the Denver business 

location for Event 3 (170–220 MHz, RBW = 100 kHz, 500 sweeps, sweep 

time = 100 ms). ....................................................................................................66

Figure A-14. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 4 (216–225 MHz, RBW = 3 kHz, 60 sweeps, 

sweep time = 900 ms)...........................................................................................67
x

Figure A-15. Maximum, mean, and median received signal power at the Denver 

residential location for Event 4 (216–225 MHz, RBW = 3 kHz, 60 sweeps, 

sweep time = 900 ms)...........................................................................................68

Figure A-16. Maximum, mean, and median received signal power at the Boulder business 

location for Event 4 (216–225 MHz, RBW = 3 kHz, 60 sweeps, sweep time 

= 900 ms). ............................................................................................................69

Figure A-17. Maximum, mean, and median received signal power at the Denver business 

location for Event 4 (216–225 MHz, RBW = 3 kHz, 60 sweeps, sweep time 

= 900 ms). ............................................................................................................70

Figure A-18. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 5 (225–405 MHz, RBW = 30 kHz, 100 

sweeps, sweep time = 100 ms)..............................................................................71

Figure A-19. Maximum, mean, and median received signal power at the Denver 

residential location for Event 5 (225–405 MHz, RBW = 30 kHz, 100 

sweeps, sweep time = 100 ms)..............................................................................72

Figure A-20. Maximum, mean, and median received signal power at the Boulder business 

location for Event 5 (225–405 MHz, RBW = 30 kHz, 100 sweeps, sweep 

time = 100 ms). ....................................................................................................73

Figure A-21. Maximum, mean, and median received signal power at the Denver business 

location for Event 5 (225–405 MHz, RBW = 30 kHz, 100 sweeps, sweep 

time = 100 ms). ....................................................................................................74

Figure A-22. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 6 (400–406 MHz, RBW = 3 kHz, 60 sweeps, 

sweep time = 900 ms)...........................................................................................75

Figure A-23. Maximum, mean, and median received signal power at the Denver 

residential location for Event 6 (400–406 MHz, RBW = 3 kHz, 60 sweeps, 

sweep time = 900 ms)...........................................................................................76

Figure A-24. Maximum, mean, and median received signal power at the Boulder business 

location for Event 6 (400–406 MHz, RBW = 3 kHz, 60 sweeps, sweep time 

= 900 ms). ............................................................................................................77

Figure A-25. Maximum, mean, and median received signal power at the Denver business 

location for Event 6 (400–406 MHz, RBW = 3 kHz, 60 sweeps, sweep time 

= 900 ms). ............................................................................................................78

Figure A-26. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 7 (400–420 MHz, RBW = 10 kHz, 200 

sweeps, sweep time = 300 ms)..............................................................................79
xi

Figure A-27. Maximum, mean, and median received signal power at the Denver 

residential location for Event 7 (400–420 MHz, RBW = 10 kHz, 200 

sweeps, sweep time = 300 ms)..............................................................................80

Figure A-28. Maximum, mean, and median received signal power at the Boulder business 

location for Event 7 (400–420 MHz, RBW = 10 kHz, 200 sweeps, sweep 

time = 300 ms). ....................................................................................................81

Figure A-29. Maximum, mean, and median received signal power at the Denver business 

location for Event 7 (400–420 MHz, RBW = 10 kHz, 200 sweeps, sweep 

time = 300 ms). ....................................................................................................82

Figure A-30. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 8 (420–450 MHz, RBW = 10 kHz, 100 

sweeps, sweep time = 300 ms)..............................................................................83

Figure A-31. Maximum, mean, and median received signal power at the Denver 

residential location for Event 8 (420–450 MHz, RBW = 10 kHz, 100 

sweeps, sweep time = 300 ms)..............................................................................84

Figure A-32. Maximum, mean, and median received signal power at the Boulder business 

location for Event 8 (420–450 MHz, RBW = 10 kHz, 100 sweeps, sweep 

time = 300 ms). ....................................................................................................85

Figure A-33. Maximum, mean, and median received signal power at the Denver business 

location for Event 8 (420–450 MHz, RBW = 10 kHz, 100 sweeps, sweep 

time = 300 ms). ....................................................................................................86

Figure A-34. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 9 (450–470 MHz, RBW = 10 kHz, 200 

sweeps, sweep time = 300 ms)..............................................................................87

Figure A-35. Maximum, mean, and median received signal power at the Denver 

residential location for Event 9 (450–470 MHz, RBW = 10 kHz, 200 

sweeps, sweep time = 300 ms)..............................................................................88

Figure A-36. Maximum, mean, and median received signal power at the Boulder business 

location for Event 9 (450–470 MHz, RBW = 10 kHz, 200 sweeps, sweep 

time = 300 ms). ....................................................................................................89

Figure A-37. Maximum, mean, and median received signal power at the Denver business 

location for Event 9 (450–470 MHz, RBW = 10 kHz, 200 sweeps, sweep 

time = 300 ms). ....................................................................................................90

Figure A-38. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 10 (470–520 MHz, RBW = 10 kHz, 100 

sweeps, sweep time = 300 ms)..............................................................................91
xii

Figure A-39. Maximum, mean, and median received signal power at the Denver 

residential location for Event 10 (470–520 MHz, RBW = 10 kHz, 100 

sweeps, sweep time = 300 ms)..............................................................................92

Figure A-40. Maximum, mean, and median received signal power at the Boulder business 

location for Event 10 (470–520 MHz, RBW = 10 kHz, 100 sweeps, sweep 

time = 300 ms). ....................................................................................................93

Figure A-41. Maximum, mean, and median received signal power at the Denver business 

location for Event 10 (470–520 MHz, RBW = 10 kHz, 100 sweeps, sweep 

time = 300 ms). ....................................................................................................94

Figure A-42. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 11 (512–812 MHz, RBW = 100 kHz, 200 

sweeps, sweep time = 100 ms)..............................................................................95

Figure A-43. Maximum, mean, and median received signal power at the Denver 

residential location for Event 11 (512–812 MHz, RBW = 100 kHz, 200 

sweeps, sweep time = 100 ms)..............................................................................96

Figure A-44. Maximum, mean, and median received signal power at the Boulder business 

location for Event 11 (512–812 MHz, RBW = 100 kHz, 200 sweeps, sweep 

time = 100 ms). ....................................................................................................97

Figure A-45. Maximum, mean, and median received signal power at the Denver business 

location for Event 11 (512–812 MHz, RBW = 100 kHz, 200 sweeps, sweep 

time = 100 ms). ....................................................................................................98

Figure A-46. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 12 (806–906 MHz, RBW = 10 kHz, 60 

sweeps, sweep time = 300 ms)..............................................................................99

Figure A-47. Maximum, mean, and median received signal power at the Denver 

residential location for Event 12 (806–906 MHz, RBW = 10 kHz, 60 

sweeps, sweep time = 300 ms)............................................................................100

Figure A-48. Maximum, mean, and median received signal power at the Boulder business 

location for Event 12 (806–906 MHz, RBW = 10 kHz, 60 sweeps, sweep 

time = 300 ms). ..................................................................................................101

Figure A-49. Maximum, mean, and median received signal power at the Denver business 

location for Event 12 (806–906 MHz, RBW = 10 kHz, 60 sweeps, sweep 

time = 300 ms). ..................................................................................................102

Figure A-50. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 13 (900–920 MHz, RBW = 10 kHz, 100 

sweeps, sweep time = 300 ms)............................................................................103
xiii

Figure A-51. Maximum, mean, and median received signal power at the Denver 

residential location for Event 13 (900–920 MHz, RBW = 10 kHz, 100 

sweeps, sweep time = 300 ms)............................................................................104

Figure A-52. Maximum, mean, and median received signal power at the Boulder business 

location for Event 13 (900–920 MHz, RBW = 10 kHz, 100 sweeps, sweep 

time = 300 ms). ..................................................................................................105

Figure A-53. Maximum, mean, and median received signal power at the Denver business 

location for Event 13 (900–920 MHz, RBW = 10 kHz, 100 sweeps, sweep 

time = 300 ms). ..................................................................................................106

Figure A-54. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 14 (920–960 MHz, RBW = 10 kHz, 300 

sweeps, sweep time = 300 ms)............................................................................107

Figure A-55. Maximum, mean, and median received signal power at the Denver 

residential location for Event 14 (920–960 MHz, RBW = 10 kHz, 300 

sweeps, sweep time = 300 ms)............................................................................108

Figure A-56. Maximum, mean, and median received signal power at the Boulder business 

location for Event 14 (920–960 MHz, RBW = 10 kHz, 300 sweeps, sweep 

time = 300 ms). ..................................................................................................109

Figure A-57. Maximum, mean, and median received signal power at the Denver business 

location for Event 14 (920–960 MHz, RBW = 10 kHz, 300 sweeps, sweep 

time = 300 ms). ..................................................................................................110

Figure A-58. Maximum, mean, and median received signal power at the Boulder 

residential location for Event 15 (960–1060 MHz, RBW = 100 kHz, 500 

sweeps, sweep time = 100 ms)............................................................................111

Figure A-59. Maximum, mean, and median received signal power at the Denver 

residential location for Event 15 (960–1060 MHz, RBW = 100 kHz, 500 

sweeps, sweep time = 100 ms)............................................................................112

Figure A-60. Maximum, mean, and median received signal power at the Boulder business 

location for Event 15 (960–1060 MHz, RBW = 100 kHz, 500 sweeps, 

sweep time = 100 ms).........................................................................................113

Figure A-61. Maximum, mean, and median received signal power at the Denver business 

location for Event 15 (960–1060 MHz, RBW = 100 kHz, 500 sweeps, 

sweep time = 100 ms).........................................................................................114
xiv

TABLES

Page

Table 1. Description of noise measurement locations ...........................................................9

Table 2. Measured system gain and noise figure at each measurement frequency and 

location ................................................................................................................24

Table 3. Statistics of the hourly medians of the mean noise power for residential 

locations...............................................................................................................41

Table 4. Statistics of the hourly medians of the mean noise power for business 

locations...............................................................................................................41

Table 5. Major differences between measurements used in the ITU Model and 

measurements taken for this study ........................................................................42

Table 6. Comparison of measured and predicted values of Fam for residential 

locations14............................................................................................................43

Table 7. Comparison of measured and predicted values of Fam for business locations.........43

Table A-1. Spectrum analyzer and preselector parameters for spectrum survey 

measurements.......................................................................................................53
WIDEBAND MAN-MADE RADIO NOISE MEASUREMENTS IN THE VHF AND LOW 

UHF BANDS

Jeffery A. Wepman and Geoffrey A. Sanders1

Man-made radio noise measurements were conducted in a 1.16-MHz bandwidth 

at 112.5, 221.5, and 401 MHz at two residential and two business locations in the 

Boulder/Denver, Colorado, area. The measurement frequencies and bandwidth 

were selected using the results of a spectrum survey performed over the 104–

1060-MHz frequency range. The noise measurement data were collected as a 

complex baseband noise data record (consisting of six million in-phase (I) and 

quadrature-phase (Q) samples) every 10 minutes over a 24-hour period for each 

frequency and location. The data were processed to provide various statistical 

descriptions of the noise such as amplitude probability distributions (APDs). 

Median values of the antenna noise figure Fam were determined for each 

measurement frequency and environment type and compared to predicted values 

from existing man-made radio noise models. The measured values of Fam, while 

larger than the values predicted by the International Telecommunication Union 

(ITU) man-made radio noise model, were still within one standard deviation of 

the predicted values. Further noise measurements are recommended in a greater 

number of locations to provide more statistically significant results.

Key words: man-made noise; man-made radio noise; impulsive noise; Gaussian noise; noise 

measurements; spectrum measurements; spectrum survey; antenna noise factor; 

external noise factor; amplitude probability distributions; International 

Telecommunications Union (ITU) radio noise model

1 INTRODUCTION

Having an accurate model of man-made radio noise at very high frequency (VHF) and ultra high 

frequency (UHF)

2

is of interest in the design and evaluation of radio communication systems and 

wireless networks [1]. While an International Telecommunications Union (ITU) model for manmade radio noise is available today [2], this model is based on measurements that were taken in 

the 1960s and 1970s.

 

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

Administration, U.S. Department of Commerce, Boulder, CO 80305.

2 The VHF band is from 30 to 300 MHz and the UHF band is from 300 to 3000 MHz.
2

The proliferation of computers, cellular telephones, wireless networks, and other electronic 

devices as well as increases in spectrum crowding, aging of the power distribution infrastructure, 

and enhancements to auto ignition systems suggest that the man-made radio noise environment 

may have changed since the 1970s. Because of these significant changes in technology, it is 

suspected that the ITU model for man-made radio noise may no longer be accurate. Noise 

measurements taken in the 1990s also raised questions about the accuracy of the ITU model [3], 

[4].

This report has three primary objectives. The first is to introduce a new, wideband noise 

measurement system suitable for measuring man-made radio noise in bandwidths more 

comparable to those used in modern wideband communication systems. The second objective is 

to present results from some initial man-made radio noise measurements taken at VHF and UHF 

and to compare these results to the current ITU model [2]. Building on the results of these initial 

measurements, the third objective is to help identify areas that warrant further study.

Section 2 of this report presents some key background information to provide a context for this 

measurement study. A discussion of noise parameters that have been traditionally used to express 

noise power measurements is presented. Models that are currently used to predict noise power 

are also given. The section also includes a look at some of the relevant man-made noise 

measurement studies previously undertaken.

Judicious selection of both appropriate measurement locations and frequencies was a necessary 

and critical prerequisite to taking the noise measurements. Section 3 discusses the selection of 

locations for making the noise measurements. The selection of the specific measurement 

frequencies and bandwidths is addressed in Section 4. This process was complicated by the 

requirement of taking relatively wide bandwidth noise measurements. A spectrum survey and 

subsequent data analysis were required, along with the development of a swept spectrum 

measurement system to aid in the selection of frequencies and bandwidths for the noise 

measurements. Details of the spectrum survey including the measurement system, procedure, and 

results are provided in the Appendix. The results are presented as maximum, mean, and median 

received signal power for the entire frequency range measured (104–1060 MHz).

The noise measurement system and procedure for making the measurements is given in 

Section 5. The data analysis is covered in Section 6. Some example amplitude probability 

distributions (APDs) of individual noise data records are given along with an example time 

domain display of a noise data record. The statistical summary data includes the median, mean, 

and peak noise power levels over a 24-hour time period at each measurement location and 

frequency. Complementary cumulative distributions of the hourly median values of the median, 

mean and peak power are given for each frequency and environment type. Median values of the 

antenna noise figure are determined for each measurement frequency and environment type. 

These values are compared to those predicted by the ITU model. Section 7 provides a brief 

summary of the report and some conclusions about the results of the data analysis and the 

comparison between these results and the predicted values from the ITU model. Some 

recommendations for further study are also offered.
3

2 BACKGROUND

Man-made radio noise was studied extensively in the 1960s and 1970s and radio noise in general 

has been studied for even longer. Therefore, there is a wealth of knowledge that is relevant to 

noise measurements conducted today. This section provides some of this background 

information, such as a description of noise parameters commonly used to quantify noise power, 

noise power models that have been developed to predict measured noise power, and previous 

noise measurements that have been undertaken.

2.1 Description of Noise Parameters

The characterization of the man-made radio noise environment traditionally has been given in 

terms of the noise power received by an antenna of a radio frequency (RF) receiving system. 

Typically, noise power is presented in terms of an antenna noise figure. In this section, 

commonly used noise parameters are described.

To describe these noise parameters, it is helpful to consider a model of an RF receiving system as 

shown in Figure 1 [5].

Figure 1. Model of an RF receiving system.

The mean overall measured system noise power, p, can be expressed in terms of the overall 

system noise factor, f, by

p  f kT0 b

(1)

where

k = Boltzmann’s constant = 1.38 x 10-23 joules/K,

T0 = reference temperature = 288 K,

b = receiver noise equivalent bandwidth in Hz.
4

Expressing (1) in decibels yields

10 log ( ) P  F  10 kT0 b

(2)

where 

P = 10 log10 p = mean overall measured system noise power in dB and

F = 10 log10 f = overall system noise figure in dB.

Using Friis’ method of combining noise factors in cascade [6], the overall system noise factor 

can be expressed as

( 1) ( 1) ( 1)

0 0

      c t r 

t

c t

c

a c

l l f

T

T

l l

T

T

f f l

(3)

where

lc = antenna circuit loss,

lt = transmission line loss,

Tc = actual temperature of the antenna circuit in K,

Tt = actual temperature of the transmission line in K,

fr = receiver noise factor and

fa = antenna noise factor.

Now, since the noise factor associated with the antenna circuit loss is given as

0

1 ( 1)

T

T

f l

c

c

  c  (4)

and the noise factor associated with the transmission line loss is given as

0

1 ( 1)

T

T

f l

t

t

  t  (5)

if Tc = Tt = T0, then (3) can be written as

1 .

a c t r

f  f   f f f

(6)

If the antenna circuit and transmission line are assumed to be lossless, (6) reduces to 

f  f

a  fr 1

(7)
5

providing a relationship between the overall system noise factor f, the antenna noise factor fa, and 

the receiver noise factor fr. A lossless antenna circuit and transmission line are assumed for the 

measurements taken for this report. This assumption is valid because:

 The quarter-wave monopole antenna used for each frequency was tuned to achieve a 

minimum voltage standing wave ratio (VSWR) of less than 1.25:1 in all cases.

 The noise diode calibration at the output terminals of the antenna removes the effects of 

any transmission line loss.

Some of the final data statistics presented in this report, under certain conditions, are given in 

terms of the antenna noise figure Fa (where Fa = 10 log10 fa) as determined from the overall 

system noise factor f and (7). Values of Fa can be converted to the mean external noise power 

available from an equivalent lossless antenna, Pn, by 

10 log ( ) Pn Fa  10 kT0 b . This will be 

discussed in greater detail in Section 6.2.

2.2 Man-Made Noise Models

The current ITU model of man-made radio noise power [2] provides predicted values of Fam

(median of Fa values) for frequencies ranging from 250 kHz to 250 MHz and is given as

log ( )

10 0 F c d fam

  (8)

where f0 is the center frequency in MHz, d = 27.7 dB/MHz, and c is 76.8 dB, 72.5 dB, and 

67.2 dB for business, residential, and rural environments, respectively.

Hagn [7] suggested using the ITU Model for frequencies below 200 MHz but proposed a 

different model for frequencies above 200 MHz.3The Hagn model is also given as in (8) except 

d = 15.8 dB/MHz and c is 49.4 dB, 45.2 dB, and 39.2 dB for business, residential, and rural

environments, respectively. Figure 2 shows a plot of the predicted Fam values versus frequency in 

business, residential, and rural locations for both the ITU and Hagn models.

 

3 Measurements by Lauber and Bertrand [8] showed that the Hagn model was more accurate than the ITU model for 

frequencies above 200 MHz.
6

Figure 2. Predicted Fam values versus frequency for both the ITU and Hagn models.

2.3 Previous Noise Measurements

The ITU model is based on measurements taken in the 1960s and 1970s by Spaulding and 

Disney [6]. The measurements consisted of mobile measurement runs taken in 23 business, 38 

residential, and 31 rural areas in Colorado, Maryland, Texas, Virginia, Washington, Wyoming, 

and the District of Columbia. The duration of each run varied from about 15 minutes to over one 

hour. The measurements were made in a 4-kHz noise equivalent bandwidth at 10 different 

frequencies from 250 kHz to 250 MHz. Short vertical monopole antennas, mounted on the 

aluminum roof of the measurement van were used for the measurements. The aluminum roof 

served as a ground plane for the antennas.

Due to the concern that the ITU model was possibly no longer accurate, further man-made noise 

measurements were made at the Institute for Telecommunication Sciences (ITS) in the 1990s [3], 

[4]. Two separate measurement campaigns were performed.

In the first campaign, measurements were performed in a variety of locations including six 

business, two residential, and four rural areas. Additional measurements were also taken to 

observe noise emissions from automobiles, electrical power networks and electronic equipment. 

All measurements were conducted with a stationary measurement system. The measurements 

were taken in a 32-kHz, 3-dB bandwidth at 137.5 MHz using a vertical, quarter-wave monopole 

antenna mounted on a ground plane. The duration of the measurements was less than one hour in 

the rural locations, more than 24 hours in the residential locations, and varied from one to more 
7

than 24 hours in the business locations. Values of Fam computed from these measurements were 

found to be within one standard deviation of the values predicted by the ITU model for the 

business and rural locations. However, for the residential locations, measured values of Fam were 

well below those predicted by the ITU model.

For the second measurement campaign, measurements were taken in a 30-kHz, 3-dB bandwidth 

at 137.5, 402.5, and 761 MHz. Vertical, quarter-wave monopoles were mounted on a ground 

plane and tuned to each measurement frequency. The measurements were performed in two 

residential and two business locations in the Boulder/Denver, Colorado, area. Again, all 

measurements were conducted with a stationary measurement system. The duration of the 

measurements at each location was 24 hours. It was not possible to compute accurate Fam values 

from the 402.5 and 761 MHz measurements because the measured noise power was too close to 

system noise. The value of Fam computed from the 137.5 MHz measurements in the business 

locations was found to be very similar to that computed from the previous ITS 137.5 MHz noise 

measurements and also within one standard deviation of the value predicted by the ITU model.

For the residential locations, values of Fam computed from the 137.5 MHz measurements were 

again well below those predicted by the ITU model.

In 2006, man-made noise measurements were conducted in the United Kingdom by MASS 

Consultants Limited in five urban, five industrial, eight suburban, and seven rural locations [9]. 

All measurements were conducted with a stationary measurement system. The measurements 

were taken in a 1-MHz bandwidth at 209.5 and 425 MHz using vertically-polarized, tuned dipole 

antennas at a height of 1.5 m above ground. At each location, measurements were conducted for 

approximately 24 hours. Values of Fam computed from the 209.5 MHz measurements were 

within one standard deviation of those predicted by the ITU model for the urban, suburban, and 

rural locations.4 Values of Fam computed from the 425 MHz measurements in the urban, 

suburban, and rural location were larger than those predicted by the Hagn model.

 

4 The types of measurement environments in the MASS study may be somewhat different from those used for the 

development of the ITU model. The urban, suburban, and rural locations described in the MASS study probably 

correspond to the business, residential, and rural locations defined in the ITU model. The industrial locations defined 

in the MASS study probably do not directly correspond to an environment type in the ITU model.
8

3 NOISE MEASUREMENT LOCATION SELECTION

The locations for conducting the noise measurements in this study were chosen to represent, as 

closely as possible, typical residential and business areas as defined in [6]. A business area, as 

defined in [6], is “any area where the predominant usage throughout the area is for any type of 

business. This includes stores and offices, industrial parks, large shopping centers, main streets 

or highways lined with various business enterprises, etc.” A residential area, as defined in [6], is 

“any area used predominantly for single or multiple family dwellings with a density of at least 

two single-family units per acre and no large or busy highways.” Several constraints, imposed by 

the noise measurement system vehicle, limited the choice of locations in this measurement study.

The noise measurements were conducted using the ITS Radio Spectrum Measurement Science 

4

th Generation (RSMS-4G) Measurement Vehicle. A photograph of the measurement vehicle is 

shown in Figure 3. 

Figure 3. Photograph of the RSMS-4G measurement vehicle.

This vehicle provided some tremendous benefits for making measurements, including a highdegree of RF shielding (60 dB) between the measurement equipment and the antenna, AC power 

(from either external shore power, an external generator, or a built-in diesel generator), 

temperature control, and shelter. However, the vehicle also imposed some constraints on the 

measurements. The location needed to be able to accommodate the large RSMS-4G vehicle,

which is roughly 9 m (29 ft) long, 2.6 m (8.5 ft) wide, and 3.4 m (11.5 ft) tall. Further, 

permission needed to be obtained to park the truck in the same location 24 hours each day for at 
9

least three consecutive days. The large size of the vehicle also precluded any practical mobile 

measurements.

Since the vast majority of locations could not provide AC power to the vehicle, the vehicle’s 

built-in diesel generator was used to supply AC power for the equipment. Previous noise 

measurement system characterization measurements were taken in a radio quiet area in Boulder 

Canyon. The noise measurement system detected no appreciable radio noise from the built-in 

diesel generator. However, location selection required consideration of the audible noise 

produced by the generator. Since the measurements were taken over 24-hour time periods, this 

was a particular concern in residential locations. Security of the measurement vehicle, 

equipment, and personnel was also taken into account in location selection. Since the noise 

measurements were primarily automated and did not require measurement personnel to be 

present most of the time, security guards were employed to protect the vehicle and equipment.

Consideration of all of the constraints on selection of measurement locations led to the choice of 

one residential location and one business location in Boulder, Colorado, and one residential and 

one business location in Denver, Colorado.

5

Table 1 lists a description of these locations. Aerial 

photographs6of these locations, as shown in Figures 4–7, provide a better portrayal of the types 

of measurement environments.

Table 1. Description of noise measurement locations

Location Description of Location

Residential Boulder North edge of U.S. Dept. of Commerce Boulder Laboratories campus 

immediately adjacent to the residential area at King Ave. and 22nd St.

Business Boulder Downtown Boulder near Canyon Blvd. and 16th St.

Residential Denver Urban St. near West Colfax Ave. in Lakewood, Colorado

Business Denver Downtown Denver near Champa and 21st St.

 

5 The residential locations selected in this study were not strictly residential as defined above and in [6]; they were 

residential with some nearby businesses or busy roads. The residential location in Boulder, while adjacent to a 

strictly residential area, was also close to the U.S. Department of Commerce Boulder Laboratories. The residential 

location in Denver, while near several houses and on the edge of a strictly residential area, was also close to a large 

street with some businesses.

6 Data available from U.S. Geological Survey, Earth Resources Observation and Science (EROS) Center, Sioux 

Falls, SD.
10

Figure 4. Aerial photograph of residential measurement location in Boulder (courtesy of the 

U.S. Geological Survey). The marker near the bottom of the photograph shows the location of 

the residential Boulder spectrum survey measurements discussed in Section 4 and described in 

the Appendix.
11

Figure 5. Aerial photograph of business measurement location in Boulder (courtesy of the U.S. 

Geological Survey). 
12

Figure 6. Aerial photograph of residential measurement location in Denver (courtesy of the 

U.S. Geological Survey). 
13

Figure 7. Aerial photograph of business measurement location in Denver (courtesy of the U.S. 

Geological Survey).
14

4 NOISE MEASUREMENT FREQUENCY AND BANDWIDTH SELECTION

The selection of appropriate frequencies and bandwidths between 100 and 1000 MHz at which to 

perform the noise measurements required a good understanding of the radio environment at the 

proposed measurement locations. Since recent spectrum survey measurements in these areas 

were not available, a spectrum survey of the radio environment was required. To accomplish 

this, an automated swept spectrum measurement system was developed for frequencies between 

100 and 1100 MHz. A spectrum survey was then conducted at the four measurement locations 

proposed for the noise measurements. Details of the spectrum survey measurement system, 

measurement procedure, and results are provided in the Appendix.

4.1 Noise Measurement Bandwidth Selection

Before selection of the noise measurement frequencies, the bandwidth to be used in the noise 

measurements needed to be considered. Only relatively narrowband noise measurements (30 kHz 

or less) had been made in the past at ITS. There was considerable interest in making noise 

measurements in much wider bandwidths. Data taken in wide bandwidths can be processed 

directly or filtered to narrower bandwidths and then further processed. Therefore, data taken in 

wide bandwidths is more versatile than data taken in narrow bandwidths. However, there are 

significant challenges in making wideband noise measurements. The wider the bandwidth used 

for noise measurements, the more difficult it becomes to ensure that the noise measurements 

meet the requirement of being essentially free from intentionally radiated signals, and the more 

susceptible the measurements are to overload. Furthermore, if wideband noise data is going to be 

filtered to narrower bandwidths for statistical data processing such as APDs or mean power 

values, a longer data capture time (and hence more data storage) is required compared to that 

required for statistical processing of only the wideband data. The longer data capture time is 

required to ensure a sufficient number of independent samples for the computation of the 

statistics for the filtered noise data.

While wideband noise measurements were desirable and the noise measurement system can 

support measurements in bandwidths as wide as 36 MHz, it was difficult to find areas of the 

spectrum (particularly in the 100–200-MHz range) more than 1 MHz wide with no (or even very 

few) low-power intentionally radiated signals. Therefore, a 1-MHz measurement bandwidth was 

selected for the wideband noise measurements. 

4.2 Noise Measurement Frequency Selection

The received signal power versus frequency data shown in Figures A-2 to A-61 in the Appendix

were analyzed to determine three optimal frequencies at which to conduct the noise 

measurements. Ideally, these three frequencies would be spaced approximately an octave apart to 

provide a good characterization of how noise power varies with frequency. The selection of 

optimal frequencies included the consideration of the number and power levels of signals within 

and adjacent to a 1-MHz bandwidth (the bandwidth used for the wideband noise measurements). 

Consideration was also given to the types and database listings of licensed transmitters both 

within and outside the 1-MHz bandwidth. Where possible, to be able to best compare results, 
15

selection of frequencies near those studied in previous noise measurement efforts at ITS was 

attempted [3], [4].

In the selection of the first frequency, 137.5 MHz was considered as it had been used in previous 

noise measurements at ITS in the mid- to late 1990s [3], [4]. Those measurements, however, 

were conducted in a 30-kHz bandwidth. It was not possible to find 1 MHz of spectrum around 

137.5 MHz that was free from intentional emitters. However, Figures A-2–A-5 show that 

spectrum exists between 108 and 118 MHz that has some 1-MHz wide areas relatively free from 

intentional emitters. This band is allocated for VHF omnidirectional range (VOR) aeronautical 

navigation beacons [10]. Figure 8 shows an expanded view of the received signal power versus

frequency for all four measurement locations from 110 to 115 MHz. The resolution bandwidth 

(RBW), number of sweeps, and duration of each sweep are also given. Analyzing the spectrum 

in Figures A-2–A-5 and Figure 8, and using sectional aeronautical charts to identify the locations 

and operating frequencies of the VORs around the Denver area, a suitable noise measurement 

frequency was found at 112.5 MHz. (Note that VOR signals in the Denver area can be seen in 

the median plot in Figure 8.)

The frequency at the next octave would be 225 MHz. This is at the end of an amateur radio band 

and therefore was unsuitable for the noise measurements. Looking at the received signal power 

versus frequency data for all four measurement locations from 216 to 225 MHz in Figures A-14–

A-17 and the expanded view of the spectrum from 219 to 224 MHz in Figure 9, 221.5 MHz was 

identified as the best possible frequency to use for the second noise measurement frequency. 

This frequency falls within a band that is used for private land mobile radio and radiolocation 

[10]. 

The selection of the final noise measurement frequency was based on finding a frequency close 

to 402.5 MHz. This frequency was also used for previous noise measurements at ITS in the late 

1990s [4] and it is roughly an octave above 221.5 MHz. However, after examining the received 

signal power versus frequency data for all four measurement locations from 400 to 406 MHz in 

Figures A-22–A-25 and the expanded view of the spectrum from 400 to 404 MHz in Figure 10, 

401 MHz was chosen for the final noise measurement frequency. The 1 MHz of spectrum 

centered at 401 MHz includes bands allocated for meteorological aids; space operation and 

research; and meteorological, mobile, and earth exploration satellites [10].
16

Figure 8. Maximum, mean, and median received signal power at all measurement locations for 

110–115 MHz (RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
17

Figure 9. Maximum, mean, and median received signal power at all measurement locations for 

219–224 MHz (RBW = 3 kHz, 60 sweeps, sweep time = 900 ms).
18

Figure 10. Maximum, mean, and median received signal power at all measurement locations for 

400–404 MHz (RBW = 3 kHz, 60 sweeps, sweep time = 900 ms).
19

5 NOISE MEASUREMENTS

The noise measurement system and how it is optimized and verified are described in this section. 

The procedure used to collect the noise measurement data at all of the measurement locations 

and frequencies is then detailed.

5.1 Noise Measurement System

The noise measurements presented in this report were taken using a new, automated, wideband 

noise measurement system developed by ITS. Figure 11 shows a block diagram of the noise 

measurement system. The system consists of an antenna, ITS custom-built preselector, vector 

signal analyzer (VSA), thermostat control unit, and two personal computers.

Vector Signal Analyzer (VSA)

Thermostat Control Unit

1⁄4-Wave Monopole

Bandpass Filter Low-pass Filter Low Noise Amplifier Gain ~ 38dB Noise Figure ~ 0.8dB

Ethernet Switch

RSMS-4G Measurement Vehicle Thermostat

Thermostat Control Lines:

6 dB Firewire

VSA Computer Noise Measurement Preselector

Shielded Area in RSMS-4G Measurement Vehicle

Control Computer A/C Heat Fan

Noise Measurement Receiver

Figure 11. Block diagram of the noise measurement system installed in the RSMS-4G 

measurement vehicle.

For each distinct measurement frequency, a separate quarter-wave monopole antenna is required. 

Each antenna is carefully tuned to the measurement frequency and mounted on a circular ground 

plane with a diameter of approximately 1.3 m that is attached to the roof of the RSMS-4G 
20

vehicle. The ground plane diameter corresponds to roughly 0.5, 1.0, and 1.7 wavelengths at 

112.5, 221.5, and 401 MHz, respectively. An indication of the frequency response of the 

antennas can be seen from the plots of VSWR versus normalized frequency shown in Figure 12.

Figure 12. VSWR versus normalized frequency for the quarter-wave monopole antennas.

Man-made noise is believed to arrive at the receive antenna at relatively low elevation angles and 

from widely distributed directions [11]. The quarter-wave monopole antenna mounted on a 

circular ground plane was chosen for the noise measurements in this study because it provides an 

omnidirectional, azimuthal pattern and good gain at the horizon and at relatively low elevation 

angles. Using the same antenna type for different noise measurement studies makes it easier to 

provide a comparison of the results. This was another reason why quarter-wave monopoles over 

a ground plane were used; noise measurements at ITS in the 1990s [3], [4] used the same antenna 

type. Electrically short monopoles over a ground plane, which also have an omnidirectional,

azimuthal pattern and a similar elevation pattern as the quarter-wave monopole, were used for 

the measurements on which the current ITU model for man-made noise is based [6].

The custom built preselector consists of a fixed-cavity bandpass filter centered on the 

measurement frequency; a fixed, low-pass filter with a cutoff frequency just above the bandpass 

filter stopband (to attenuate repeated bandpass responses); a low-noise amplifier; and some 

attenuators to adjust the gain of the overall preselector. All of these components are housed 

inside an RF shielded box.
21

For each measurement frequency, the appropriate fixed bandpass and low-pass filters are

installed in the preselector shielded box; changing frequencies requires that a different set of 

filters be installed. Fixed bandpass filters are used instead of tunable ones to achieve a very steep 

roll-off and low insertion loss. The bandpass filters have an insertion loss of less than 1.9 dB 

over a bandwidth of at least 1 MHz and an attenuation of 50–60 dB beyond ±5 MHz from the 

center frequency. The 1-MHz passband amplitude variation is less than 0.25 dB with a deviation 

from linear phase less than ±5o.

The core of the new measurement system is the VSA. This instrument is capable of recording 

digitized in-phase (I) and quadrature (Q) samples in up to 36 MHz of bandwidth. The ability to 

record I and Q data, properly sampled at a rate above Nyquist, makes it possible to process the 

noise data in ways that were not possible with many previous noise measurement systems that 

only recorded amplitude data. With the I and Q data it is possible not only to obtain noise 

amplitude statistics such as APDs, but also to fully characterize the time and frequency domain 

characteristics of the noise data. Properly sampled data can also be filtered to narrower 

bandwidths. In addition, the I and Q data are valuable because they can be used in simulations. 

The VSA is controlled by commercial software operating on a dedicated personal computer as 

shown in Figure 11.

The thermostat control unit consists of three Ethernet-controlled electro-mechanical relays. 

These relays are placed in-line with the RSMS-4G measurement vehicle thermostat control lines 

for the fan, air conditioner (A/C), and heater. The fan, A/C, and heater are disabled by the noise 

measurement software during noise data acquisition. This eliminates any possibility of the noise 

measurement system measuring unintentional RF emissions from this equipment.

The noise measurement software operates on a personal computer, labeled as the control 

computer in Figure 11. The software controls both the VSA and the thermostat control unit. The 

software allows the user to set the VSA measurement frequency, bandwidth (span), number of 

data points to collect, input range, and other parameters. Once the measurement is started, it will 

automatically collect data at user-defined time intervals for a user-specified duration. The 

capability to perform and display results of noise diode calibrations, spectrum captures, and 

single, manual noise measurement data captures is also included in the software.

For the noise measurements taken in this study, the measurement system was installed in the 

RSMS-4G measurement vehicle as discussed in Section 3. Figure 13 shows a photograph of the 

noise measurement system equipment set up inside the measurement vehicle.
22

Figure 13. Photograph of the noise measurement system installed in the RSMS-4G measurement 

vehicle.

5.2 Noise Measurement System Optimization and Verification

Assuming an input range setting of -30 dBm on the VSA7in the noise measurement system, the 

preselector gain was adjusted, with the use of attenuators, such that the overall measurement 

system dynamic range was maximized while maintaining a noise figure of approximately 3 to 

4 dB over the selected noise measurement frequencies. In order to avoid VSA overloads from 

impulsive noise in the field, it was necessary to increase the input attenuation in the front end of 

the VSA by 15 dB8. This improved the overall dynamic range of the noise measurement system 

by 13 dB but degraded the sensitivity by 2 dB. Therefore, the resulting noise figure of the overall 

system varied from 5 to 6 dB over the selected noise measurement frequencies with a dynamic 

range of approximately 69 dB.

The measurement system was set up to determine the variation in receiver noise figure Fr over a 

24-hour period. To accomplish this, the antenna was disconnected and replaced by a 50 Ω load. 

 

7 The input range setting on the VSA controls its sensitivity and dynamic range. A setting of -30 dBm provides an 

optimal balance between good VSA sensitivity and high dynamic range.

8 The input attenuation in the front end of the VSA is increased by 15 dB by increasing the input range setting on the 

VSA from -30 dBm to -15 dBm.
23

The preselector was configured with the bandpass and low-pass filters for measurements at a 

112.5 MHz center frequency. The receiver noise figure was measured in a 1-MHz bandwidth 

over a 24-hour period. The variation in the receiver noise figure was seen to be less than 

±0.25 dB. Measurements of the receiver noise figure at both 221.5 and 401 MHz showed a 

similar variation.

5.3 Noise Measurement Procedure

The noise measurements were conducted at the four locations described in Section 3. At each 

location, before beginning the measurements, the preselector was configured with the proper 

bandpass and low-pass filters corresponding to the desired measurement frequency. Next, the 

quarter-wave monopole antenna tuned to the correct frequency was installed on the ground plane 

mounted on the roof of the vehicle. The equipment was turned on and allowed to warm up for at 

least 30 minutes. Using a commercial cable and antenna analyzer, the antenna VSWR was 

measured to help verify that the antenna was working properly. After verifying proper antenna 

operation and ensuring that the equipment had been sufficiently warmed up, the noise 

measurement software was initiated.

Before starting the noise measurements, the signal environment around the measurement center 

frequency was observed using the VSA spectrum display with a span of 36 MHz (the maximum 

VSA span) and an input range of -30 dBm. The VSA display was first observed to determine the 

occurrence of any overloads. As mentioned in Section 5.2, it was necessary to increase the input 

attenuation in the front end of the VSA by 15 dB to prevent VSA overloads due to impulsive 

noise.

Once the input range was set, the VSA spectrum display was checked for any obvious signals 

within a measurement span of 1.16 MHz about the center frequency. If there were noticeable 

signals within this span then the VSA measurement center frequency was adjusted slightly 

(550 kHz at most) so the signals would occur outside of the span.9 Care was taken to keep the 

entire measurement span within the RF filter’s flat magnitude response and relatively linear 

phase region. The frequency allocations of the bands the measurement span encompassed were 

also taken into consideration.

The gain and noise figure of the system were then determined by performing a noise diode 

calibration as described in Section A.2.

The system gain and noise figure values are used to verify the proper operation of the 

measurement system. The resulting measured system gain and noise figure values for each 

measurement frequency and location are shown in Table 2.

 

9

For better readability of this report, the center frequencies used for the measurements are stated as being taken at 

the nominal center frequencies of 112.5, 221.5, and 401 MHz even when the actual measurement frequencies were 

slightly different.
24

Table 2. Measured system gain and noise figure at each measurement frequency and location

Approx. Center Frequency

 112.5 MHz 221.5 MHz 401 MHz

Location Gain

(dB)

Noise 

Figure (dB)

Gain

(dB)

Noise 

Figure (dB)

Gain

(dB)

Noise 

Figure (dB)

Boulder Residential 32.7 5.1 32.5 5.3 32.2 6.0

Denver Residential 32.2 5.5 32.4 5.4 32.0 6.0

Boulder Business 32.6 5.5 32.1 5.5 32.2 6.0

Denver Business 32.7 5.1 32.1 5.6 32.2 6.0

Following the noise diode calibration, single noise data record captures, both with a 50 Ω 

dummy load and with the quarter-wave monopole antenna, were performed to ensure that the 

system was working properly. First, the antenna was replaced by a 50 Ω dummy load and a 

single noise data record was captured using the manual measurement capability within the noise 

measurement software. Next, the antenna was reconnected and another noise data record was 

captured. The APDs of both captures were then computed and displayed using the noise 

measurement software. APDs provide a convenient way of displaying the amplitude 

characteristics of noise. Explanations of APDs and how they are computed are given in [12] and

[13].

The APD corresponding to the 50 Ω load capture was expected to be a straight line with the 

same slope as, but higher amplitude than, an APD generated from simulated complex Gaussian 

noise with a thermal noise power within the receiver bandwidth. The APD corresponding to the 

50 Ω load capture was expected to be higher in amplitude than the APD of complex Gaussian 

noise by the noise figure of the measurement system. The APD corresponding to the capture with 

the antenna connected was seen to vary considerably depending on the location, frequency, and 

time of the capture.

After confirmation that the measurement system was working properly, the noise measurement 

software was set up to collect noise data automatically for a 24-hour period. The measurements 

were set up so that every 10 minutes a noise data record consisting of six million I and Q data 

samples was taken in a 1.16-MHz VSA span.10 The reason that six million data samples were 

collected is that it ensures that one million independent data samples are available to compute 

APDs. This is covered in more detail during the discussion of APDs in Section 6.1.

The 24-hour automated noise measurements were then initiated. Before leaving the measurement 

system unattended, the measurements were observed for at least 20 minutes to ensure that VSA 

overloads were not occurring and that the air conditioner, heater, and fan did not run during the 

data acquisition. Once the 24-hour data collection was complete, the data were saved to a 

portable external hard drive as a backup.

 

10 The 1.16-MHz VSA span is the closest cardinal span available on the VSA to the desired 1-MHz noise 

measurement bandwidth. VSA cardinal spans use hardware decimation filters while other VSA spans use additional 

software filtering. Cardinal spans are used since they provide much faster recording of the data.
25

If a VSA overload occurred for a particular six-million-sample data capture, it was thrown out 

and not included in the data analysis. At most locations and frequencies either no VSA overloads 

occurred at all or one VSA overload occurred out of 144 data captures. The most VSA overloads 

occurred at a center frequency of 112.5 MHz at the Boulder residential location where a VSA 

overload occurred in 9 out of 144 data captures.
26

6 DATA ANALYSIS

The first type of data analysis examines characteristics of the individual noise data records. The 

second type of data analysis examines noise power statistics over a 24-hour period.

As mentioned previously, a noise data record consists of six million I and Q noise data samples 

that were collected in a 1.16-MHz VSA span every 10 minutes over a 24-hour time period for 

each frequency and location. Before analyzing the data, each noise data record is filtered in 

software using a low-pass finite impulse response (FIR) filter with a 0.01 dB ripple, 500-kHz

bandwidth (1-MHz double-sided bandwidth) that provides a 60 dB double-sided bandwidth of 

1.16 MHz. Note that frequencies in the noise data record obtained from the VSA between 1.16 

MHz and the double-sided Nyquist frequency of 1.484375 MHz can contain aliased components. 

These aliased components have already been attenuated by at least 20 dB by the VSA. The lowpass FIR filter ensures that any aliased components are attenuated by at least 80 dB.

The I and Q data samples in each noise data record represent complex envelope voltage values of 

the noise. These samples are converted to magnitude values and scaled by a factor of 

1/ 2

to 

ensure the correct total average power [14] and form a scaled-magnitude noise data record.

6.1 Time Domain Characteristics and APDs of Individual Noise Data Records

First, the time domain characteristics of the individual noise data records are examined. The 

samples in the scaled-magnitude noise data records are converted to power received at the input 

to the VSA in dBm. The overall system noise power, at the antenna output terminals, is obtained 

by subtracting the gain of the measurement system in dB (defined as the gain from the antenna 

output terminals to the input of the VSA) from the noise power at the input to the VSA (see 

Figure 11).

Figure 14 provides an example of a time domain plot showing 60 ms of a noise data record taken 

at the residential Boulder location at a center frequency of 112.5 MHz at 0349 on September 1, 

2009. In this plot it is possible to see evidence of 60 Hz unintentional emissions from the AC 

power distribution system. Evidence of 60 Hz unintentional emissions is seen in at least some of 

the noise data records at every measurement location and frequency. Harmonics of 60 Hz are 

also noted in many of the noise data records.

Next, APDs of the individual noise data records are examined. To compute the APD, the six 

million data samples in each scaled-magnitude data record are first decimated by a factor of six 

to ensure that the resulting samples are independent of correlation introduced by the 

measurement system. The first L samples out of the remaining one million samples (where L is 

the number of taps in the FIR filter) are discarded to ensure that the filter has settled. An APD is 

then computed [13] using the remaining samples. The amplitude values in the APD are 

converted into values of overall system noise power following the same procedure described 

above for the time domain characteristics. Figures 15–18 show example APDs along with the 

APD of the measured receiver noise power as a reference.
27

Figure 14. Example time domain plot showing 60 ms of a noise data record from the residential 

Boulder location at 0349 on September 1, 2009 with a 112.5-MHz center frequency and 1.16-

MHz span.

Figure 15 shows the APD from the same noise data record used to produce the time-domain plot 

seen in Figure 14. Figures 16–18 provide example APDs from other noise measurement 

locations and frequencies. In the example APD in Figure 15, with a 112.5-MHz center 

frequency, note the increased power levels at percent exceeding ordinate values corresponding to 

the reciprocal of 60 Hz and 120 Hz (1.6 % and 0.8 %, respectively). This indicates the presence 

of noise from the AC power distribution system. This is not seen in the APDs at higher 

frequencies (Figures 16 and 17).

Impulsive noise is present in the vast majority of the noise data records. At the 401-MHz

measurement frequency and residential measurement locations, Gaussian noise without 

impulsive noise is observed more often than at the other measurement frequencies, but still only 

occasionally. Figures 15–17 provide good examples of what impulsive noise looks like in an 

APD. Figure 18 shows what appears to be primarily Gaussian noise that is elevated substantially 

above the measured receiver noise power.
28

Figure 15. Example APD from the residential Boulder location at 0349 on September 1, 2009

with a 112.5-MHz center frequency and 1.16-MHz span.

Figure 16. Example APD from the Denver business location at 0723 on August 19, 2009 with a

221.5-MHz center frequency and 1.16-MHz span.
29

Figure 17. Example APD from the Boulder business location at 1211 on July 22, 2009 with a 

401-MHz center frequency and 1.16-MHz span.

Figure 18. Example APD from the Denver residential location at 2319 on July 29, 2009 with a 

112.5-MHz center frequency and 1.16-MHz span.
30

6.2 Median, Mean, and Peak Noise Power Analysis

The first type of data processing for statistically summarizing all of the noise data collected

provides the median, mean, and peak power of the overall measured system noise power

(expressed in dB above kT0b) for each scaled-magnitude noise data record collected. Note that 

for the purposes of this report, as in [3] and [4], the peak noise power is defined as the noise 

power level exceeded 0.01% of the time.

The procedure for computing the median, mean, and peak noise power follows that for 

computing the APD as described in Sections 6 and 6.1, with the exception that median, mean, 

and peak noise power values are computed instead of the APD for each scaled-magnitude noise 

data record. Figures 19–30 show the median, mean, and peak noise power (bottom, middle, and 

top curves of each figure, respectively) for each noise data record taken every 10 minutes over a 

24-hour period and for each measurement frequency and location.

The mean and peak noise power plots in Figures 19–30 typically show, as would be expected, 

that the noise power is higher during the day than during the night. At most of the frequencies 

and locations the noise is clearly non-Gaussian, as the peak noise power is more than 10 dB 

greater than the mean noise power. (For complex Gaussian noise, the peak noise power is 9.6 dB 

greater than the mean noise power.) The noise appears as if it may be Gaussian during the 

nighttime hours (between 2000 and 0800) for the 401-MHz data at the residential location in 

Boulder (Figure 21) and during some of the time between 0200 and 0600 for the 401-MHz data 

at the residential location in Denver (Figure 27).

The mean noise power was substantially higher than the system noise power (the system noise 

power was between 5 and 5.5 dB above kT0b) for the measurements around 112.5 MHz at all 

locations. At around 221.5 MHz, the mean noise power was substantially higher than the system 

noise power (the system noise power was approximately 5.5 dB above kT0b) at the business 

locations at all times of the day, at the residential location in Boulder between 1000 and 2000, 

and at the residential location in Denver only at certain times between 1000 and 1600. The mean 

noise power was close to or slightly above the system noise power (the system noise power was 

6.0 dB above kT0b) for the measurements at 401 MHz at all locations. For the 401-MHz

measurements, the mean noise power was slightly higher in the business locations than in the 

residential locations and also slightly higher during business hours than during non-business 

hours.

The median power generally varied less than the mean or peak power for almost all of the 

frequencies and locations. An exception to this is for the 112.5-MHz residential location in 

Denver (Figure 25) where the mean and median power vary similarly. The peak power varied 

significantly for all frequencies and locations.

Man-made radio noise power is often characterized by analyzing how the noise power statistics 

(such as mean power) vary over time and between locations and also by computing statistics 

(such as the median) of these noise power statistics [3], [4], and [6]. Therefore, the median, 

mean, and peak noise power statistics were used as a starting point for further analysis.
31

Figure 19. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 112.5 MHz at the Boulder residential location (August 31–September 1, 2009).

Figure 20. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 221.5 MHz at the Boulder residential location (September 3–4, 2009).
32

Figure 21. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 401 MHz at the Boulder residential location (September 2–3, 2009).

Figure 22. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 112.5 MHz at the Boulder business location (July 21–22, 2009).
33

Figure 23. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 221.5 MHz at the Boulder business location (July 20–21, 2009).

Figure 24. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 401 MHz at the Boulder business location (July 22–23, 2009).
34

Figure 25. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 112.5 MHz at the Denver residential location (July 29–30, 2009).

Figure 26. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 221.5 MHz at the Denver residential location (July 28–29, 2009).
35

Figure 27. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 401 MHz at the Denver residential location (July 27–28, 2009).

Figure 28. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 112.5 MHz at the Denver business location (August 17–18, 2009).
36

Figure 29. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 221.5 MHz at the Denver business location (August 18–19, 2009).

Figure 30. Median, mean, and peak measured noise power in a 1-MHz bandwidth at a center 

frequency of 401 MHz at the Denver business location (August 19–20, 2009).
37

6.3 Complementary Cumulative Distributions of Hourly Median Noise Power

To further analyze the data, first, an hourly median value is determined for the median, mean, 

and peak noise power for each noise data record that was taken every 10 minutes over a 24-hour 

period for each frequency and location.

11 Then the complementary cumulative distribution of the 

hourly median values is determined for each frequency and location type (residential and 

business). Data from both residential locations are grouped together and data from both urban 

locations are grouped together for this analysis. The complementary cumulative distribution of 

the hourly median values of the median, mean, and peak powers are plotted on normal 

probability paper in Figures 31–36 as the bottom, middle, and top curves of each figure, 

respectively.

On normal probability paper, Gaussian-distributed data appears as a straight line with the slope 

indicating the standard deviation. The hourly medians of the mean powers appear to be roughly 

Gaussian distributed for both the 401-MHz residential and urban locations as seen in Figures 33

and 36. General conclusions about the distributions at other frequencies are not readily apparent.

6.4 Statistics of the Hourly Medians of Mean Noise Power

The most useful statistic, from a standpoint of being able to compare with results from previous 

noise measurement studies, is the median of the hourly medians of the mean powers denoted as 

Fm [4]. This statistic can be found from the 50% point on the complementary cumulative 

distribution plots of the mean power (middle curve in Figures 31–36).

Tables 3 and 4 show the values for both Fm and the standard deviation of the hourly medians of 

the mean powers (σ) for each measurement frequency. When Fm > (Fr + 0.5 dB), values of Fam

are obtained from values of Fm by applying (7). Requiring Fm > (Fr + 0.5 dB) ensures that the 

variation in Fam due to variation in Fr is less than ±0.75 dB. This can be shown using (7) with an 

Fr of 5 or 6 dB and a variation in Fr of ±0.25 dB.12 Note that the larger Fm is compared to Fr, the 

less impact variation in Fr has on Fam. Values of Fam and the corresponding standard deviation 

σa, when applicable, are also shown in Tables 3 and 4.

The values shown in the first four columns of Tables 3 and 4 were derived from the data taken 

over 24 hours for each frequency. Because the mean noise power is typically highest during 

business hours (0800–1700) and the data taken to develop the ITU man-made radio noise model 

[2] and [6] was only taken during business hours, additional values of Fam and σa are also 

computed from data taken only during business hours. These additional values are also shown in 

Tables 3 and 4.

 

11 Because the hourly median is computed based on six values, the median is found by taking the third and fourth 

ranked values and averaging them.

12 Recall from Section 5.2 that the variation in Fr was measured and found to be less than ±0.25 dB.
38

Figure 31. Complementary cumulative distribution of the hourly median values of the median, 

mean, and peak powers in a 1-MHz bandwidth at a center frequency of approximately 

112.5 MHz over both residential locations.

Figure 32. Complementary cumulative distribution of the hourly median values of the median, 

mean, and peak powers in a 1-MHz bandwidth at a center frequency of approximately 

221.5 MHz over both residential locations.
39

Figure 33. Complementary cumulative distribution of the hourly median values of the median, 

mean, and peak powers in a 1-MHz bandwidth at a center frequency of 401 MHz over both 

residential locations.

Figure 34. Complementary cumulative distribution of the hourly median values of the median, 

mean, and peak powers in a 1-MHz bandwidth at a center frequency of approximately 

112.5 MHz over both business locations.
40

Figure 35. Complementary cumulative distribution of the hourly median values of the median, 

mean, and peak powers in a 1-MHz bandwidth at a center frequency of approximately 

221.5 MHz over both business locations.

Figure 36. Complementary cumulative distribution of the hourly median values of the median, 

mean, and peak powers in a 1-MHz bandwidth at a center frequency of 401 MHz over both 

business locations.
41

Table 3. Statistics of the hourly medians of the mean noise power for residential locations

Time of Day for Data Collection

 

0000–2400 0000–2400 0800–1700

Frequency 

(MHz)

Fm (dB) σ (dB) Fam (dB) σa (dB) Fam (dB) σa (dB)

112.5 16.7 4.4 16.5 4.6 18.2 5.5

221.5 6.6 2.9 3.3 4.3 9.3 4.7

401 5.5 1.0 † † † †

†

Values of Fam and σa are not computed because not all of the hourly medians of the mean powers are greater than 

0.5 dB above the receiver noise figure Fr.

Table 4. Statistics of the hourly medians of the mean noise power for business locations

Time of Day for Data Collection

 

0000–2400 0000–2400 0800–1700

Frequency 

(MHz)

Fm (dB) σ (dB) Fam (dB) σa (dB) Fam (dB) σa (dB)

112.5 27.2 2.1 27.2 2.2 28.1 1.5

221.5 15.3 3.8 14.9 4.0 16.7 2.4

401 7.3 0.7 3.8 1.5 4.1 1.6

Several trends become apparent when looking at the data in Tables 3 and 4. For both residential 

and business locations, as expected, Fam decreases with increasing frequency. Note that for the 

401 MHz case, for the residential locations, Fm was too small (relative to Fr) to obtain a good 

estimate of Fam. Also as expected, for a given frequency, Fam is significantly larger in the 

business locations than in the residential locations. Finally, as might be surmised by studying the 

plots of the median, mean, and peak noise power variation over 24 hours (Figures 19–30), values 

of Fam are larger for data taken just over the business hours as compared to those taken over all 

hours.

6.5 Comparison of Measured Results with Models

The current ITU model showing median values of man-made radio noise power is based on 

measurements that were taken from 1966 to 1971. These measurements were briefly described in 

Section 2.3; a more detailed description is found in [6]. One of the primary objectives of the 

current measurement study is to help determine if levels of man-made radio noise have changed 

since the measurements used for development of the ITU man-made radio noise model were 

made. In this section, the results of the current measurement study are compared to those 

predicted by the ITU model. Before comparing the results, it is important to understand the 

differences in how the measurement data were collected and processed.
42

The measurements used to develop the ITU model were taken with a measurement system that 

records a root mean square (rms) envelope voltage (among other parameters) every 10 seconds in 

a 4-kHz equivalent noise bandwidth. An effective antenna noise figure Fa is determined from 

each rms voltage. The data were processed by first separating the data according to environment 

type (business, residential, or rural). For each mobile measurement run, the median Fa (Fam), the 

ratio of the upper decile to Fam (Du) , and the ratio of Fam to the lower decile (Dl) were computed 

for each of the eight frequencies measured. (The frequencies ranged from 0.25 to 250 MHz.)

Linear regression was used on the Fam values for all measurement runs and for all frequencies 

within an environment type to determine the best straight line approximation of Fam as a function 

of frequency. For each frequency within an environment type, the standard deviation of Fam

values was calculated providing an indication of the variation in Fam from location to location 

[6]. The expected variation of the Fa values about Fam within the hour for a location was found 

by taking the rms of all the Du values and the rms of all of the Dl values for each location and 

frequency within an environment type. Table 5 summarizes some of the major differences 

between the measurements taken for the data used in developing the ITU model and the 

measurements taken in this study.

Table 5. Major differences between measurements used in the ITU Model and measurements 

taken for this study

Measurements for this Study Measurements Used in ITU Model

1-MHz 0.25 dB bandwidth 4-kHz noise equivalent bandwidth

Fixed location measurements Mobile measurements

Few locations measured for a relatively long 

time duration at each location

Many locations measured for relatively short 

duration mobile measurement runs

Duration of measurement at each location = 

24 hours

Duration of measurement runs = 15 min to 

more than 1 hour

Fam = median of hourly medians of Fa Fam = linear regression of medians of Fa

To provide a better comparison between the results of the current measurement study and the 

ITU model, the measurement data from the current study was reprocessed using a filter with a 4-

kHz noise equivalent bandwidth instead of the 1-MHz filter.13

Tables 6 and 7 show the comparison between Fam and its standard deviation σa from this study 

(for the 4-kHz filtered data taken over only the business hours) and Fam and its standard 

deviation σaL (location variability) from the data used in the ITU model for the residential and 

business environments, respectively.

14 Values of σaL are found by using linear interpolation of 

the measured standard deviation values found in Table 1 of [6]. Tables 6 and 7 also show Fam

values for the Hagn model.

 

13 Specifically, before reprocessing the data, each noise data record was filtered using a low-pass FIR filter with a 

0.01 dB, 1.88-kHz bandwidth (3.76 kHz double-sided bandwidth) that provides a 60 dB double-sided bandwidth of 

4.35 kHz (see Section 6).

14 Recall that measured values of Fam and σa from this study were determined from data taken in residential locations 

that were not strictly residential. The predicted values from the ITU model are for strictly residential locations.
43

Table 6. Comparison of measured and predicted values of Fam for residential locations14

Current Measurements ITU Model Hagn 

Model

Approx. Center 

Frequency (MHz) Fam (dB) σa (dB) Fam (dB) σaL (dB) Fam (dB)

112.5 17.8 5.9 15.7 2.7 ‡

221.5 8.9 4.8 7.5 2.8 8.1

401 * * † † 4.0

* Values of Fam and σa are not computed because not all of the hourly medians of the mean powers are greater than 

0.5 dB above the receiver noise figure Fr.

† Values of Fam for frequencies above 250 MHz are not defined in the ITU Model.

‡ Hagn [7] recommends using values of Fam predicted by the ITU Model for frequencies below 200 MHz.

Table 7. Comparison of measured and predicted values of Fam for business locations

Current Measurements ITU Model Hagn 

Model

Approx. Center 

Frequency (MHz) Fam (dB) σa (dB) Fam (dB) σaL (dB) Fam (dB)

112.5 28.1 1.4 20.0 8.4 ‡

221.5 15.5 2.5 11.8 4.7 12.3

401 * * † † 8.3

* Values of Fam and σa are not computed because not all of the hourly medians of the mean powers are greater than 

0.5 dB above the receiver noise figure Fr.

† Values of Fam for frequencies above 250 MHz are not defined in the ITU Model.

‡ Hagn [7] recommends using values of Fam predicted by the ITU Model for frequencies below 200 MHz.

To facilitate the comparison, Figures 37 and 38 provide a graphical representation of the Fam data 

given in Tables 6 and 7. Also included in these figures are values of Fam from the 137.5 MHz 

measurements taken by ITS from 1996 to 1997 [3] and from the 209.5 and 425 MHz 

measurements taken in the United Kingdom by MASS Consultants Limited in 2006 [9].
44

Figure 37. Comparison of measured and predicted values of Fam and standard deviation of Fam

for residential locations.

14

Figure 38. Comparison of measured and predicted values of Fam and standard deviation of Fam

for business locations.
45

For the business locations at 112.5 and 221.5 MHz, measured values of Fam found in this study,

for the 4-kHz filtered data, were larger than predicted with the ITU and Hagn models. However, 

the measured values of Fam are within a standard deviation of Fam from the ITU model.

For the residential locations, the measured values of Fam , for the 4-kHz filtered data, were also 

larger at 112.5 and 221.5 than predicted with the ITU and Hagn models. However, for the 

residential locations, the measured values and the values predicted from the models were closer 

to agreement than for the business locations. The measured values of Fam are clearly within one 

standard deviation of Fam from the ITU model. (Note that the standard deviation is much smaller 

for the residential locations than for the business locations in the ITU model.)

For both the business and residential locations at 401 MHz, values of Fam and σa are not 

computed for the 4-kHz filtered data because not all of the hourly medians of the mean powers 

are greater than 0.5 dB above the receiver noise figure Fr.

A quantitative assessment of within the hour variation of Fa values was not performed for this 

study. Therefore, no comparison for within the hour variation is given. However, within the hour 

variation of Fa values can be observed qualitatively from the mean noise power curves in Figures 

19–30. Each mean noise power curve shows six measured values of Fa per hour over a 24-hour 

period for a particular frequency and location. Over many of the hourly intervals, Fa does not 

change much; however, a few hourly intervals do show significant variation in Fa.
46

7 SUMMARY AND CONCLUSIONS

This report discussed an initial set of man-made radio noise measurements that were taken in the 

Boulder/Denver, Colorado, area in the summer of 2009. The measurement locations were chosen 

to represent as closely as possible typical residential and business areas as defined in [6]. One 

residential and one business location in Boulder and one residential and one business location in 

Denver were selected. 

The selection of appropriate frequencies between 100 and 1000 MHz at which to perform the 

noise measurements required a good understanding of the radio environment at the proposed 

measurement locations. Since recent spectrum survey measurements in these areas were not 

available, a spectrum survey of the radio environment was performed. Based on the subsequent 

analysis of the spectrum survey data, noise measurement frequencies of 112.5, 221.5, and 401 

MHz were selected.

While wideband noise measurements were desirable and the noise measurement system could 

support measurements in up to a 36-MHz bandwidth, it was difficult to find areas of the 

spectrum (particularly in the 100–200-MHz range) more than 1 MHz wide with no (or even very 

few) low-power intentionally radiated signals. Therefore, a 1-MHz measurement bandwidth was 

selected for the wideband noise measurements.

The noise measurements presented in this report were taken using the new, automated, wideband 

noise measurement system developed by ITS and installed in the ITS RSMS-4G measurement 

vehicle. This vehicle provided significant advantages for making measurements, including a 

high-degree of RF shielding (60 dB) between the measurement equipment and the antenna, AC 

power (from either external shore power, an external generator, or a built-in diesel generator), 

temperature control, and shelter. Noise measurement data were collected in a 1.16-MHz VSA 

span at all locations and frequencies.

The data were analyzed to show the characteristics of individual noise data records and to 

provide various statistical descriptions of the noise. Some example APDs of individual noise data 

records were given along with an example time domain display of a noise data record clearly 

showing the presence of 60 Hz noise indicative of unintentional emissions from the AC power 

distribution system. The statistical summary data included the median, mean, and peak noise 

power levels over a 24-hour time period at each measurement location and frequency. 

Complementary cumulative distributions of the hourly median values of the median, mean and 

peak power were also given for each frequency and environment type. Finally, median values of 

the antenna noise figure Fam were determined for each measurement frequency and environment 

type and compared to those predicted by the ITU model and, alternatively, the Hagn model.

For the business locations at 112.5 and 221.5 MHz, this study found that measured values of Fam

were larger than predicted with the ITU and Hagn models. However, the measured values of Fam

were still within a standard deviation of Fam from the predicted values using the ITU model.

For the residential locations, the measured values of Fam were also larger at 112.5 and 

221.5 MHz than predicted with the ITU and Hagn models. However, for the residential locations, 

the measured values and the values predicted from the models were closer to agreement than for 
47

the business locations. The measured values of Fam were clearly within one standard deviation of 

Fam as predicted by the ITU model. (Note that the predicted standard deviation values for the 

residential locations in the ITU model are much smaller than those for the business locations.)

The measurements taken for this study, while collected over a 24-hour period, were only from 

two separate locations for each environment type and frequency. It is possible that the specific 

measurement locations chosen for this noise measurement study unduly influenced the measured 

Fam values. The business locations that were selected were in downtown areas and these 

locations may have higher noise levels than other business locations as defined in Section 3 and 

[6]. The measurement vehicle was located near some overhead power lines in both the Denver 

and Boulder business locations. 

The residential locations selected in this study were not strictly residential; they were residential 

with some nearby businesses or busy roads. The residential location in Boulder, while adjacent to 

an exemplary residential area, was also close to the U.S. Department of Commerce Boulder 

Laboratories. The residential location in Denver, while near several houses and on the edge of a 

residential area, was also close to a large street with some businesses. It was also line-of-sight to 

FM and television broadcast antennas located nearby on Lookout Mountain in Golden, Colorado. 

Therefore, the noise levels measured in residential locations for this study may have been higher 

than in more strictly residential locations.

Based on these factors, it is recommended that further noise measurements be taken in a greater 

number of locations to provide some more statistically significant results and therefore a better 

comparison to the values predicted by the existing models.
48

8 ACKNOWLEDGEMENTS

The authors would like to thank the following individuals for their efforts in helping achieve the 

objectives of this study. Robert Achatz and Roger Dalke provided invaluable advice and 

guidance during the planning and execution of the measurements and the data analysis. Raian 

Kaiser determined appropriate measurement locations and handled all of the many logistics 

involved in the selection and use of those locations. Ms. Kaiser also contributed much needed 

support in performing some of the spectrum survey and noise measurements. A special thanks 

goes to Randy Hoffman who had the foresight, vision, and drive to establish a modern noise 

measurement program at ITS. Mr. Hoffman was also instrumental in the development of the 

software used in making the spectrum survey measurements. Without the assistance of these 

individuals, this work would not have been possible.
49

9 REFERENCES

[1] L. Barclay, “Radio noise: Recent considerations of man-made noise,” in Proc 

International Symposium on Advanced Radio Technologies/ ClimDiff 2008, Boulder, 

Colorado, Jun. 2–4, 2008, pp. 17–24 (NTIA Special Pub SP-08-452, Jun. 2008).

[2] ITU-R Recommendation P.371-10 (10/2009), “Radio noise,” Recommendations of the 

ITU, Radiocommunication Sector.

[3] R. J. Achatz, Y. Lo, P. B. Papazian, R. A. Dalke, and G. A. Hufford, “Man-made noise in 

the 136 to 138-MHz VHF meteorological satellite band,” NTIA Report 98-355, Sep. 

1998.

[4] R. J. Achatz and R. A. Dalke, “Man-made noise power measurements at VHF and UHF 

frequencies,” NTIA Report 02-390, Dec. 2001.

[5] A. D. Spaulding, “Man-made noise: The problem and recommended steps toward 

solution,” OT Report 76-85, Apr.1976.

[6] A. D. Spaulding and R. T. Disney, “Man-made radio noise part 1: Estimates for business, 

residential, and rural areas,” OT Report 74-38, Jun. 1974.

[7] G. H. Hagn, “Man-made radio noise and interference,” in Proc. of the 1987 AGARD 

Conference, No. 420, Lisbon, Portugal, Oct. 26–30, 1987, pp.5.1–5.15.

[8] W.R. Lauber and J.M. Bertrand, “Man-made noise level measurements of the UHF radio 

environment,” in Proc. of the 1984 IEEE National Symposium on EMC, San Antonio, 

TX, Apr. 24–26, 1984, pp. 185–192.

[9] A.J. Wagstaff and N.P. Merricks, “Autonomous interference monitoring system phase 2 

final report, vol. 1—summary report, issue 1,” MASS Consultants Limited 

MC/SC0585/REP016/1, Mar. 2007.

[10] National Telecommunications and Information Administration, “Manual of regulations 

and procedures for federal radio frequency management (Redbook),” May 2010 Revision 

of the Jan. 2008 Edition.

[11] R. Dalke, “Radio noise,” in The Wiley Encyclopedia of Electrical and Electronics 

Engineering, J.G. Webster, Ed., New York: John Wiley & Sons, Inc. 1999, vol. 18, p. 

134.

[12] W. A. Kissick, Editor, “The temporal and spectral characteristics of ultrawideband 

signals,” NTIA Report 01-383, Jan. 2001.

[13] M. Cotton, R. Achatz, J. Wepman, and B. Bedford, “Interference potential of 

ultrawideband signals Part 1: Procedures to characterize ultrawideband emissions and 

measure interference susceptibility of C-band satellite digital television receivers,” NTIA 

Report TR-05-419, Feb. 2005.
50

[14] L. W. Couch II, Digital and Analog Communications Systems, Upper Saddle River, NJ: 

Prentice-Hall, Inc. 1993, pp. 244–255.
51

APPENDIX: SPECTRUM SURVEY MEASUREMENTS

This appendix describes a spectrum survey measurement system and measurement procedure 

used in conducting a spectrum survey from 104 MHz to 1060 MHz. The spectrum survey was 

performed to help select appropriate frequencies and bandwidths at which to perform the noise 

measurements. The results of the spectrum survey are provided as a series of plots of the 

maximum, mean, and median received signal power versus frequency for each of the frequency 

ranges measured.

A.1 Spectrum Survey Measurement System

The spectrum survey measurement system was designed to conduct automated measurements 

from 104 MHz to 1060 MHz. A block diagram of the system is shown in Figure A-1.

Personal Computer Ethernet Switch

100-220 MHz

200-1060 MHz

Antenna Switch Preselector Spectrum Analyzer

Ethernet to GPIB Converter

Figure A-1. Block diagram of the spectrum survey measurement system.

The measurement system consists of two omnidirectional discone antennas; an ITS-designed,

software-controlled RF antenna switch; and a legacy, commercial off-the-shelf RF preselector 

and spectrum analyzer. A personal computer (PC) is used to operate ITS-developed custom 

software that controls the preselector, spectrum analyzer, and antenna switch.

The software automatically controls the antenna switch so that one discone antenna or the other 

is selected depending on the frequencies to be measured. The received signal is filtered and 

amplified by the preselector. The appropriate preselector filter is automatically selected based on 

the measurement frequency range. The preselector also contains an attenuator that can be used 
52

when large signals are present. The filter attenuates out-of-band signals and, along with the 

attenuator, helps prevent potential front-end overload. The amplifier improves the system 

sensitivity. After preselection, the received signal is measured by the spectrum analyzer. 

Received signal power versus frequency data from the spectrum analyzer is then transferred to 

and stored in files on the PC.

The measurement system was installed in the RSMS-4G measurement vehicle. This vehicle, also 

used for the noise measurements, is described in Section 3.

A.2 Spectrum Survey Measurement Procedure

The spectrum survey measurements were conducted at the same four measurement locations 

proposed for the noise measurements.1 At each location, to begin the measurements, the 

measurement equipment was turned on and allowed to warm up for at least 30 minutes. After 

equipment warm-up, the swept spectrum measurement control software was initiated. A noise 

diode calibration was then performed using the Y-factor method described in [A-1] and [A-2] 

and implemented in the measurement software. The noise diode calibration is performed by 

replacing one antenna at a time with a noise diode. The measurement software automates the 

noise diode calibration by measuring the received noise power of the measurement system as a 

function of frequency first with the noise diode powered on and then with the noise diode 

powered off. The system gain and noise figure as a function of frequency are then computed via 

the measurement software from the noise-diode-on and noise-diode-off received power values. 

The system gain and noise figure values are used to verify the proper operation of the 

measurement system. During proper operation, over the 104–1060 MHz frequency range, the 

noise figure varied from approximately 11 to 16 dB and the gain varied from approximately 16 

to 14 dB.

The actual spectrum survey measurements were taken automatically and would run for most of 

the day at each measurement location, typically during business hours. To accomplish this, the 

desired spectrum survey measurements were set up in a table that the measurement software uses 

to carry out the measurements. The table, called an event table, consists of parameters used to set 

up the spectrum analyzer and preselector to perform swept measurements over a user-defined 

frequency range.

To measure the spectrum from 104 MHz to 1060 MHz, the frequency range is first divided into 

fifteen smaller frequency sub bands (called events) as shown in Table A-1. Each event is further 

divided into a certain number of equally spaced measurement spans. Measurements are taken by 

setting the spectrum analyzer and preselector to sweep over each span. Each span is measured 

multiple times by taking multiple sweeps. The number of sweeps per span and the sweep time 

for each sweep is given in Table A-1 for each event. Each sweep of the spectrum analyzer is set 

 

1 The spectrum survey and noise measurements at the residential location in Boulder were actually taken in slightly 

different areas on the U.S Department of Commerce Boulder Laboratories Campus. The spectrum survey 

measurements were taken on the south side of the Campus immediately adjacent to the residential area at Dartmouth 

Ave. and Kenwood Dr. The noise measurements were taken on the north side of the Campus immediately adjacent 

to the residential area at King Ave. and 22nd St.
53

up to store N = 1001 points (1001 values of received power). The resolution bandwidth (RBW) 

of the spectrum analyzer is set to maintain the ratio

(N 1)  RBW  Span

(A-1)

and sample detection is used. Therefore, each sweep provides received power versus frequency 

data where a value of received power is recorded every RBW Hz for the entire span. 

The relationship between the span, RBW, and sweep time is given as

.

( )

2 RBW

k Span Sweep Time 



(A-2)

To ensure that the intermediate frequency (IF) filters have sufficient time to settle, values of k

should be at least 2 to 3 [A-3].

Measurements were repeated automatically at different times during the day for events that 

covered frequency bands whose spectrum usage was expected to change with time during the 

day. These events, called dynamic events, include bands used by mobile radios and airborne 

radars. Events that covered frequency bands whose spectrum usage was expected to remain 

relatively constant with time during the day were only measured once a day. These events, called 

static events, include bands used by commercial radio and television. In general, the static events 

required fewer sweeps per span than the dynamic events. For the most part, the parameters used 

for the events in Table A-1 were developed by following the procedures and tables in [A-1].

Table A-1. Spectrum analyzer and preselector parameters for spectrum survey measurements

Event

Start 

Frequency 

(MHz)

Stop 

Frequency 

(MHz)

# of 

Spans

Span 

(MHz)

RBW 

(kHz)

# of 

Sweeps

per 

Span

Sweep 

Time 

(ms)

# of 

Times 

per 

Day

1 104 164 6 10 10 100 300 2

2 160 180 2 10 10 500 300 3

3 170 220 1 50 100 500 100 1

4 216 225 3 3 3 60 900 2

5 225 405 6 30 30 100 100 1

6 400 406 2 3 3 60 900 1

7 400 420 2 10 10 200 300 3

8 420 450 3 10 10 100 300 2

9 450 470 2 10 10 200 300 3

10 470 520 5 10 10 100 300 3

11 512 812 3 100 100 200 100 1

12 806 906 10 10 10 60 300 2

13 900 920 2 10 10 100 300 2

14 920 960 4 10 10 300 300 3

15 960 1060 1 100 100 500 100 3
54

To clarify how measurements are taken for a given event, consider Event 1 in Table A-1. This 

event provides for the measurement of the 104–164-MHz frequency range. This event is 

measured by taking 100 sweeps of each of the six 10-MHz spans within the 104–164-MHz 

frequency range with an RBW = 10 kHz and a sweep time of 300 ms.

A.3 Spectrum Survey Measurement Results

Once all the spectrum survey data from each of the four measurement locations were collected, 

the maximum, mean, and median power levels at each frequency were calculated and plotted for 

each event. The measurement system gain was used to determine the power levels referenced to 

the output of the antenna terminals. Figures A-2 to A-61 show the maximum, mean, and median 

received signal power (referenced to the output of the antenna terminals) versus frequency for 

each of the 15 events given in Table A-1.
55

Figure A-2. Maximum, mean, and median received signal power at the Boulder residential

location for Event 1 (104–164 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
56

Figure A-3. Maximum, mean, and median received signal power at the Denver residential

location for Event 1 (104–164 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
57

Figure A-4. Maximum, mean, and median received signal power at the Boulder business 

location for Event 1 (104–164 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
58

Figure A-5. Maximum, mean, and median received signal power at the Denver business

location for Event 1 (104–164 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
59

Figure A-6. Maximum, mean, and median received signal power at the Boulder residential

location for Event 2 (160–180 MHz, RBW = 10 kHz, 500 sweeps, sweep time = 300 ms).
60

Figure A-7. Maximum, mean, and median received signal power at the Denver residential 

location for Event 2 (160–180 MHz, RBW = 10 kHz, 500 sweeps, sweep time = 300 ms).
61

Figure A-8. Maximum, mean, and median received signal power at the Boulder business 

location for Event 2 (160–180 MHz, RBW = 10 kHz, 500 sweeps, sweep time = 300 ms).
62

Figure A-9. Maximum, mean, and median received signal power at the Denver business 

location for Event 2 (160–180 MHz, RBW = 10 kHz, 500 sweeps, sweep time = 300 ms).
63

Figure A-10. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 3 (170–220 MHz, RBW = 100 kHz, 500 sweeps, sweep time = 100 ms).
64

Figure A-11. Maximum, mean, and median received signal power at the Denver residential 

location for Event 3 (170–220 MHz, RBW = 100 kHz, 500 sweeps, sweep time = 100 ms).
65

Figure A-12. Maximum, mean, and median received signal power at the Boulder business 

location for Event 3 (170–220 MHz, RBW = 100 kHz, 500 sweeps, sweep time = 100 ms).
66

Figure A-13. Maximum, mean, and median received signal power at the Denver business 

location for Event 3 (170–220 MHz, RBW = 100 kHz, 500 sweeps, sweep time = 100 ms).
67

Figure A-14. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 4 (216–225 MHz, RBW = 3 kHz, 60 sweeps, sweep time = 900 ms).
68

Figure A-15. Maximum, mean, and median received signal power at the Denver residential 

location for Event 4 (216–225 MHz, RBW = 3 kHz, 60 sweeps, sweep time = 900 ms).
69

Figure A-16. Maximum, mean, and median received signal power at the Boulder business 

location for Event 4 (216–225 MHz, RBW = 3 kHz, 60 sweeps, sweep time = 900 ms).
70

Figure A-17. Maximum, mean, and median received signal power at the Denver business 

location for Event 4 (216–225 MHz, RBW = 3 kHz, 60 sweeps, sweep time = 900 ms).
71

Figure A-18. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 5 (225–405 MHz, RBW = 30 kHz, 100 sweeps, sweep time = 100 ms).
72

Figure A-19. Maximum, mean, and median received signal power at the Denver residential 

location for Event 5 (225–405 MHz, RBW = 30 kHz, 100 sweeps, sweep time = 100 ms).
73

Figure A-20. Maximum, mean, and median received signal power at the Boulder business 

location for Event 5 (225–405 MHz, RBW = 30 kHz, 100 sweeps, sweep time = 100 ms).
74

Figure A-21. Maximum, mean, and median received signal power at the Denver business 

location for Event 5 (225–405 MHz, RBW = 30 kHz, 100 sweeps, sweep time = 100 ms).
75

Figure A-22. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 6 (400–406 MHz, RBW = 3 kHz, 60 sweeps, sweep time = 900 ms).
76

Figure A-23. Maximum, mean, and median received signal power at the Denver residential 

location for Event 6 (400–406 MHz, RBW = 3 kHz, 60 sweeps, sweep time = 900 ms).
77

Figure A-24. Maximum, mean, and median received signal power at the Boulder business 

location for Event 6 (400–406 MHz, RBW = 3 kHz, 60 sweeps, sweep time = 900 ms).
78

Figure A-25. Maximum, mean, and median received signal power at the Denver business 

location for Event 6 (400–406 MHz, RBW = 3 kHz, 60 sweeps, sweep time = 900 ms).
79

Figure A-26. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 7 (400–420 MHz, RBW = 10 kHz, 200 sweeps, sweep time = 300 ms).
80

Figure A-27. Maximum, mean, and median received signal power at the Denver residential 

location for Event 7 (400–420 MHz, RBW = 10 kHz, 200 sweeps, sweep time = 300 ms).
81

Figure A-28. Maximum, mean, and median received signal power at the Boulder business 

location for Event 7 (400–420 MHz, RBW = 10 kHz, 200 sweeps, sweep time = 300 ms).
82

Figure A-29. Maximum, mean, and median received signal power at the Denver business 

location for Event 7 (400–420 MHz, RBW = 10 kHz, 200 sweeps, sweep time = 300 ms).
83

Figure A-30. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 8 (420–450 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
84

Figure A-31. Maximum, mean, and median received signal power at the Denver residential 

location for Event 8 (420–450 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
85

Figure A-32. Maximum, mean, and median received signal power at the Boulder business 

location for Event 8 (420–450 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
86

Figure A-33. Maximum, mean, and median received signal power at the Denver business 

location for Event 8 (420–450 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
87

Figure A-34. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 9 (450–470 MHz, RBW = 10 kHz, 200 sweeps, sweep time = 300 ms).
88

Figure A-35. Maximum, mean, and median received signal power at the Denver residential 

location for Event 9 (450–470 MHz, RBW = 10 kHz, 200 sweeps, sweep time = 300 ms).
89

Figure A-36. Maximum, mean, and median received signal power at the Boulder business 

location for Event 9 (450–470 MHz, RBW = 10 kHz, 200 sweeps, sweep time = 300 ms).
90

Figure A-37. Maximum, mean, and median received signal power at the Denver business 

location for Event 9 (450–470 MHz, RBW = 10 kHz, 200 sweeps, sweep time = 300 ms).
91

Figure A-38. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 10 (470–520 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
92

Figure A-39. Maximum, mean, and median received signal power at the Denver residential 

location for Event 10 (470–520 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
93

Figure A-40. Maximum, mean, and median received signal power at the Boulder business 

location for Event 10 (470–520 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
94

Figure A-41. Maximum, mean, and median received signal power at the Denver business 

location for Event 10 (470–520 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
95

Figure A-42. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 11 (512–812 MHz, RBW = 100 kHz, 200 sweeps, sweep time = 100 ms).
96

Figure A-43. Maximum, mean, and median received signal power at the Denver residential 

location for Event 11 (512–812 MHz, RBW = 100 kHz, 200 sweeps, sweep time = 100 ms).
97

Figure A-44. Maximum, mean, and median received signal power at the Boulder business 

location for Event 11 (512–812 MHz, RBW = 100 kHz, 200 sweeps, sweep time = 100 ms).
98

Figure A-45. Maximum, mean, and median received signal power at the Denver business 

location for Event 11 (512–812 MHz, RBW = 100 kHz, 200 sweeps, sweep time = 100 ms).
99

Figure A-46. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 12 (806–906 MHz, RBW = 10 kHz, 60 sweeps, sweep time = 300 ms).
100

Figure A-47. Maximum, mean, and median received signal power at the Denver residential 

location for Event 12 (806–906 MHz, RBW = 10 kHz, 60 sweeps, sweep time = 300 ms).
101

Figure A-48. Maximum, mean, and median received signal power at the Boulder business 

location for Event 12 (806–906 MHz, RBW = 10 kHz, 60 sweeps, sweep time = 300 ms).
102

Figure A-49. Maximum, mean, and median received signal power at the Denver business 

location for Event 12 (806–906 MHz, RBW = 10 kHz, 60 sweeps, sweep time = 300 ms).
103

Figure A-50. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 13 (900–920 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
104

Figure A-51. Maximum, mean, and median received signal power at the Denver residential 

location for Event 13 (900–920 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
105

Figure A-52. Maximum, mean, and median received signal power at the Boulder business 

location for Event 13 (900–920 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
106

Figure A-53. Maximum, mean, and median received signal power at the Denver business 

location for Event 13 (900–920 MHz, RBW = 10 kHz, 100 sweeps, sweep time = 300 ms).
107

Figure A-54. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 14 (920–960 MHz, RBW = 10 kHz, 300 sweeps, sweep time = 300 ms).
108

Figure A-55. Maximum, mean, and median received signal power at the Denver residential 

location for Event 14 (920–960 MHz, RBW = 10 kHz, 300 sweeps, sweep time = 300 ms).
109

Figure A-56. Maximum, mean, and median received signal power at the Boulder business 

location for Event 14 (920–960 MHz, RBW = 10 kHz, 300 sweeps, sweep time = 300 ms).
110

Figure A-57. Maximum, mean, and median received signal power at the Denver business 

location for Event 14 (920–960 MHz, RBW = 10 kHz, 300 sweeps, sweep time = 300 ms).
111

Figure A-58. Maximum, mean, and median received signal power at the Boulder residential 

location for Event 15 (960–1060 MHz, RBW = 100 kHz, 500 sweeps, sweep time = 100 ms).
112

Figure A-59. Maximum, mean, and median received signal power at the Denver residential 

location for Event 15 (960–1060 MHz, RBW = 100 kHz, 500 sweeps, sweep time = 100 ms).
113

Figure A-60. Maximum, mean, and median received signal power at the Boulder business 

location for Event 15 (960–1060 MHz, RBW = 100 kHz, 500 sweeps, sweep time = 100 ms).
114

Figure A-61. Maximum, mean, and median received signal power at the Denver business

location for Event 15 (960–1060 MHz, RBW = 100 kHz, 500 sweeps, sweep time = 100 ms).
115

A.4 References

[A-1] F. H. Sanders and V. S. Lawrence, “Broadband spectrum survey at Denver, Colorado,” 

NTIA Report 95-321, Sept. 1995.

[A-2] Agilent Technologies, “Noise figure measurement accuracy—the Y-Factor Method,” 

Agilent Technologies Application Note 57-2, Mar. 19, 2004.

[A-3] Agilent Technologies, “Agilent spectrum analysis basics,” Agilent Technologies 

Application Note 150, Aug. 2, 2006.

FORM NTIA-29 U.S. DEPARTMENT OF COMMERCE

(4-80) NAT’L. TELECOMMUNICATIONS AND INFORMATION ADMINISTRATION

BIBLIOGRAPHIC DATA SHEET

1. PUBLICATION NO.

TR-11-478.

2. Government Accession No. 3. Recipient’s Accession No.

4. TITLE AND SUBTITLE

Wideband Man-Made Radio Noise Measurements in the VHF and Low UHF Bands

5. Publication Date

July 2011

6. Performing Organization Code

ITS.M

7. AUTHOR(S)

Jeffery A. Wepman and Geoffrey A. Sanders

9. Project/Task/Work Unit No.

8. PERFORMING ORGANIZATION NAME AND ADDRESS 113158011-300

Institute for Telecommunication Sciences

National Telecommunications & Information Administration

U.S. Department of Commerce

325 Broadway

Boulder, CO 80305

10. Contract/Grant Number.

11. Sponsoring Organization Name and Address

National Telecommunications & Information Administration

Herbert C. Hoover Building

14th & Constitution Ave., NW

Washington, DC 20230

12. Type of Report and Period Covered

14. SUPPLEMENTARY NOTES

15. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant bibliography or 

literature survey, mention it here.)

Man-made radio noise measurements were conducted in a 1.16-MHz bandwidth at 112.5, 221.5, and 401 MHz at two

residential and two business locations in the Boulder/Denver, Colorado, area. The measurement frequencies and bandwidth 

were selected using the results of a spectrum survey performed over the 104–1060 MHz frequency range. The noise 

measurement data were collected as a complex baseband noise data record (consisting of six million in-phase (I) and 

quadrature (Q) samples) every 10 minutes over a 24-hour period for each frequency and location. The data were processed to 

provide various statistical descriptions of the noise such as amplitude probability distributions (APDs). Median values of the 

antenna noise figure Fam were determined for each measurement frequency and environment type and compared to predicted 

values from existing man-made radio noise models. The measured values of Fam , while larger than the values predicted by 

the International Telecommunication Union (ITU) man-made radio noise model, were still within one standard deviation of 

the predicted values. Further noise measurements are recommended in a greater number of locations to provide more 

statistically significant results.

16. Key Words (Alphabetical order, separated by semicolons)

man-made noise; man-made radio noise; impulsive noise; Gaussian noise; noise measurements; spectrum measurements; 

spectrum survey; antenna noise factor; external noise factor; amplitude probability distributions; International 

Telecommunications Union (ITU) radio noise model

17. AVAILABILITY STATEMENT

UNLIMITED.

FOR OFFICIAL DISTRIBUTION.

18. Security Class. (This report)

Unclassified

20. Number of pages

115

19. Security Class. (This page)

Unclassified

21. Price:

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