Reference

NBS

PUBLICATIONS

.^*TOFc<\\

**r.«<** NBS TECHNICAL NOTE 1089

NATL INST. OF STAND & TECH

AlllOb 3MD327

Ktni3yi:iii'ii !NT OF COMMERCE/ National Bureau of Standards
Tm he National Bureau of Standards' was established by an act of Congress on March 3, 1901. The

§K Bureau's overall goal is to strengthen and advance the nation's science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research and provides: (1) a

basis for the nation's physical measurement system, (2) scientific and technological services for industry and

government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety.

The Bureau's technical work is performed by the National Measurement Laboratory, the National

Engineering Laboratory, the Institute for Computer Sciences and Technology, and the Institute for Materials

Science and Engineering

The National Measurement Laboratory

Provides the national system of physical and chemical measurement;

coordinates the system with measurement systems of other nations and

furnishes essential services leading to accurate and uniform physical and

chemical measurement throughout the Nation's scientific community, in- dustry, and commerce; provides advisory and research services to other Government agencies; conducts physical and chemical research; develops,

produces, and distributes Standard Reference Materials; and provides

calibration services. The Laboratory consists of the following centers:

• Basic Standards2

• Radiation Research

• Chemical Physics

• Analytical Chemistry

The National Engineering Laboratory

Provides technology and technical services to the public and private sectors to address national needs and to solve national problems; conducts research in engineering and applied science in support of these efforts; builds and maintains competence in the necessary disciplines required to carry out this research and technical service; develops engineering data and measurement

capabilities; provides engineering measurement traceability services; develops

test methods and proposes engineering standards and code changes; develops

and proposes new engineering practices; and develops and improves

mechanisms to transfer results of its research to the ultimate user. The

Laboratory consists of the following centers:

Applied Mathematics

Electronics and Electrical Engineering2 Manufacturing Engineering

Building Technology

Fire Research

Chemical Engineering2

The Institute for Computer Sciences and Technology

Conducts research and provides scientific and technical services to aid Federal agencies in the selection, acquisition, application, and use of computer technology to improve effectiveness and economy in Government

operations in accordance with Public Law 89-306 (40 U.S.C. 759), relevant Executive Orders, and other directives; carries out this mission by managing

the Federal Information Processing Standards Program, developing Federal ADP standards guidelines, and managing Federal participation in ADP

voluntary standardization activities; provides scientific and technological advisory services and assistance to Federal agencies; and provides the technical foundation for computer-related policies of the Federal Government. The Institute consists of the following centers:

• Programming Science and

Technology

• Computer Systems

Engineering

The Institute for Materials Science and Engineering

Conducts research and provides measurements, data, standards, reference

materials, quantitative understanding and other technical information fundamental to the processing, structure, properties and performance of materials; addresses the scientific basis for new advanced materials technologies; plans

research around cross-country scientific themes such as nondestructive

evaluation and phase diagram development; oversees Bureau-wide technical programs in nuclear reactor radiation research and nondestructive evaluation; and broadly disseminates generic technical information resulting from

its programs. The Institute consists of the following Divisions:

Inorganic Materials Fracture and Deformation3 Polymers

Metallurgy Reactor Radiation

'Headquarters and Laboratories at Gaithersburg, MD, unless otherwise noted; mailing address

Gaithersburg, MD 20899.

2 Some divisions within the center are located at Boulder, CO 80303. 'Located at Boulder, CO, with some elements at Gaithersburg, MD.
\&*> ^tcM^ACU note

NBS iESSASCH INFORMATION CENTE3

Site Attenuation

R. G. FitzGerrell

Electromagnetic Fields Division

Center for Electronics and Electrical Engineering

National Engineering Laboratory

National Bureau of Standards

Boulder, Colorado 80303

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U.S. DEPARTMENT OF COMMERCE, Malcolm Baldrige, Secretary

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

Issued November 1985
National Bureau of Standards Technical Note 1089

Natl. Bur. Stand. (U.S.), Tech Note 1089, 48 pages (Nov. 1985)

CODEN: NBTNAE

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1985

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402
Contents

Page

1

Introduction 1

2. Calculations 2

3. Measurements 4

4. Error Estimate 6

5. Conclusions 7

6. References 7

Appendix I The Dipole Antennnas 13

1. Physical Characteristics 13

2. Mismatch Loss 14

3. Input Impedance 16

4. Dipole Droop 17

5. Mutual Impedance of Dipoles in Echelon 19

References for Appendix 1 21

Appendix II Computer Programs HVD3 and ZMM1 29

i n

SITE ATTENUATION

R. G. FitzGerrell

Electromagnetic Fields Division

National Bureau of Standards

Boulder, Colorado 80303

Site attenuation is a measure of performance of an open test site

used at frequencies below about 1 GHz for antenna calibration and

equipment emission and susceptibility testing. These sites

typically consist of a large, obstruction-free ground plane and

the hemisphere above it. Site attenuation of an ideal site is

calculated and compared to data measured using the 30 m by 60 m

NBS ground screen.

Key words: antenna measurements; dipole antennas; site

attenuation.

1. Introduction

Site attenuation is a measure of performance of an open test site used to

determine the levels of emissions from electromagnetic sources or to calibrate

monopole and dipole antennas used for field strength measurements. An ideal

site consists of obstruction-free plane ground and the hemisphere above it —

both infinite in extent. Ground constants may range from typical earth values

to values for good conductors. Site attenuation measurements are used to

compare performance of real sites to the ideal or reference site. Calculations

presented here provide a reference for the measurement results obtained from a 30 m by 60 m wire rnesh ground screen.

Site attenuation is defined as the minimum relative insertion loss

measured between the terminals of two polarization-matched antennas located on the test site when one antenna is moved vertically over a specified height

range. The following parameters must also be specified: separation distance

between the two antennas, measured horizontally; antenna type and polarization;

and impedance of the receiving and transmitting systems attached to the antenna

terminals. Calculated and measured site attenuation includes mismatch losses

but not balun or cable losses.
2. Calculations

Insertion loss between two thin dipoles in echelon located in free space

may be calculated using the mutual impedance between the dipoles [1] and self

impedance of the dipoles [2]. The mutual impedance is given as follows:

V 21 7 = . tl— (1)

21 I

'

K ' Ll x lb

Assuming the dipoles are identical, the self impedance, Z.- , of each dipole

is calculated as described in Appendix I. An arbitrary power level, P-j nc , is

assumed to be delivered to the transmitting dipole and, with Z^ and the

transmitter impedance, is used to calculate the base current, 1^. The mutual

impedance ~L^\* is calculated based upon the antenna geometry, and V21, the

receiving dipole open circuit voltage, is obtained using (1). The power at the

receiving dipole terminals, P rec » is calculated using V 21 , Zj and the receiver

impedance assuming the receiving dipole current has no effect on the

transmitting dipole impedance. That is, any additional mutual impedance

effects are ignored. The ratio, p -j nc / p rec > is the insertion loss between the

dipoles.

Insertion loss between two thin dipoles in echelon over perfectly

conducting ground may be calculated if they are vertically or horizontally

polarized (a restriction occurring only because of the mutual impedance

formulations used in this document) and their positions are specified. The

test range geometry and multiple mutual impedances required for the calculation

are shown in figure 1 for horizontal polarization. The value of 1^ is

calculated assuming that 1 W is delivered to a transmitting dipole that has an input impedance, Z^, equal to Z^ properly combined with the mutual impedance

between it and its image in the perfectly conducting ground. A total mutual

impedance consisting of 1^ and 1^ is calculated and used with 1^ to obtain

V QC , the open circuit voltage in the receiving dipole. Input impedance of the

receiving dipole is calculated and used with V QC to calculate P rec

. Again, the

impedance of the transmitting dipole is assumed to be unaffected by the current
in the receiving di pole's finite load impedance. This assumption results in an approximation to the true value of P rec

and reduces the number of mutual

impedance equations required to the four shown in figure 1.

The input impedance for dipole antennas over perfect ground may be written

using the notation in figure 1 as follows:

Z. = Z. + Z, for the transmitting dipole (2)

l n l Id

and

Z. (h) = Z. ± Z , for the receivinq dipole . (3) in i dn •

The sign of the mutual impedance terms depend upon polarization, and the

fact that the receiving dipole impedance is a function of height, h, is

emphasized in the notation. (The transmitting dipole is always at a fixed

height.) The mutual impedances are calculated using equations in [1] and Z_- is

calculated using equation (4A) given in Appendix I.

The power from the transmitting dipole is given by

P trans - P inc

(1 " I (Z in " Z

s )/(Z

1n

+ V I' - (4)

where P

1

- nc

is the power delivered to the dipole terminals and Z

s is the

transmitter impedance presented to the dipole terminals. The current required

in (1) can now be written as

'lb ' (P trans

/Real ,Z in'

^ • (5)

The total mutual impedance between the dipole antennas is

Zm(h) = Z

21

(h) ± Z 23

(h) , (6)

with the height dependance again emphasized. The receiving dipole open-circuit

voltage is obtained as a result of the definition of mutual impedance as V (h ' 'ib i zTM

(h > i •

< 7 >
and the received power is approximately given by

P rec (h)=Z

R

(V oc ,h)/ l Z

R

+Z

in

(h >

I »' • (8)

where Z R is the receiver impedance presented to the dipole terminals.

Finally, site attenuation is obtained as

S

NBS " 10 lo'l0

(P inc/P rec(H

> >

> (9)

where P rec

(H) is the maximum value of P rec

(h) which occurs at a height H in

the range of heights considered. For the calculations presented in this paper,

Z

R

= Z

s

= 100 ohms and P-j nc , an arbitrary value, is set to 1 W.

Insertion loss is the ratio of the power delivered to the transmitting

dipole terminals to the power received at the receiving dipole terminals and

is a positive quantity. Site attenuation is the minimum insertion loss

occurring when the receiving dipole is scanned in height. The height-scan

patterns in figure 2 show calculated insertion loss for horizontally polarized

(HP) and vertically polarized (VP) dipoles with a 3 m separation distance. The

transmitting dipole is 2 m above perfectly conducting ground. Site attenuation

is the single minimum value of each pattern. Figure 3 shows site attenuation

versus frequency for separation distances (S) of 3 m, 10 m, and 30 m. Heights

scanned are 1 m to 4 m at the 3 m and 10 m separation distances and 2 m to 6 m at the 30 m separation distance except for vertical polarization when the halflength of the receiving dipole exceeds the dipole height. The lower tip of the

vertically polarized dipole is always positioned 5 cm, or more, above the

ground.

Calculated site attenuation provides an ideal reference. Deviations of

measured data from the reference indicate site imperfections or dipole failure.

3. Measurements

Figure 4 shows the measurement procedure used for determining site

attenuation. The reference insertion loss, figure 4(a), is a received signal

level, expressed in dBm, dependent upon the output level of the signal
generator and balun, cable, and attenuator losses. The output level remains

fixed during the measurement procedure and is somewhat arbitrary. It is less

than the maximum level acceptable by the receiver but great enough so the

signal level in figure 4(b) is well above the ambient noise level.

Implicit in the measurement technique is the assumption that the signal

generator output level is constant for both the reference insertion loss

measurement and the site attenuation measurement at the measurement

frequency. That is, it is assumed that the incident power at the 3 dB

attenuator (pad) port is constant for the two measurement conditions. The

signal generator used for these measurements contains an automatic level

control, ALC, and it is assumed that this circuit works perfectly for the small

load VSWR variation (estimated to be 5 percent or less) occurring between the

two measurement conditions [3]. The incident power may be monitored using

directional couplers and a power meter but these devices are not considered

necessary when using high quality signal generators with ALC.

The dipole antennas have hybrid junctions for antenna baluns. Equal

length coaxial cables from the dipole terminals to the hybrid junction form a 100 ohm, balanced, shielded transmission line. As a result, the receiving and

transmitting system impedances are 100 ohms. This value is used to calculate

the reference site attenuation data shown in figure 3 as the solid lines for

yery thin dipoles and (+) points for dipoles with dimensions of those actually

used for the measurements. To insure that this impedance is 100 ohms,

miniature 3 dB attenuators are permanently installed in the four separate

cables at the point of attachment to the dipole terminals.

The receiving dipole is moved up and down over the specified height range

by a person below the ground screen who observes the receiver display. The

maximum received signal level is recorded by a peak sample-and-hold circuit in

the receiver. The magnitude of the difference between the reference insertion

loss value and this maximum measured value gives site attenuation directly. No

additional measurements or corrections are required. The measured data are

shown as the circles in figure 3.
4 . Error Estimate

Test range antenna heights and separation distances are set within +1 cm assuming the ground screen surface is perfectly flat. Dipole height is

measured at the dipole feedpoint. Calculated errors in site attenuation are at

most +0.09 dB as a result of possible positioning errors. The extensible

dipoles used at 97 MHz and lower frequencies droop about 16 cm at the tips at

30 MHz. No effort is made to keep these dipoles straight and the resulting

error, discussed in Appendix I, is negligible.

The stability of the combination of the receiver, signal generator, hybrid

junctions, and cables is determined by the repeatability of the reference

insertion loss measurements, figure 4(a), performed before and after each

subset of measurements. (The three subsets of measurement frequencies are determined by the frequency ranges of the three sets of hybrid junctions).

Over these typically two hour time periods, the difference between the initial

and final reference insertion loss data is at most ±0.11 dB. This variability

appears to be predominantly caused by cable handling, connector mating, and

moving the signal generator. Since this is a relative measurement, not an absolute one, the primary accuracy limitation is the manufacturer's specified

"cumulative fidelity" for the receiver (spectrum analyzer) of "< ±1.0 dB over

to 80 dB display, 20-30° C." Errors in calculated mismatch loss at the 3 dB

attenuators is discussed in Appendix I. The inability of the 3 dB attenuators

to force the signal source and receiving system reflection coefficients to

results in estimated errors of 0.27 dB, 0.17 dB due to source system VSWR and

0.1 dB due to receiving system VSWR. Therefore, a simple worst case error estimate gives (±0.09+0. 11+1. 0±0. 27) = ±1.47 dB. The largest single error,

that of the receiver cumulative fidelity, can be reduced by carefully

calibrating the receiver.

The average difference between the measured and calculated (calculated - measured, dB) data for horizontal polarization is -0.2 dB with a standard

deviation of 0.4 dB calculated using the dB values. For vertical polarization,

these statistics are 0.03 dB and 0.86 dB respectively. The greatest difference

between measured and calculated site attenuation is 1.02 dB for horizontal

polarization, where the effect of feed cable reflections is negligible, and

1.94 dB for vertical polarization.
The data for the single measurement set upon which this paper is based are shown in Table 1. This was the first set of data measured after the

preliminary set used to determine the suitability of the various test

components. Failure of the air-supported fabric cover over the NBS ground

screen facility has temporarily halted further measurements.

5. Conclusions

The agreement between measured and calculated site attenuation data is

good, even for vertical polarization. The good agreement for vertical

polarization is believed to result from the use of commercial hybrid junctions

as dipole antenna baluns. These devices split the E port power 180° +1° at the

1 and 2 ports. Little or no unbalanced (common mode) current flows on the feed

cables and produces unwanted radiation.

Implementation of the deceptively simple mutual impedance equations is

actually a fairly straightforward computer programming exercise. To relieve

interested readers of this exercise, Appendix II contains Program ZMM1 , the

listing of the FORTRAN 4 code used to calculate site attenuation. No claim is

made for the efficiency or structure of the code or its accuracy beyond the

comparison of measured and calculated results presented here.

The actual measurement technique is certainly not new. It is basically a "two identical antenna" gain measurement that stops short of the last step -- subtracting the path loss and mismatch loss from the measured data to obtain

the product of the gain of two identical antennas over ground.

6. References

[1] King, H.E., "Mutual impedance of unequal length antennas in echelon,"

IEEE T-AP-5, pp. 306-313, July 1957.

[2] Schelkunoff, S.A., and Friis, H.T., Antennas, Theory and Practice , New

York: Wiley, 1952, Ch. 13, pp. 431-434.

[3] Engen, G.F., "Amplitude stabilization of a microwave signal source,"

IEEE T-MTT-6, pp. 202-206, April 1958.
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44, 143, 459, 1000 MHZ

10.0 15.0 20.0 25.0 30.0 35.0 40.0

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Figure 2. Selected relative insertion loss data calculated for horizontally

polarized, HP, and vertically polarized, VP, dipoles over perfect

ground. Site attenuation is the single minimum relative insertion

loss value of each curve. Separation distance is 3 m; transmitting

dipole height is 2 m.

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Figure 3. Site attenuation for horizontally polarized, HP, and vertically

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Appendix I. The Dipole Antennas

1. Physical Characteristics

Figures 1A through 4A are photographs showing the dipole antenna fabrication

details. The 2.54 cm diameter white teflon feedpoint assembly is machined from a 8.89 cm length of rod stock. A cylindrical hole 2.22 cm long, 1.27 cm wide, and

1.31 cm deep provides room for the SMA panel jacks which form the dipole

feedpoint. A flat surface opposite this hole supports the panel jack nuts.

These dimensions are chosen to allow a nut driver to fit on the panel jacks

during tightening, allow just enough separation between the panel jacks for

attaching SMA connectors, and give a sufficient thickness of teflon to support

the panel jacks yet allow the SMA connectors to seat full depth on the jack

body. Another flat surface, 90 deg around the feedpoint assembly with a centered

hole, provides the mounting surface for a 2.54 cm diameter wood dowel used as the

antenna mast.

The ends of the feedpoint assembly are drilled to a 1 cm diameter to form

holes 2.64 cm deep. These holes provide a press fit for the extensible dipole

elements used from 30 MHz to 97 MHz. Small holes are drilled in the center of

the bottom of these 1 cm holes into the feedpoint cylinder and tapped with 6-32

threads. Stock banana plugs (13/16 in x 6-32, threaded shank) are screwed into

place and the threaded shank is soldered to the panel jack center pin. A solder

bridge is formed to join the outer conductor hexagonal surfaces of the panel

jacks as shown in figure 3A; figure 4A shows the banana plug in the 1 cm diameter

hole. The ends of the extensible dipole elements are drilled with a hole for a snug fit over the banana plug. These extensible elements are four section

stainless steel whips with a 68.58 cm minimum length and a 243.84 cm maximum

length.

None of the dimensions are critical to the electrical performance of the

dipole. Basically, the feedpoint assembly is made from a low loss dielectric

material that is strong enough to support the 30 MHz half-wave elements and

provide a feedpoint gap that is much smaller than a wavelength at the highest

frequency of interest. Dipole elements for the frequencies above 97 MHz are fixed lengths of thin wall brass tubing having a 0.48 cm outer diameter. These

elements are supported by the banana plug and a 1 cm diameter dielectric washer

positioned at the end of the feedpoint assembly.

13
Antenna half-length, measured from the center of the feedpoint assembly, is

approximately one-half wavelength. It is chosen so that the calculated freespace input impedance is purely real. These lengths are determined using Program

HVD3 which is included in Appendix II.

The 50 ohm coaxial hybrid junctions, serving as antenna baluns, are fourport devices having the following minimum performance specifications:

1

Isolation: 30 dB

2. Phase balance, E (diff) port feed: 180 deg + 1 deg

3. Amplitude balance: 0.2 dB

4. VSWR: 1.3

5. Insertion loss, E(diff) port feed: 0.75 dB.

Equal length coaxial cables, 2 m long, separate the hybrid junctions from

the feedpoint assembly. These cables are cut physically the same length from a single spool of cable and the connectors are carefully attached according to the

manufacturer's instructions. Insertion loss versus frequency of two cable-hybrid

junction assemblies is measured between the E ports. The H ports are terminated

with 50 ohm loads. The cable pair attached to the colinear ports of the hybrid

junctions form a shielded, balanced, 100 ohm transmission line. Satisfactory

performance is observed when the measured insertion loss is a smooth function of

frequency and approximately equal to the cable loss plus the hybrid junction

insertion loss.

2. Mismatch Loss

As mentioned in the main body of the text, high performance, miniature 3 dB

attenuators having maximum VSWR specifications of 1.07 + 0.015f(GHz), DC to 8 GHz are permanently attached to the equal length cables at the dipole feedpoint. The

attenuators reduce the errors incurred in assuming the source and receiving

system impedances are exactly 100 ohms in the site attenuation calculation.

These impedances are not exactly 100 ohms because the source signal generator is

specified to have a VSWR < 2 and the receiver is specified to have a VSWR < 1.5.

A commercial computer software package, "General Microwave Circuit Analysis

Program" [Al], is used to determine the input VSWR at the attenuator ports

attached via one of the equal length cables to the hybrid junction and the source

signal generator or receiver as shown in figure 5A. The attenuator and hybrid

14
junction are modeled with resistive "T" networks to match manufacturer

specifications. The signal generator is modeled with 25 ohm and 100 ohm

resistors and the receiver is modeled with 33.3 ohm and 75 ohm resistors. Worst

case input VSWR values occur at 44 MHz (calculations use the 10 test frequencies)

and the smaller of the two resistive values representing receiver and source

signal generator impedances. Without the 3 dB attenuators, the source circuit

input VSWR is 2.01 and the receiving circuit input VSWR is 1.64. With the

attenuators, these VSWR values are 1.5 and 1.4 respectively. The mismatch losses

resulting from these non-perfect input impedances are the magnitudes of the errors which may occur if the worst case conditions are realized; 0.17 dB and 0.1

dB respectively. Therefore, a total worst case error of 0.27 dB may occur because the impedances of the source and receiving circuitry attached to the

dipole terminals are not exactly 50 ohms at each attenuator. Larger attenuators

will reduce these errors even more if the reduced signal levels can be tolerated

during the site attenuation measurements.

The conjugate mismatch loss, M|_ (referred to simply as mismatch loss in this

paper) is calculated as follows [A2]:

i i ?

l - r r r

M, = 10 log in V^ 7- ' ( 1A > (1 - |r

s

| ) U -I r a l )

where r

s = complex reflection coefficient of the source circuitry, and

r a = complex reflection coefficient of the antenna.

Forcing the source VSWR to 1 with large enough attenuators, i.e., forcing r

s = 0,

gives

M, = 10 log in —*- . (2A)

L iU

1 - I r I 1 a ' Computer Program HVD3 evaluates this expression using

r = R = (ZR - ZCHAR)/(ZR + ZCHAR) , (3A)

a

where ZR = dipole input impedance, and

15
ZCHAR = 100 ohms, the receiving or source system impedance.

Tuning devices may be used at fixed frequencies to force r

s to zero but this

technique is not normally used for antenna measurements over a wide range of

frequencies.

3. Input Impedance

Dipole input impedance is calculated using well documented equations.

"Aside from the shunt admittance of the input region, which may or may not be

significant, the input impedance of the antenna is" [A3]:

(K - M) cos u + j(Z a + j wC+ kI -j'N) sin B£

1. = x

2 5 I E

s (4/\)

1 d (Z + jojC. Kf + jN) cos 6£ + j(K + M) sin Qi

a X, a a

11

120 \

S

t where K = 120 lu &- + — in — , a a

b ab

" a t

a b

a*. = radius of tip of linearly tapered antenna

a^ = radius of base of linearly tapered antenna ,

or K = 120 Un f^ -1) for a. = a, , a a, t. d

l = dipole half length ,

M = 60 (Cin 2b l -1 + cos 2B£) ,

N = 60 (Si 26£ - sin 26£) ,

B = 2^/x ,

x

r - r 1 - COSt Cin x = | dt

,

o

l

x

c- r sin t ,, Si x =

J —

z

dt , b L

16
jos C. - J3

t

t 30x

Z = R + j X

a a

J a

R = 60 Gin 28J> + 30(2 Cin 2B£ - Cin 4p£) cos 28£

a + 30(Si 4B£ -2Si 2S£) sin 2B£ ,

and X = 60 Si 2BI -30(Cin 48£ - £n4)sin 2B£ -30 Si 4B£ cos 2B£ . a

These equations appear in lines 1070 - 1180, Program HVD3 and lines 1600 - 1710,

Program ZMM1, both in Appendix II, and apply only to straight dipoles.

4. Dipole Droop

Unfortunately, real dipoles droop at the lower frequencies considered in

this paper. A relatively new computer program does enable the calculation of

gain pattern and input impedance of arbitrary wire antennas of finite dimensions

over perfect ground. Drooping dipole input impedance can be calculated using

this program, called MI NI NEC , which is a small version of a larger numerical

electromagnetics code [A4, A5].

The profile of the actual 30 MHz dipole was measured and the resulting

MINI NEC model utilizes eight wires, one for each telescoping section comprising

the antenna. Each of the 8 wires is represented by 10 equal length segments.

Currents on the wire are expanded in pulses centered at the junctions of adjacent

segments

.

MI NI NEC must be used carefully and enough segments selected to insure near convergence of the input impedance data. Table 1A shows input impedance data

calculated for the 30 MHz tapered dipole used for the site attenuation

measurement. Input impedance data for the straight dipole calculated using

Schelkunoff 's equations are included for interest and entitled HVD3, straight.

This is the "worst case" dipole because it is physically the longest, has the

most droop, and is electrically closest to the ground. Since MI NI NEC and HVD3

give slightly different input impedances for the straight dipoles over perfect

ground, the effect of droop is approximated by comparing the difference in

17
Table 1A. Calculated Input Impedance for Horizontal, 30 MHz, HalfWave Di poles Over Perfect Ground

Half-length = 2.4 m

Tip radius = 0.0013 m

Base radius = 0.005 m

Calculation, Geometry Height, m Zin, ohms Mismatch Loss, dB

HVD3, straight

MINI NEC, straight

MININEC, drooping

2 60.1 + J33.1 0.46

4 82.1 - jll.O 0.06

6 52.2 - j 2.0 0.45

00 65.7 - j 0.3 0.19

2 62.8 + j 2.3 0.23

4 79.9 - J44.8 0.32

6 51.5 - J32.7 0.67

00 65.0 - J'32.3 0.36

2 62.9 + j 6.8 0.24

4 81.2 - J41.6 0.27

6 51.7 - J30.0 0.63

00 65.5 - J'29.1 0.33

Note: It would require an uneconomical amount of computer

time to determine Zin continuously versus height above

ground for both straight and drooping 30 MHz di poles.

The 0.05 dB mismatch loss difference, attributable to

dipole droop, is assumed to be the worst case value.
impedances, more specifically the difference in mismatch loss, between the

MININEC results. This difference is at most 0.05 dB and is considered

negligible.

Dipole droop will slightly change the effective height of the dipole above

ground. However, the current distribution is sinusoidal, not linear, and the

least drooped sections support the greatest current density. This, together with

the fact that the site attenuation measurement utilizes height scanning, means

that the exact height is not important. Figures 6A and 7A show the height versus frequency at which the site attenuation data are calculated.

5. The Mutual Impedance of Di poles in Echelon

In contrast to the input impedance calculations, King [A6] states that "the

mutual impedance equations apply accurately to infinitely thin antennas only, but

nonetheless serve as a practical approximation for real antennas of finite

thickness". Half-wave dipoles were chosen for the site attenuation measurements

because their performance parameters are calculable. Professor Jordan states,

"Inasmuch as the actual current distribution is known to be \/ery nearly

sinusoidal for thin transmitting antennas (dipoles and monopoles), the

(calculated radiated field) obtained is a good approximation to the true power

radiated" [A7]. For receiving dipoles he states, "For a resonant-length half- wave receiving dipole, the current distribution is found to be sinusoidal and, to

a first approximation, the current amplitude is independent of the thickness of

the antenna" [A7, p. 549]. Finally he assigns a problem which completes these

comments on the current distribution of half-wave dipoles as follows:

"The current distribution in a half-wave transmitting antenna is

known to be nearly sinusoidal. The current distribution of a half-wave dipole receiving antenna is also nearly sinusoidal when

the terminals are short-circuited. Using the superposition and

compensation theorems, verify that the current distribution of the

half-wave dipole as a receiving antenna must be approximately

sinusoidal when the terminals are connected to any load impedance

Z" [A7, p. 338].

Therefore, calculated site attenuation based almost entirely upon King's mutual

impedance formulations and sinusoidal current distribution gives a good

reference model when half-wave dipoles are employed.

19
Subroutine ZZ in Program ZMM1, Appendix II, is used to calculate 18

arguments for sine and cosine integrals required by the mutual impedance

equations. Ninety-six of these integral terms are used in the general

formulations to obtain the mutual impedance referred to the loop current. The

mutual impedance referred to the base current is the quantity needed to

evaluate dipole input impedance, the power transmitted, and the power

received. Professor Jordan also discusses the relations between the base and

loop current references for input and mutual impedance calculations [A7,p. 345-

351], This change of reference is implemented in Program ZMM1 line 03970 as follows:

Z12B (K) = Z12L(K)/((SIN(BETA*L))**2)

where Z12B is the mutual impedance referred to the base current and Z12L is the

mutual impedance referred to the loop current.

Since Program ZMM1 calculates site attenuation for both vertical and

horizontal dipoles, the reversal of the apparent current direction in the image

dipole for horizontal polarization is handled in lines 03940 to 03960.

Subroutine MUTUAL, used to compute the mutual impedance between the

dipoles and their images in perfect ground, uses a subset of the general

formulations given in Subroutine ZZ. These two subroutines were developed

separately and left that way for clarity. Subroutine MUTUAL could be replaced

with a call to Subroutine ZZ if ZZ were modified to handle the call. This

would shorten the program substantially.

The sine and cosine integrals are evaluated using series expansion

equations given in Abramowitz and Stegun [A8]. The computer implementation of

these equations was developed many years ago and different ones may be

available in mathematical software packages. As noted in Program ZMM1, a linear interpolation is imposed to smooth the functions in the transition

region occurring between the large argument and small argument approximations

to these integrals.

20
References for Appendix I

[Al] Tektronix Product Number 4050A06, Tektronix, Inc., Beaverton, OR; 1975.

[A2] Beatty, R.W., "Insertion loss concepts," Proc. IEEE, Vol. 52: 663-671;

1964 June.

[A3] Schelkunoff, S.A., Friis, H.T., Antennas, Theory and Practice , New York,

NY: John Wiley & Sons; 1952. 431-434.

[A4] Julian, A.J., Logan, J.C., Rockway, J.W., "MININEC: A mini-numerical

electromagnetic code," Tech. Doc. 516, Naval Ocean Systems Center, San

Diego, CA; 1982 6 Sept.

[A5] Campbell, D.V., "Personal computer applications of MININEC," IEEE AP-S

Newsletter, Vol. 26; 1984 February.

[A6] King, H.E., "Mutual impedance of unequal length antennas in echelon,"

IEEE T-AP-5, pp. 306-313; July 1957.

[A7] Jordan, E.C., Electromagnetic Waves and Radiating Systems , Englewood

Cliffs, NJ: Prentice-Hall; 1950. p. 365.

[A8] Abramowitz, M., Stegun, I. A., Handbook of Mathematical Functions With

Formulas, Graphs, and Mathematical Tables , Washington, DC; Nat. Bur. of

Stand. (U.S.) Applied Mathematics Series 55; 1964; pp. 231-233.

21
-a

<v

CD fO X 4-> •i- 4-> • M- fC 00

4~> -a O) c C S- cu

(O IO E

cu

CD to i

C CD CD O r— c re 4-> •i- o en

to "O CD

+->

C r—

C 03

CD "O E e CD CD O X

CD +-> <4- en c: •> c: ^ +-> •r- •!-> S- Q_ O O "O -C a •!- to

to sCD -Q CD -— >>-c

cd nr +->

4-> ot • 4-> E S- -r- r- CD 2 O 4-> >,

-E

O <—

to _Q

CD E

to JT CD

CD 4-5 to I- 01 i— C (O E +-> CD to c:

to +-> -i- oi c o

fO CD Q- E -a

CD CD CD r— r— CD o <uv

•r- -C CD -a 4-> _c

cr>4->

cd e r DO

CD

SCT>

22
CO

S-o+J

fO

Z3C

CD

4->

+-> 03 CQ-a

<y~> >1

CD -Q sz E

4-> OJto CD 00 E fO

•i

s 4-> o c

.c: 1

00 o

o. >>x i

0) -Q CD E <4- CD

00

C

00 o

03 1

M-

<D CD i

+->

O

CL CD • i— +-s "O •i

_f^ fO >

<+- CD O x:

+j s

CD -M

•1

rd > o

CD CD GO _^ o u I

rtD o +-> +J < OS

=c

OJ

CD

s_

23
24
25
-»«^ IDID <D (D n

DC 03O E

C\]

LO «CD 1 > II CD DC o

<: DC CO>b

1_o-t—

03

i_ CNJ CDC II Q) DC

C5 £

"^ CO c >

O)

CO n—^

to

LO Q) <3 -9

DC

g E

<M 1

CD 00

4-> •i—^

CDu

C s-

•i

•1

-Mu c

cu s- CO cu

CD >

s- •I— o. cu

(U

u

S- cu

s- oo +J "O

•1

c: ^ fO o

S- s- • 1— o u +-> ro

+-> Ss- cu o c

Q. cu 1 cn o2 i

-)-> <oc

4- C7) O •i

00 e

fT3 cu

SO

cn Srt3 ^

•i— o

"O 00 O CU

"i— >

4-> • 1— fH -•-> b: u

CD cu _^ 4- U 4-

oo CU

<Cin

d>

s03

26
en

IT) en t\

LJ

E—

LJ O

•\ E—X ID CD ^r

* LJ

nz o

LJ r-o _jo

Q_ IT)

l 1 Q

O

o

o

1

DIPOLE HEIGHT V5 FREQUENCY HP

SOURCE HEIGHT, 2.0 M

S - 3, 10, & 30 n

icr

FREQUENCY, MHZ

10"

Figure 6A. Heights versus frequency for which site attenuation is calculated

for horizontal di poles.

Solid line - 3m separation distance

Dashed line - 10 m separation distance

Dotted line - 30 m separation distance.

27
o

DIPOLE HEIGHT VS FREQUENCY . . . VP

CD

CO ^

SOURCE HEIGHT, 2.0 M

5 = 3, 10, & 30 M _

o

3

LJ

E—

LJ o

2Z • _

E—CD ,j- —

LJ1 o

;- '•

IPOLE .53 \_

"

a ~

a

a

1 o

1 12

1 FREQUENCY, MHZ

Figure 7A. Heights versus frequency for which site attenuation is calculated

for vertical di poles.

Solid line

Dashed line - Dotted line -

3 m separation distance

10 m separation distance

30 m separation distance,

28
APPENDIX II

Computer Program HVD3

and

Computer Program ZMM1

29
00100

00110C

00120C

00130C

0C1*0C

00150C

00160C

ooi7or

coieoc

00190C

00200C

00210C

0C220C

00230

002*0

0C250

0O260C

00270C

00280C

0C290C

00300C

00310C

00320C

00330

003*0

0035O+

00*60

00370

00380

00390

00*00

00*10

00*20

00*30

00**0

00*50

00*60

00*70

00*80

0C*90

00500

0C51CC

00520C

005300

005*0

00550

00560

C05?0

00580

00590

00600

00610

00620

00630

006*0

0O650

00660

00670

00680

00690

00700

00710

00>20

00730

°ROGR *****

* ga

ov

scAN

0.

IS^cMA

BE

FE *****

I^EN*

r ompl

REAL *****

* TH

*

*

*******

1 CON

2 FOR

NO

GR

SF

AM H ****

IN V ER G HELK

TENN

1*LA

CAL

=>4RA

Y RE 7ER

EDPD

****

SIGN

EX C KA,L

 

F US

TE t QUND

T TO ** ** TI^J

»AT<

VD3(IN ******

S. ELE

ROUND

UNOFF'

A IMPE

MBOA

CULATE

TION 5 SULT I OR T INT TO ******

SI ( 2> T,E» J* A*BDA* ******

ER SPE

FOR A ONLY)

7.ER0. ******

E*TY°E

FREOU

PUT*QUTPUT1 **************************************************

VATION ANGLE FOR VERTICAL ANO HORIZONTAL DIPOLES

AND FOR MONOPQLES OVER PERFECT GROUND. NOTE*

S MODE THEORY IS USED TO CALCULATE FREE SPACE

DANCE. IF THE DI<>OLE FEEDPCINT HEIGHT IS WITHIN

F THE GROUND* THE SELF IMPEDANCE OF THE ANTENNA

D USING THE MUTUAL IMPEDANCE WITH 0. 0001*L AM8D A ECAUSE USE ne SCHELKUNOFF • S SELF IMPEDANCE

N NEGATIVE INPUT IMPEDANCES. ANTENNA RADII MAY

HE ANTENNA MAY HAVE A LINEAR TAPER FROM THE

THE ENO. **************************************************

*CIN(2),S(21),C(21)*T(**)*Z(2>

NPI,,<,RH,RV*RH90*RV90*TSQ»7A,ZIND>ZINN»ZM*ZR,ZI»ZM1

L*L2»L0SS*MBL»M0N0 ******************************

CIFIES THE ANTENNA GEOMETRY *

* WONDPOLE (FED AGAINST PERFECT*

THE CONDUCTIVITY MUST BE ** ******************************

THE RFOUESTED DATA AFTER EACH ? ENCY* MH7*)

HALF-LENGTH* M, LAMBDA/* OR LESS*)

ORTNT 2

3 F09MAT( Fl?,*)

RFAO 3, FREQ

* FHPMAT( *ANTENNA

PCTNT * RPAO 3, L 5 FH^MATf *ANTFNNA R\DTI, END THEN FEEDPOINT, M*)

PRINT 5 READ 3,RT

READ ?, P8

IF(RT.EO.

IF(RT.EO.

6 FOSMAT(

PCINT 6 READ 3, SI *********

* PFRFEC *********

IF (SIGMA.

IMSIGMA.

IF (SIGMA.

IF (SIGMA.

IF(SIGMA.

IF(SIGMA.

7 FORMAK

POINT 7 READ 3,E°

8 CONTINU

9 CORMAK

OPINT 9 RFAD 3»H

1C CDNTIN

11 FORMAT

PRINT 11

READ 3* ZC

J » CMPLX

LAMOOA • BFTA 6.

O.ANP.«B.EQ.O)RT"1.E-30

l.E-30)PB-l.E-30

GROUND CONDUCTIVITY* M I LL IMHOS/ M*)

GM A ***

T G ***

GF.

GE.

GE.

EQ.

EQ.

EO.

*GR

**********************

a

, T ******** ******* **********

ROUND AND FREE-SPACE APPROXIMATIONS ARE MADE. * ***********************************************

10000000.0) SIGMA » 1.E30

1G0000C0.0) E°SILON • 1.0

1C0C00C0.0) GO TO 8 0.) EPSILON 1.

0.) H-l.E-30

0. ) GO TO 10

OUND RELATIVE DIELECTRIC CONSTANT*)

STLTN

EniPOLE FFED-POINT HEIGHT ABOVE GROUND* M*)

UE(IMPEDANCE OF T-LINE ATTACHED TO ANTENNA* OHMS*)

HAR

(0 . * 1 . ) 299.792*58/FRE0

2P31853/LAMBDA

30
00740C *********************** **********

007 50C* TWE CALCUCaTIONS BEGIN HERE * 00760C****** ******************* ********

00770 12 B « 2.*BETA*L

00760 BL BETA*L

007Q0 RH « BETA*H

00800 X • 18.*SIGM.A/FPFQ

00810 Y • EPSILON

008 20C********* ******************************** *******

00830C* COMPUTE SINE AND COSINE INTEGRALS FOR SFL^ * 00B40C* IMPEDANCE CALCULATION, SI(M) AND CIN(M) * OO^OC************************************************

JD08 60 20 K 1 00870 T<1) 1.0

00»80 DO 30 H - 1,42

00890 K * +1

00900 30 T(K ) - M*T<K-1)

00910 DO 60 M»l,2

00920 Z(M) - M*B

00930 DO 40 N 1,20

00940 40 S(N) ( (-1)**N)*(Z(M)**{2*N*1))/((2*N*1)*T(2*N*2))

009 50 SI(M)-Z(M)*S(l)*S(?)*S(3)*S(4)*S(5)*S<6)*S(7)*S(e)*S(9)*S<10)

00960* S(11)*S(12)*S(13)+S(14)+S(15)+S(16)+S(17)+S(18)+S(19)+S<20)

00970 DO 50 N 1,20

009BQ 50 C(N) « ( <-l)**N)»(Z(M)**(2*N))/( ( 2*N )*T

(

2*N*1 )

)

—

50990 6 C I N ( M ) —( C ( 1 )VC (2 ) +C (3 ) +C ( 4 ) C"C 5 ) *C ( 6 ) *C ( 7 ) + C ( 8 ) + C (9 ) C (10)

01000* +C(ll)+C(12)*C(13)+C(14»+C(15)*C(16)+C(17)+C(ie)+C(19)+C(20))

01 01 OC *************** **************************************************

01020C* NO LAR6E ARGUMENT APPROXIMATION IS REQUIRED FOR SI AND CIN * 01030C* BECAUSE 0^ THE RESTRICTION ON THE DIPOLF LENGTH IN LINE 260 * 01 040C********* ********************************************************

~~01050C* CO^PljTE^SE'rFnEl^PEDANCE, ZT, USING EON. 108 OF REFERENCE C33 * 010 60C*** ****************************************************** ********

01070 IF(RT.EQ.R3)KA - 1 20 .* ( AL OG ( 2 .*L /RT ) -1 .

)

010 80 IF(RT.NE.RB)KA-120.*(AL0G(2*L/RB)+(RT/(PB-RT))*AL0G(RT/RB))

01090 MBL - 60.*<CIN(l)-l.*C0Sm)

01100 NBL J*60.»(SI(1)-SIN(B))

Oil 10 Z AR • 60 . *C INC 1 ) 30.* ( 2 .*C IN ( 1

) -C IN ( 2 ) > *C OS ( B ) 30.* (SI C 2 > 01120+ -2.+SI(l))*SIN(B)

01130 ZAI - 60.*Sim-30.*(CIN(2)-AL0G(4.))*SlN(B)-30.*SI(2)*C0S(B)

01140 ZA ZAR+J*ZAI

01150 CT J*RT/(30.*LAMBDA)

01160 ZINN KA*( (KA-MBL)*C0S(BL>+J*<ZA+CT*KA*KA-N8L)*SIN(BL) ) 01170 ZIND * <ZA*CT*KA*KA+NBL)*COS(BL)*J*{KA+HBL)*SIN(BL)

01180 ZI ZINN/ZIND

01190 62 CONTINUE

01200 64 FOPNAT(*TYPE 1. FOR HORIZONTAL POLARIZATION, FOR VERTICAL*)

01210 PRINT 64

01220 READ 3, POLAR

012 30 "MONO- 1.

01240 66 FORMAT(*TYPE 1. FOR DIPOLE OR FOR MONOPOLE*)

01250 IF(P0LAR.EQ.0. AND. SIGMA. EO.O.) PRINT 66

01260 IF(PnLAR. EO.C. AND. SIGMA. EO.O.) READ 3, MONO

012 70C*********** ******************************************** ****** 01280C* COMPUTE ANTENNA INPUT IMPEDANCE, ZR . SUBROUTINE J1UTUAL * 01290C* RETURNS THE CORRECT MUTUAL IMPEDANCE* ZHf BETWEEN TWO * 01300C* DIPOLES IN PREE SPACE «=0R THE SPECIFIED POLARIZATION

0131 OC *********************************************** **************

01320 CALL MUTUAL(BETA,H,J,L,RH90»RV90,ZM,X,Y,P0LAR,T)

01330 ZM1-ZM

01340 67 FORNAT(_*INPUT IMPEDANCE -*P12 .4** JC*F12 .4*10HMS*

)

01350 IF{H.GE.O.i*LAMBDA.OR. SIGNA»EQ.O)" GO TO 68

01360 H1-0.0001*LAMBDA

01370 P0LAR1-1.

31
01390

01400

01410C

C1420C

0143OC

01440C

01450C

01460C

01470

01*80

01490

J)1500

01510

01520

01530

01540

01550

_01560

01570C

01580C

01590C

C1600C

01610

_01620

01630C

01640C

0l650r

01660

01670

_01680_

01690

01700

01710

01720

01730*

_01740_

01750

01760

01770

01780

01790

01800

01810

01820C

01830C

01840C

01850C

01860

01870

01880

01890

01900+

01910

0192C

01930

01940

01950

01960

01970

01980

01990

02000

02010C

CALL *U

ZWM/(

68 CONT *******

* THE

* FOR

INPU

* SUBR *******

IF<POLA

IF(PHLA

IF(MONO

PJ!INT_6

L2 L 81 FORI

PRINT 8 READ 3,

TF(L.GT

L L2 *******

* COUP

* PARA *******

IF(HrjNO

IF(«ONQ *******

* ANTE *******

82 FORM

83 FORM

84 FORM

PRINT 8 IF(MQNO

IF(MONO

90 FORM

I

F

(MONO

R (ZR

VSWR

110 FOR

PRINT 1 LOSS - 200_ FJ)R

PRINT 2 *******

* COHP

* GAIN *******

300 FOR

PRINT 3 PAUSE

350 FOR

TUAL (_B SIN(BL

INUE ******

ABOVE

HORIZO

T IMPE

OUTINE ******

R.EO.l

R.EO.O

.EO.O.

7»ZR

ETA,HX*J>l,OUMMYljDyMMYl,ZW,y,Y,POLAPl»T)

)**2) ************************************************

6 LINES HELP PREVENT NEGATIVE INPUT IMPEDANCES * NTAL DIPOLES NEAR GROUND BECAUSE SCHELKUNOFF • S * DANCE DOES_N0T_C0NVERGF TO THAT COMPUTED BY * MUTUAL. * ************************************************

.) ZR-ZI+PH90*ZN1/(SIN(BL)**2)

.) ZP"ZI*RV90*ZM1/(SIN(BL)**2)

) ZP-ZR/2.

AT(*ENTER NEW HALF-LENGTH IF DESIRED* OTHERWISE ENTER 0*

)

1

L.0.) GO TO 12 ******

UTE AN METERS ******

.EO.O.

•10.1. ******

NNA FA ******

AT<*AN

AT(*AN

ATJ*AN

2*Z~CHA~

.EO.l.

.EO.O.

AT(*MU

******

TENNA

» MUT ******

)AF-(C

)AF-(C ******

CTPR ******

TENNA

D A It

D TRA N

R

) PRIN

) PRIN

TUAL I

********

FACTOR*

UAL IMPE ********

ABS(ZCHA

A B SJLZC HA ********

VOLTAGE ********

FACTOR A

1 BALUN

S MISS ION

****************************

AF» AND OTHER IMPEDANCE RELA

DANCE* VSWR* AND MISMATCH LO ****************************

R + ZRJ/ZCHAR) /( (l./BETA)*TAN(

R*ZR)/ZCHAP)/((2./BETA)*TAN( ****************************

DIVIDER FACTOR/EFFECTIVE LE ****************************

SSUMING A *F6.2*-0HM RECEIVE

ARE EMPLOYED *«: 8.2* DB*)

.LIRE ARE EM PLOYED _**F8,2* D

)

) ANTENNA'S IMAGE

*F12.4**J[*F12.4*]0HMS*)

******

TED * SS * ******

BL/2.))

BL/2.)) *******

NGTH * *******

R*)

B*) _

T 83* 20.*AL0G10<AF

T 84* 20.*ALDG10(AF

MPEDANCE DUE TO THE

IN THE GROUND » 90, ZR-ZI

R ZCHAR)

/(l.-CABS(R) ) F12.4)

1.0/(1.0-(CABS(R))*(CABS(R))))

H LOSS «*F12.4* DB*]) ******

FLECTI

S ELEV ******

RESS R

*******************

ON COEFFICIENTS* AN

ATION ANGLE *******************

ETURN FOR GAIN VS P

*********

D THEN *

* *********

HI, OTHERWISE TYPE CNTL T*

)

MAT(*ELEV ANGLE INCREMENT FOR BELOW 10 DEG AND THE

ADDITIONAL INCREMENT FOR ABOVE 10 DEG*)

PRINT 350

REA0_3* _ENC

RFAD 3* ENC2

355 FORMAT(*H

356 FORMAT(*V

IF(P0LAR.E0.0

360 FORMAT(*H

PRINT 360

PRINT 355

PSI - *************

ORIZONTAL POLARIZATION*)

ERTICAL POLARIZATION*)

.) GO TO 660

-PLANE ELEVATION ANGLE IN DEGREFS AND GAIN IN DB*)

****************

32
02020C* _Hnci70NTAL

20 3CC ****** *******

02C*0 400 PSI PS 02050 IF (PSI .GT.

02060 IF (PSI .LT.

02070 PSI - »SI E 02080 450 PSIRAD "_

2 090 SN PS I S I N (

02100 CNPSI • C0S(P

02110 TSO » CSQRT(Y

02120 PH - (SNPSI - 02130C *************

02140C* RH S RV AR 021 50 C ****** * * * ** * * 02160 E » TAN(BL/2.

02170 E2 • 120.*CAB

021B0C*** **********

02190C* THE GAIN E 022C0C* EFFECTIVE

022 IOC* "PATTERN OF

022 20C*************

02230 GAIN - 10.0*A

022*0 500 F0R*AT(2F

02250 PRINT 500, PSI

02260 GO TO 400

02270 600 FORMAT (*P

02280 640 PRINT 600

02290 PAUSE

02300 650 FOR

02310 660 PRI

02320 IFHMDLA

02330 IF(POLA

02340 PSI - 02350C*******

02360C* VERT

02370C*******

02380 700PSI

02390 IF (PSI .GT." 02400 IF (PSI .LT.

02410 PSI • PSI E 02420 800 PSIRAD

02430 SNPSI SIN(P

_02 4 40 J NP

I » C OS (

024 50 TSO • CSQRT(Y

02460 RV (( (Y-J*X

02470 IF(P0LAR.E0.1

02480 E - (CEXP(J*B

02490* -COS(BL*SNP

025 00 C****** *******

02510C* THE TERNS

02520C* A GENERAL

02530C* FLEVATION

02540C*************

02550 E2 - 120.*CAB

02560 IFCE2.E0.0.)

02570 GAIN • 10.0*A

02580 PRINT 500»PSI

02590 GO TO 700

026 COC ******* ******

02610C* VERTICAL P 26 20C*** **********

026 30 8 50 E_

"~TCEXP

02640+ -COS(

026 50 C***** ********

POLARI *******

I ENC

90.0) G 10.1) G NC2

0.01745

STPADr"

SIRAD)

-J*X-(C

TSO)/(

E HORIZ *******

)*(CFXP

S(E*E)/

*******

QUATTGN

LENGTH

A HORI *******

L0G10(E

15.3)

#GAIN

ZATIO *****

TO

TO

N * ****

64

450

329252*PSI

NPSI*

SNPSI *****

PNTAL

*****

(J*BH

RFAL( *****

IS B

* iZ L ZONTA *****

2)

*2))

T ****

AND

* * * * *SNP

ZR) ****

ASIC

BFTA

L ""D'l  

SO) ** ****************

VERTICAL REFLECTI ******************

SI)*RH*CONJG(CFXP( ******************

ALLY JORDAN'S EON.

)*TAN(BL/2) FOB TH

POLE ******************

*****************

ON COEFFICIENTS * *****************

J*BH*SNPSI))) ***************

12-18 USING *

E_ H-PLANE *

* ***************

PESS RETURN FOR E-PLANE PATTERN OR TYPE CNTL T*

)

NAT(*E-PLANE ELEVATION ANGLE IN DEGREES AND GAIN IN DB*)

NT 650

R_.E0.1

R.EO.O,

ENC ********************

ICAL POLARIZATION * ********************

PSI

) JR

. ) PR 0.000

*****

OLARI ***** _+_JN

90.0)

10.1)

NC2

0.017

SIRAD

SIRAD

-j*X-

)*SNP

.) GO

H*SNP

SI))/ *****

IN TH

FORM

ANGLE *****

S(E*E

E2-1.

L0G10

#GAIN

INT 355

INT 356

1*******

ZATION *******

C GO TO

GO TO

900

800

45329252*PSI

)

)(CNPSI*

sd-tso

TO 850

SIJ+RV*

(CNPSI* *******

E PRE VI OF THE

FOR A *******

)/REAL(

E-12

(E2)

*2))

)/(( (Y-J*X)*SNPSI)+TSO)

CONJG(CEXP(J*BH*SNPSI) ))*(COS(BL)

SIN(BD)

**********************

OUS LINE FOLLOWING' THE

EFFFCTIVE LENGTH INCOR

VERTICAL DIPOLE **********************

ZR)

***************

SIXTH * APE * PORATING *

* ***************

************ OLARIZATION

************ U*BH*SNPSI)

BL*CNPSI))/( ************

**********************

FOR A HORIZONTAL DIPOL **********************

-¥V*CON JG TCEXP

(

J*3H*SN

SNPSI*SIN(BD)

**********************

****

E * **** PSI))T*TCOS(BL)~

******************

33
02670T

02*600

02690C

r?7ro

02710

02720

02730

C2740C

02750'*

027600

02770C

02790

02? 00

02810

028200

02830C

028*00

02«"*0C

C2 a 60

02P70

0?8«0

02 S 9Q

O'QOO

02910

C2920

02930C

02c*0

02950C

02960

H2970

02980

029C0C

03C00C

03010C

03G20

03030

030*0

030500

03060C

03070C

C308n

03091

031 00

03110

03120

03130C

03140*"

031 C 0C

03160C

0317CC

03ieO

03190

03200

03210

03220

03230

03240

03250

03260

03270

ft 3?80

03290

* T

* f- * A ****

P? * PAIS

PS? I N GO T ****

* C

* S ****

070

OGO

910

920 ****

* M

****

IF( M IF(«

IF(M

PFAO

T F ( » TF(M

END  

S ** **

DI M E PEAL

C 0" D ****

* C ****

R V9^

PM90

IF(X

* + **

* C ****

YO

xo " IF(P

YO « XO - ****

* X * ~D * T ****

1

D Y02

HL1

H12

HL^

WL*

HL5

ABO(

APG(

APC(

ARG(

APP(

L FC

Fnp

** ** o*ca

.0*4

»PSI

** ** 4Tin

TPOL

** ** T(*-

870

T(*E

T(*T

**** con

not  

0.0.

C.l.

o.i.

IN Thf PPFVTO'JS LIN

p„ np THF F^FFCTIVE

THE E-PLANE PATTERN ** *****************

8S(E*F) /PF4L( Z»)

Ln010(F2 ) /GAIN. *******************

NS END HEPF. USER

E ANTENNA GEO M ETPY *******************

NTFR DIPOLE HEIGHT

YPE TO STA=T 3VEP *******************

TP"L T IS THF bpeak

RATING <^Y?TE M . *******************

) ppimt 920

) PRINT 910

) PRINT 920

D TO 12

C to i

HF TE ENERA

NGL c *****

12 0.

» 10

T 500

700 *****

ALCUL

A ^E

* + * **

c OR M A PPINT

PHP W A P Q R 1

A

*****

OTE : *****

PNO.E

D

k-'Q. C ONO.E

3t «

• ST.O

.EO.O

*** ** U8P DU *****

kj 3 j nig L,L1

LEY J *** **

-] M p IJ J *****

1 (

« - (1

.FQ.O *****

OMP [>J *****

0.

? , *h

"JLAR.EQ.O, J GO TO 1 2 , *H

D. *****

IS

IPOLE

HE HP *****

« B

C T

« YC*

<C- xo-

« xo

xo + xo+

E FOLLOWING the ^IXTw * ARE A * LENGTH INCORPORATING ELEVATION * O

c A HORIZONTAL 01P0LE. * *********************************

*********************************

1AY START DV C R OR CONTINUE WITH *

"*l' T A DIPFEPENT HEIGHT* OR STOP * ********************************* __ __________ -///)

IN VETEPS,*)

, n? type ONTL T*) *****************************

("DOE FOP the CYBER 1 7 0/750 *

* *****************************

  TINr ** **

S(?

,12.

»-RH9  

E RE ** **

Y-J*

,-cs

. ) G ****

c AP  

** ** *

" V T U ** ***

1 )>Cf

L3»L<r

, P V 9 *****

FLECT

* *** * XJ-CS

ORT{ y

n TO *****

G U » E N *****

**************

AL f RETA,h, j,l* **************

21),T(<,<,),APGj

***

ION *** CRT

-J*

30***

TS***

SC»7M ***********

CPEFi-ICTEN ***********

(Y-j*y>) /(

(

X) ) /(l. + CSO ***********

FOP SINF AN *** ********

11

2)

3)

*)

5 )

**** TWF

AND

RI70

****

A*2

2.*L

L

L2.*L

3*(S

B*(S

3*(S

R*(S

B*(S

*******************

S F P A P A T I N_ 8 cJ W c F N_

ITS COL I NEAR IMAGE

NTAL DIPOLE AND ITS *******************

****************************

RUO0,PV90,7M,X,Y, POLAR, T) ****************************

5).SI(5),CI(5).

**********************

TS FDR PS I 90 DEG * **********************

Y-J**)+CSCPT( Y-J+X) ) PT( Y_J*X) ) *********************

D COSINE INTEGRALS * *********************

*********************************

THE FFECPOINTS OF THF VERTICAL *

. Vo" IS "THE SEPARATION 3ETWEEN * IMAGE. * *********************************

ORT( YC2 + HL1**2 »+HLl

OPT( Y02 + HL2**"') +HL2

CRT(Y0 2+HL3**2)+WL3

OPT( Y02+HL-**') +HL4

OPT( YC2 + HL5**2 ) + -*l'>

34
0*00 D 03310 Z 03320 I 03330C*

03340C*

033*0C*

03360 n 03370 5 03380 S 03390*

03400 n 0341" 6 03420 S 03*30*

03440 C 03*50 r- 03460C*

03470 r * 034eOC*

03490 7 035^0+

03510+

03520 G 03530+

03 c 40+

03550 5 03560 C 03 R 7D 9 C35P0 I 0359-OC*

02*, Cor*

O3610C*

O3620C*

03630 P 03*40+

03650+

03*60 * C?*70+

C6«0 + 03690 7 03700 P 03720C*

0*730C*

03740C*

03750 1 03760 L 0*770 L 03780 L 03790

038C0

03810

03820

C3830 B 03840 o 0385 0+

C?860*

03870*

0*880+

03»OC+

039C0 X 03910+

03920+

03930*

9, I APf,

C (7.GT ******

COMP ******

n «= mS ( K| ) 1(1)

P 6 Nb

C(N)«

A * C(

+c Id) - P T

n 9 ******

CO MD ******

F7» ( 7 + 3 + 5

Z - (7

+ 2 *(

III) • HI) » CnvTI

F(PPLA ******

C0 VD [63 ******

12 » 3

M - 31 FT MPS ******

CPMP

FTP ******

5 LI «

2 • «L

3 » AL

4 - AL

I & 8*

? - 8*

? R*

4 a R*

•5 a*

12-15.

*{'C

L3

*(-

*CP

-CI

3 2-1 5 •

-SI

ST

It 5 (I ) .1. ) ****

UTE  

If 20

((-1

7+S

S(

If 20

( (-1

1)+C

(12)

0.5 ** **

UTE  

**  R +

B .10

70.2

**8 + 1.82

Z**4

1.5

FZ*

Nl'F P.EO

* * + * UTF

FOR ****

0.*(

+ S4 0.*(

+ S -4

? + J*

GO TP 7 ****************************

SI (ARG( I ) ) AMO CI( APGII ) ) Fn ****************************

)**N)*(7**(2*N+1))/((2*N+1)*

(1)+S(2)+S(3)+S(4) + S(M+S(6)

32)+S(13)+S(14)+S(15)+S(15)+

)**N)*{7**(2*^')) /{ (2*N)*T(2*

(2)+C(3)+C(4)+C(5)+C(6)+C(7)

+ C(13) + C(14)+C(15)+C(1M+C(1

77215665 AL0G(7) + SA *** ***

SI (APG ******

3 a. 27

2495)

/

3&28*(

42.242

1«99)/

)+1114

707963

S I K ( 7 )

****

(I ) ) * *** 264*

( 7*(

7**2

8' 5*

( (Z*

.978

27-F

-07*

******

ANO C ******

(7**6)

(Z**8)

) + 1 5 7 . (7**6)

+ 2 )*( < 885*(

Z*COS(

C0S(7)

**** K AP ****

+ 2 6

e + 40.

10*4

+ 307

Z**8

**2)

Z)-o

********

G( I) ) FQ ********

.18703 3*

021433*(

23))

.7578***

J+4R.196

+44Q.690

Z*SIN(7)

.0. *** "UT

wnir ***

CPS

IN(

.*C

CPS

TN(

.*S

X12

) GP

* *** PAL

I7PN

****

(2.*

?.*P

1 (3)

(2.*

2 .* n T(3)

TP **** nPE

TAL ****

P*L ) *D*

-2.*

o* L ) *D*

+ 2.*

1******

DANCt

PPL AP *****

*(CI(

(-SK

CT(2)

*(-SI

(-CK

SI (2)

************

USING FOIIAT I7ATin^J ************

l)+CI(5)-2.*

l)+SI(5)+2.*

-'.*CI(4))

(l)-SI(5)+2.

1) +C1 (5)+2.*

+2.*SI(4)

)

******

UTF MU

VEPTIC

******

A L n C- f 0G(HL4

PGHL2

0C-(HL4

ML1

ML3

HL*

HL2

ML4

*(CPS(

I(3)-C

)+SIN(

ST{4)+

S(°*L)

(4)+L2

*(CPS(

ST (3) + (3))+S

N( 83 )*

**************************

TUAL IMPEDASCF USING EO'JAT

AL PPL ARI7ATTnM, **************************

ML2/HL1)

/HL3)

/HL3)

/HI 5 )

*****************

P 0<APG( 1X1 * *****************

T(2*N+2) ) +S(7)+S(8)+S(9)+S(10)+S(11)

S(17)+S(l&)+S(l^)+S(20)

* + 1 )

)

+C(8)*C (0)*C(10)*C(11)

7)+C(18)+C (19)+C(20)

***********************

F 1<APG( IXINFINITY * ***********************

(7**<») + 335.67732*( 7**Z)

7**6) +3 2 2. 62491]* (7**4)

(7**4) +352. CI 84 5 8* (7**2)

<327*(7**6)+482.4P59«4

326))

**********************

I C N S FROM H.E. KING *

* **********************

CI(2)-2.*CI(4)+2.*CI (3) ) SI(2)-2.*SI(4) ) *SI(2)+2.*SI(4)-2.*SI(3) ) CI(?)-2.*CI(4) )

**********************

IPN C frtm M.S. KING *

* **********************

81)*(CI(1)-CI(2) +L1)+STN(R

I (4 ) + if) + SI N ( 8 2 ) * ( S I ( 3 > - S

R7)*(-SI(2)+SI(3))+CPS(8?)

SK5) )+2.*CGS(°*L)*C0S(B4)

*SIN(P4)*(-SI(2)+SI(3))+2.

)+2.*C0S(P*L)*SIN(B5)*(SI(

81)*(-SI(1)+SI(?))+SIN(B1)

S I ( 4 ) I S IN (32 ) *

(

' C: I ( 3 ) -C I ( 4 IN(P2)*(-CI(2)+CI(3)-L3)+C

(-CI(4)+CI(5)-L4)+2.*CPS(8

1)*(SI(1)-SI (2) )+CPS(B2)

(4))+CPS(B')*(-CI(2)+CI(3)

*(-CI(4)+CI(5)+L4)+SIN(R3)

*(-CT(2)+CI(3)+L3)+2.

*C0S(9*L )*C0S(B5)*(CI( 3)

?)-SI(4) ))

*(CI(1)-CI(£)-L1)+C0S(B2)

)-L2)+CPS(B2)*(SI(2)

PS(83)*(SI (4)-SI(5))

*L )*C1S(P4)*(SI(2)

35
03Q4C4 -Sim)+?.*rn<:(q*u*5lN(<H)'M-CI(2)*CI(3)-L3)*2,*CrS(3*L)

03950+ *<-SI(3)+SK*))+2.*CnSCB + LJ+SI»*(B5)*(CI(31-CI(4)-L2)l

03<?f? Z

M » ci?+j*xi2

03O7O PFTMOM

030PO 3C 2" « D.D*J*0.0

04 C

C N'^

36
00100 PROGRAM 7MMKINPUT, OUTPUT, TAPE! ) 001 IOC***************************************************************

001200 THIS PROGRAM CALCULATE* SITE ATTENUATION BETWEE W A * 001 3 0C* PARTICULAR SET QP HALF-WAVE DIPQLES POS ITIQNED OVER PLANE _* _ 00140C* PERFECT GROUND. THE OPEN CIRCUIT PROBE VOLTAGE IS OBTAINED*

00150C* USING MUTUAL IMPEDANCES BETWEEN PROBE AND SOURCE ANTENNAS * 00160C* AND SOURCE ANTENNA IMAGES. INPUT IMPFDANCES ARE CALCULATE"*

00170C* TAKING "UTUAL IMPEDANCES IN GROUND INTO ACCOUNT. * 00180C* THE INCIDENT POWER FROM A SIGNAL SOURCF IS 1 W WHICH * 00190C* IS USED WITH THE SOUPCF DIPQLE INPUT IMPEDANCE* REFERRED TO*

00200C* THE BASE, TO DETERMINE THE BASE CURRENT USED IN THE "UTUAL * 00210C* IMPEDANCE CALCULATIONS. * 0C220C* TAPE3 CONTAINS THE SITE ATTENUATION AMPLITUDE DATA. * 00230C* NOTESt * 00240C* 1. THE PROBE IS ASSUMED TO BE ATTACHED DIRECTLY TO A * 00250C* RECEIVER. THAT IS* A LOSSLESS LINE IS ASSl' M En. * 00260C* ?. A LOSSLESS BALUN WITH A ltl TRANSFORMER RATIO IS * 00270C* ASSUMED. * Q0280C* 3. PPPC. FILES W OR D7M ARE USED T O PLOT THE DATA. _*

00290C* 4. SAVE TAPES WITH REPLACE COMMAND AFTER RUN COLLET'S*

003C0C* 5. IN THE DATA FILESi LE" IS DIPOLE HALF-LFNGTH. * 00310C* RT TS THE RADIUS np THE DIPQLE TIP IN METEPS. * 00320C* RB IS THE RADIUS OF THE BASE OF THE DIPOLE* (AT * 00330C* THE FEEDPOINT). RT RB FOR A STRAIGHT ELEMENT. * 00340r* OBVIOUSLY* A LINEAR TAPER IS ASSUMED. * 003 50C*** ************************************************************

00360 DIMENSION T (44 ) , 712 ( 1000 ) , 71 ( 1000 )

,

PREC ( 100C ) * VOC (1000 )

,

00370*FRE0(10)*LEN(1C)*PT(1Q)*RB(10)

00380 REAL I1*L*L A«BDA, LEN

00390 COMPLEX J , Z12 » Zl» 7P» 7R» 7S1

00400 DATA PREe/30.*44.*6 5.*97.>143.>210.*311.*»59.*677.*100G./

00410 DATA LEN/2.4,1.62 5*1.082,.717, .4 9*. 331*. 221*. 147*. 09°*. 06 44/

004 20 DATA RT /.0013 , .0026* .0036, . 00 S* . 0023 5 ,. 0023?, . 00? 35* . 00 2 3 5,

00430+. 00235* .00235/

00440 DATA RB / .005, .00?, . 0C5, .005* . 0023", .00235, .00235 *. 00235 , . 002? 5,

00450+.00235/

00460 10 FQPMAT(Fl->.4>

00470 If FOR"AT(2F10.3)

00480 17 FORMAT^IM

00490 20 FQPMAT(*INPUT DATA AFTER EACH 7*)

00500 PRINT 20

00510 30 FORMAT(*SOURCE DIP n LE FEEDPOINT HEIGHT OVER PERFECT GROUND, M*)

00520 PRINT 30

00530 READ 10, H?

00540 40 FOPMAT(*PR0PE DIPOLE NORMAL DISTANCE FROM SOURCE PLANE, M*)

00550 PRINT 40

AA K 4. A DCin 1 A . D C 00560 READ 10, RS

00570 IF(RS.LT.25.) HPSS-1.

00580 IF(RS.GT.25.) HPSS»2.

00590 IF(RS.LT.25.) HPF-4.

00600 IF(RS.GT.25.) HPF«6.

00610 MPI-0.01

00620C************************************************************

00630C* THE ABOVE LINE SETS THE HEIGHT SCAN INCREMENT TO 0.01 * * 006 4 PC ************************************************************

00650 45 CONTINUE

00660 50 FORMAT(*TYPE 1. FOP H0PI70NTAL POLARIZATION, FOR VERTICAL*)

00670 PRINT 50

00680C READ 10,,P0LAP POLR

006 90C******* ****** ************ *************** **************

00700C* RECEIVER AND TRANSMITTER IMPEDANCES ARE 100 P"MS * 007 IOC ******************************************************

00720 REC7-100.

00730 TXZ -100.

37
00740 INQO

00750 IF(POLAR.EO.O) INC-1

0076 OC *******************************************************************

00770C* INC IS ADJUSTED TO SKIP THE 30 NHZ DATA <= C T BECAUSE THE 30 «HZ

00780C* DIPOLE HALF-LENGTH EXCLUDES ITS USE VERTICALLY POLARIZED

00790C******* ************************************************ ************

00600 60 INOINC*!

00610 F»FREO( INC)

00820 L-LEN(INC)

00830 RT-PT(INC)

00840 RB-RS(INC)

00850 HPS"Ht>SS

00860 IF(PQLAR.EQ.O.AND.HPS.LE.L) HPS«L+0.^5

00870 N»INT(0.0001*(HPF-MPS)/HPI)*l

00880 J»CMPLX(0.,1.)

00890 PI-3. 14159265

00900 LA"PDA«299.792458/F

00910 8FTA-2.*PI/LA*PDA

00920 K«l

00930 T(l)-1.

00940 DO 200 MM-1,42

00950 K-K+l

00960 200 T(K)«MM*T{K-1)

00970C******* ****************************+******* **************

00980C* ALL INPUT A^O MUTUAL IMPEDANCES ARE PEFERRED TO THE * 00990C* PASE OR TERMINAL CURRENT. * 010C0C **********************************************************

01010 CALL IHPED(H2j«ETA, J j L»

A1Q DA,RT, PP , ?R

PQL AR, T

01020 ZS1-ZR

01030 CALL Z7(8ETA,HPS#WPF,HPI,H2*J»L»LAHPnA>RS#Z12»t> 0LARfT)

01040 DO 300 T«1.N

01050 300 ZKIW12 (I)

01060 PINC • 1.0

01070 PTR»PINC*(1.-(CABS((ZS1-TXZ)MZS1+TXZ) ))»*?)

01080 Il«SORT<f>TR/REAL(ZSl)>

01090 HP-HPS-HPI

01100 DO 500 W.N

OHIO V0C(I)-CAPS(U*Z1(I) ) 01120 HP-HP+HPI

01130 CALL IHPEO(HP, BETA, J, LjLAN8DA,RTiRP,7R, POLAR. T)

01140 ZP-ZR

01150 500 PREC(I>-< (V0C(I)/CAPS(REC7+ZP))**2)*PECZ

01160 Pf*AX-PPFC(l)

01170 DO 600 I-2»N

01180 600 PNAy«A"AXl(PMAX,PPEC(I> ) 01190 SMIN.1Q.*AL0G10(PINC/PMAX)

01200C********************************************************

01210C* THE ABOVF 5 LINES OF Cine FIND THE MAXI^U* RECEIVED * 01??0C* POWFR INTO A RFCFIVFP ATTACHED TO THF PROBE *_

01230C* DIPOLE AND USE IT TO CALCULATE THE MINIMUM RELATIVE * 01240C* INSERTION LOSS WHICH IS THE SITE ATTENUATION * 01250C ***»**»»*»**********»*»*********************

01260 WRITE(1#15)SHIN,F

01270 800 F0RMAT(*EXECUTING1*)

012BQ PRINT 80Q

01290 IF(FRE0(INC).iT.10C0.) GO TO 60

01300 IF(P0LAR.E0.1.) GO TO 45

0131 E ND

0132 OC ********************************************************

01330 SUBROUTINE I *PFD { A

PFTA# J , L ,

AMRD A,C T»P°, Z<> * POL AR, T)

01340C* TS USFD TO QPTAT* THF SELF IMPEDANCf OF THE SHL'PCE *_ 01350C* AND PROBE ANTENNAS USING SCHE L KUNOFF • S EQUATIONS * 01360C* WE START BY COMPUTING THE SINE * 01370C* AND COSINE INTEGRALS S T

( *1 ) AND CIN(M). SUBROUTINE *

38
01380C* MUTUAL IS FINALLY CALLED TO ENABLE THE CALCULATION * 01390C* OF THE INPUT IMPEDANCE OVER GROUND. * 01 400 C***** ********************************** *****************

01410 DIMENSION S I ( 2 ) ,C IN<2 ), S ( 21 )» C ( 21 ) ,T ( 44 ) , Z (2

)

01420 PEAL KA,L, LAMBDA, MBL

01430 COMPLEX CT, J, NBL, R, ZA, ZIND, ZINN, ZM, ZR , ZI 01440 BL - BETA*L

01450 B 2.*BETA*L

01460 DO 60 M-1,2

01470 Z(M) • M*B

01460 DO 40 N • 1,20

01490 40 S(N) • ( (-l)**N)*(Z(M)**(2*N+l))/( (2*N+l)*TC2*N+2) ) 015 00 SI(M)-Z(M)+S(1)*S(2)+S(3)+S(4)+S(5)+S(6)+S(7)+S(8)+S(9)+S( 10)

01510+ +S(11)+S(12)+S(13)+$(14)+S(1?)+S(16)+S(17)+S(18)+S(19)+S(20)

01520 DO 50 N 1,20

01530 50 C(N) - ( (-1)**N)*(Z(M)**(2*N) )/(

(

2*N )*T (2*N + 1 )

)

01540 60 CIN(N) —(C (1 ) +C (2 )+C (3 )+C ( 4) +C ( 5 ) +C ( 6) +C (7 ) +C( 8) +C (9)+C (10)

015 50+ +C(11)+C(12)+C(13)+C(14)+C(15)+C(16)+C(17)+C(18)+C(19)+C(20))

015 60 C********* ************************************************ ********

01570C* COMPUTE SELF IMPEDANCE, ZI, USING EON 108 OF SCHELKUNOFF * 01580C* ANO FRIIS. * 015 90C********* ************************************************ ********

01600 IF(RT.EQ.RB) KA » 120.* (AL0G(2 .*L/RT )-l .

)

01610 IF(RT.NE.RB) KA»120.*( ALOG( 2+L/RB )

(

RT/ ( RB-RT)

)

*AL0G( RT/RB) ) 01620 MBL • 60.*(CIN(1)-1.+C0S(B))

01630 NBL J*60.*(SI(1)-SIN(B) ) 01640 ZAR • 60.*CIN(1)+30.*(2.*CIN(1)-CIN(2))*C0S(B)+30.*(SI(2>

01650+ -2.*SI(1))*SIN(B)

01660 ZAI - 60.*SI(1)-30.*(CIN(2)-AL0G(4.))*SIN(B)-30.*SI(2)*C0S(B)

01670 ZA ZAR+J*ZAI

01680 CT » J*RT/(30.*LAMBDA)

01690 ZINN - KA*( (KA-MBL ) *COS (BL ) +J* ( ZA*CT*KA*KA-N8L ) *SIN( BL )

)

01700 ZIND (ZA+CT*KA*KA+NBL)*COS(BL)+J*(KA+MBL)*SIN(BL)

01710 ZI - ZINN/ZIND

01720 IF(A.GT.0.066*LAMBDA) GO TO 70

01730 H1-0.0001*LANBDA

01740 POL-1.

01750 CALL MUTUAL(BETA,H1,J,L,ZM,P0L,T)

01760 ZI-ZM/(SIN(BL)**2)

01770 70 CONTINUE

01780C******* ******************************** **********************

01790C* THE ABOVE 6 LINES HELP PREVENT NEGATIVE INPUT IMPEDANCES * 01800C* FOR HORIZONTAL DIPOLES NEAR GROUND BECAUSE SCHELKUNOFF • S * 01810C* INPUT IMPEDANCE DOES NOT CONVERGE TO THAT COMPUTED BY * 01820C* SUBROUTINE MUTUAL. * 01830C***** ************************************************** ****** 01840 CALL MUTUAL(BETA,A,J,L,ZM,POLAR,TJ

01850 IF(P0LAR.E0.1.) ZR -ZI-ZM/ (

(

SIN ( BL )**2 ) 8 01860 IF(POLAR.EO.O.) ZR-Z I + ZM/ ( ( S IN( BL ) **2 ) > 01870 RETURN

01880 END

01 8 90C *********************************************** *************

01900 SUBROUTINE MUTUAL

(

BETA, H, J ,L , ZM, POL AP, T)

01910C* USES EQUATIONS FROM H.E. KING, "MUTUAL IMPEDANCE OF * 01920C* UNEQUAL LENGTH ANTENNAS IN ECHELON", IRE TRANS. ANT. * ul930C* AND PROP., JULY 1957.

01940C* **************************************************** *******

01950 DIMENSION S (21 ) ,C ( 21 ) ,T(44 )

,

ARG (5 ) , SI (5 ),C I ( 5

)

01960 REAL L, LI, L 2, L3, L4

01970 COMPLEX J,ZM

019 80C** ********************************************* ****** 01990C* CUnPUTE ARGUMENTS FOR SINE AND COSINE INTEGRALS * 02000C ******************************************** *********

02010 YO 0.

39
02020 X0 - 2.*H

02030 IF(POLAR.EQ.O.) GO TO 1 020*0 YO • 2.*H

02050 XO - 0.

02060C* **************************************************** ************

02070C* XO IS THE SEPARATION BETWEEN THE FEEPPOINTS OF THE VERTICAL * 020P0C* DIPOLE AND ITS COLINEAR IMAGE. YO IS THE SEPARATION BETWEEN * 02090C* THE HORIZONTAL DIPOLE A*n ITS IMAGE. * 021 OOC ******************************************************* **********

02110 IB- BETA

02120 Y02 » Y0**2

02130 HL1 X0-2.*L

021*0 HL2 XO-L

02150 HL3 XO

021fO HL* XO+L

02170 HL5 X0+2.*L

02180 APG(l) • B*(SQRT<Y02*HL1**2)+HL1)

02190 ARG(2) - B* (SQRT( Y02*HL2**2

)

*HL2 ) 02200 A0G(3) - B*(S0RT(Y02*HL3**2)*HL3)

02210 ARG(*) B*(SORT( Y02*HL***2

)

*HL* ) 02220 APGCS) • B*(S0RT(Y02*HL5**2)+HL5)

02230 DO 9, 1-1,5

022*0 Z - ARG(I)

02250 IF(Z.GT.l.) GO TO 7

02260C*********************** ************************ ********

02270C* COMPUTE SKARG(D) AND CKAPG(I)) FOR 0<ARG(I)<1 * 022 80C* ********************************************* *********

02290 DO 5 N-1,20

02300 5 S(N)-((-l)**N)*(Z**(2*N+l))/((2*N+l)*T{2*N*2))

02310 SKI) Z+S(l)+S(2)+S(3)+S(*)+S(5)+S(6)*S(7)*S(e)+S(9)*S(10)*S(ll)

023 20+ +S(12)+S<13)+S(1*)+S(15)+S<16)+S(17)+S(18)+S(19)+S(20)

02330 DO 6 N-1,20

023*0 6 C(N)-K-1)**N)*(Z**(2*N))/((2*N)*T(2*N*1))

02350 SA C(1)+C(2)*C(3)+C{*)*C(5)*C(6)*C<7)*C<8)*C(9)*C(10)*C<11)

023 60* *C<12)*C(13)*C(1*)*C<15)*CU6)*C(17)*C(18)*C(19)*C(20)

02370 CIC II • 0.577215665 ALOG(Z) + SA

02380 GO TO 9

023 90C ******************************************************* ****** 02*00C* COMPUTE SI(APGd)) AND CKARG(I)) FOR KARG ( I XINF INITY * 02*10C*************************************************************

2*20 7 FZ- (Z** 8*38. 02726** (Z**6)*265.1 87033* (Z***) +335. 67732* (Z**2)

02*30* +3 8.102*95)/(Z*((Z**8)+*0.021*33*(Z**6)*3 2 2.62*911*(Z***)

02**0* *5 70. 2 362 8* (Z**2) +15 7.105*23))

02*50 GZ - (Z**8**2.2*2855*(Z**6)*302.757865*(Z***)*352.018*98*(Z**2)

02*60* +21 .821899) /( ( Z**2 )*(( Z**e )* 6 . 196927* ( Z** 6) **82 .* 8598*

02*70* *( Z* **) 111*. 978885* (Z**2)*** 9. 6 90326))

02*80 SKI) 1.570796327-FZ*C0Sm-GZ*SIN(Z)

02*90 CKI) • FZ*SIN(Z)-GZ*C0S(Z)

02500 9 CONTINUE

02510 IF(PnLAR.E0.0.) GO TO 15

025 20C ***************************************************** ********

02530C* COMPUTE MUTUAL IMPEDANCE USING EOUATIPNS FROM H.E. KING * 025*OC* FOR HORIZONTAL POLARIZATION * 02 5 50C *********************************************** **************

02560 R12- 30.*(C0S(2.*B*L)*(CK1)*CI(5)-2.*CK2)-2.*CK*)*2.*CK3))

02570* *SIN(2.*B*L)*<-SK1)*SK5)*2.*SK2)-2.*SK*) ) 025 80* *.*CK3)-2.*CK2)-2.*CK*n

02590 X12 - 30.*(C0S{2.*B*L)*(-SK1)-SK5)+2.*SK2) + 2.*SK*)-2.*SK3))

2600* *SIN{2.*B*L)*{-CK1)*CK5)*2.*CK2)-2.*CK*) ) 02610+ -*.*SK3)*2.*SK2)*2.*SK*)>

02620 ZM R12+J*X12

02630 RETURN

026*0C ******************************************************* ****** 02650C* CHMPUTF MUTUAL IMPEDANCE USING EQUATIONS FROM H.E. KING *

40
02660C* FOR VERTICAL POLARIZATION * 026 70 C***** ************************************************** ****** 02680 15 LI - AL0G(HL2/HL1)

02690 L2 • AL0G(HL4/HL3)

02700 L3 • AL0G(HL2/HL3)

02710 L4 ALOG(HL4/HL5)

02720 Bl - B*HL1

02730 B2 « B*HL3

02740 B3 • B*HL5

02750 B4 B*HL2

02760 B5 B*HL4

02770 R12-15.*(C0S(B1)*(CI<1)-CI(2)+L1)+SIN(B1)*(SI<1)-SI(2))+C0S(B2)

027 80* *(CI(3)-CI(4)+L2)+SIN(B2)*(SI(3)-SI(4))+C0S(B2)*(-CI(2)+CI(3)

02790+ +L3)+SIN(B2)*(-SI(?)+SI(3})+C0${93)*(-CI(4)+CI(5)+L4)+SIN(B3)

02800* (-SI(4)+SI(5))+2.*C0$(B*L)*C0S(B4)*C-CI(2)+CI(3)+L3)+2.

02810* *C0S(9*L)*SIN(B4)*(-SI(2)+SI(3))+2.*CnS(B*L)*C0S(B5)*(CI(3)

02820+ -CI(4)+L2)+2.*C0S(B*L)*SIN{B5)*(SI(3)-SI(4)))

02830 X12 - 15.*(C0S(B1)*(-SI(1)+SI(2))+SIN(B1)*(CI(1)-CI(2)-L1)+C0S(B2)

028*0+ _ *(-SI(3)+SI(4))+SIN(B2)*(CI(3>-CI(4)-L2)+C0S(B2)*(SI(2)

02 850+ -SI(3))+SIN(B2)*(-CI(2)+CI(3)-L3)+C0S(B3)*(SI(4)-SI(5))

028 60+ +SIN(B3)*(-CI(4)+CI(5)-L4)+2.*C0S(B*L)*C0S(B4)*(SI(2)

02870+ -$I(3))+2.*C0S(B*L)*SIN(B4)*(-CI(2)+CI(3)-L3)+2.*C0S(B*L)

02880+ *(-SI(3)+SI(4))+2.*C0S(8*L)*SIN(B5)*(CI(3)-CI(4)-L2))

02890 ZM • R12+J*X12

02900 RETURN

02910 END

02 92 OC *********************************************************** ********

029 30 SUBROUTINE Z Z

{

BET A, MPS ,HPF, HP I ,HS, J , L,

AMBDA,RS, Z12B,P0L AR,T)

02940C* C01PUTES THE MUTUAL IMPEDANCE BETWEEN EACH SOURCE AND SOURCE * 02950C* IMAGE AND THE PROBE ANTENNA. M-0 FOR THE PROBE AND ONE SOURCE * 02O60C* CALCULATION AND M-l FOR THE PROBE TO IMAGE CALCULATIONS. * 029 70C***** ************************************************ **************

02980 DIMENSION ARG (18 ) ,S (21) ,C ( 21) ,T(44) , SI ( 18), CI (IB) ,R 12 (1000),

02990+X12 (1000) , Z12L ( 1000), Z12B ( 1000 ), SIS ( 18), SIL(18) ,CIS( 18 )»CIL( 18)

03000 REAL LAMBDA, L 03010 COMPLEX J,Z12L,Z12B

03020 B-BETA

03030 M-0

03040 10 HP-HPS-HPI

03050 K-0

03060 20 HP-HP+HPI

03070 K-K+l

03080 IF(POLAR.EO.O.) D-RS

03090 IF(P0LAR.E0.1.AND.M.E0.0.) D-SORT ( RS*RS+ ( HS-HP ) **2

)

03100 IF(POLAR.E0.1.AND.M.E0.1.) D-SORT( R S*RS+ ( HS+HP ) **2)

03110 IF(POLAR.EO.O.AND.M.EO.O.) H»H$-HP-L

03120 IF(P0LAR.E0.1.) H —

03130 IF(P0LAR.E0.0.AND.M.E0.1.) H-HS+H«>-L

03140 ARGUJ-B* (SORT (D*D+(H-L) **2> + (H-L) ) 03150 ARGm-B*(SQRT(D*D + (H-L)**2)-(H-D)

03160 ARG(3)-B*(S0RT(D*D+(H + L)**2)-(H + D)

03170 ARG(4)"B*(S0RT(D*D+(H+L)**2)+(H+L))

03180 ARG(5)«B*(S0RT(D*D+(H)**2)+(H))

03190 ARG(6)-B*(SQRT(0*D+(H)**2)-(H))

03200 ARG(7)-B*(S0RT(D*D+(H + 2*L)**2)-(H+2*D)

03210 ARG(8)«B*(SQRT(D*D+(H + 2*L)**2) + (H + 2*D)

32 20 APG(9)«B*(S0RT(D*D + (H + L)**2) + (H + D)

03230 ARG(10)»B*(SQRT(0*D+(H+L)**2)-(H+L) ) 032 40 ARG(ll)»B*(SORT(D*D+(H+3*L)**2)-(H+3*L) ) 032 50 ARG(12)»B*(S0RT(D*D+(H+3*L)**2)+(H+3*L) ) 03260 ARG(13)»B*(SQRT(D*D+H*H)-H)

03270 ARG(14) »B*(SORT(D*D+H*H)+H)

032 80 ARG(15)»B*(S0RT(0*D+(H+L)**2)-(H+L>)

032 90 ARG(16)-B*(SQRT(D*D+(H+L)**2)+(H+L) )

41
03300

03310

03320

03330

03340

03350C

03360C

03370C

03380

03390

03400

03410*

03420

03430

03440

03450*

03460

03470C

03480C

03490C

03500

03510

03520*

03530*

03540

03550*

03560*

03570

03580

03590C

036C0C

03610C

03620C

03630C

03640

03650

03660

03670

03680

03690

03700

03710C

03720C

03730C

03740

03750+

03760*

03770+

03760*

03790*

03800+

03610+

03820+

03830+

03840

03850+

03860+

03870+

03880+

03890+

03900+

03910+

0392C+

03930+

GZ

APG(17)

ARGU9)

DO 100,

Z»ARG(I

IF(Z.GT *******

* COHP *******

DO 50 N 50 S(N)

SIS(I)

DO 60 N 60 C(N)

SA • C(

c

CIS(I) *******

* COHP *******

IF(Z.LE

70 FZ-(

+ 3

+ 5 (Z

2 *(

SIL (I ) cum-

*******

* THE

* S*00

* ARGU *******

80 IF(Z

IF(Z.LE

IFCZ.GT

IF(Z.GT

IF(Z.GT

IF(Z.GT

100 CON *******

* CO«P ******* R12(K)«

*(-SI(l

SIN(B*

(-CK5)

+ SK10)

(L+2.*L

(-CK13

-SK15)

-CI (18)

-SK19)

X12(K)-

M-CK1

+SIN(3*

(+SK5)

+ CK10)

(L+2.*L

(+SK13

-CK15)

+ SK18)

-CK18)

B*(SORT(D

B*(SQRT(0

1-1,18

).2.) GO TO **********

UTE SKARG

**********

-1,20

-( <-l)**N)

- Z+S(l)+S

S(12)+S(

1,20

-( (-1)**N)

1)+C(2)+C(

(12)+C(13)

- 0.577215 **********

UTE SKARG

**********

.1.) GO TO

Z**8+38.02

8.102495)/

70.23628M

**8+42.242

1.821899)/

Z**4)+1114

- 1.570796

F7*$IN(7)- ********** following

th The tra

MENT APPRO **********

.LE.l.) SI .1.) CKI)

.l.AND.Z.L

.l.AND.Z.L

.2.) SKI)

.2.) CKI)

TINUE **********

UTE HUTUAL **********

15.*(C0S(B

)+SI(2)+SI

(L+H))*(-S

-CI(6)+CI(

)+CO$(B*(L

+ H))*(SK7

)-CI(14)+C

+ SK16))+2

)+2.*C0S(B

))

15.*(C0S(B

)+CI(2)+CI

(L+H))*(-C

+SK6)-SI(

)+COS(B*(L

H))*(CI(7

)+$I(14)-S

CK16))+2

)+2.*C0S(B

))

*D+(H+2.*L)**2)-(H+?.*L) ) *D+(H+2.*L)**2)+(H+2.*L> )

70 *************************************

(I)) AND CKARG(I)) FOR 0<ARG(I)<1 * ************************************* (Z**(2*N+1) )/((2*N+l)*T(2*N+2))

(2)+S(3)+S(4)+S(5)+S(6)+S(7)+S(8)+S(9)+S(10)+$(ll)

13)+S(14)+S(15)+S(16)+S(17)+S(18)+S(19)+S(20)

*(Z**(2*

3)+C(4)+

C(14)+C

665 AL ********

(I)) AND ********

80

7264*(Z*

<Z*( (Z**

Z**2)+15

855*(Z**

( (Z**2)*

.978885*

327-FZ*C

GZ*CO$(Z ********

SIX LINE

NSITION

XINATION ********

(I)-SIS(

-CIS(I)

E.2.) SI

E.2.) CI

-SIL(I)

CIL(I)

N))/( (2*N)*T(2*N

C(5)+C<6)+C(7)+C

(15)+C(16)+C(17)

OG(Z) SA **************** CKARG(D) FDR ****************

*6)+26

8)+40.

7.1054

6J+302

((Z**8

(Z**2)

OS(Z)-

)******

S ARE

REGION

S TO T ******

I)

5.187033M

021433*(Z*

23) ) .757865*(Z

)+48. 19692

+449.69032

GZ*SIN(Z) **********

AN INTERPO

BETWEEN T HE SINE AN ********** m-sism + (z-i.

(I)»CIS(I)+(Z-1.

+ D)

(8)+C(9)+C(10)+C{ll)

C(18)+C(19)+C (20) ******************** KARGdXINFINITY * ********************

Z**4)+335.67732*(Z**2)

*6)+322.624911*(Z**4)

**4)+352.018498*(Z**2)

7*(Z**6)+482. 485984

6))

********************

LATION ROUTINF TO * HE LARGE AND SMALL *

D COSINE INTEGRALS * ********************

)*(SIL(I)-SIS(I))

)*(CIL(I)-CIS(I>)

*****

INPE *****

*(L-H

(5)-S

K3) + 9)+CI

2,*L

)-SK

1(15)

.COS

*L)*S

*****

DANCE *****

) )*(C

1(6))

SK4)

(10))

H) )*

8J-SI

+ CK1

(8*L)

IN(B*

*****

USIN ***** Kl) + COS(

SK7

SIN(

(-CK

(11) + 6))+2

*COS(

(2.*L

******

G EOUA ****** CK2)-

B*(L+H

J-SK6

B*(L-2

7)-CI(

SK12)

.*COS(

B*(2.*

+H))*(

********

TIONS FR ********

CI(5)-CI

) )*(CI(3

) )+COS(B

.*L-H) )*

8)+CI(ll

)+2.*C0S

B*L)*SIN

L+H))*(C

-SK15)*

***************

ON H.E. KING * ***************

(6) ) + SIN(B*(L-H))

)+CI(4)-CK7)-CI(8))

*(L-2.*L-H) )*

(SI(5)-SI(6)-SK9)

)+CI(12))+SIN(B*

(B*L)*COS(B*H)*

(B*H)*(SK13)-SK14)

K15)+CK16)-CK17)

SK16J+SK17)

42
03940 IF(POLAR.EO.O.AND.M.EQ.l) Z12L (K ) -712 L ( K ) + R12( K ) + J*X12 ( K

)

03950 IF(POLAR.EQ.l.AND.M.EQ.l) Z12 L < K

)

-Z12L (

>-R12( K

)

-J*X12 < K

)

03960 TF(M.EO.O) Z12HK) «R12(K) +J + X12 (K)

03970 Z12MK)-Z12L{K)/{(SIN(BETA*L))**2)

039 80C ******************************************************* **********

03990C* THE TERMS IN THE PROCEEDING LINE FOLLOWING THE / CHANGE THE * 04000C* HUTUAL IMPEDANCE REFERENCE FROM THE LOOP CURRENT TO THE BASE * 04010C* CURRENT. SEE JORDAN ??, 345-351. * 040 20C******* ******************************** **************************

04030 IF(HO.LT.HPF) GOTO 20

04040 "*!

04050 IFCM.LE.l) GOTO 10

04060 RETURN

04070 END

43
NBS-114A (rev. 2-ao

U.S. DEPT. OF COMM.

BIBLIOGRAPHIC DATA

SHEET (See instructions)

1. PUBLICATION OR

REPORT NO. NBS TN-1089

2. Performing Organ. Report No. 3. Publ ication Date

November 1985

4. TITLE AND SUBTITLE

Site Attenuation

5. AUTHOR(S)

R. G. FitzGerrell

6. PERFORMING ORGANIZATION (If joint or other than NBS, see instructions)

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, D.C. 20234

7. Contract/Grant No.

8. Type of Report & Period Covered

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street. City, State, ZIP)

10. SUPPLEMENTARY NOTES

H Document describes a computer program; SF-185, FIPS Software Summary, is attached.

11. ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a si gnificant

bibliography or literature survey, mention it here)

Site attenuation is a measure of performance of an open test site used

at frequencies below about 1 GHz for antenna calibration and equipment

emission and susceptibility testing. These sites typically consist of

a large, obstruction-free ground plane and the hemisphere above it.

Site attenuation of an ideal site is calculated and compared to data

measured using the 30 m by 60 m NBS ground screen.

12. KEY WORDS (Six to twelve entries; alphabetical order; capitalize only proper names; and separate key words by semicolons)

antenna measurements; dipole antennas; site attenuation

13. AVAILABILITY

[5CXj Unlimited

| | For Official Distribution. Do Not Release to NTIS

|)CX) Order From Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. H Order From National Technical Information Service (NTIS), Springfield, VA. 22161

14. NO. OF

PRINTED PAGES

48

15. Price

USCOMM-DC 6043-P80

U.S. GOVERNMENT PRINTING OFFICE: 1985—676-877 45044 REGION NO.
NBSTechnical Publications

Periodical

Journal of Research—The Journal of Research of the National Bureau of Standards reports NBS research ana development in those disciplines of the physical and engineering sciences in which the Bureau is active. These include physics, chemistry, engineering, mathematics, and computer sciences. Papers cover a broad

range of subjects, with major emphasis on measurement methodology and the basic technology underlying

standardization. Also included from time to time are survey articles on topics closely related to the Bureau's

technical and scientific programs. Issued six times a year.

Nonperiodicals

Monographs—Major contributions to the technical literature on various subjects related to the Bureau's scientific and technical activities. Handbooks—Recommended codes of engineering and industrial practice (including safety codes) developed in cooperation with interested industries, professional organizations, and regulatory bodies.

Special Publications—Include proceedings of conferences sponsored by NBS, NBS annual reports, and other

special publications appropriate to this grouping such as wall charts, pocket cards, and bibliographies.

Applied Mathematics Series—Mathematical tables, manuals, and studies of special interest to physicists,

engineers, chemists, biologists, mathematicians, computer programmers, and others engaged in scientific and

technical work.

National Standard Reference Data Series—Provides quantitative data on the physical and chemical properties

of materials, compiled from the world's literature and critically evaluated. Developed under a worldwide pro- gram coordinated by NBS under the authority of the National Standard Data Act (Public Law 90-396).

NOTE: The Journal of Physical and Chemical Reference Data (JPCRD) is published quarterly for NBS by

the American Chemical Society (ACS) and the American Institute of Physics (AIP). Subscriptions, reprints,

and supplements are available from ACS, 1155 Sixteenth St., NW, Washington, DC 20056.

Building Science Series—Disseminates technical information developed at the Bureau on building materials,

components, systems, and whole structures. The series presents research results, test methods, and perfor- mance criteria related to the structural and environmental functions and the durability and safety

characteristics of building elements and systems. Technical Notes—Studies or reports which are complete in themselves but restrictive in their treatment of a

subject. Analogous to monographs but not so comprehensive in scope or definitive in treatment of the subject

area. Often serve as a vehicle for final reports of work performed at NBS under the sponsorship of other government agencies.

Voluntary Product Standards—Developed under procedures published by the Department of Commerce in Part 10, Title 15, of the Code of Federal Regulations. The standards establish nationally recognized re- quirements for products, and provide all concerned interests with a basis for common understanding of the

characteristics of the products. NBS administers this program as a supplement to the activities of the private

sector standardizing organizations.

Consumer Information Series—Practical information, based on NBS research and experience, covering areas of interest to the consumer. Easily understandable language and illustrations provide useful background

knowledge for shopping in today's technological marketplace.

Order the above NBS publications from: Superintendent of Documents, Government Printing Office,

Washington, DC 20402. Order the following NBS publications—FIPS and NBSIR's—from the National Technical Information Service, Springfield, VA 22161.

Federal Information Processing Standards Publications (FTPS PUB)—Publications in this series collectively constitute the Federal Information Processing Standards Register. The Register serves as the official source of

information in the Federal Government regarding standards issued by NBS pursuant to the Federal Property

and Administrative Services Act of 1949 as amended, Public Law 89-306 (79 Stat. 1127), and as implemented

by Executive Order 11717 (38 FR 12315, dated May 11, 1973) and Part 6 of Title 15 CFR (Code of Federal

Regulations).

NBS Interagency Reports (NBSIR)—A special series of interim or final reports on work performed by NBS

for outside sponsors (both government and non-government). In general, initial distribution is handled by the sponsor; public distribution is by the National Technical Information Service, Springfield, VA 22161, in paper copy or microfiche form.
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