Report No. FAA-RO-79-75

THE SELECTION OF GLIDE SLOPE ANTENNA PATTERNSFOR USE IN THE FREQUENCY ASSIGNMENT PROCESS

Mark Lopez

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of YT4

O ' AUG

July 1919U Final Report

Document is available to the U.S. publ'c throughthe National Technical Information Service,

Springfield, Virginia 22161.

Prepared for

U.S. DEPARTMENT OF TRANSPORTATIONFEDERAL AVIATION ADMINISTRATION

Systems Research & Development ServiceWashington, D.C. 20590

NOTICE

This document is disseminated under the sponsorship of theDepartment of Transportation in the interest of in'ormationexchange. The United States Government assumes no liabilityfor its contents or use thereof.

Technivel Report Oecumentation Pegs

2 Govem. no, Acc ston No 3. Recipient' .atelog No.

4. T,,lo and SubtitleThe Selection of Glide Slope Antenna Patterns Ju -79

Use in the Frequency Asfignment Process. ,ion Code

I .. -' *j;.t.t',. 0______________ . P =ft 40

P. foiiin o onsomastion Nomie and Akdd,, 10 wo'door 0f 9

Federal Aviation AdministrationSystems Research and Development Service 1I Cont.oct or Giant NoSpectrum Management Staff, ARD-60AT Spectrum Engineering Branch, ARD-62 13 Type of Report end Pe' r.NJ&

U.S. Department of Transportation, FinalFederal Aviation AdministrationSystems Research and Development ServiceWashington, 0. C. 20591 - -

15 Suppltmelertey Not**

-16 Abtract

The trequency assignment process is meant to preclude harmful interferencewithin servic'- volumes. This is done by choosing frequencies in a mannerwhich provides certain a',imum cochannel and adjacent channel desired toundesired signal ratios a; critical points of the service volume. One of thefactors which affects a stations signal strength in space is its horisontalantenina pattern. Consequently, the horizontal pattern can have a substkntillettect onthe separation required between glide slope frequency assignments. Insome cases, it is desirable to consider the actual antenna patterns involvedrather than using woratcase station separations. This report has been assembledso that the directivity of the horizontal pattern may be considered in theassignment process. For each antenna type, a particular antenna pattern isrecommended.

PK+ *oruOritributlrn StO.#I.m n

i-strusear Landing System (11,S) Document is available to the publicCl id,, Slopr, through the National Technical InformationAnt vnas Service, Springfield, Virginia, 22151.l'i equency Management

19 sot~oti Ooss$, Qft hts fooort, 20, Nocurtlj clossit. tof;I this e) 21. Nr' o . 2 Pr ice

K Unclassi i~d Unclassitied 90

Fotm DOT F 170.7 , Roproduction of coTPletd Page outhorwted

ii AS

FEDERL AVIATION ADMINIS TTONSSTSZ SEAC N DEVELOPMENT SERVICESMANGEMENT STAFF

The mission of the Spectrum Management Staff is to assist theDepartment of State, National Telecommunications and Informa-tion Administration, and the Federal Communications Commissionin assuring the FAA s and the nation's aviation interests withsufficient protected electromagnetic telecommunicationsresources throughout the world and to provide for the safeconduct of aeronautical flight by fostering effective andeff'cient use of a natural resource - the electromagnetic radiofrequency spectrum.

This objective is achieved -hrough the following services:

. Planning and defending the acquisition and retention ofsufficient radio frequency spectrum to support the aero-nautical interests of the nation, at home and abroad,and spectrum standardization for the world's aviationcommunity.

. Providing research, analysis, engineering, and evalua-tion in the development of spectrum related policy,planning, standards, criteria, measurement equipment,and measurement ,tchniques.

* Conducting electroma&netic compatibility analyses todetermine intra/intersystem viability and design para-meters, to assure certification of adequate spectrumto support systoo operational use and projected Srowthpatterns, to deteld aeronautical services spectrumrow encroachmt.%- by others, and to provide for the

efficient use of the aeronautical spectrum.

0 Developing autcmated frequency selection computerp rograms/routir es to provide frequency planning,

frequency assignment, and spectrum analysis capabili-ties in the spectrum supporting the National AirspaceSystem.

a Providing spectrum management consu'tation, assistance,and guidance to all aviation interests, users, and pro-viders of equipment and services, both national andinternational.

ii

FEDERAL AVIATION ADMINISTRATIONSYSTEMS RESEARCH AND DEVELOPHENT SERVICE

SPLCTRUM MANAGEMENT STAFF

STATEMENT OF MISSION

The mission of the Spectrum Management Staff is to assist theDepartment of State, National Telecommuunications and Informa-tion AdministrationI and the Federal Communications Commissionin assuring the FAA s and the nation's aviation interests withsufficient protected electromagnetic telecommunicationsresources throughout the world and to provide for the safeconduct of aeronautical flight by fostering effective andeff:cient use of a natural resource - the electromagnetic radiofrequency spectrum.

This objective is achieved .hrough the following services:

Planning and defending the acquisition and retention ofsufficient radio frequency spectrum to support the aero-nautical interests of the nation, at home and abroad,and spectrum standardiza:ion for the world's aviationc otrimu n i ty.

Providing research, analysis, engineering, and evalua-tion in the development of spectrum related policy,planning, standards, criteria, measurement equipment,and measurement techniques.

Conducting electrom.,bnetic compatibility analy'ses todetermine intra/intersy'stem viability and design para-meters, to assu-e certification of adequate spectrumto support systco, operational use and projected growthpatterns, to det'ad aeronautical services spectrumfrow encroachmt-." by others, and to provide for theefficient use of the aeronautical spectrum.

Developing autcmated frequency selection computerprograms/routires to provide frequency planning,frequency assignment, and spectrum analysis c abili-ties in the spectrum supporting the National AirspaceSystem.

Providing spectrum management consu'tation, assistance,and guidance to all aviation interests, users, and pro-viders of equipment and services, both national andinternational.

II

TABLE OF CONTENTS

Page No.

INTROD UCTION -.......................................................... 1

DISCJSSSION ----------------------------------------------------------- 3

CONIUcSIONS ---------------------------------------------------------- 5

RECOMMENDED ANTENNA PATTERNS ------------------------------------------ 6

RELATED DOCUMENTS ----------------------------------------------------- 13

ACRONYMS AND ABBREVIATIONS -------------------------------------------- 17

APPENDIXES

A. TYPE I and TYPE II Antennas

B. TYPE III and TYPE IV Antennas

C. 2-Lambda Cassegranian Antenna

D. Stan-38 Antenna

E. End - Fire Slotted Cable Antenna

F. AIL Type 55 Antenna

G. FAA Antenna Specifications

H. Original NAFEC Data

I. Photographs of Different Antenna Types

'V

INTRODUCTIO4

In the past, separation of frequency assignments for associated facilities

has not considered the individual system components. Consideration of these

components (VOR, DNE, TACAN, LOCALIZER, GLIDESLOPE) had been included in the

overall separation criteria. Separations required between VOITAC Stations did

not require that VOR and TACAN separations be considered separately. Separations

required between ILS stations did not require that LOCALIZER, GLIDESLOPE, and

MEM separations be considered separately. Years ago, there was enough standard-

isation among facilities that this could be done. In recent years, however, the

use of many stations types and the variation in the radiated powers of stations

has lead us to reexamine old assumptions and conclusions. As a result of this

examination, we have concluded that separation of frequency assignments for

associated facilities should consider the individual system components.

The use of directional antennas can have a substantial effect on the

separation required between ILS Localizer frequency assignments. Since

cochannel separations are larger, the effect will be greater for them than for

adjacent channel separtions.

V Consideration of horizontal glide slope antenna directivity is not expected

to have a substantial effect on the separation required between cochannel ILS

systems. Since the glide slope service volume is substantially smaller than

the localizer service volume, localizer separation requirements are still ex-

pected to dominate in almost all circumstances. A similar statement could be

made for those first adjacent channel glide slope which are paired with first

adjacent channel localizers (example: 18x and 18y).

The situation is somewhat different for second adjacent channel glide

slope stations and for those first adjacent channel glide slopes not paired with

first adjacent channel localizers (example: 18y and 38x). In these cases,

the glide slope separation requirement must naturally be examined individually.

The horizontal antenna patterns of the glide slope antennas may have a sign-

ificanc effect on separation required in these cases. Consideration of the

antenna pattern may be preferable to using worst case separations.

We have assembled data from a number of sourc.s. For antenna type where

horizontal patterns were not available, we have made use of NAFEC's ability

to measure them. Wherever possible, comparisons have been made between the

following types of information:

Theoretical Antenna Patterns

Measured Antenna Patterns

- Applicable FAA Antenna Specifications

Data for each antenna type is included in the appendixes. On the basis

of these data, antenna patterns have been chosen for use in the frequency

assignment process. These patterns are shown in the report conclusions.

2

DIS(ISSIO4

Itionale for Antenna Pattern Choices

from the Information available, three types of antenna data have been

compared: theoretical, measured, and FAA Specifications. Ideally, agreement

would be expected among these types of data. Practicallyo this is not always

the case. For some antennas, all three types of data are not available. In

reviewing what was available, we used the following general glide lines in

choosing horisontal antenna patterns for the frequency assignment process.

If an FAA Antenna Specification was found to be applicable

for an antenna type and if both the theoretical and the

measured data compared reasonably well with it, we depended

largely on the specification in choosing the pattern to

be used in the frequency assignment process.

If an FAA Antenna Specification was found to be applicable

and it did not compare well with the measured data, we chose

a conservative frequency assignment pattern based on - cars-

fully chosen mixture of specification and measured data. An

example of this method is seen in the frequency assignment

pattern chosen for the type I and type I antennas.

If no FAA Antenna Specification was applicable and if

theoretical data was only available for some portion of

a pattern, we tried to get as much measured data as possible

before choosing a conservative pattern.

If no FAA Antenna Specification was found to be applicable

and if no tLeoretical pattern yes available, we chose

a frequency asseSgment pattern on the basis of the measured

data. The patterns chosen for the Stan-38, End-Yirs Slotted-

Cable, end the A.I.L. Type 55 Glide Slope Antennas are exaples

of this method.

41

ca N=SIoNS

1. The difference between the horizontal antenna patterns of various 118

glide elope antenna types are not as large as what has been found for

118 localisers. Nevertheless, some differences are apparent. In some

cases, it my be desirable to take these differences into account in the

frequency assignment process.

2. Uecomended antenna patterns are shown in figures 1 thru 7. These

patterns are t.ntended as tools for avoiding interference between LS

glide slopes. In some cases, those are not the best patterns to use as

tools for avoiding interferences between ILS glide slopes and other types

of radtu aervices. Should the need arise to make such an analysis, dis-

cussion with the Spectrum Management Staff (ARD-60) is recominded.

3. A frequency assigment antenna pattern is not included for the wave-

glide antenna since no horisontal antenna patterns were found. Antenna

data on this system is therefore still required. Additional data would

also be helpful on the A.I.L. Type 55 glide slope and the end-fire

slotted cable system.

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MEIkTZD DOtWNTS

1. FAA Handbook 6050.5A, "Frequency Management Engineering Principles,

Geographical Separation Criteria for VOR, DKE, TACAN, ILS, and VOT

Frequency Aesinments," March 12, 1969.

2. FAA Instruction Booklet TI 6750.9, "Antenna, Glide Slope Type FA-80900"

FAA Contract FA68WA-1969, Scanwell Laboratories Inc., May 9, 1968.

3. Wilcox American Standard Co., Instruction Book TI 6750.21, "Glide Slope

Antenna (Type III) Type FA-8021," FAA Contract FA68WA-1890, Wilcox

American Standard Co., April 30, 1968.

4. FAA Preliminary Instruction Book TI 6750.32, "Glide Slope Antenna

System Type FA-8730," FAA Contract DOT-FA704-2451, Scanell Laboratories

Inc.. June 30, 1970.

5. FAA Preliminary Instruction Book TI 6750.44, "Glide Slope Antenna System,

Part of Mark I Instrument Landirl System," FAA Contract DOT-FA69WA-2196,

A,I.L. Cutler Haomer, June 30, 1969.

6. FAA Preliminary Instruction Book TI 6750.63, "Glide Slope Antenna System

Type FA-8870,' FAA Contract FA71WA-2525, Scanvell Laboratories Inc.,

December 30, 1970.

7. FAA Instruction Book, Book I TI 6750.69, "Glideslope Station, One

Frequency Type AN/GRN-27(V)6" FAA Contract F33657-71-C-0103, Texas

Instrumenta, June 1, 1974.

8. FAA Instruction Book, Book I TI 6750.70, "Glidealope Station, Two

frequency Type AN/GRN-27 (V)," FAA Contract F33657-71-C-0103, Texas

Instruments, June 1, 1974.

13

9. FA Instruction Book T16750.76, "Gldo. Slope Antenna System FA-8976,"

F M Contract FA73WA-3176, February 9, 1973 and FA73WA-3358, Antenna

Products Co., October 16, 1973.

10. FAA Preliminary Instruction Book T16750.83, "Glide Slope Antenna Type

FA-9373," FAA Contract FA74VWA-3364, Antenna Products Co., October 18, 1973.

11. FA Instruction Book, '"Krk III Instrument Landing System Glide Slop*

Station NAPIC," FAA Contract DOT-FA73WA-3289, Texas Instrusents.

12. FAA Order 6750.6B, "Installation Instructions for Category I and

Category II ILS Glide Slopes," July 9, 1976.

13. FAA Order 6750,16A, "Sitting Criteria for Instrument Landing Systems,"

August 18, 1973.

14. FAA Order 6750.17, '"aintenance of ILS Glide Slope Equipment," August

25, 1971, Reprinted September 14, 1976 (Includes Changes 1 through 4).

15. FA Order 6750.32, '"aintenance of Null Reference Glide Slope Equipment,"

August 9, 1976.

16. FAA Report No. RD-64-11 "Analysis of ILS Glide Slope Antennas in

Operation and Under Development," FM Contract FA-WA-4391, National

Engineering Science Co., February 1964.

17. FA Report No. RD-65-46," A Waveguide Glide Slope Antenna," FM Contract

FAA/BRD-317, A.I.L. Cutler Hamer, July 1965.

18. FAA Report No. FM-RD-71-30," Instrument Landing System Improvement

Program," FAA Contract FA69WA-2066, Avionics Research Group, Department

of lectrical Engineering, October 1971.

19. FAA Report No. FAA-RD-72-139, "Analysis of Instrument Landing System

Glide Slope Broadside Antennas," FAA Contract DOT-FA71WA-2666, Aerospace

14

#ad Electronics System Division of Westinghouse Defense and Slectromics,

~.Sys tem Center, August 19 72. F.D7.6 MdiiainadTa

Instuma Ladin SyteaGlie SopeWavguie Atena,"FAAContract

21 DQ-PA7lA-2666. Asrospece and Electronic* System Division of Westinghouse

Defense and Ilectconic System Centetr, June 1973.

22. FAA ItmRep No. FR-D-76, "The Sltion fd Test Lofe teu

Patterns for use in the Frequency Assignment Prftess." Robert D. Smithq

September 1978.

23. FAA Specification FAA-3-2245, 'Antennass Glide Slope," March 11, 1966,

Amndmnt-3. March 24, 1969.

24. FAA Specification FM.E9-2429, "Antenna System, Glide Slope." January 2,

1970, Aaenduene-2, November 14, 1973.

25. FAA Specification FAA--2557, "Amplitude and Phase Control Unit, Sideband

Reference Glide Slope," April 2, 1973. Amndwent-l, Key 11. 1973.

26. Photographs Obtained from Robert Littlepage, Program Manager, Glide Slope

Antenna Systems, Westinghouse Electric Corp., Letter To ARD-60 Dated

December 20, 1977.

27. Scenvell laboratories, Inc., "Instruction Manual for Glide Slope Antenna

System Type 4400," Prepared for Pueblo Memorial Airport to Serve Ruvay

25R. July, 1970.

15

28. Technical Manual TT1 309, "Instrument Landing System Equipment Glide Path

Type Stan 38,"1 British Docummtt HB. 1268/2-A Issue 1, June 1968.

29. Unpublished Measured Data Obtained from Neil Creedon, A.I.L. Cutler

Haamumer, Latter To ARD-60 Dated December 19, 1977.

30. Watts Jr., C.B., "Description of the End-Fire Slotted-Cable Glide Slope,,

Medium Aperture," January 1977.

16

I

ACRK W AND AIIREVIATIONS

AGL Above Ground Level

A.I.L. Airborne Instrument Laboratory

A.P.C. Antenna Products Company

CE Capture Effect Glide Slope System

dl Decibel

DAA Drawinl

FAA Federal Aviation AdmSnlotrateon

I/S "nride slope

kLS Instrument Lnding System

kHs Kilohertz

k. Kilometer

MRC ieEahertz

NAC National Aviation Facilities perimental Center

na Nautical fele e

RNull Reference Glide Slope Sstem

Y Radio requency

IY Runway

SBR Sidebmnd Reference Glide Slope System

SRDS Systems Research end Development Service

T.1, Texas Instruments

TTH Telecommunication Technical Handbook

17

APPENDIX A

TYPE I AND TYPE 11 ANTENNAS

The Type I antenna consists of a half - wave dipole mounted on an

elliptical ground plane and enclosed in a radome. The Type II antenna is

the same as the Type I, except it is equipped with a heater. The addition

of the heater does not affect the antenna pattern. These antennas have

primarily been used with the older tube type transmitters. They are grad-

ually being phased out in favor of antennas with a more directional azimuthal

pattern. Only limited measured data was found on these antennas.

The measured data taken at NAFEC (Fig. AD) compares well with the

theoretical patterns. In addition, it compares reasonably well with the

requirements of specification FAA-E-2245 (&Hg. GI). The measured data from

Trenton (Fig. A4) does not compare quite as well. The main lobe of the

pattern is somewhat narrower and the pattern slightly exceeds the -16dB

limit between 242 and 264 degrees. No explanation was available f, r these

discrepancies. Tht frequency assignment antenna pattern recomrended for the

Type I and Type II Glideelope Antennas (Fig. 1) is based on the specification

(FAA-E-2245) and figures in Appendix A.

18

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APPENDIX B

TYPE III AND TYPE IV ANTENNAS

The Type III antenna is composed of three Type I antennas mount,.-d on an

iron frame with an array spacqig of approximately 0.75 wave lengths at the mid-

band frequency (332.0 MHz). The Type IV antenna is similar to the Type III

antenna, except it contains three Type II antennas. (This amounts to the add-

ition of 3 heaters and does not affect the horizontal antenna pattern). These

two types are the most widely used glide slope antennas.

The available data includes nine theoretical and measured patterns taken

fro various publications (Figs. B1 Lhru B8 and Bl). These data compare

reasonably well with the applicable specifications; FAA-E-2245 and FAA-E-2429

(Figs. G2 and GS). An additional five measured patterns were obtained from

NAFEC data (Figs. B9, BIO, B12, B13, and B14). These patterns show some dis-

crepancies. Allentown and Hagerstown compare well with both the theoretical

pattern and the specifications, but don't appear to meet the modified require-

ment of the contract specification with tegard to the lower limit of the antenna

pattern between 0 and 50 degrees. Dulles does not compare well with either

the theoretical pattern or the two specifications. No axplanation for this dis-

agreement is available at this time. Allegheny County compares reasonably well

with the recommended Type III - Type IV trequency assignment pattern, but

contains an unexplained peak between 60 and 8' devgrtes whert, the data exceeds

the -16dB maximum. Reading agrees well with the Type 1II - Type, IV pattern

in the front course, but contains some unusual varifations in the data outside

20 degrees. NAFEC could provide no exp anatioiS tort |hest, tttregularities.

The frequency assignment antenna pattt tn reconmuended tor tiv Type Ill and

23

Type IV glide slope antenn~as is based on specification FAA-E-2245 (Fig. G2)

and the material in Appendix V.

24

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APPENDIX C

THE TWO-LAMBDA CASSEGRANIAN ANTENNA

The two-lambda cassegranian glide slope antenna is produced by Texas

Instruments for use with its AN/GRN-27 (V) and Mark III glide slope systems.

Each antenna consists of a single dipole with a director, reflector, secondary

two-lambda by one-lambda reflecting surface, and two proximity (monitor) probes,

all enclosed in a radome.

Only limited data on this system was available. The three measured pat-

terns supplied by T.I. (Figs. C2 thru C4) agree well with the theoretical pat-

tern (Fig. Cl). In addition, they fall within the limits of FAA specification

FAA-E-2429 (Fig. G5). The two patterns produced from NAFEC data (Figs. C5 and

C6) don't agree very well with the theoretical pattern. In addition, they

appear to have a narrower front course pattern than what is required by the

specification.

The frequency assignment antenna pattern recommended for the two-lambda

cassegranian glide slope antenna is based on specification FAA-E-2429 (Fig.

5) and the figures in Appendix C.

J9

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. -

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42

rd

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t REATV ANTNN GANIDCBL

459.f.I.

APPENDIX D

THE STAX-38 ANTENNA

The Stan-38 glide slope is a part of the British ILS system located at

Dulles Airport. This is the only system of its kind presently conmissioned in

the U.S. Additional installations in this country are unlikely.

This system uses an image - type antenna designed for use in the conventional

null reference, sideband reference, and capture effect systems. The antenna

is unique in that each aerial contains six dipoles (U.S. manufactured arrays

house a maximum of three).

Only limited information was available on the Stan-38. The one antenna

pattern obtained (Fig. DI) was taken from the British instruction manual. The

frequency assignment pattern is based a this pattern, the theoretical 3dB

points, the side lobe ratio, and the front-to-back ratio.

46

... .. ....J

+ V1RELTIV POE'd EUI

...... 1

i7

APPENDIX E

THE END-FIRE SLOTTED CABLE ANTENNA

This antenna system is a non-image, end-fire type glide slope currently

under developement. A ground image is not required to form the glide path.

Rather, the difference in path lengths from the two antennas to the aircraft

produces the on-or-off course signals. This system is designed to provide

glide slope service for runways where site conditions make it difficult to in-

stall the existing systems.

The only pattern available (Fig. El) was taken from- the test evaluation

at Rock Springs, Wy. The frequency assignment pattern was chosen using this

data and a conservative estimate of the systems off-course szimuthal pattern.

48

1~ 1 -2FTh

-. T- I,

11 )

'

ti. i .-.t-- r

4-3

0 0... .... j U3 4 '1

V U)

-77 =- 7:=

-"I

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RELATIVE POWERIN DEC IBELS 1:

LA]..~~i i L L L i I

49

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> 0.)

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F1RELATIVE ANTENNA GAIN IN DECIBELS

o-.

.74..

Id-.* I#

'R Fl TIVFIkWIIN F F

ti2

r Kj~ .. , >4q v ...-

0l-i + ) 0

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... .. ..

LIT:T

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51.

APPENDIX G

FAA SPECIFICATIONS

In our search for glide slope antenna specifications, the following

documents were found to be applicable:

FAA-E-2245. This document was originally published March 11, 1966.

Three amendments, the most recent dating March 24, 1969, have been authorized.

Seven types of antennas are described in this specification.

Type I - This antenna contains a single dipole mounted on

an elliptical ground plane and completely enclosed

in a radome. Its horizontal free space radiation

pattern is shown in Figure G1.

Type II - Type II antennas are the same as Type I, except

they are equipped with a heater system. Its

antenna pattern is the same as the Type I.

Type III- This is an array of three Type I antennas grouped

to provide azimuthal directivity. The curve in

Figure G2 provides the horizontal free space

pattern for the Type III and the Type IV antennas.

Type IV- This antenna is the same as a Type III antenna, except

for the addition of heaters (Type II antenna elements).

Its pattern is the same as the Type III.

Type V - This is an array of two dipoles mounted one quarter-

wavelength from a vertical ground plane. The horizontal

free space radiation patterns given in Figure G3.

53

Type VI - This is a single dipole identical to those comprising

the Type V antenna, but utilizes a smaller ground

plane. The nominal antenna pattern is to be defined

by the contractor at the time that the initial equip-

ment is submitted.

Type VII - This antenna consists of an array of two colinear

dipoles mounted one quarter-wavelength from a parabolic

ground plane. Figure G4 provides the horizontal

free space pattern requirements.

This specification (FAA-E-2245) covers most glide slope antennas in use

today. Type III and Type IV antennas are the most abundant.

FAA-E-2429. This specification, dated January 2, 1970, is used in pur-

chasing new image-type glide slope antenna systems. Both class 1 (null refer-

ence) and class 2 (capture affect) systems are co'.ered. The sideband refer-

ence system is a modified version of the null reference syotem (Section 1.1,

FAA-E-2557, April 2, 1973) and must meet the same horizontal pattern require-

"Ients.

This document does not differenciate between antenna types or element

numbers, but rather sets general antenna array requirements. The antenna

array is defined as "single or muitiple horizontally polarized elements..."

Thus, wheth.2r the antennas are in the null reference, sideband reference, or

capture effect configuration, the same horizontal radiation pattern will be

required by the specification.

The lower limit of this spec ification was modified in the contract

spec it teat ien F-74WA-3364. M,1sured data indicates tlt this requirement iS

Jutticult to me'et, even tot tilte' nAV1.enas built under this COt 'rCt (Figs.

},4

59 and B10).

The end-fire slotted cable and the waveguide glide slope antennas are

still under development. Consequently, there are no current FAA specifications

which apply to these non-image type antenna systems.

55

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APPENDIX H

DATA OBTAINED FRHM KAFEC

This section contains copies of the raw data collected by NAFEC. The

following list shows the type of antenna elements are used in each intenna.

LOCATION FIGURE NO. SYSTEM TYPE ELEMENT TYPE

Allentown, Pa. B9 NR III or IV

Allegheny Co., Pa. B14 N7R III or IV

Reading, Pa. B15 NR III or IV

Hagerstown, Md. B1O SBR III or IV

Dulles, Va. B12 CE III or IV

Trenton, N.J, A4 SBR I or II

Atlanti ,' City, N.J. C5 CE Two-Lambda

Gr. Pittsburgh, Pa. C6 CE 'o-Lambda

Data from the Allentown glide slope is the only antenna pattern replotted

in detail. In order to save time, the remaining antenna patterns were replotted

using lines to outline the maximum and minimum limits of the data. Should de-

tailed information be desired on a particular antenna pattern, it is available

in this appendix.

The data taken at Johnstown, Pa. has not been replotted. This glide slope

system was shut down just prior to when the test orbit was flown. The data is

no more than the ambient noise level.

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ICD7I.'

APPENDIX I

PICTURES OF ILS GLIDE SLOPE ANTENNAS

Different types of glide slope antennas have different antenna patterns.

Consideration of these differences may be desirable in the frequency assignment

process. Consideration requires knowledge of the desired and undesired stations'

antenna types. FAA sector offices provide this information to the Electro-

magnetic Compatibility Analysis Center (ECAC). FAA has an interagency agree-

ment with ECAC. The FAA provides to ECAC data on telecommunication systems.

ECAC does the record keeping and provides to FAA computer printouts upon request.

For the frequency assignment process, the Frequency Management Officer (FMO)

may choose to use the ECAC records or he may contact the FAA sector offices

directly. In either case, the identification of the antenna type comes from

the FAA sector maintenance office. Since this is the case, sector personnel

should be capable of identifying the different antenna types. With the many

different glide slope antenna types, this can be a difficult assignment. FAA

type numbers are helpful but they have not been assigned to all antenna types.

In many cases, visual identification is essential. Since, to our knowledge

no single FAA publication shows all glide slope antenna types, this appendix

has been an attewpt to do that.

CAP'U$~ U~~ NLL (F~~N~SIDEBANO teRINCE

,:PUtE~c ULCR~RN.ONF IGU RAT ION COW RfATIONd CONFIUGfRATION

-Ip

-REFLECTOR PICK-UP DEVICE

ASSEMBLYDIPOLE ANT.

CONNECTOR

COAXIAL STUB ASSEMBLYFIGURE I 2

Type I Antenna With Pic k-Up DeviceAntenna Type FA-8090

At'~.Wit" ~~2V~ e

SiDEBAND

ANTENNA

GLIDE SLOP

ANTENNASTYPE FA STSO

CAtRIERt ANTENNA

Null Reference I

SLIDE SLOPEANTE NNA S II I 9 Ji

Antenna Ty~pe FA-8730 In

The Null Reference And

FIGURE 1 4

Capture Effect

Dipole For Antenna Type FA-8730FIGURE I 5

Type TV Antenna Withc,,nt 1reAntenna Type FA-S7,0

FIGURE 1 6

Typne III Antelmu With adome.-,An~tenna Trype V~A-tIO21

FIGURE 7

CARRIERANTE NNA

Il I IAlt oi i I 11W Nul I

C I S i

U U

PICK-UP LOOPS

MOIO DPL

CONNEZIM CONECTOR

FIGURE 1 10Inside View Of The Casing For The

AIL Type 55 Glide Slope Antenna Element

FILLFEDE 1

AIL Type 55 Glide Sloipe Ant'enna Element

79

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