TM 11-5820-467-15

D E P A R T M E N T O F T H E A R M Y T E C H N I C A L M A N U A L

OPERATOR, ORGANIZATIONAL, FIELD,

AND DEPOT MAINTENANCE MANUAL

ANTENNA GROUP AN/GRA-50

Headquarters, Department of the Army, Washington 25, D. C.

19 July 1961

WARNING
DANGEROUS VOLTAGES EXIST ON THE ANTENNA WHEN IN OPERATION

Before working on any part of the antenna, be sure that all equipment has
been disconnected from the power source.

DON’T TAKE CHANCES !

Paragraph Page

C H A P T E R 1 . I N T R O D U C T I O N 5
S e c t i o n I . General 3
S c o p e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 5
Forms and records . . . . . . . . . . . . . . . . . . . . . . . 2 5
II. Description and data 5
Purpose and Use . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 5
Techncal characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 5
C o m p o n e n t s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6
Common names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 7
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 7
C H A P T E R 2 . I N S T A L L A T I O N 8
Unpacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 8
Checking unpacked equipment . . . . . . . . . . . . . . . . . . . . . . . . . . 9 8
Siting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 0 8
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1 8
CHAPTER 3. M A I N T E N A N C E 14
S e c t i o n I . Operator’s maintenance 14
Scope of operator’s maintenance . . . . . . . . . . . . . . . . . . . . . . . 12 14
Operator’s preventive maintenance . . . . . . . . . . . . . . . . . . . . . . . 13 14
Operator’s visual inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 14
II. Organizational and field maintenance (third echelon) 17
Scope of organizational maintenance. . . . . . . . . . . . . . . . . . . . . . 15 17
Tools, materials, and test equipment required . . . . . . . . . . . . . . . . 16 17
Organizational preventive maintenance. . . . . . . . . . . . . . . . . . . . . 17 17
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 17
Repair of rf cable (third echelon) . . . . . . . . . . . . . . . . . . .... . 19 17
C h a p t e r 4 . T H E O R Y 19
Antenna theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 19

Theory of antenna assembly . . . . . . . . . . . . . . . . . . . . . . 21 19

This reprint includes all changes in effect at the time of 1

publication; changes 3, 5, and 6.

 Paragraph Page

C H A P T E R 5 . SHIPMENT, LIMITED STORAGE, AND DEMOLITION TO PREVENT

E N E M Y U S E 2 1
S e c t i o n I . Shipment and limited storage 2 1
Disassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2 2 1
Repacking for shipment or limited storage. . . . . . . . . . . . . . . . . . . 2 3 2 1
II. Demolition of material to prevent enemy use . 2 1
Authority for demolition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 4 2 1
Methods of destruction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5 2 1
APPENDIX I. REFERENCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 2
II. BASIC ISSUE ITEMS LIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 3
III. MAINTENANCE ALLOCATION CHART . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 5

2
 Changes in force: C 3, C 5, C 6 and C 7

TM 11-5820-467-15
C7

CHANGE HEADQUARTERS
DEPARTMENT OF THE ARMY
No. 7 Washington, DC, 1 July 1989

Operator’s, Organizational, Direct Support,

General Support, and Depot Maintenance Manual
ANTENNA GROUP AN/GRA-50
(NSN 5985-00-892-0758)

TM 11-5820-467-15, 19 July 1961, is changed as follows:

Inside front cover. After the inside front cover, add the following warning and first aid
safety steps.
 FIXED OPERATION WITH LONG RANGE ANTENNAS
WARNING

TELESCOPING TYPICAL TOWER EXTENDED RANGE DOUBLET ANTENNA

ANTENNA MAST ANTENNA

NEVER ERECT THESE LONG RANGE ANTENNAS DIRECTLY UNDER POWERLINES.

IF YOU MUST ERECT THESE LONG RANGE ANTENNAS NEAR POWERLINES, POWERLINE POLES OR
TOWERS, OR BUILDINGS WITH OVERHEAD POWERLINE CONNECTIONS, NEVER PUT THE ANTENNA
CLOSER THAN TWO TIMES THE ANTENNA HEIGHT FROM THE BASE OF THE POWERLINE, POLE.
TOWER OR BUILDINGS.

NEVER ATTEMPT TO ERECT ANY LONG RANGE ANTENNA WITHOUT A FULL TEAM.
BEFORE ERECTING ANY LONG RANGE ANTENNA, INSPECT ALL THE PARTS MAKING UP THE
ANTENNA KIT. DO NOT ERECT THE ANTENNA IF ANY PARTS ARE MISSING OR DAMAGED.

DO AS MUCH OF THE ASSEMBLY WORK AS POSSIBLE ON THE GROUND.

WHEN ERECTING THE ANTENNA, ALLOW ONLY TEAM PERSONNEL IN THE ERECTION AREA.

MAKE SURE THAT THE AREA FOR THE ANCHORS IS FIRM. IF THE GROUND IS MARSHY OR SANDY,
GET SPECIFIC INSTRUCTIONS FROM YOUR CREW CHIEF OR SUPERVISOR ON HOW TO REINFORCE
THE ANCHORS.

WHEN SELECTING LOCATlONS FOR ANCHORS, AVOID TRAVELED AREAS AND ROADS. IF YOU CANNOT
AVOID THESE AREAS, GET SPECIFIC lNSTRUCTlONS FROM YOUR SUPERVISOR AS TO WHAT CLEAR-
ANCE YOUR GUY WIRES AND ROPES MUST HAVE OVER THE TRAVELED AREAS AND ROAD.

CLEARLY MARK ALL GUY WIRES AND ROPES WITH THE WARNING FLAGS OR SIGNS SUPPLIED BY YOUR
UNIT. IN AN EMERGENCY, USE STRIPS OF WHITE CLOTH AS WARNING STREAMERS.

IF YOU SUSPECT THAT POWERLINES HAVE MADE ACCIDENTAL CONTACT WITH YOUR ANTENNA, STOP
OPERATING, ROPE OFF THE ANTENNA AREA, AND NOTIFY YOUR SUPERIORS.

IF THE WEATHER IN YOUR AREA CAN CAUSE ICE TO FORM ON YOUR LONG RANGE ANTENNA AND ITS
GUY WIRES AND ROPES, ADD EXTRA GUYS TO SUPPORT THE SYSTEM. ROPE OFF THE AREA AND
POST IT WITH WARNING SIGNS LIKE "BEWARE OF FALLING ICE."

DO NOT TRY TO ERECT ANY ANTENNA DURING AN ELECTRICAL STORM.

KEEP A SHARP EYE ON YOUR ANCHORS AND GUYS. CHECK THEM DAILY AND IMMEDIATELY
BEFORE AND AFTER BAD WEATHER.
SAFETY STEPS TO FOLLOW IF SOMEONE
IS THE VICTIM OF ELECTRICAL SHOCK

DO NOT TRY TO PULL OR GRAB THE INDIVIDUAL

IF POSSIBLE, TURN OFF THE ELECTRICAL POWER

IF YOU CANNOT TURN OFF THE ELECTRICAL

POWER, PULL, PUSH, OR LIFT THE PERSON TO
SAFETY USING A DRY WOODEN POLE OR A DRY
ROPE OR SOME OTHER INSULATING MATERIAL

SEND FOR HELP AS SOON AS POSSIBLE

AFTER THE INJURED PERSON IS FREE OF

CONTACT WITH THE SOURCE OF ELECTRICAL
SHOCK, MOVE THE PERSON A SHORT DISTANCE
AWAY AND IMMEDIATELY START ARTIFICIAL
RESUSCITATION
 Page 5. Paragraph 1.1 is superseded as follows:

1.1. Consolidated Index of Army Publications and Blank Forms

Refer to the latest issue of DA Pam 25-30 to determine whether there are new editions, changes or additional
publications pertaining to the equipment.

Page 5. Paragraph 2 is superseded as follows:

2. Maintenance Forms, Records and Reports

a. Reports of Maintenance and Unsatisfactory Equipment. Department of the Army forms

and procedures used for equipment maintenance will be those prescribed by DA Pam 738-750 as contained in
Maintenance Management Update.

b. Report of Item and Packaging Deficiencies. Fill out and forward SF 364 (Report of
Discrepancy [ROD]) as prescribed in AR 735-11-2/DLAR 4140.55/SECNAVINST 4355.73B/AFR 400-54/MCO
4430.3J.

c. Transportation Discrepancy Report (TDR) (SF 361). Fill out and forward Transportation
Discrepancy Report (TDR) (SF 361) as prescribed in AR 55-38/NAVSUPINST 4610.33C/AFR 75-18/MCO
P4610.19D/DLAR 4500.15.

Page 5. Paragraph 2.1 is superseded as follows:

2.1 Reporting Errors and Recommending Improvements

You can help improve this manual. If you find any mistakes or if you know of a way to improve the procedures, please
let us know. Mail your letter, DA Form 2028 (Recommended Changes to Publications and Blank Forms), or DA Form
2028-2 located in back of this manual direct to: Commander, US Army Communications-Electronics Command and
Fort Monmouth, ATTN: AMSEL-LC-ME-PS, Fort Monmouth, New Jersey 07703-5000.

In either case, a reply will be furnished direct to you.

Page 5. Paragraph 2.3 is superseded as follows:

2.3 Destruction of Army Electronics Material

Destruction of Army electronics material to prevent enemy use shall be in accordance with TM 750-244-2.

Page 5. Paragraph 2.4 is superseded as follows:

2.4 Reporting Equipment Improvement Recommendations (EIR)

If your AN/GRA-50 needs improvement, let us know. Send us an EIR. You, the user, are the only one who can tell
us what you don’t like about your equipment. Let us know why you don’t like the design or performance. Put it on
an SF 368 (Product Quality Deficiency Report). Mail it to: Commander, US Amy Communications-Electronics Command
and Fort Monmouth, ATTN: AMSEL-PA-MA-D, Fort Monmouth, New Jersey 07703-5000. We’ll send you a reply.
 Page 9. The following note is added after paragraph llb(3):

NOTE

To determine the correct length

of antenna wire that is required
to obtain the desired corresponding
frequency, use the following
formula:

This formula should be imprinted

on the case of the tape measure
as a ready reference and con-
venience to installation personnel.

Page 14. Paragraph 13.2 is superseded as follows:

13.2. Operator’s Daily Preventive Maintenance Checks and Services

B - BEFORE A - AFTER W - WEEKLY

ITEM INTERVAL ITEM ITEM TO BE INSPECTED EQUIPMENT IS NOT

NO. w PROCEDURE READY/AVAILABLE IF:

1 Antenna Inspect the antenna assembly

Assembly for completeness (App. II)

2 Antenna Inspect the antenna assembly

Assembly for cleanliness (para. 13.3)

3 RF Cable Inspect the rf cable for cuts, RF cable lacks

breaks, and undue strain (fig. 1). continuity.

4 Antenna Check the antenna assembly for normal Weak or no

Assembly operation when connected to a transmitter transmission
or receiver. or reception.
 Page 22. Appendix I is superseded as follows:

APPENDIX I
REFERENCES

Following is a list of applicable references that are available to the operator and unit repairman of
Antenna Group AN/GRA-50.

DA Pam 25-30 Consolidated Index of Army Publications and Blank Forms.

DA Pam 738-750 The Army Maintenance Management System (TAMMS).
TM 11-5820-295-10 Operator’s Manual for Radio Set AN/GRC-19 (NSN
5820-00-030-0155).
TM 11-5820-295-20 Organizational Maintenance for Radio Set AN/GRC-19
5820-00-030-0155).
TM 11-5820-467-24P Organizational, Direct Support and General Support Maintenance
Repair Parts and Special Tools Lists (Including Depot Maintenance
Repair Parts and Special Tools) for Antenna Group AN/GRA-50
(NSN 5985-00-892-0758).
TM 43-0139 Painting Instructions for Field Use.
TM 750-244-2 Procedures for Destruction of Electronics Material to Prevent Enemy
Use (Electronics Command).
By Order of the Secretary of the Army:

CARL E. VUONO
General, United States Army
Official: Chief of Staff

WILLIAM J. MEEHAN II
Brigadier General, United States Army
The Adjutant General

DISTRIBUTION:
To be distributed in accordance with DA Form 12-51 Operator, Unit,
and DS/GS requirements for AN/GRA-50.

PIN: 018745-007
 Changes in force: C 3, C 5, and C 6

TM 11-5620-467-15
C6

CHANGE HEADQUARTERS
DEPARTMENT OF THE ARMY
No. 6 W ASHINGTON , DC, 9 September 1977

Operator’s, Organizational, Direct Support,

General Support, and Depot Maintenance Manual
ANTENNA GROUP AN/GRA-50
(NSN 5985-00-892-0758)

TM 11-5820-467-15, 19 July 1961, is changed as follows:

The title is changed as shown above.
Page 5. Paragraph 2 is superseded as follows:

2. Forms and Records 2-4. Reporting Equipment Improvement

a. Reports of Maintenance and Unsatisfactory Recommendations (EIR)
Equipment. Maintenance forms, records, and EIR’s will be prepared using DA Form 2407
reports which are to be used by maintenance (Maintenance Request). Instructions for pre-
personnel at all maintenance levels are listed in paring EIR’s are provided in TM 38-750, The
and prescribed by TM 38-750. Army Maintenance Management System.
b. Report of Packaging and Handling De- EIR’s should be mailed direct to Commander,
ficiencies. Fill out and forward DD Form 6 US Army Electronics Command, ATTN:
(Packaging Improvement Report) as prescribed DRSEL-MA-Q, Fort Monmouth, NJ 07703. A
in AR 700-58/NAVSUPINST 4030.29/AFR 71- reply will be furnished direct to you.
13/MCO P4030.29A, and DSAR 4145.8.
c. Discrepancy in Shipment Report (DISREP) Paragraph 3b, line 7, change "100 watts" to
(SF 361). Fill out and forward Discrepancy in read "500W."
Shipment Report (DISREP) (SF 361) as pre- Paragraph 4, line 4, change "100 watts" to
scribed in AR 55-38/NAVSUPINST 4610.33A/ read "500 W."
AFR 75-18/MCO P4610.19B and DSAR 4500.15. Page 25. Appendix III is superseded as
Paragraph 2.4 is added after paragraph 2.3. follows:

APPENDIX Ill
MAINTENANCE ALLOCATION

Section 1. INTRODUCTION

1. General specific maintenance functions on repairable

items and components and the tools and equip-
This appendix provides a summary of the ment required to perform each function. This
maintenance operations for AN/GRA-50. It appendix may be used as an aid in planning
authorizes categories of maintenance for maintenance operations.
1
2. Maintenance Function j. Overhaul. That maintenance effort
(service/action) necessary to restore an item to a
Maintenance functions will be limited to and completely serviceable/operational condition as
defined as follows: prescribed by maintenance standards (i.e.,
a. Inspect. To determine the serviceability of DMWR) in. appropriate technical publications.
an item by comparing its physical, mechanical, Overhaul is normally the highest degree of
and/or electrical characteristics with estab- maintenance performed by the Army. Overhaul
lished standards through examination. does not normally return an item to like new
b. Test. To verify serviceability and to detect condition.
incipient failure by measuring the mechanical k. Rebuild. Consists of those services/actions
or electrical characteristics of an item and necessary for the restoration of unserviceable
comparing those characteristics with prescribed equipment to a like new condition in accordance
standards. with original manufacturing standards. Re-
c. Service. Operations required periodically to build is the highest degree of materiel mainte-
keep an item in proper operating condition, i.e., nance applied to Army equipment. The rebuild
to clean (decontaminate), to preserve, to drain, operation includes the act of returning to zero
to paint, or to replenish fuel, lubricants, hy- there age measurements (hours, miles, etc.)
draulic fluids, or compressed air supplies. considered in classifying Army equipments/
d. Adjust. To maintain, within prescribed components.
limits, by bringing into proper or exact position,
or by setting the operating characteristics to the 3. Column Entries
specified parameters. a. Column 1, Group Number. Column 1 lists
e. Align. To adjust specified variable elements group numbers, the purpose of which is to
of an item to bring about optimum or desired identify components, assemblies, subas-
performance. semblies, and modules with the next higher
f. Calibrate. To determine and cause correc- assembly.
tions to be made or to be adjusted on instru- b. Column 2, Component/Assembly. Column 2
ments or test measuring and diagnostic equip- contains the noun names of components, as-
ments used in precision measurement. Consists semblies, subassemblies, and modules for which
of comparisons of two instruments, one of which maintenance is authorized.
is a certified standard of known accuracy, to c. Column 3, Maintenance Functions. Column
detect and adjust any discrepancy in the 3 lists the functions to be performed on the item
accuracy of the instrument being compared. listed in column 2. When items are listed without
g. Install. The act of emplacing, seating, or maintenance functions, it is solely for purpose of
fixing into position an item, part, module having the group numbers in the MAC and
(component or assembly) in a manner to allow RPSTL coincide.
the proper functioning of the equipment or d. Column 4, Maintenance Category. Column 4
system. Specifies, by the listing of a "work time" figure in
h. Replace. The act of substituting a service- the appropriate subcolumn(s), the lowest level of
able like type part, subassembly, or module maintenance authorized to perform the func-
(component or assembly) for an unserviceable tion listed in column 3. This figure represents
counterpart. the active time required to perform that
i. Repair. The application of maintenance maintenance function at the indicated category
services (inspect, test, service, adjust, align, of maintenance. If the number or complexity of
calibrate, replace) or other maintenance actions the tasks within the listed maintenance func-
(welding, grinding, riveting, straightening, fac- tion vary at different maintenance categories,
ing, remachining, or resurfacing) to restore appropriate "work time" figures will be shown
serviceability to an item by correcting specific for each category. The number of task-hours
damage, fault, malfunction, or failure in a part, specified by the "work time" figure represents
subassembly, module (component or assembly), the average time required to restore an item
end item, or system. This function does not (assembly, subassembly, component, module,
include the trial and error replacement of end item or system) to a serviceable condition
running spare type items such as fuses, lamps, under typical field operating conditions. This
or electron tubes. time includes preparation time, troubleshooting

2
time, and quality assurance/quality control time numbers used in the tools and equipment
in addition to the time required to perform the column of the MAC. The numbers indicate the
specific tasks identified for the maintenance applicable tool or test equipment for the
functions authorized in the maintenance alloca- maintenance functions.
tion chart. Subcolumns of column 4 are as b. Maintenance Category. The codes in this
follows: column indicate the maintenance category
C - Operator/Crew allocated the tool or test equipment.
O - Organizational c. Nomenclature. This column lists the noun
F - Direct Support name and nomenclature of the tools and test
H - General Support equipment required to perform the mainte-
D - Depot nance functions.
e. Column 5, Tools and Equipment. Column 5 d. National/NATO Stock Number. This column
specifies by code, those common tool sets (not lists the National/NATO stock number of the
individual tools) and special tools, test, and specific tool or test equipment.
support. equipment required to perform the e. Tool Number. This column lists the man-
designated function. ufacturer’s part number of the tool followed by
f. Column 6, Remarks. Column 6 contains an the Federal Supply Code for manufacturers
alphabetic code which leads to the remark in (5-digit) in parentheses.
section IV, Remarks, which is pertinent to the
item opposite the particular code. 5. Remarks (Sect. IV)
a. Reference Code. This code refers to the
4. Tool and Test Equipment Require- appropriate item in section II, column 6.
ments (Sect. III) b. Remarks. This column provides the re-
a. Tool or Test Equipment Reference Code. The quired explanatory information necessary to
numbers in this column coincide with the clarify items appearing in section II.

3
 S E C T I O N I I MAINTENANCE ALLOCATION CHART
FOR

ANTENNA GROUP AN/GRA-50

(4)
(1) (2) (3) MAINTENANCE CATEGORY
(5) (6)
GROUP COMPONENT/ASSEMBLY MAINTENANCE TOOLS REMARKS
NUMBER FUNCTION AND
c O F H D
EQPT.

00 ANTENNA GROUP AN/GRA-50 Inspect 0.1 A

Service 0.2 A
Test 0.2 1,2 B
Replace 0.2 1,2 C
Repair 0.2 3,4 D

4
 SECTION III. TOOL AND TEST EQUIPMENT REQUIREMENTS
FOR

ANTENNA GROUP AN/GRA-50

TOOL OR TEST MAINTENANCE NATIONAL/NATO

EQUIPMENT NOMENCLATURE TOOL NUMBER
CATEGORY STOCK NUMBER
REF CODE

1 O MULTIMETER AN/URM-105 6625-00-581-2036

6625
2 O TOOL KIT, ELECTRONIC EQUIPMENT TK-101/G 5180-00-064-5178
5180-00-064-5178
3 F TOOL KIT, ELECTRONIC EQUIPMENT TK-105/G 5180-00-610-8177
5180-00-610-8177
4 F MULTIMETER TS-352/U 6625-00-242-5023
6625-00-242-5023

5
 SECTION IV. REMARKS
ANTENNA GROUP AN/GRA-50

REFERENCE
REMARKS
CODE

A Preventive maintenance.

B Continuity and leakage tests of cable CG-678/U.

C Replace components.
D Repair of RF cable assembly.

6
By Order of the Secretary of the Army:
BERNARD W. ROGERS
General, United States Army
Official: Chief of Staff

J.C. PENNINGTON
Brigadier General, United States Army
The Adjutant General

Distribution:
To be distributed in accordance with DA Form 12-51, Operator TM literature requirements for
AN/GRA-50.

234-377 0 - 89 - 2
 Changes In force: C 3, and C5

TM 11-5820-467-15
* C 5
Change HEADQUARTERS,
DEPARTMENT OF THE ARMY
No. 5 Washington, D. C., 28 December 1973

Operator’s Organizational, Direct Support,

General Support, and Depot Maintenance Manual
ANTENNA GROUP AN/GRA-50

TM 11-5820-467-15, 19 July 1961, is changed as follows:

The title of the manual is changed as shown PUB 459 (Navy)/AFM 75-34 (Air Force)/and
above. MCO P4610.19 (Marine Corps).
Page 5. Paragraph 1.1 is superseded by the Paragraph 2.1 is added as follows:
following: 2.1. Reporting of Errors
1.1. Indexes of Publications The reporting of errors, omissions, and re-
a. DA Pam 310-4. Refer to the latest issue of commendations for improving this publication
DA Pam 310-4 to determine whether there are by the individual user is encouraged. Reports
new editions, changes, or additional publica- should be submitted on DA Form 2028, Re-
tions pertaining to the equipment. commended Changes to Publications, and for-
b. DA Pam 310-7. Refer to DA Pam 310-7 to warded direct to Commander, US Army Elec-
determine whether there are modification tronics Command, ATTN: AMSEL-MA-CR,
work orders (MWO’s) pertaining to the equip- Fort Monmouth, NJ 07703.
ment.
2.2. Administrative Storage
Paragraph 2 is superseded by the follow- For procedures, forms and records, and in-
ing:
spection required for equipment in adminis-
2. Forms and Records trative storage, refer to TM 740-90-1.
a. Reports of Maintenance and Unsatisfac-
tory Equipment. Maintenance forms, records,
and reports which are to be used by mainte- 2.3. Destruction of Army Materiel to Pre-
nance personnel at all maintenance levels are vent Enemy Use
listed in and prescribed by TM 38-750. For information on this subject, refer to TM
b. Report of Packaging and Handling De- 750-244-2.
ficiencies. Fill out and forward DD Form 6 Paragraph 4, lines 3, 4, and 5. Delete and
(Report of Packaging and Handling Deficien- substitute:
Power handling capability . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
c i e s ) a s prescribed in AR 700-58
200 watts, average
(Army)/NAVSUP PUB 378 (Navy )/AFR 71-4 (maximum).
(Air Force)/and MCO P4030.29 (Marine Corps). Page 6, paragraph 5. Change the heading of
c. Discrepancy in Shipment Report (DIS- paragraph 5 to read:
REP) (SF 361). Fill out and forward Discre-
pancy in Shipment Report (DISREP) (SF 361) Components and Dimensions
as prescribed in AR 55-38 (Army)/NAVSUP Add paragraph 5.1 after paragraph 5.

•This Change supersedes C 4, 27 June 1972.

1
5.1. Items Comprising and Operable An- WARNING
tenna Group AN/GRA-50 (FSN 5985-892- The fumes of cleaning compound,
0758). Trichloroethane (FSN 6810-292-
FSN Qty Nomenclature
9625, 1 qt) are toxic. Provide enough
5995-823-2176 1 Cable Assembly RF ventilation whenever used. Do not
CG-678/U
(75 ft 3 in.) uses cable
use near an open flame. Trich-
RG-58A/U, connector UG- loroethane is not flammable, but ex-
536/U ea end. (Not in- posure to an open flame converts the
stalled) fumes to a highly toxic and danger-
5985-893-1438 2 Halyard MX-2706/G ous gas.
5970-405-8223 1 Insulator IL-4GRA-4
(Not installed) Page 17, paragraph 16b(1). Paragraph 16b(1) is
5895-896-3179 2 Reeling Machine
superseded by the following:
Cable, Hand RC-432/G
(Not installed) (1) Cleaning compound, Trichloroethane
5985-757-2130 2 Wire Assembly, Antenna (FSN 6810-292-9625; (1 qt)). Observe the warn-
CX-7303/G (160 ft ing in paragraph 13.3.
0 in.).
Note: Stored and
Page 22, appendix I. Make the following
used with (but not
p/o) Reel RC-432/G changes:
(Not installed) Change the title of DA Pam 310-4 to read:
Page 8. Paragraph 9b is superseded by the fol- Index of Technical Manuals, Technical Bulle-
lowing: tins, Supply Manuals (types 7, 8, and 9), Supply
b. See that the equipment is complete as Bulletins, and Lubrication Orders.
listed on the packing slip. If a packing slip is Change the title of TM 38-750 to read: The
not available, check the equipment against Army Maintenance Management System
paragraph 5 and appendix II. (TAMMS).
Page 9, paragraph 11a (2). Add the following Add the following:
data to the chart:
Frequency Length of each
(mc) antenna wire a
TM 740-90-1 Administrative Storage of
(ft) Equipment,
21 11.27 TM 750-244-2 Procedures for Des-
22 10.63 truction of Electronics
23 10.25 Materiel to Prevent
24 9.72 Enemy Use (Elec-
25 9.35 tronics Command).
26 9.00 DA Pam 310-7 U.S. Army Equip-
27 8.75 ment Index of
28 8.35 Modification Work
29 8.00 Orders.
30 7.80
Page 14, paragraph 13.3. Delete the warning Page 23. Appendix II is superseded by the fol-
notice and substitute the following: lowing:

2
 APPENDIX II
BASIC LIST ITEMS LIST (BIIL) AND ITEMS TROOP
INSTALLED OR AUTHORIZED LIST (ITIAL)

Section I. INTRODUCTION
c. Part Number. Indicates the primary
1. Scope. number used by the manufacturer (individual,
This appendix lists basic issue items and items company, firm, corporation, or Government
troop installed or authorized required by the activity), which controls the design and
crew/operator for installation, operations, and characteristics of the item by means of its en-
maintenance of Antenna Group AN/GRA-50. gineering drawings, specifications standards,
and inspection requirements, to identify an
2. General item or range of items.
This Basic Issue Items and Items Troop In- d. Federal Supply Code for Manufacturer
stalled or Authorized List is divided into the (FSCM). The FSCM is a 5-digit numeric code
following sections: to identify the manufacturer, distributor, or
a. Basic Issue Items List - Section II. A list, Government agency, etc., and is identified in
in alphabetical sequence, of items which are SB 708-42.
furnished with, and which must be turned in e. Description. Indicates the Federal item
with the end item. name and a minimum description required to
b. Items Troop Installed or Authorized List - identify the item.
Section III. A List, in alphabetical sequence of f. Unit of Measure (U/M). Indicates the stan-
items which, at the discretion of the unit com- dard of basic quantity of the listed item as used
mander, may accompany the end item, but are in performing the actual maintenance func-
not subject to be turned in with the end item. tion. This measure is expressed by a two-
character alphabetical abbreviation, (e.g., ea,
3. Explanation of Columns. in, pr, etc). When the unit of measure differs
The following provides an explanation of col- from the unit of issue, the lowest unit of issue
umns found in the tabular listings: that will satisfy the required units of measure
a. Illustration. This column is divided as fol- will be requisitioned.
lows: g. Quantity Furnished with Equipment
(1) Figure number. Indicates the figure (Basic Issue Items Only). Indicates the-quan-
number of the illustration in which the item is tity of the basic issue item furnished with the
shown. equipment.
(2) Item number. Not applicable. h. Quantity Authorized (Items Troop Instal-
b. Federal Stock Number. Indicates the Fed- led or Authorized Only). Indicates the quan-
eral stock number assigned to the item and tity of the item authorized to be used with the
will be used for requisitioning purposes. equipment.
Section Il. BASIC ISSUE ITEMS LIST

6115-498-3973

3
 Section III. ITEMS TROOP INSTALLED OR AUTHORIZED LIST

5120-897-6077 859-501

By Order of the Secretary of the Army:

CREIGHTON W. ABRAMS
General, United States Army
Official: Chief of Staff
VERNE L. BOWERS
Major General, United States Army
The Adjutant General

Distribution:
To be distributed in accordance with DA Form 12-51 (qty rqr block No. 45), Operator requirements for AN/GRA-50.

4
 Change in force: C 3

TM 11-5820-467-15
*C 3

Operator, Organizational, Field and Depot Maintenance Manual

ANTENNA GROUP AN/GRA-50

HEADQUARTERS
DEPARTMENT OF THE ARMY
W ASHINGTON , D.C., 28 April 1964
TM 11-5820-467-15, 19 July 1961, is changed as follows:
Page 5 (as changed by C 2, 4 Sep 63). Make the Materiel Support Agency, ATTN: SELMS-MP,
following changes: Fort Monmouth, N. J. 07703. One informa-
Add paragraph 1.1 after paragraph 1. tion copy will be furnished to the individual’s
immediate supervisor (officer, noncommissioned
1.1. Index of Publications officer supervisor, etc.).
Refer to the latest issue of DA Pam 310-4 to Page 8. Delete paragraph 9 and substitute:
determine whether there are new editions, changes,
or additional publications pertaining to the equip- 9. Checking Unpacked Equipment
ment. DA Pam 310-4 is an index of current tech- a. Inspect the equipment for damage incurred
nical manuals, technical bulletins, supply manuals, during shipment. If the equipment has been
supply bulletins, lubrication orders, and modifica- damaged, report the damage on DD Form 6
tion work orders available through publications (para. 2).
supply channels. The index lists the individual b. See that the equipment is complete as listed
parts (-10, -20, -35P, etc. ) and the latest changes on the packing slip. If a packing slip is not avail-
to and revisions of each equipment publication. able, check the equipment against the basic issue
Delete paragraph 2 and substitute: items list (app. II). Report all discrepancies in
accordance with TM 38-750. Shortage of a minor
2. Forms and Records assembly or part that does not affect proper
a. Reports of Maintenance and Unsatisfactory functioning of the equipment should not prevent
Equipment. Use equipment forms and records in use of the equipment.
accordance with instructions in TM 38-750. Page 9, paragraph llb(9). Make the following
b. Report of Damaged or Improper Shipment. changes:
Fill out and forward DD Form 6 (Report of Dam- Add the following after the last sentence:
aged or Improper Shipment) as prescribed in AR Place the antenna as high as possible.
700-58 (Army) NAVASANDA Publication 378 Caution. line 2. Change "6" to: 24.
(Navy), and AFR 71-4 (Air Force). Page 14 (as changed by C 2, 4 Sep 63). Delete
c. Reporting of Equipment Manual Improve-
paragraph 13 and substitute:
ments. The direct reporting, by the individual
13. Operator’s Preventive Maintenance
user, of errors, omissions, and recommendations
for improving this manual, is authorized and en- Preventive maintenance is the systematic care,
couraged. DA Form 2028 (Recommended servicing, and inspection of equipment to prevent
Changes to DA Technisal Manual Parts Lists or the occurrence of trouble, to reduce downtime, and
Supply Manual 7, 8, or 9) will be used for reporting to assure that the equipment is serviceable.
these improvements. This form will be completed a. Systematic Care. The procedures given in
in triplicate using pencil, pen, or typewriter. The paragraphs 13.1 and 13.2 cover routine systematic
original and one copy will be forwarded direct to care and cleaning essential to proper up keep and
Commanding Officer, U. S. Army Electronics operation of the equipment.
* This change supercedes C 2, 4 September I963.

234-377 0 - 89 - 1
 b. Preventive Maintenance Checks and Services. set forth in TM 38-750.
The preventive maintenance checks and services Add paragraphs 13.1, 13.2, and 13.3 after
chart (para. 13.2) outlines functions to be per- paragraph 13.
formed at specific intervals. These checks and
services are to maintain Army electronic equip- 13.1. Operator’s Preventive Maintenance
ment in a combat serviceable condition; that is, in Checks and Services Periods
good general (physical) condition and in good
Preventive maintenance checks and services on
operating condition. To assist operators in main- the AN/GRA-50 are required on a daily basis.
taining combat serviceability, the chart indicates
Paragraph 13.2 specifies services and inspections
what to check, how to check, and what the normal
that must be accomplished daily and under special
conditions are. The References column lists the conditions listed below.
illustrations, paragraphs, or manuals that contain
detailed repair or replacement procedures. If the a. When the antenna is initially installed.
defect cannot be remedied by the operator, higher b. When the antenna is reinstalled after being
echelon maintenance or repair is required. Re- taken down for any reason.
cords and reports of these checks and services c. At least once each week if the antenna is
must be made in accordance with the requirements maintained in standby condition.
13.2.

App. II.
Para. 13.3.
Fig. 1.

Fig. 1.

13.3. Cleaning e. Starting with the broken end, rewind the

Inspect all components. They must be free of wire onto the reel assembly.
dirt, grease, and fungus. Page 15 (as changed by C 2, 4 Sep 63). Delete
Warning: Cleaning Compound (Federal stock figure 8.
No. 7930-395-9542( is flammable and its fumes are Page 16 (as changed by C 2, 4 Sep 63). Delete
toxic. Do not use near a flame; provide adequate figure 9.
ventilation. Page 17 (as changed by C 2, 4 Sep 63). Delete
a. Remove grease and fungus from the antenna paragraph 17 and substitute:
assembly. Use a cloth dampened (not wet) with 17. Organizationl Preventive Maintenance
cleaning compound.
b. Remove dirt from components with a brush. a. Preventive maintenance is the systematic
Add paragraph 14.1 after paragraph 14. care, inspection, and servicing of equipment to
maintain it in serviceable condition, prevent
14.1. Replacing Broken Wire Ends breakdowns, and assure maximum operational
If the looped end of one of the wires (shown capability. Preventive maintenance is the responsi-
under the outer wingnuts in fig. 5) breaks off, bility of all echelons concerned with the antenna
replace it as follows: assembly and includes the inspection, testing, and
a. Loosen the wingnut and remove the broken repair or replacement of components that inspec-
loop. tion and tests indicate probably would fail before
b. Unwind all the wire from the reel assembly. the next scheduled periodic service. Preventive
c. Remove the outer wingnut from the reel maintenance checks and services on the antenna
assembly (fig. 6) and slip off the looped end. assembly at the second echelon level are made at
d. Slip the loop under the wingnut (a above) monthly intervals unless otherwise directed by the
and tighten the nut. commanding officer.

2
 b. Maintenance forms and records to be used in paragraph 17.2 once each month. When the
and maintained on the antenna assembly are antenna assembly is maintained in a standby
specified in TM 38-750. (ready for immediate operation) condition, per-
Add paragraphs 17.1 and 17.2 after paragraph form the monthly preventive maintenance checks.
17. Equipment in limited storage (requires service
17.1. Monthly Maintenance before operation) does not require monthly pre-
Perform the maintenance functions indicated ventive maintenance.

17.2. Monthly Preventive Maintenance Checks and Services Chart

Fig. 6.

Fig. 5.

Fig. 2.

Fig. 2.

Page 22 (as changed by C 2, 4 Sep 63). Add the Work Orders.

following to appendix I: TM 9-213 Painting Instructions for Field
DA Pam 310-4 Index of Technical Manuals, use.
Technical Bulletins, Supply TM 38-750 Army Equipment Record Pro-
Manuals (types 4, 6, 7, 8, and cedures.
9), Supply Bulletins, Lubrica- Page 23 (as changed by C 2, 4 Sep 63). Delete
tion Orders, and Modification appendix II and substitute:

APPENDIX II
BASIC ISSUE ITEM LIST

Section I. INTRODUCTION
1. General 2. Columns
This appendix lists items supplied for initial Columns are as follows:
operation. The list includes tools, parts, and
materiel issued as part of the major end item. a. Federal Stock Number. This column lists the
The list includes all items authorized for basic 11-digit Federal stock number.
operator maintenance of the equipment. End b. Designation by Model. Not used.
items of equipment are issued on the basis of c. Description. Nomenclature or the standard
allowance prescribed in equipment authorization item name and brief identifying data for each item
tables and other docurments that are a basis for are listed in this column. When requisitioning,
requisitioning. enter the nomenclature and description.
3
 d. Unit of Issue. The unit of issue is each, f. Quantity Authorized. Under "Items Compris
unless otherwise indicated, and is the supply term ing an Operable Equipment", the column lists the
by which the individual item is counted for pro- quantity of items supplied for the initial operation
curement, storage, requisitioning, allowances, and of the equipment.
issue purposes. g. Illustrations. The numbers in the "Figure
e. Expendability. Nonexpendable items are No." column refer to the illustrations where the
indicated by NX. Expendable items are not noted. parts are shown.
Section II.

5895-892-0758

6115-498-3973

5995-823-2176

5895-893-1438

5970-405-8223

5985-896-3179

5210-897-6077

5985-757-2130

4
 By Order of the Secretary of the Army:
EARLE G. WHEELER,
General, United States Army,
Official: Chief of Staff.
J. C. LAMBERT,
Major General, United States Army,
The Adjutant General.
Distribution:
Active Army:
USASA (2) Lexington (12), Ft Worth (8) 11-98
CNGB (1) Tobyhanna (12), Sharpe (3) 11-117
C/COMMEL (7) Letterkenny (5) 11-155
cofT (1) Sig Sec, GENDEP (OS) (5) 11-157
CofEngrs (1) USASCC (4) 11-500
TSG (1) USA Elct Mat Agcy (9) (AA-AE) (4)
CofsptS (1) USASA 1st Fld Sta (5) 11-557
USCONARC (5) USATC AD (3) 11-587
USAMC (5) USATC Armor (3) 11-592
USAARMBD (2) USATC Engr (3) 11-597
USAARTYBD (2) USATC Inf (3) 17
USAECDA (2) USASTC (3) 17-100
USACBRCDA (1) WRAMC (1) 19-55
USAMSCDA (2) Army Pic Cen (2) 19-56
USAOCDA (2) USA Equip Spt Cen (1) 19-57
USAQMCDA (2) USAERDL (2) 29-1
USATCDA (2) USA Cold Rgn RE Lab (2) 29-5
USACECDA (1) Chicago Proc Dist (1) 29-6
USACECDA (Monmouth Ofc) (1) AMS (1) 29-11
USAADCDA (2) USATCARC (1) 29-15
USAARMCDA (2) USATCA (1) 29-16
USAAVNCDA (2) USATCG (1) 29-21
USAARTYCDA (2) USATCP (1) 29-25
USASWCDA (1) USAERDLA (White Sands) (13) 29-26
UAECOM (7) USAELRDL Trp Comd (10) 29-35
USAMICOM (4) Army Tml (1) except Oakland (5) 29-36
USASMCOM (2) POE (1) 29-45
ARADCOM (2) Sig Fld Maint Shops (3) 29-46
ARADCOM Rgn (2) WSMR (5) 29-51
OS Maj Comd (3) Units org under fol TOE: (2 copies 29-55
OS Base Comd (2) each except as indicated) 29-56
LOGCOMD (2) 1-55 5-155 10-105 29-65
MDW (1) 1-75 5-156 10-106 26-75
Armies (2) 1-76 5-157 10-107 29-77
Corps (2) l-ro c mn 1 n-701 29-79
USA Corps (3) 1-127 6-501 10-202 30-25
11th Air Assault Div (3) 1-137 7 10-206 37
Instl (2) except Ft Gordon (5) 1-207 7-25 10-445 37-100
Ft Hancock (4), Ft Huachuca (10) 5-25 7-26 10-446 44-235
Ft Monmouth (63) 5-26 7-100 10-500 44-236
Svc Colleges (2) 5-27 8-35 (AA-AD) 44-237
Br Svc Sch (2) 5-112 8-36 11-16 44-500 (AA-AB)
GENDEP (OS) (2) 5-145 8-37 11 – 57 55-56
Sig Sec. GENDEP (OS) (5) 5-146 8-65 11-85
Army Dep (2) except Navajo, 5-147 9-22 11-87
Savanna (5), Sacramento (28) 5-148 10-22 11-97
NG: State AG (3); units—same as Active Army except allowance is one copy to each unit.
USAR: N o n e .
For explanation of abbreviations used, see AR 320-50.

5
 Figure 1. Antenna Group AN/GRA-50, typical installation.

4
 CHAPTER 1
INTRODUCTION

Section I. G E N E R A L

1. Scope (Report of Damaged or Improper shipment

as prescribed in AR 700-58 (Army), Navy
This manual describes Antenna Group Shipping Guide, Article 1850-4 (Navy), and
AN/GRA-50 (fig. 1) and covers installa- AFR 71-4 (Air Force).
tion, maintenance, and theory of operation.
c. Preventive Maintenance Form. Pre-
pare DA Form 11-238 (fig. 8 and 9) (Maint-
2. Forms and Records enance Check List for Signal Equipment
(Sound Equipment, Radio, Direction Find-
a. Unsatisfactory Equipment Report. ing, Radar, Carrier, Radiosonde and Tele-
(1) Fill out and forward DA Form 468 vision) ), in accordance with the instruc-
(Unsatisfactory Equipment Report) tions on the form.
to Commanding Officer, U. S. Army d. Parts List Form. Forward DA Form
Signal Materiel Support Agency,
2028 (Recommended Changes to DA Tech-
ATTN: SIGMS-ML, Fort Mon- nical Manual Parts Lists or Supply Manual
mouth, N. J., as prescribed in AR
700-38. 7, 8, or 9) direct to the Commanding Offi-
cer, U. S. Army Signal Materiel Support
(2) Fill out and forward AF TO Form Agency, ATTN: SIGMS-ML, Fort Mon-
29 (Unsatisfactory Report) to the
Commander, Air Materiel Com- mouth, N. J., with comments on appendixes
mand, Wright-Patterson Air Force II and III.
Base, Ohio, as prescribed in AF e. Comments on Manual. Forward all
TO 00-35D-54. other comments on this publication direct
to the Commanding Officer, U. S. Army
b. Report of Damaged or Improper Ship- Signal Materiel Support Agency, ATTN:
ment. Fill out and forward DD Form 6 SIGMS-PA2d, Fort Monmouth, N. J.

Section Il. DESCRIPTION AND DATA

3. Purpose and Use proper frequency range and a transmitter

power output of less than 100 watts at an
a. Purpose. Antenna Group AN/GRA-50 output impedance of approximately 50
(fig. 1) is a doublet antenna assembly used ohms.
for the transmission and reception of radio
signals between 1.5 and 20 megacycles 4. Technical Characteristics
(mc).
Antenna type . . . . . . . Half way doublet.
b. Use. Antenna Group AN/GRA-50 is Frequency range . . . . . 1.5 to 20 mc.
used primarily with Radio Set AN/GRC-19 Power handling
for greater range and reliability than the capability . . . . . . . . . . 100 watts (maxi-
standard 15-foot whip antenna provides. It mum).
can be used with any radio set that has the Weight . . . . . . . . . . . ll.75 lb.

5
 5. Components

Figure 2. Antenna Group AN/GRA-50, components.

6
6. Common Names c. Cable Assembly, RF CG-678/U is 75
feet 3 inches long and consists of cable
RG-58A/U with a connector UG-536/U at
each end. Cable Assembly RD CG-78/U
connects between Insulator IL-4/GRA-4
and the radio set.
d. Insulator IL-4/GRA is a phenolic
housing which has two terminals for con-
nection of the antenna wires and a female
coaxial fitting for connecting Cable As-
sembly RF CG-678/U. Insulator IL-4/
GRA-4 is installed at the center of the
antenna assembly.
e. Halyard MX-2706/G consists of 75
feet of l/8-inch diameter Dacron rope.
7. Description A snaphook fastener at one end of the rope
(fig. 2) connects to Reeling Machine, Cable, Hand
a. Bag BG-175, made of heavy canvas, RC-432/G, a snaphook fastener and a lead
is used to store all components. weight is attached to the other end.
b. Each Reeling Machine, Cable, Hand f. The tape, measuring (tape measure),
RC-432/G consists of a reel on which 160 made of nonconducting woven fabric, is
feet of Wire Assembly, Antenna CX- 156 feet long. It is calibrated on one side
7303/G is wound. A terminal hook on the in feet and on the other side in frequency.
loose end of Wire Assembly, Antenna CX- It is used to measure the length of antenna
7303/G attaches to Insulator IL-4/GRA-4. necessary for operation at any given fre-
Halyard MX-2706/G is secured to a small quency. The tape measure is marked at
hole in the Reeling Machine, Cable, Hand each 100 kilocycles (kc) from 1.6 to 6 mc,
RC-432/G frame. A spring action handle at each 200 kc from 4 to 6 mc, at each
on the outer flange of the spool facilitates 500 kc from 6 to 10 mc, and at each mc
winding. from 10 to 20 mc.

7
 CHAPTER 2
INSTALLATION

8. Unpacking are inefficient because of the absorption of

their radiation by the surrounding growth.
a. Packaging Data. When packed for The antenna assembly, however, provides
shipment, the components of the antenna more reliable communications than a
assembly are individually enclosed in vertical antenna in dense growth areas.
polyethylene envelopes and packed in Bag b. Locate the antenna in a clearing and
BG-175. Bag BG-175 is enclosed in a assemble the antenna with the antenna wire
moistureproof barrier and sealed in a cor- broadside to the direction of the desired
rugated fiberboard carton. Packed for station. When communication is desired
shipment, the carton weighs 13 pounds and with two or more stations, orient the an-
is 10 inches high, 9 inches deep, and 10 tenna assembly so that the antenna wire is
inches wide; its volume is 0.5 cubic feet. broadside to the weakest station.
A typical shipping carton and its contents
are shown in figure 3. 11. Installation
b. Removing contents. To unpack the a. Determining Length of Antenna Wire.
equipment, proceed as follows: (1) In the installation procedure in b
(1) Open the carton. Do not cut open below, use the tape measure to de-
the carton, because the equipment termine the proper length of an-
may become damaged. tenna wire for the desired fre-
(2) Open the moistureproof barrier quency of operation. Unroll the tape
and remove Bag BG-175. measure to the desired frequency
(3) Open Bag BG-175 and remove its marking and unroll an equal amount
contents. of antenna wire from each reel as-
(4) Remove the components from the sembly (fig. 4). The length indi-
polyethylene evelopes. cated on the tape measure opposite
the desired frequency marking is
9. Checking Unpacked Equipment half of the required total antenna
a. Inspect the equipment for damage in- length at that frequency.
curred during shipment. If the equipment (2) The following chart lists the length
has been damaged, refer to paragraph 2. of each antenna wire (including the
reel assembly frame) required for
b. See that the equipment is complete as frequencies between 1.5 and 20 mc.
listed on the packing slip. If a packing slip When the tape measure is not avail-
is not available, check the equipment able, use the chart to determine
against the table of components (para 5) or each antenna wire length. Pace off
basic issue items list (appx II). (one stride is approximately 3feet)
the indicated antenna length; make
10. Siting final adjustment by lengthening or
a. In areas, such as jungles, where shortening the antenna assembly
vegetation is very dense, vertical antennas for the best transmitter loading.

8
 Length of each Length of each Length of each
Frequency a Frequency Frequency a
antenna wire antenna wire antenna wire
(mc) (mc) (mc)
(ft) (ft) (ft)

1.58 148.10 2.5 93.60 6.2 37.74

1.60 146.25 2.55 91.76 6.4 36.56
1.62 144.44 2.6 90.00 6.6 35.45
1.64 142.68 2.65 88.30 6.8 34.41
1.66 140.96 2.7 86.66 7.0 33.42
1.68 139.28 2.75 85.09 7.5 31.20
1.70 137.64 2.8 83.57 8.0 29.25
1.72 136.04 2.85 82.10 8.5 27.52
1.74 134.48 2.9 80.68 9.0 26.0
1.76 132.95 2.95 79.32 9.5 24.63
1.78 131.46 3.0 78.0 10.0 23.40
1.80 130.0 3.1 75.48 10.5 22.29
1.82 128.57 3.2 73.12 11.0 21.27
1.84 127.17 3.3 70.9 12.0 19.51
1.86 125.80 3.4 68.82 13.0 18.0
1.88 124.46 3.5 66.85 14.0 16.71
1.90 123.15 3.6 65.0 15.0 15.60
1.92 121.87 3.7 63.24 16.0 14.62
1.94 120.61 3.8 61.57 17.0 13.76
1.96 119.38 3.9 60.0 18.0 13.0
1.98 118.18 4.0 58.50 19.0 12.31
2.0 117.0 4.2 55.71 20.0 11.7
2.05 114.14 4.4 53.18
2.1 111.42 4.6 50.86
2.15 108.83 4.8 48.75
2.2 106.36 5.0 46.80
2.25 104.0 5.2 45.0

Each antenna wire length includes the reel assembly frame.

b. Installation Procedure. (d) Tighten the thumb nut at the cen-

(1) Connect the antenna wire terminal ter of the reel.
hooks to the thumb nuts on the op- (6) Unfasten the tape measure from the
posite ends of the insulator (fig. 5). insulator, unfasten the insulator
(2) Temporarily fasten the insulator to from the support, and lay the an-
one of the desired supports. tenna wires out in a straight line.
(3) Temporarily fasten the free end of (7) Check the overall length of the two
the tape measure to the center of wires plus the insulator and reel
the insulator. assemblies. The overall length will
(4) Unwind the tape measure to the be twice the length indicated on the
length corresponding to the desired tape measure for the desired fre-
frequency. quency or twice the length obtained
(5) Refer to figure 6 and unroll a like from the chart in a (2) above. Adjust
amount of wire from each reel as- the antenna for an exact overall
sembly as follows: length. Be sure to keep the insula-
(a) Grasp the reel assembly firmly tor centered.
in one hand and loosen the thumb (8) Attach each reel assembly to a
nut at the center of the reel and halyard snaphook fastener (fig. 7).
the thumb nut on the wire clamp (9) Tie the halyards to the best avail-
on the reel assembly frame. able supports (tree, fence post,
(b) Move away from the antenna cen- vehicle, etc) at a height of 4 feet or
ter slowly, keeping the wire taut higher.
at all times. Hold your thumb on Caution: Allow the antenna as-
the wire to prevent backlash. sembly to sag at least 6 inches.
(c) After unwinding the required (10) Connect the ends of the rf cable
amount of wire, tighten the thumb between the insulator connector
nut on the wire clamp. (fig. 5) and the antenna connector

9
 on the radio set. Shorten or Note. The rf cable should be at right
lengthen the antenna assembly a angles to the antenna wires for the first
few inches at a time when difficulty few feet from the connection at the insu-
lator. Lay the rf cable out as straight as
in transmitter loading is encoun-
possible; do not allow the cable to form
tered. loops.

Figure 3. Typical packaging.

10
Figure 4. Use of tape measure to determine antenna wire length.

11
 Figure 5. Connecting rf cable to insulator (antenna wires shown connected).

12
Figure 6.

Figure 7.

13
 CHAPTER 3
MAINTENANCE

Section I. OPERATOR’S MAINTENANCE

12. Scope of Operator’s Maintenance Antenna Group AN/GRA-50 are lined out
in the figures. Instructions for the use
a. The following is a list of mainte- of the form appear on the form.
nance duties normally performed by the
operator of the antenna assembly. Spe- 14. Operator's Visual Inspection
cial tools or test equipment is not re-
quired. When the antenna assembly fails to op-
b. Operator’s maintenance for the an- erate properly, disconnect the radio set -
tenna assembly consists of the following: from the power source and check the items
(1) Preventive maintenance (para 13). given below. Do not check any item with
(2) Visual inspection (para 14). the power on.
a. Inspect all electrical connections of
13. Operator's Preventive Maintenance the antenna assembly for tightness and
DA Form 11-238 (fig. 8 and 9) is a pre- corrosion.
ventive maintenance checklist to be used b. Inspect the insulator for cracks or
by the operator. Items not applicable to chips and dirt.

14
 TM5820-467-15-8
1 5
 TM5820-467-15-9
Figure 9.
16
 Section II. ORGANIZATIONAL AND FIELD MAINTENANCE (THIRD ECHELON)

15. Scope of Organizational Maintenance (2) Cleaning cloth, lint-free.

(3) Sandpaper No. 000.
The following is a list of maintenance c. Test Equipment. M u l t i m e t e r AN/
duties performed by organizational main- URM- 105.
tenance personnel for the antenna assem-
bly. The scope of these instructions has 17. Organizational Preventive Maintenance
been determined by the available tools,
materials, test equipment, spare parts, DA Form 11-238 (fig. 8 and 9) is a pre-
and the MOS of the repairman. ventive maintenance checklist to be used
a. Preventive maintenance (para 17). by organizational maintenance personnel.
b. Troubleshooting (para 18). Items not applicable to the equipment are
c. Replacement of parts (para 19). lined out in the figures. Instructions for
the use of the form appear on the form.

16. Tools, Materials, and Test Equipment 18. Troubleshooting

Required a. The troubleshooting chart is for use
of second through fifth echelon mainte-
A list of parts normally stocked for or-
nance personnel. Upon noting a defect in
ganizational maintenance is contained in
either transmission or reception, shut
TM 11-5820-467-25P. The tools, mate-
down the power at the transmitter/re-
rials, and test equipment required for or-
ceiver, disconnect the rf cable from the
ganizational maintenance are listed below:
transmitter/receiver antenna connector,
a. Tools. Tool Equipment TE-41.
and perform the appropriate procedure
b. Materials.
listed in the chart below.
(1) Cleaning compound (Federal stock
No. 7930-395-9542). b. Chart.

19. Repair of Rf Cable (Third Echelon) (1) Tool Equipment TE-113.

(fig. 10) (2) Multimeter TS-352/U.
The only item of the antenna assembly b. Installation of Connector on End of
that can be readily repaired is the rf cable Rf Cable.
(b and c below). (1) Remove three-quarters of an inch
a. Tools and Test Equipment Required. of the rf cable outer jacket.

17
 (2) Disassemble the UG-536/U and lay and solder through the hole in the
out its parts in the order of dis- contact. File the soldered area
assembly. smooth.
(3) Slide the nut over the rf cable. (11) Insert the cable into the shell.
(4) Slide the washer over the rf cable. (12) Tighten the nut securely. When the
(5) Slide the gasket over the rf cable, cable and connector are properly
one-sixth of an inch beyond the edge assembled, the contact tip should
of the rf cable outer jacket. be flush with, or not more than one
(6) Slide the flanged sleeve over the thirty-second of an inch beneath the
copper braid shield. edge of the coupling.
(7) Flare the shield around the flanged (13) Use multimeter TS-352/U to check
sleeve. the rf cable for continuity and
(8) Remove the excess shield braid so shorts.
that it is even with the outer edge c. Replacement of Cable RG58A/U.
of the flanged sleeve. (1) Measure and cut off 75 feet of cable
(9) Remove three-sixteenths of an inch
of insulation from the end of the (2) Install connector UG-536/U to each
conductor. end of cable RG-58A/U as in b
(10) Slide the contact over the conductor above.

Figure 10. Cross section of rf cable and connector.

18
 CHAPTER 4
THEORY

20. Antenna Theory of the antenna axis, there are dif-

ferent amounts of radiation at dif-
The characteristics of transmitting and angles to the axis. There is little
receiving antennas are similar; a good radiation in direction OA, greater
transmitting antenna is also a good re- radiation in direction OB, and max-
ceiving antenna. imum radiation in direction OC.
a. Basic Half Wave Antenna. D u r i n g (2) That part of the radiation field
transmission, the rf current in the antenna which travels upward, strikes the
wire produces a radiated field. During re- ionosphere, and is returned at a
ception, a radiated field from a distant considerable distance from the
station antenna cuts the antenna wire and radiating antenna is called a sky-
causes a current flow in the wire. In a half wave. A horizontal half wave an-
wave antenna, current is maximum at the tenna is very broadly bidirectional
center and minimum at the ends, while in the horizontal plane. In practice,
voltage is minimum at the center and maxi- the antenna is oriented in the di-
mum at the ends (fig. 11); therefore, im- rection that provides maximum
pedance is minimum at the center and signal strength.
maximum at the ends. The impedance at
the center of a basic half wave antenna is 21. Theory of Antenna Assembly
72 ohms. The current distribution in the The antenna assembly is a horizontal
antenna is the same regardless of the center-fed Hertz antenna (doublet). A cen-
amount of current flow; the amplitude ter-fed Hertz is one-half wavelength long
of the current at any point on the antenna at the operating frequency and is fed at its
varies directly with the amplitude of the physical center. The antenna assembly is
signal voltage. adjustable and can be used for operating
b. Directional Pattern.
frequencies from 1.5 to 20 mc. It consists
(1) Maximum radiation occurs at the of two lengths of wire, each adjustable to
center of a half wave antenna, be- a little less than a quarter wavelength at
cause the current is greatest at the operating frequency. The transmission
that point. Minimum radiation takes line is a low-impedance coaxial cable that
place at the ends, because the cur- connects to the low-impedance point at the
rent is least at the ends. Radiation center of the antenna assembly. A certain
is at right angles to the plane of amount of mismatch exists between the
the antenna wire and completely rf cable and the antenna, but it is not
encircles the antenna wire. The critical. Current and voltage distribution
resulting antenna directional pat- is the same as that described for a simple
tern can be compared to a dough- half wave antenna (para 20). The formula
nut with the radiator passing for determining the actual total length
through its center. Figure 12 shows of the antenna assembly required for a
a cross section of the doughnut particular operating frequency is:
shaped pattern. Although there is 468
no radiation along the direct line Length in feet =
Frequency in mc.

19
 Figure 11. Current and voltage distribution in half wave antenna.

Figure 12. Radiation pattern of half wave antenna.

20
 CHAPTER 5

SHIPMENT, LIMITED STORAGE, AND DEMOLITION

TO PREVENT ENEMY USE

Section 1. SHIPMENT AND LIMITED STORAGE

22. Disassembly (2) Coil the remainder of the cable.

f. Coil and bind the halyards.
Warning: Disconnect the equipment from
the power source before performing any 23. Repacking for Shipment or Limited
disassembly.
Disassemble the antenna assembly as a. The exact procedure used in packing
follows: for shipment or limited storarge depends on
a. Disconnect the rf cable from the the material available and tie conditions
transmitter. under which the equipment is to be shipped
b. Release the tied ends of the halyards or stored. The information concerning the
and lower the antenna slowly; be careful original packing (para 8) will be helpful.
not to damage the insulator. b. Pack the equipment as follows:
c. Unfasten the antenna wire termina- (1) Place the components in individual
tions from the insulator and unfasten the plastic bags and store them in Bag
reel assemblies from the halyards. BG-175.
d. Wind the antenna wire onto each reel (2) Enclose and seal Bag BG-175 in a
assembly; use the index finger and thumb moisture proof paper envelope.
to help make a tight wind (fig. 6). (3) Place the enclosed Bag BG-175 in
e. Unfasten the rf cable connector from a suitable carton.
the insulator and coil the cable as follows: (4) Place pads inside the carton to hold
(1) Make one coil and tie the coil with Bag BG-175 securely in place.
friction tape. (5) Close and seal the carton with tape.

Section Il. DEMOLITION OF MATERIEL TO PREVENT ENEMY U S E

24. Authority for Demolition it is better to demolish completely the

same parts of all the antennas rather than
The destruction procedures given in to partially damage all the antennas.
paragraph 25 will be used to prevent the
enemy from using or salvaging this equip- a. Smash. Use sledges, axes, crowbars,
and any other heavy tools available. First
ment. Demolition of the equipment will be
smash the reel assemblies then smash the
accomplished only upon the order of the
insulator and the rf cable connectors.
commander.
b. Cut. Use any available sharp tools to
cut the rf cable, the antenna wires, and the
25. Methods of Destruction
halyards in a number of places.
Any or all of the following methods of de- c. Burn. Burn as much of the equipment
struction may be used. The time available as is flammable. Pour gasoline over the
will usually be the most important factor instruction books, the rf cable, the insula-
to consider in deciding which methods will tor, and the halyards and ignite it.
be used, but the tactical situation must also d. Disposal. Bury or scatter all de-
be considered. If a number of antennas are stroyed parts, or throw them into nearby
in use in the same or nearby installations, waterways.
21
 APPENDIX I
REFERENCES

Following is a list of applicable references that are available to the operator and unit
repairman of Antenna Group AN/GRA-50.

SB 38-100 Preservation, Packaging, and Packing Materials,

Supplies, and Equipment Used by the Army.
TM 11-5820-295-10 Operator’s Manual: Radio Set AN/GRC-19.
TM 11-5820-295-20 Organizational Maintenance: Radio Set AN/GRC-19.
TM 11-5820-467-25P Organizational, Field and Depot Maintenance Repair
Parts and Special Tool Lists, Antenna Group AN/
GRA-50.

22
 APPENDIX II
BASIC ISSUE ITEMS LIST

Section I. INTRODUCTION

1. General cates that a Federal stock number

is being processed for assignment.
a. This appendix lists items supplied for
The L number may be used in
initial operation. The list includes tools, emergencies to identify items.
parts, and material issued as part of the (3) Designation by model. Not used.
major end item. The list includes all items
(4) Description. Nomenclature or the
authorized for basic operator maintenance standard item name and brief iden-
of the equipment. End items of equipment tifying data for each item are listed
are issued on the basis of allowances pre-
scribed in equipment authorization tables in this column. When requisition-
and other documents that are a basis for ing, enter the nomenclature and
description.
requisitioning.
(5) Unit of issue. Not used.
b. The columns are as follows: (6) Expendability. Nonexpendable
(1) Source, maintenance, and recover- items are indicated by NX.
ability code. Not used. (7) Quantity authorized. This column
(2) Federal stock number. This col- lists the quantity of items supplied
umn lists the 11-digit Federal for the initial operation of the
stock number. In the absence of a equipment.
Federal stock number, an interim (8) Illustrations. The "Figure No."
number, for example L8Ra41C- column lists the figure for identi-
12 in the description column, indi- fication of the items.

23
24

6115-498-3973
5995-823-2176
5895-893-1438
5970-405-8223
 APPENDIX Ill
MAINTENANCE ALLOCATION

Section I. MAINTENANCE ALLOCATION

1. General level. Echelons higher than the
a. This section assigns maintenance echelon marked by X are author-
functions and repair operations to be per- ized to perform the indicated
formed by the lowest appropriate mainte- operation.
nance echelon. (4) Tools required. This column indi-
b. Columns in the maintenance allo- cates codes assigned to each
cation chart are as follows: individual tool equipment, test
(1) Part or component. This column equipment, and maintenance equip-
shows only the nomenclature or ment referenced. The grouping of
standard item name. Components codes in this column of the mainte-
and parts comprising a major end nance allocation chart indicates the
item are listed alphabetically. tool, test, and maintenance equip-
(2) Maintenance function. This column ment required to perform the
indicates the various maintenance maintenance function.
functions allocated to the echelon (5) Remarks. Entries in this column
capable of performing the opera- will be utilized when necessary to
tions. clarify any of the data cited in the
(a) Service. To clean and to pre- preceding columns.
serve. c. Columns in the allocation of tools for
(b) Inspect. To verify serviceability maintenance functions are as follows:
and to detect incipient elec- (1) Tools required for maintenance
trical or mechanical failure by functions. This column lists the
scrutiny. tools, test, and maintenance equip-
(c) Test. To verify serviceability ment required to perform the
and to detect incipient electrical maintenance functions.
or mechanical failure by use of (2) 1st, 2d, 3d, 4th, 5th echelon. The
special equipment such as gages, dagger symbol indicates the
meters, etc. echelons allocated the facility.
(d) Replace. To substitute service-
(3) Tool code. This column lists the
able assemblies and parts for tool code assigned.
unserviceable components.
(e) Repair. To restore an item to 2. Maintenance by Using Organizations
serviceable conditions through When this equipment is used by signal
correction of a specific failure or services organizations organic to theater
unserviceable condition. This headquarters or communications zones to
function includes, but is not provide theater communications, those
limited to, inspecting, clean- maintenance functions allocated up to and
ing, preserving, adjusting, re- including fourth echelon are authorized to
placing, welding, riveting, and the organization operating this equipment.
straightening.
(3) 1st, 2nd, 3rd, 4th, 5th echelon. The
3. Mounting Hardware
symbol X indicates the echelon re-
sponsible for performing that par- The basic entries of the maintenance al-
ticular maintenance operation, but location chart do not include mounting
does not necessarily indicate that hardware such as screws, nuts, bolts,
repair parts will be stooked at that washers, brackets, clamps, etc.

25
Section II.
2 6
Section III.
2 7
 By Order of Secretary of the Army:

G. H. DECKER,
General, United States Army,
Official: Chief of Staff.
R. V. LEE,
Major General, United States Army,
The Adjutant General.
Distribution:

Active Army:
DASA (5) AFIP (1)
USASA (2) WRAMC (1)
CNGB (1) YUma Test Sta (2)
Tech Stf, DA (1) except USAEPG (2)
CSigo (18) EMC (1)
Tech Stf Bd (1) USACA (3)
USCONARC (5) USASEA (1)
USAARTYBD (1) USA Caribbean Sig Agcy (1)
USAARMBD (2) USA Sig Msl Spt Agcy (l3)
USAIB (1) USASSA (20)
USARADBD (2) USASSAMRO (1)
USAABELCTBD (1) Army Pictorial Cen (2)
USAAVNBD (1) USAOMC (3)
USAATBD (1) USA Trans Tml Comd (1)
ARADCOM (2) Army Tml (1)
ARADCOM Rgn (2) POE (OS) (1)
OS Maj Comd (3) OSA (1)
0S Base Comd (2) AMS (1)
LOGCOMD (2) Sig Fld Maint Show (a)
MDW (1) JBUSMC (2)
Armies (2) Units org under fol TOE:
Corps (5) 10-105 (2)
USATC Armor (2) 1O-106 (2)
USATC Engr (2) 10-107 (2)
USATC FA (2) 10-445 (2)
USATC Inf (2) 11-7 (2)
USATC AD (2) 11-16 (2)
Svc Colleges (2) 11-57 (2)
Br Svc Sch (2) 11-98 (2)
GENDEP (2) except 11-117 (2)
Atlanta, GENDEP (none) 11-155 (2)
Sig Sec, GENDEP (5) 11-500 (AA-AE) (4)
Sig Dep (12) 11-557 (2)
Fort Monmouth (71) 11-587 (2)
AFSSC (1) 11-592 (2)
11-597 (2)
NG: State AG (3) Units - Same as Active Army except allowance is one oopy to each unit.
USAR: None.
For explanation of abbreviations used, see AR 320-50.

28
U.S. GOVERNMENT PRINTING OFFICE : 1989 0 - 234-377
PIN: 018745-000