Navy Transmitting Antenna Switch, Tuner, Coupler, & Multicoupler Page

Info on NRL's development of Transmitter Multicouplers

Diagrams of USS Northampton CLC-1 Multicouplers and Antennas

Transmitting Antenna RF Patch Panels & Switches

Shore Station - high power RF patch panels

xmtr-sw-02.JPG (162500 bytes)


Guam Communications Station 005.jpg (177693 bytes)


Guam Communications Station 017.jpg (174458 bytes)

Guam Communications Station 014.jpg (199026 bytes)

xmtr-patch-01.JPG (57622 bytes)

Shore Stations - Transmitter-Antenna Crossbar Switch 

Delta Electronics - link

ant-crossbar-01.jpg (1609964 bytes)

Crossbar at NRTF Chollas Heights
chollas_4026.JPG (1662348 bytes)
Rear View
chollas_4043.JPG (1769219 bytes)
Transmitter Feedlines (Side Feed)
chollas_4047.JPG (948515 bytes)
Transmitter rows, Antenna columns
chollas_4034.JPG (1291090 bytes)
Switch indicator matrix - RF crossbar is not visible.
chollas_4053.JPG (1890866 bytes)
Antenna Feedlines (Top Feed)
chollas_4128.JPG (1669943 bytes)

SA-2691/GRT-36 Crossbar
patch-SA2691-GRT36-2011-01.jpg (143794 bytes)

EIA hardline connectors for each row are on the right
patch-SA2691-GRT36-2011-02.jpg (186770 bytes)
EIA hardline connectors for each column come out the top
patch-SA2691-GRT36-2011-04.jpg (165727 bytes)
Guam Communications Station 182.jpg (870168 bytes)
Interface for Remote Control (C-12330/GRT-36) 
patch-SA2691-GRT36-2011-03.jpg (136461 bytes)
patch-SA2691-GRT36-2011-06.jpg (57252 bytes) patch-SA2691-GRT36-2011-07.jpg (146549 bytes) patch-SA2691-GRT36-2011-08.jpg (149971 bytes)

Shipboard - Transmitters, RF Patch Panel, and Multicoupler

xmtr-patch-01.JPG (324628 bytes)

-- --
Transmitter RF & Control Patch System - Chu & Associates CA1100 - Manual
Cables from transmitter connectors are attached via quick-disconnect connectors to multicoupler ports

BB-61 - Patch cables are not installed
DSC02096.JPG (4252347 bytes)

Transmitter RF and 24 control lines
DSC02116.JPG (4056425 bytes)
Multicoupler quick-disconnect
DSC02099.JPG (3773785 bytes)
patch-ca1100-01.jpg (94180 bytes)

Shipboard Transmit-Receive Antenna Relays

Antenna Transmit-Receive Switch

c1670a-u-91.JPG (84752 bytes) used with TBL

2-20 mc

up to 60wpm break-in CW

C-1670A/U spec sheets

Manual NAVSHIPS 92566

Antenna Transmit-Receive Switch

c4882-wrt.JPG (40329 bytes) Similar to C-1670/U

used with AN/WRT-2, WRT-4

2-30 mc

up to 60wpm break-in CW

C-4882/WRT spec sheets

Manual NAVSHIPS 94248


AN/BRA-6 HF tuner for AT-774A/UR submarine emergency whip antenna

2-30 mc 

Manual NAVSHIPS 94198

TN-341/BRT Tuner
bra6-tn341-01.jpg (1788233 bytes)
TN-341/BRT Tuner Schematic
bra6-tn341-02.jpg (198999 bytes)
RF-91/BRT Series Coil 
(used for 2-6mc)
bra6-rf91-01.jpg (1544038 bytes)


fra49-1808-01.jpg (1710010 bytes)

fra49-spec-01.JPG (124612 bytes)

fra49-spec-02.JPG (132611 bytes)

10 KW HF multicoupler
Shore Stations 

see NRL development page for info

Manual - NAVSHIPS 94253

fra49-spec-03.JPG (43181 bytes)

fra49-1808-02.jpg (1938629 bytes) fra49-1808-03.jpg (1738907 bytes) fra49-1808-10.jpg (2099548 bytes) fra49-1808-05.jpg (2262555 bytes)
fra49-1808-11.jpg (1725693 bytes) fra49-1808-06.jpg (2085507 bytes) fra49-1808-12.jpg (1549534 bytes) fra49-1808-07.jpg (1588768 bytes)
fra49-1808-08.jpg (2297643 bytes) fra49-1808-14.jpg (2418804 bytes) fra49-1808-15.jpg (1881094 bytes)    Simplified Schematic Diagram

   Complete Schematic Diagram



Spec Sheets

four 500 watt inputs to one antenna
xmtrs must be 10% diff in freq.
sra15-31.JPG (71301 bytes)

AN/SRA-13 -  2 to 6 mc
AN/SRA-14 -  4 to 12 mc
AN/SRA-15 -  6 to 18 mc
sra15-101.JPG (142763 bytes)

sra15-1.jpg (197786 bytes)
CU-421B/SRA-15 coupler

see NRL development page for info

SRA-13/14/15 NAVSHIPS 92746

Manuals available from Fair Radio Sales

cu419b-sra13-101.jpg (26854 bytes)
cu419b-sra13-121.jpg (48757 bytes)
cu419b-sra13-122.jpg (74709 bytes)
cu419b-sra13-123.jpg (68252 bytes)
cu419b-sra13-124.jpg (76887 bytes)
cu419b-sra13-125.jpg (49015 bytes)
cu421-sra15-91.jpg (31453 bytes)
cu421-sra15-92.jpg (94906 bytes)
CU-421/SRA-15 - busted vacuum cap
cu421-sra15-93.jpg (87239 bytes)
CU-421/SRA-15 - busted vacuum cap
cu421-sra15-94.jpg (92112 bytes)
cu421-sra15-95.jpg (81579 bytes)
cu421-sra15-96.jpg (94049 bytes)


sra16-spec-01.JPG (257355 bytes) sra16-spec-02.JPG (247766 bytes) four 500 watt inputs to one antenna
xmtrs must be 10% diff in freq.
9 to 26 mc

see NRL development page for info

manual NAVSHIPS 92839 

antenna tuner

sra18-01.JPG (326412 bytes) 0.3-30 Mc 500w max system for use with AN/URT-2 series (autotune), AN/SRT-14 series, TBK, and other transmitters (manual tune)
  • C-1360/SRT Control Monitor Unit
  • CU-402/SRT Transmitter Coupler (impedance transformer)
  • CU-372/SRT Antenna Coupler Unit (fixed L, C)
  • TN-229/SRT RF Tuner (tunable L)
sra18control.jpg (120207 bytes)
C-1360/SRT Control Monitor Unit


antenna coupler

sra20-srt-01.JPG (467205 bytes)

Developed for use with 4-channel RCA SSB-1 transceiver - see detailed SRA-20 info on SSB-1 page

manual NAVSHIPS 93202

C-2372/SRT controller
sra20-srt-03.JPG (219655 bytes)
TN-329/SRT tuner
sra20-srt-04.JPG (224895 bytes)

antenna coupler

sra22-31.JPG (141564 bytes)

sra22-101.jpg (14202 bytes)

sra22-102.jpg (17575 bytes)

AN/SRA-22 Info and Manual Page

sra22-06.jpg (12323 bytes)

sra22-104.jpg (18560 bytes)

sra22-12.jpg (16167 bytes)

CU-714/SRA-22 antenna coupler +
C-2698/SRA-22 coupler control
or C-2494/SRA-22 coupler control

manuf Collins 180R-6

sra22-11.jpg (16844 bytes)

sra22-02.jpg (19497 bytes)

Notes on Operation - PDF

Operation With 35' Whip - PDF

NAVSHIPS 0967-136-6010

Manual Download Page


sra23-31.JPG (76999 bytes)    Antenna multicoupler AN /SRA-23 consists of three couplers and associated control and blower units. The couplers cover the frequency range 2 to 27 mc in three frequency bands. Each coupler operates in a different band. These bands are 2 to 6 mc, 5 to 15 mc, and 9 to 27 mc. The coupler group was developed for use with 500-watt transmitters, but, with minor adjustments. it is capable of handling transmitters with 1000-watt outputs.
    One coupler group accommodates only one transmitter. Provisions are made, however, for connecting up to eight of these groups together to form a multicoupler system. This arrangement permits the simultaneous operation of eight transmitters into a single broadband antenna.

Manual NAVSHIPS 93196

antenna coupler

sra25-01.jpg (52206 bytes) 4-channel HF tuner developed for use with Eldico S-100 transceiver? Appears similar to AN/SRA-20

sra25-02.jpg (54561 bytes)

Please send e-mail if you have any info

sra25-03.jpg (44822 bytes)

UHF antenna multicoupler

sra33-01.jpg (36748 bytes)  

4 couplers, 225-400 MHz, 140 watts
uses C-4586/SRA-33 control/power supply

The  AN/SRA-33 is designed for operation with shipboard radio set AN/WSC-3. 

sra33-31.JPG (232767 bytes)

units and manuals are available from Fair Radio Sales

sra33-02.jpg (34762 bytes)

The AN/SRA-33 consists of four antenna couplers (CU-1131/SRA-33 through CU-1134/SRA-33), a control power supply C-4586/SRA-33, an electronic equipment cabinet CY-3852/SRA-33, and a set of special-purpose cables.

 - also see CU-1169/SRC-16

Download CU-1169 manual AN/SRA-34 information sra34-block-01.jpg (217272 bytes)

HF Multicouplers

10 KW HF multicouplers
for Communications Ships

need better photos

sra35-01.jpg (1673452 bytes)

Aboard USS Arlington AGMR-2
sra35-agmr2-1967.jpg (502035 bytes)

  Spec sheets

  see NRL development page for info


xmtr-t1.jpg (101561 bytes) 1kw (2kw PEP) per input

sra56-31.JPG (114555 bytes)

components -
AN/SRA-56 (2-6mc)
four CU-1772/SRA-56 coupler units
PP-4993/SRA power supply
CV-6422/SRA-56 cabinet
CU-1773/SRA-56 matching network
  (to add four more coupler units)

AN/SRA-57 (4-12mc)
four CU-1774/SRA-57 coupler units
PP-4993/SRA power supply
CV-6422/SRA-57 cabinet
CU-1773/SRA-57 matching network
  (to add four more coupler units)

AN/SRA-58 (10-30mc)
four CU-1776/SRA-58 coupler units
PP-4993/SRA power supply
CV-6422/SRA-58 cabinet

Specification document

Manuals available from Fair Radio Sales

need more info!! - see also tuner section of Shipboard Equipment Manual

(50 ohm)
Antenna Coupler

(70 ohm)
Antenna Coupler

ura27-01.JPG (168509 bytes)
tuner photos thanks to WA5AVK
Antenna tuner 2-30mc, 1kw
    CU-772/URA-27 tuner
    CU-773/URA-27 directional coupler
    C-2995/URA-27 control monitor

ura27-02.JPG (212709 bytes)

manuf TMC model ATS-50-2 (50 ohm)
manuf TMC model ATS-70-2 (70 ohm)

manual   thanks to K4OZY
spec sheets   thanks to K4OZY

ura27-03.JPG (226111 bytes)

ura27-11.JPG (168272 bytes)

ura27-14.jpg (182562 bytes)

ura27-15.jpg (113875 bytes)

ura27-12.jpg (142393 bytes)

ura27-04.JPG (29545 bytes)

ura27-16.jpg (260565 bytes)

ura27a-1310-01.jpg (313580 bytes) ura27a-1310-02.jpg (314396 bytes) ura27a-1310-03.jpg (313179 bytes) ura27a-1310-04.jpg (383535 bytes)
ura27a-1310-05.jpg (337536 bytes) ura27a-1310-06.jpg (344890 bytes) ura27a-1310-07.jpg (352082 bytes) ura27a-1310-08.jpg (337706 bytes)
ura27a-1310-09.jpg (319460 bytes) ura27a-1310-10.jpg (325460 bytes) ura27a-1310-11.jpg (309849 bytes) ura27a-1310-12.jpg (329703 bytes)
ura27a-1310-14.jpg (302923 bytes) ura27a-1310-15.jpg (321349 bytes) ura27a-1310-16.jpg (325959 bytes) ura27a-1310-17.jpg (377281 bytes)

Antenna Coupler

HF coupler used with AN/URT-23
ura38-31.JPG (130609 bytes) cu-938C.jpg (37794 bytes) CU-938C-control.jpg (40829 bytes)
C-3698/URA-38 Control Unit C3698-URA38-120301.JPG (28876 bytes) C3698-URA38-120302.JPG (52398 bytes) C3698-URA38-120303.JPG (26031 bytes)
TS-3228/URA-38 Test Set TS3228-ura38-120301.JPG (56011 bytes) TS3228-ura38-120302.JPG (49898 bytes) TS3228-ura38-120303.JPG (41966 bytes)

CU-402/SRT Transmitter Coupler

(for AN/SRA-18 tuner system and AN/SRT-14 series transmitters)

cu402-srt-120118-01.jpg (176599 bytes) cu402-srt-120118-02.jpg (165304 bytes) cu402-srt-120207.JPG (447986 bytes)

     CU-402/SRT is an antenna current meter plus impedance matching auto-transformer - it was mounted below-decks near the transmitter and then low-loss coax ran from it up on deck to a motor-driven variable inductor and remotely switched capacitors which were used to tune the antenna (35' whip or 60-100' long wire). It is rated for 200w for 0.3-2.0 mc and 500w for 2.0-30.0 mc
     The CU-402 would step-up or step-down the output impedance of the transmitter (which varied with frequency) to match the 50 ohm coax load, but the extra L & C units were needed to tune out the reactance of the antenna.
     The CU-402  also has a directional coupler that ran back to a metering circuit located in the SRT-14 transmitter (via the 3-pin connector).

CU-691/U & CU-692/U
UHF multicouplers

cu691-u-31.JPG (103493 bytes)


cu691-man-01.JPG (281723 bytes)

CU-691/U handles four sets
CU-692/U handles two sets

cu691-man-02.JPG (362748 bytes)

cu691-man-03.JPG (198280 bytes)

CU-731/SRT & CU-732/SRT
Bandpass filters
cu731-srt-spec-01.JPG (378994 bytes)
cu731-srt-spec-02.JPG (27518 bytes)

See F-156/SRT series below

068.JPG (865810 bytes)

074.JPG (878218 bytes) 073.JPG (872991 bytes)
092.JPG (989755 bytes) 088.JPG (989580 bytes) 099.JPG (939140 bytes)

024.JPG (1034484 bytes)

027.JPG (1039948 bytes) 031.JPG (906653 bytes) 033.JPG (952577 bytes)

036.JPG (896511 bytes)

038.JPG (981115 bytes) 013.JPG (955592 bytes) 011.JPG (897468 bytes)

008.JPG (991844 bytes)

044.JPG (976494 bytes) 046.JPG (1036677 bytes) 048.JPG (965395 bytes)

051.JPG (991673 bytes)

052.JPG (933908 bytes) 055.JPG (982556 bytes) 057.JPG (941768 bytes)

063.JPG (1016871 bytes)

002.JPG (937825 bytes) 022.JPG (1023971 bytes) 023.JPG (993606 bytes)

CU-791/URT Coupler
(Collins 180Y-1)

cu791-urt-1708-04.jpg (54814 bytes)

cu791-urt-1708-01.jpg (357071 bytes) Download manual  

cu791-urt-1708-02.jpg (378836 bytes)


Matching Network

cu837-urc-01.JPG (21700 bytes) network matching switch
50 ohm output for TCS
(use with AN/SRA-22 coupler)
2-3 mc
3-5 mc
5-7 mc
7-12 mc

CU-837/URC Spec Sheets

cu837-urc-91.JPG (29194 bytes)

Antenna Tuner

cu937-ur-01.JPG (43249 bytes) cu937-ur-02.JPG (52164 bytes) cu937-ur-07.JPG (36581 bytes)

    More photos

(part of AN/SRA-34)

Download CU-1169 manual AN/SRA-34 information --


cu2184-urc94-01.png (176028 bytes) cu2184-urc94-02.png (230628 bytes) Harris RF-281

Used with URC-35, WRC-1, etc.

Manual download

Transmitting Filters

f162-srt-01.JPG (148035 bytes) f162-srt-02.JPG (148430 bytes) f162-srt-03.JPG (113829 bytes)

Transmitting Filter Assemblies - The filters that will now be described have been designed for use with shipboard transmitters and antennas that are unbalanced to ground. This series includes Electrical Filter Assemblies F-159/SRT, F-160/SRT, F-161/SRT, F-162/SRT, and F-163/SRT. A representative filter assembly of this series, the F-162A/SRT, is shown in figure7-8. 

Each filter assembly consists of low-pass and high-pass subassemblies. They are used with transmitters operating in the frequency range between 175 kc and 27 mc. Single filter assemblies (fig. 7-9) can be used alone or combined with other subassemblies to operate two or more transmitters (using different frequencies) into a single antenna.

Because a low-pass filter and a high-pass filter are used in each filter assembly, there is a definite crossover frequency for each filter. In the vicinity of the crossover frequency there is a band of frequencies, called the precluded band, which cannot be used because appreciable power would be lost in the filter. When frequencies in the vicinity of the crossover frequency are to be used, it is necessary to change the crossover point. By removing the crossover point around as the precluded band is approached, it is possible to obtain continuous coverage of the 175-kc to 27-mc frequency range, A switch in the center of the front panel on all assemblies except the F-160/SRT, permits shifting of the crossover frequency. Figure 7-10 shows curves for both low-pass and high-pass filters for the F-162A/SRT.

The filter assemblies are constructed in the form of plug-in drawers. Normally, the lowpass drawer is installed on the left side of the cabinet and the high-pass drawer on the right side, as viewed from the front, however it is possible to interchange the subassemblies from left to right in the cabinet by changing a connecting strap in each subassembly.

In normal operation, the filter assemblies dissipate less then 20 percent of the r-f power output of the transmitter. Because it is possible for a fault, such as a grounded antenna, to develop, each filter subassembly is designed to dissipate over 500 watts, if necessary.

Because the low-pass filter section provides a termination for the high-pass section and vice versa, it is not advisable to operate a transmitter into one section alone. If it becomes necessary to operate a transmitter when either filter section is removed, a jumper assembly furnished with each cabinet is used to connect the transmitter directly to the antenna. Other transmitting filter assemblies presently in use include the F-156, -157, and -l58/URT.  

antenna tuner for URT-2 series transmitters

System components:
OA-297/URT controller group
CB-5/URT capacitor tuning unit
TN-197/URT inductor tuning unit

scan-05.jpg (105577 bytes)
TN-197/URT inductor tuning unit
DSCN0357.jpg (2369997 bytes)
motor/control end
DSCN0358.jpg (2377644 bytes)
tuning coil end

antenna tuner for SRA-18 system and SRT-14 series transmitters

System components
TN-229/SRT antenna tuner
CU-372/SRT antenna coupler
CU-402/SRT load adjusting unit

need photo of assembled unit - similar to TN-342 below tn229-53.jpg (2356004 bytes)
motor/control end
tn229-54.jpg (2367161 bytes)
tuning coil end

antenna tuner for AN/WRT-2 transmitter

TN-342 pages from the AN/WRT-2 manual - Download 13 MB pdf

Photos of my restoration job on a TN-342

P1010020.JPG (182988 bytes)

tn342-356.jpg (2335782 bytes)
tuning coil end

tn342-355.jpg (2347917 bytes)
motor/control end