Navy Receiving RF Patch Panels & Switches

NOTE - NT means "Navy Type" and is replaced with the manufacturer code - for example, CN-49121A is the NT-49121A plug manufactured by National Electrical Supply (code CN)

1950's Shore Station Receiver RF Distribution



RF and AF Signal Distribution Unit Type A, B, C  
rf-af-01.JPG (279071 bytes)
for communication station receiving sites

photo,  info, manual download

Please send e-mail if you have any parts of an SDU

manual is NAVSHIPS 91047    -


RF switching group for shore station receiver installationsfra3-01.JPG (300287 bytes) Allows 5 operators to remotely select one of 40 antennasfra3-02.JPG (240556 bytes) RF distribution diagram

NAVSHIPS 91500 - 

Please send e-mail if you have any parts of AN/FRA-3

Remote Control Panel C-923/FRA-3
fra3-man-02.JPG (1044366 bytes)



Antenna Selector SA-256/FRA-3
fra3-man-03.JPG (972875 bytes)

fra3-man-07.JPG (693243 bytes)


fra3-man-04.JPG (147440 bytes) fra3-man-05.JPG (42073 bytes) fra3-man-01.JPG (1605700 bytes) fra3-man-06.JPG (1694229 bytes)


nt23406-01.JPG (102237 bytes)

nt23406-02.JPG (105940 bytes)

Antenna and Interspace RF patch panels

DSCN0807.jpg (2321564 bytes)
NT-23406 in Radio II aboard BB-35
(9 in, 18 out)

DSCN0867.jpg (5223351 bytes)
NT-23407 in Radio III aboard BB-35
(12 in, 12 out)

patch-23404.jpg (123758 bytes)
NT-23404 in Radio I aboard BB-55
(30 in, 30 out)
23404 - 30 antennas, 30 receivers
23405 - 18 antennas, 18 receivers
23406 - 9 antennas, 18 receivers
23407 - 12 antennas, 12 receivers
Each antenna (or interspace cable) is connected to 4 jacks, 1 directly and 3 through 600 ohm decoupling resistors 
Patch Panels use NT-49120 jacks and NT-49121 plugs


wpe5C.gif (61047 bytes) antenna patch panel similar to above
3 antennas, 12 receivers
Type C connectors for patch cords and antennas, Type N on rear for receiver connections.
sb346-01.JPG (10227 bytes)

sb346-02.JPG (6414 bytes)

manuf Federal Television


3-46.jpg (21915 bytes)Antenna Transfer Panel SB-346/S is similar to the standard antenna transfer panels except that it uses "quick-disconnect" type connectors [Type C]. It permits the operation of a maximum of twelve receivers from three antennas.

The SB-346/S consists of an aluminum case on which are mounted the upper and lower halves of an aluminum front panel (Figure 2-51). Twelve jacks are mounted on the upper half of this front panel and arranged in three vertical rows of four jacks each. Aluminum partitions in the case shield the vertical rows of jacks from one another.

Three antenna input jacks are mounted on top of the case, one for each vertical row of four jacks. The top jack in the row is connected directly to the corresponding antenna jack; the remaining three jacks in the row are connected through 62-ohm decoupling resistors .

On the lower half of the front panel are mounted twelve jacks which are connected to corresponding jacks on the rear of the case . Twelve UG-941A/U plugs are supplied with the unit to connect the lines from the receivers to the jacks on the rear of the case. Also supplied are twelve patch cables for connecting the jacks on the lower front panel with those on the upper front panel.


DSCN0858.jpg (2207843 bytes) RF Jack Panel in BB-35 radio room

Six NT-49120 jacks

==. --



j237-g-04.JPG (27065 bytes)
j237-g-07.JPG (32852 bytes)
j237-g-05.JPG (33512 bytes)
RF jack panel used in shore station installations - contains eleven UG-294/U feed-through jacks
j237-g-09.JPG (12656 bytes)
UG-294/U - Navy Type jack feed-through to UHF jack on rear
j237-g-08.JPG (30165 bytes)
CN - National Electrical Supply


j238-g-05.JPG (60258 bytes)

RF bridging jack panel used in shore station installations - contains eleven NT-491729 modules
j238-29.JPG (29572 bytes)
NT-491729 module with 4 front NT-49120 jacks and 3 rear UHF jacks all tied together
j238-31.JPG (44586 bytes)

manuf CIA - Dumont Radio 


j239-g-61.JPG (14640 bytes)

j239-g-62.JPG (21170 bytes)

RF switching jack panel used in shore station installations - contains eleven NT-491388 modules 
sb-switch-02.jpg (6508 bytes)


NT-491388 module
sb-switch-01.JPG (27079 bytes)
"Normal-Through" operation - the loop between two UHF jacks on rear is broken when NT-49121 plug is inserted in front jack

manuf CIA - Dumont Radio 

patch-j239-1609-03.jpg (108625 bytes) patch-j239-1609-01.jpg (123556 bytes) patch-j239-1609-02.jpg (126514 bytes) --


need photo Receiver Protective Device
50 or 100 watt light bulb in a cylindrical can to protect rcvr front end,
- -


jack-49063.jpg (297673 bytes)
BB-35 Photo thanks to Konrad Werzner - or are these just 49063 covers used on a different junction box?
Shielded Jackbox

jack-49063-11.jpg (12407 bytes)

jack-49063-10.jpg (14453 bytes) --


j237-g-05.JPG (33512 bytes) mating jack for NT-49121 plug - -



patch-49121A.JPG (8229 bytes)
photo thanks to W7QHO

Connector used for RF patch cords
(also for RBA/RBB/RBC and other receivers)

manuf CN - National Electrical Supply 

Type CN-49121A Antenna Plug, Navy Stock Number N17-C-71120-4869

Connector, Plug: 1 round female contact; straight type; over-all 2-7/8" long by 13/16 " diameter; RF connector; cylindrical body; brass; nickel plated; Bakelite insert; 13/32 max cable opening.

49121-A is same as 49121 except for omission of parts 7,8, and 9, and the modification of part 2 to provide a depth of 3/8" instead of 1/4" for the slots on the cable end.

nt-coax-assy-02.JPG (107487 bytes)
Assembly Instructions

conn-49121-install-01.JPG (237344 bytes)
Assembly Instructions


need photos Patch cords using NT-94121 plugs
49122 - 18" long
49123 - 36" long
49150 - 48" long
    - -


conn-49151-1608-01.jpg (60326 bytes) Right angle adaptor - one end plugs into a 49120 receptacle and the other end receives a 49121 plug
conn-49151-1608-02.jpg (71148 bytes)
49120, 49151, 49121
conn-49151-1411-01.JPG (122819 bytes)


con-49490-02.jpg (183409 bytes) Adaptor to convert a receiver's antenna screw terminals to a 49120 co-axial jack con-49490-03.jpg (223936 bytes) --


sa137-1905-02.jpg (3537280 bytes)
sa137-1905-01.jpg (4832123 bytes)
Manual RF switch panels used in shore station installations
SA-136/G is 20 position panel
SA-137/G is 40 position panel
SA-138/G is 60 position panel


sa274-u-02.JPG (34707 bytes) sa274-u-03.JPG (32112 bytes) 4 position selector switch -


sa275-u-01.jpg (10769 bytes) sa275-u-03.jpg (11493 bytes) 6 position selector switch -


sb3047-brc-01.JPG (294823 bytes) Submarine RF switch

Four 6-position switches with indicators

need more info --


sa598-u-01.JPG (45082 bytes) switching jack module - replaces NT-491388 in J-239/G but with TMC QDS front panel jacks

Note - Mating plug is UG-968/U

sa598-u-02.JPG (7748 bytes) manuf TMC model SW-195


sb931-u-01.JPG (5335 bytes)
need better photo
replaces J-237/G panel but with eleven TMC QDS front panel jacks QDS on front, UHF on rear manuf TMC model QDP-411A


sb932-u-01.JPG (110966 bytes) RF switching jack panel used in shore station installations - eleven modules
- replaces two J-239/G - uses two TMC QDS jacks on front and two UHF jacks on rear
Dual "Normal Through" - the loop between two UHF jacks on rear is broken when QDS plug is inserted in either front jack manuf TMC model SPP-3



like SB-932/U but with BNC jacks on rear
tmc-spp-04.JPG (126845 bytes)
tmc-spp-03.JPG (112297 bytes)

Rear (with one UHF-connector module)
tmc-spp-02.JPG (110545 bytes)

tmc-spp-01.JPG (186344 bytes) manuf TMC model SPP

TMC SW-224

Dual "Normal-Through" modules used in SPP
tmc-sw224-01.JPG (81185 bytes)
tmc-sw224-04.JPG (164314 bytes) Plug not inserted
tmc-sw224-03.JPG (157748 bytes)
Plug inserted
tmc-sw224-02.JPG (172659 bytes)