There were several variants of the SSB-1 - The NAVSHIPS 92917 manual covers the original version (it doesn't say Mk I) so presumably this is the first version used by the Navy. I have a Mk IV unit with Navy property tags as well. - Please e-mail me with any info or additional photos. Thanks
Commercial model from RCA used as an interim SSB transceiver until
replaced by AN/URC-32, etc. - see info below. Navy also used Eldico S-100
transceiver.
60 watts, LSB only, 3-15 mc, two 6146's in output.
250kc and 1400 kc IF's.
See block diagram below for signal flow.
Uses 3 kc wide mechanical filters in the 250kc IF.
Crystal-controlled - four channels - crystals are 1400 kc above desired frequency.
The channel selector switch selects the following:
crystal, rcvr RF amp tank, rcvr 1st mixer tank, xmtr 3rd balanced mod. tank,
xmtr driver tank, final tank coil taps, final tuning cap, final loading coil
taps.
Notes from Fred Chapman, Navy project engineer -
In 1958 the U.S. Navy became interested in SSB. Initial tests were conducted on ships using mostly Collins Radio available amateur equipment. There were 16 ships, as I recall, outfitted and used in air defense exercises to prove the advantage over the then used CW/AM circuits. Twenty-Four hour tapes on the side-by-side circuits proved the overwhelming advantage of SSB communications.
The Bureau of Ships project searched for suitable and temporary use of equipments that were available until military equipment (AN/WRC-2, AN/URT-23, AN/URC-32, AN/URC-35, R-1051/URR) could be designed, produced and installed.
The only near suitable commercially available equipment was the RCA SSB-1. This was selected, procured and installed primarily on combatant ships to provide the SSB capability. The intent was to fix-install in the ship's wheel house. When it was determined that a location was to be in CIC or other selected areas, the problem became apparent for the need of a remote antenna tuner. The AN/SRA-20 was quickly designed and produced in a short time to meet the need.
The intent for use was for the equipment to be set up on the four crystal-controlled channels and not changed. These commercial equipments were not ruggedized for the frequent channel changing that fleet operations employed causing equipment casualties. This commercial equipment could not withstand the frequent channel changing requiring crystals and the retuning of screwdriver components.
The SSB-1 was removed from ships when the more ruggedized military equipment became available and then provided to Naval Reserve units for their use.
AN/SRA-20 |
C-2372/SRT controller |
TN-329/SRT tuner |
The antenna tuning group AN/ SRA-20 has been procured to eliminate antenna difficulties experienced with the transceiver RCA model SSB-1. A similar antenna tuning group is being developed for use with the Eldico S-100 single sideband equipment.
The SSB-1, a commercial equipment, was procured by the Navy to provide an immediate single sideband capability for nearly all ships. Though not specifically designed for naval shipboard use, this equipment has gained wide acceptance by the forces afloat.
The major discrepancy of the single sideband installations has been the inability to provide a satisfactory antenna and transmission line system. For this reason, the Bureau of Ships investigated and developed antenna tuning group AN/SRA-20. The AN/SRA-20 is provided as field change 2 to the SSB-1.
Development of the AN/SRA-20 by International Electronic Engineering Company began in November 1957. After numerous engineering tests, a technical and operational test was conducted on the USS Des Moines (CA-134). Because an antenna tuner was urgently needed, procurement action for the AN/ SRA-20 was initiated as soon as the Des Moines tests were completed.
The antenna tuner provides a means of matching a 35-foot whip to a 50-ohm transmission line in the frequency range of 2 to 15 megacycles. The tuner can be used with transmitters rated up to 100 watts (average power). The insertion loss is less than 0.5 decibel and the power required is 115 volts, 60 cycles, single phase, 100 watts. The power is necessary only during the period of equipment channeling operations.
The AN/SRA-20 consists of two units shown in figure 1, namely:
- Control tuner C-2372/SRT
- Tuner, RF TN-329/SRT
Figures 2 and 3 are interior views of the C-2372/SRT and TN-329/ SRT. The
C-2372/SRT control unit contains a 120-watt antenna dummy load which can be selected by a front panel switch, a 2-30
megacycle bandpass filter, a SWR meter, an auxiliary tuner channeling switch, and a sound-powered telephone receptacle.
The TN-329/SRT tuner contains all the electrical circuitry and mechanical parts for the operation of the tuning elements. The tuner provides for presetting four individual channels and for matching the 50-ohm transmission line to a standard Navy 35-foot whip or longer antenna. The preset channels are selected remotely and simultaneously by the transceiver SSB-l. Parts are supplied with the field change for modifying the SSB-1 to provide this capability.
In addition, the tuner contains a SWR meter, a transmitter plate current meter, a transmitter keying switch, and a sound-powered telephone receptacle which is used in the antenna tuning process. The field change kit also contains a plate current meter for installation in the SSB-1 equipment.
The field change bulletin for modification to the SSB-1 is included with the AN/SRA-20.
The applicable Bureau of Ships installation outline plan is RE 47F2012. The technical manual is NavShips 93202.
RCA SSB-3XMTR Linear Amplifier - presumably not a Navy item but
interesting anyway - looks like it has 3 gang-tuned amps in parallel, each with
a 6146???
Please e-mail if you have any
info.
 |
 |
 |
 |
 |
 |
