First to appear were the SEM 25 and SEM 35 radios, augmented by the EM 25 receiver. The SEM 35 is a fully solid state man pack transceiver, the SEM 25 - three tubes - and EM 25 are primarily meant to be used in vehicles or as stationary apparatus. The oldest manuals I have seen date back to 1965, the latest are as recent as 1993. Only recently these radios are coming available on the surplus market.
The SEM 52-A - oldest manual I know dates back to 1975 - was a much more modern design. Still crystal controlled, but very much a handheld model transceiver. Though with it's carrying harness it is hardly to be seen carried about in the hand, it's strapped on to the person using it. An amazing feature with this radio is it's headset, that actually clips around one ear. It's microphone is a bone conducting model incorporated in that headset.
Soon afterwards more technically advanced models of the SEM 52 came available. A SEM 52-AS is mentioned in some documentation dated 1977, but I never have seen the actual beast. However, the real replacement for the SEM 52-A was the SEM 52-S - S stands for synthesized. No more crystals. The earliest documentation I have seen on the SEM 52-AS is dated 1984.
Newer models include the SEM 70, the SEM 80 and the SEM 90. These are all still in use and I know hardly anything about these, though I have found the odd manual.
26-10-2003 13:49 +0100