I saw this radio at a CTARC swapmeet, snagged it because of the Emcom logo.
When I showed it to my father-in-law, he smiled broadly and said "I invented that!". While the correct word might have been conceptualised, the claim is entirely justified. While working at Emcom, he saw the need for a portable radio to be used at job sites to communicate with other points on the job sites as well as with the vehicles on site. This is the result.
The two halves clip together, the top half houses the transceiver, while the bottom is a replaceable battery.
Built on two boards, one for transmit, one for receive. In this respect it kind of reminds me of the Philips SXA. It even shares the 21.4 MHz first IF, using an NDK 21F15DH 8 pole 15kHz filter. IF is an MC3359 with a 20.945 MHz crystal to convert to the second IF, which is a Murata CF455. Audio amplifier is a TDA1103.
The PCBs have provision for six channels, this one only has one channel populated (and no channel switch of course).
It's kind of strange that the T/R relay is on the receive board, the coax run would have been a lot shorter had they been able to squeeze it on to the transmit board
The Rx crystal is marked 155.450R and 44.683333 so it's xtal * 3 + 21.4.
The tally is somewhat out of config control. Serial 19038. I seriously doubt they built that many though.
Output transistor lineup is an MRF227 followed by a 2N5590 which is good for 10W -- running off batteries you probably don't want more than this.
The Tx crystal is marked 148.400T and 37.10000 so xtal * 4
Some kind of a transmit timeout timer?
No idea what the little veroboarded circuit does, it's connected to pins 12 and 22 of the MX325 CTCSS encoder/decoder.
There's an inaccessible-when-assembled microphone socket, presumably for testing, the speaker mike is soldered to the back of it.
The battery box is detachable, and has a built-in transformer and associated circuitry to charge the battery.
Strangely (to me) the batteries are nicads and not lead-acid as I would have expected. It was the eighties. Nicads were popular.
All in all a well-thought-out unit.
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