[MRCA] BC-659 Fun and Games

[Ray Fantini]

Been working on a BC-659J( SCR-609/610) and usually don’t work on stuff this old for other people but decided to take this set on. Can see how Galvin later to become Motorola started to develop a lot of what was used in two-way stuff from the fifties in terms of layout and design. The loctal tubes are weird but imagined they thought it was a good idea to keep tubes in place. AI told me they were developed by Sylvania in 1939 for car radios, and I have to wonder why they never found much application in other military radios. The lack of a T/R relay and the transmitter keying design is more along the lines of a backpack or later handheld radio using the PTT line to turn the transmitter filaments on and off for transmitting. Still working on figuring out how the transmitter oscillator is locked by the output of the discriminator and how they had to use a dry battery pack to get this all to come together. Weirdly, there is a manufactured potted assembly that takes the place of the battery and is fed by the receiver filament bus that somehow appears odd to me that someone would market an assembly for such a useless radio.  After all, anything that covers that frequency and is FM only would have real limited use.
That brings me to the question, this radio only has rocks for 27.0 and 38.80 MHz Going to assume that the person who owns it wants to use it so imagine you can play around with 38.80 on low power and talk to things like VRC-12 and PRC-25 sets but have to wonder if there is any given frequency that Military Vehicle people use below 30 MHz? Think channels 295 to 297 may be useful being 29.5 to 29.7 MHz . I think 29.6 is the FM calling frequency but never used that before.
So, anybody got a rock for channel 296? (6.325MHz) have seen these crystals around for years and now finally know what they are used for.


Ray F/KA3EKH

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/mrca/attachments/20260704/94157e56/attachment.html>