[Boatanchors] My First "Forest Service" Radio

[David Stinson]

Found a really cute little AM transceiver at the HamCom
hamfest in Irving, Texas on 10 June:
a Northern Radio Company type 450 AM transceiver,
circa 1963.  It's marked with a BLM callsign but I think
 it was intended for "Forest Service" style operation.
About the size of a shoe box.   It came from Alaska
and had a KL7 call dymo-labeled on it.
Not a single word available on the web about it, 
nor any leads from mail reflectors or boards, 
so out came the scope and the meter and started tracing.

The transmitter filament circuit said the rig was
12 VDC primary power.
TX and RX are both crystal-control on 6 channels.
So far, I've determined that Channel 1 will cover 
7160 MC, Channel 2 will cover 5 MC, Channels 
3 and 4 will do 75 M phone. Not certain about 
channels 5 and 6 just yet, but they appear to 
cover 6 MC.  I *think* you solder-up jumpers 
on the big bandswitch to decide what band 
of frequencies goes with what channel.

The receiver is solid-state using early PNP germaniums,
 is sensitive and fairly selective.  455 KC IF.
Transmitter is a solid-state supply, 6CL6 oscillator 
and 6146 PA.  About 12 W out properly matched.
Output matching is similar to WWII rigs intended for
short, capacitive antennas.  Reminds me of an "updated" 
and miniturized BC-669.

Got it figured-out, crystalled-up and made the first contact 
with my old friend Ronnie W5SUM on 3885 this evening.  
Photos at:

https://goo.gl/photos/dmpa7cY3ddwfAUXc9

If some folks want more details on this little rig, 
let me know and I'll write more about it.

73 DE Dave AB5S