Interesting DIY'd Transceiver!

[thefragger]

This is a crossover from Audiokarma. Electroking suggested that I post this guy on here...

Originally Posted by electroking

Hello,

This is a most likely a transmitter-receiver combination: the W1AW marking
on the dial is the name of the ARRL station, and one would not want to
deliberately transmit on the frequency used by that station. Cannibalizing
this unit is up to you, and some of the tubes and transformers are definitely
interesting for audio work, but many parts in there (especially the variable
capacitors) are somewhat rare and desirable for ham radio work. I would
try to trade this with a ham radio operator interested in vintage equipment,
and get some audio tubes or other parts in exchange.

This may have been built using ideas presented in an old edition of the
ARRL Handbook, maybe you could post it in the ham radio section of
videokarma.org. Good luck!

----------------------------------

I was told that it was a transceiver, but I just don't see how that could be.

It's very, VERY heavy; I struggled getting it to the car, had to take a couple breaks during the one-minute walk.

A whole bunch juicy looking iron, tubes are two 0C3-type, a black plate RCA JAN CRC-5R4-GY, a GE 5R4-GYA, and a... 6Y6GTB (iirc). As shown, there are a couple empty sockets, seller didn't know what went there, and there's a couple others in the tin can.

Price was cheap, the seller didn't want to carry it back to his car, and had no idea how to get it back up and running.


I love HAM Fests!

Underside:

The one transformer that has a tag (facing the front, the rear left one) is a Hammond 2030, which is in the 1965 catalog as a 30W audio output for 6L6 tube types, clipping attached.

What's the best way to figure out what the missing tubes are? Nothing is written on the chassis... (sadly) this thing will be a pile of parts soon enough, and as an avid DIYer, I feel really bad about breaking down such a well-done project that someone must've put many many hours into all those years ago!

Decisions decisions...

[bob91343]

It's a 1940s transmitter, with an 807 in the final. Maybe 75W CW and 50W AM but I am not sure if the power supply is in there. If not, it probably will need 600-700V high voltage at about 100 mA, and 300V or so low voltage, plus filaments.

[thefragger]

Thanks for that info! How did you figure all that out? (I'm honestly curious if you could walk me through your reasoning)

The plug at the bottom right on the under-chassis looks like it's meant to accept an extension cord (it's two prongs, recessed) and they go to the power switch up front, then to the BIG transformer on the chassis.

[thefragger]

I'm guessing that the headphone jack next to the dial is for a key while the front 'BNC' jack is for a microphone (and rear for an antenna)?

[bob91343]

Well about the only old tube with a plate cap that resembles what you have is an 807, the most popular tube used back then. It's rated for a max of 750V on the plate but few rigs took it quite that high. If you are using AM, you need to back off the voltage to 600V so the modulator can have headroom to swing it up.

The tube in the next compartment is probably a 6AG7 and there seems to be a plugin coil there also. There is at least one VR tube in the power supply, perhaps to regulate the screen of the final and/or the B+ to the VFO. Yeah that 6AG7 is the VFO so the rig is much lower power, maybe 40W input because you can only get so much drive out of a decent VFO.

Chances are, it's an ARRL handbook design. You can rummage through those books in the vicinity of 1940 or 1941 looking for the circuit.

[thefragger]

Thanks! I'll be doing just that!! Fantastic place, this.

[thefragger]

Found copies of the book online, there are a few examples that look close (superficially, three knobs, few switches) just in the receivers section. I'll keep flipping, this looks like the right era.


http://www.tubebooks.org/Books/arrl_1941.pdf

[N2IXK]

I don't see anything on that chassis that would indicate any receiver functionality. Just a basic CW/AM transmitter, as far as I can tell.

[electroking]

Originally Posted by N2IXK

I don't see anything on that chassis that would indicate any receiver functionality. Just a basic CW/AM transmitter, as far as I can tell.

The reason I mentioned (on audiokarma) that it might have included
a receiver section is the W1AW marking on the dial. Hope your interest
in ham radio is growing, thefragger! 73.

You get to look up what 73 means...

P.S.: I have been a ham for 29 years, but not very active lately.
Hope to change that soon!