Thanks to everyone for the encouragement. Next step is to make the conversion
to this little power supply, then tweak that oscillator plate voltage etc. and
see if I can get it on the air. I have already decided not to worry about
keeping this thing "original", eg. will be putting in a new power plug, key
jack, and coax connector etc. I am sure I will have many more questions as I
proceed and will keep you posted with the progress and inevitable mysteries
that will need solving....

Why do you think the regulated dc on the filaments makes such a difference?
Closer to the original battery powered situation? Would that be true for any
old tube transmitter? Or because these particularly were originally designed to
run on 28 volt DC.


Bill, K6TAJ


COLIN LAMB wrote:

The ARC-5 transmitter is one of the great piece of electronics out of WWII.
As a kid, my first transmitter was an ARC-5 bought from JJ Glass of Los
Angeles for about $5.95. It was brand new and a beauty to behold. Getting
it working right will teach you everything that you need to know about
electronics (well as of 1957 anyway).

I was able to get mine to key nicely with no chirp at all. I still have a
wall full of them, they are nice to look at. You should be able to find a
schematic on the internet. I found that adjusting the oscillator plate
voltage to the individual transmitter could help solve a lot of problems and
regulated dc on the filaments does wonders, too. They will run 100 watts
without too much strain, although the power supplyis often twice the size of
the transmitter. But, they also run qrp on a much smaller supply and lower
voltage.

Have fun, Colin K7FM

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