[ARC5] AN/ARC-60 to 220

[Jack Antonio]

First of all, does anyone have any documentation
on the AN/ARC-60A?  Note the A. I have info on
the plain AN/ARC-60, and its type 12 equivalents.

Apparently the A version increased transmit power
to 2 Watts, with a different tube lineup,
and increased B+ current draw. The biggest question
is whether or  not the A version uses the receiver
dynamotor for the transmitter B+ supply. Pulling 130mA from
an 80mA dynamotor just doesn't seem right. Maybe
this is where they subbed the transistorized dynamotor
replacement?

So I'm looking for any information I can find on the
A version.

A list member kindly sent me a copy of a magazine article describing
the conversion of the CV-431(or TV-10) to 220, which involves
altering the crystal oscillator of the receive converter section.

I have elected to take a different course. The converter uses
a 110Mc local oscillator to convert 228-258Mc to 118-148Mc. I
have replaced the 118-148Mc receiver(R-508) with the 108-135Mc
version(R-509).

Without making any changes in tuning, I notice a 6db loss in sensitivity
from the original low end of 228Mc, to 224.5, which is as far down as
I'm wanting to go. Probably OK for close by work, such as demo set ups
at Gilbert, but I'll be seeing if I can get it better.

One downside of this approach is that the 2nd harmonic of the crystal
oscillator is at 220Mc, which would cause some problems if operation
that low in the band was contemplated, but in my case, this is not an
issue.

Thanks

Jack Antonio
WA7DIA