[Milsurplus] R-1735 Receiver Report

[Jack Antonio]

A pair of R-1735/URR receivers followed me home
from a swap recently, and I finally got them
going.

They have a Coast Guard nameplate, and are made
by Galaxy, the same ham transceiver Galaxy people.

Single channel, crystal controlled. The front
end is permeability tuned by a front panel dial.
A pair of receivers are intended to mount side by
side in a 19" rack cabinet. No cabinet came with
my pair.

4 Bands covering 2-30 MHz. Switchable selectivity
for AM, LSB, USB, RTTY wide, RTTY narrow and CW.

Even though they have a mil nameplate, these are
not rugged receivers. About the only concession
to the military I see are the use of MS310x series
connectors for power and audio, and a C connector
for RF in.

Found a number of problems with both receivers,
cracked resistors, bad solder connections, open
transistors, transistors plugged into sockets
wrong(but the book had some errors in basing
diagrams)and a badly misaligned front end on one of them.

And the sockets themselves are a pain. Had to
reseat numerous transistors using DeOxit on
the leads.

But it turns out the misalignment wasn't the
previous owners fault. The previous owner
simply tried to align it by the book.

Every other receiver I have owned aligns
by adjusting the coil at the low end, and
trimmer caps at the high end. The manual
did it the other way. And when I did it
the manual way, it never came out right,
doing it "backwards" and it tuned right up.

Now as for crystals. I took Dave Stinson's
hint and ordered some of the Epson programmable
PLL chips. Running them at 5V from a 78L05
to use the receiver's 12V supply, and built
up on a little piece of perfboard.

Works OK. The IF is 1650 kc, so
for 3885kc you need 5535kc. BONUS! 5535 plus
1650 is 7185 and sure enough, I was able
to listen to a 40M SSB QSO. However, the
USB and LSB switch positions are reversed.

The bad news is that since these little chips are
not "warpable", and the clarifier control
on this receiver functions by warping the
first oscillator crystal, there is no clarifier.
Even so, there was a QSO on 7185 and it
was good copy.

I'm thinking about ordering a chip to
put the other receiver on one of the
HF ATC channels, just to see how well it
will work.

Haven't seen much about these receivers, so
thought I'd share what I've found out.

Jack Antonio WA7DIA/4