[Premium-Rx] WJ Microwave Receivers

[S. Schappert]

G'day to the list !

Please forgive my technically off-topic post.

I recently acquired a near-mint condition Watkins Johnson Type 112 Microwave
Receiver with tuner 2 - 4.5 GHz.  I have a couple of pretty straightforward
questions to anyone out there with experience with these receivers.

1.)  I am looking for any technical documentation available (please reply
off list if anyone can help me with this)

2.)  The receiver appears receive very low signal strength well, but I am
curious about the RF input level.  Using an out-of-band LPDA, I am able to
pick up signals that I have yet to characterize, but I notice that
apparently strong audio output signals barely moves the signal strength
meter, and using the 21.4 MHz SMO output and a working WJ SM9804A Signal
Monitor, the output level is so low it looks almost non-existent ( No
apparent noise being displayed on the floor at maximum gain ).  I was
surprised to find both 21.4 AND 160 MHz SMO outputs on this receiver.  All
other outputs (pre-detection, video, LO) are present.

I notice on the rear of the receiver there is a blank panel for an optional
RF pre-amplifier.  Since I currently lack RF signal generation in this band,
I cannot determine a threshold input power level for both the signal
strength meter and detection of a signal on the SMO output.  So I am curious
to know if the receiver input is designed to be driven at some minimum RF
level.

I am in the process of looking at different antennas in this band, so there
is no gain at the input currently.

I would be very interested to hear from anyone who knows these receivers, or
could point me in the direction of some documentation.

Thanks very much in advance !

My kindest regards to all,

-Scott