[K6BW] GRC-129

[Bill Smith]

Here is further information regarding the GRC-129.  Part Hallicrafters!
This was taken from the R-390 mail reflector, where one of the members was
asking about a receiver he had just obtained.   Dual Diversity is a means of
using two receivers with their AGC lines tied together to improve reception.

Your receiver is an R-1247/GRC-129 Receiver,  modified from the R-390A by
Manson Labs.

This equipment was part of  the AN/GRC-129  system which had 2 R-1247
receivers for dual diversity. The 2 receivers had the CV-1694/GRC-129 Single
Sideband Converter, (Manson Labs) connected to them, The CV-1693/GRC-129 is
the 1 MHz step synthesizer and the O-1203/GRC-129 is the 1 KHz step
synthesizer locked to the same frequency standard. With the 2 synthesizers
the receiver is tunable within its normal frequency range in 1 KHz steps.

The frequency still has to be dialed in the receiver, because the RF stages
and mixers have to be peaked up at the frequency of operation. The receiver
can be operated normally, too. Both synthesizers and the converter were
built by Manson Labs,  but the synthesizers  were also made under contract
by Hallicrafters, in their last throes of death...

The system transmitter was the modified (for sideband) T-368, under the
nomenclature T-946/GR1C-129, driven by the O-1555/URC  synthesizer.

73 de Bill, AB6MT
billsmith@ispwest.com