Dear Brian, LF group,
My RA1792 also has a 100kHz IF output; it is generated by a
module that sits in the place intended for the ISB option. I have no
documentation for this module - but I had a peek inside, and it
appears to contain a mixer, LC filters, and a PLL conversion
oscillator locked to the main reference oscillator, which mixes
down the normal 455kHz output. I suppose it is intended to adapt
the RA1792 to work with modems intended originally for receivers
with 100kHz IFs like the RA17. I don't think it does anything special
to the signal apart from shifting it in frequency. I don't suppose it
would be a problem to disconnect it and use the original 455kHz
output instead.
I have not had any problems with the RA1792 jumping from one
state to another - but I did have a similar problem with some
Marconi - Adret signal generators, which also appeared to be
caused by the back-up batteries going flat; the less often they were
used, the more often they would reset themselves at apparently
random intervals when they were switched on.
Cheers, Jim Moritz
73 de M0BMU
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