Singer - Comm Service Monitor CSM-1 use and hints

[Bruce Brackin]

Slightly off topic but will used on boat anchors.  Received a Singer
CSM-1 communications service monitor and looks like very useful box.
Has RF gen (0 to -110 db, 400/1000 Hz mod ), sweeper, modulation tester,
spectrum analyzer and low freq scope.  Generator is dead on by two
different freq counters to over 500 MHZ.  Heck, with a short antenna in
the rf input, you can even listen to the radio!

Was used by FAA - Dates to mid 70's.  Curious as to experience of others
with the unit - HF/VHF/UHF.  Any FAA engineers or techs out there?
Seems intended primarily for AM use so curious about SSB and FM (has
provision for external FM modulation).  Also interested in possible
sources of a power attenuator, about 100 watts, at reasonable cost to
use with it as max rf input is only 0.5 volts for spectrum analyzer
section and I don't want to cook the front end.

Thanks in advance for the bandwidth. - Bruce Brackin