Below, my Type 608E VHF
generator, which isn't much use in a domestic repair workshop
as they do not include FM. I suppose they would be more useful
for overhauling aircraft equipment as they still use VHF-AM.
This monster, weighing in at around
100lbs covers 10-480MHz.
These equipments were made in the days
before clever methods of frequency stabilisation had been invented
and relied on mechanical ruggedness (=weight) to ensure that
the output frequency was stable. Another requirement of these
things, with their very accurate output attenuators (the dial
on the bottom right), was not to leak any RF which might upset
Even with professional test equipment,
RF leakage can pose problems. I was once servicing a marine VHF
transceiver and was checking the distress frequency calibration,
when the local Coast Guard popped up and complained about my
test signal on his receiver. This despite the use of screened
leads and a dummy load.