On Tue, 2 Jul 2013, dave wrote:


You forgot to turn on the BFO. BFO level is frequently too low for demodding
SSB hence the need to reduce RF gain.

No I didn't. It should be a given that you need the BFO. I was making
the point that it's one of those radios of the time that didn't have a
product detector, so you had to do what all the books said to do. A few
years later, most receivers did have product detectors. Indeed, the
GPR-90 came along right at the cusp, so you could get an external unit
that added a product detector (and I think some extra selectivity) and
some really fine tuning. The receiver has the an IF output jack on the
back, even has a jack for feeding audio back into the receiver (though the
TMC adapter had a built in audio amplifier). Other receivers had similar
units. The R388 and the R390 didn't have product detectors, though they
are considered some of the best receivers from the time (and perhaps for
all time).

But with that level of receiver, turning down RF gain wasn't a real issue.
I had no problem receiving SSB, even on six meters, on the SP-600 I had
forty years ago.

ON the other hand, that Hallicrafters S-120A (the transistorized model)
that I got in the summer of 1971 had a horribly weak BFO, so by the time
I'd attenuated the incoming signal (a pot between the antenna and the
receiver), there weren't many signals left strong enough to receive.