"Count Floyd" (CountFloyd@MonsterChillerHorrorTheater) writes:
I have an HE-10 with an IF Gain control. The manual says to turn it
all the way for AM reception. Is this the same thing as an RF gain
control? The RF Gain on my Panasonic 2200 controls the sensitivity,
and so does the IF gain on the HE-10. So, what is the difference?

The manual says "all the way..." what?

The HE-10 is a Lafayette cheapie, or is it some comletely other
receiver? Because I have a vague idea that the receiver I'm thinking
of used regeneration in the IF amplifier to provide a locatl beat
oscillator for CW reception. And in that case, varying the IF gain
would affect whether or not the stage went into oscillation.

RF gain and IF gain will affect things somewhat differently, but
not in terms of overall gain. Some receivers may not even have an
RF stage. The point is to reduce the overall radio gain (as opposed
to audio gain) for various purposes, mostly to prevent overload. A
receiver that had both RF and IF gain controls, and I seem to recall
that some did, in terms of gain it wouldn't matter which one you played
with. But it might matter in crucial issues. If a local station was
overloading, reducing RF gain might reduce or eliminate front end overload,
because the signal wouldn't get amplified much before there was good
selectivity, while if you reduced IF gain for the same signal, it would
have no affect because it was the RF stage being overloaded.

The real time you'd see much mention of RF or IF gain controls was
in dealing with SSB, once it came along. For receivers that had no product
detector, you were told to reduce RF gain and then increase audio gain
(to compensate for the reduced RF gain, in effect overall gain would remain
the same or close to it while the distribution of that gain would change).
This was so the incoming signal was weak compared to the receiver's BFO
signal, because it needed to be much stronger than the incoming signal in
order to properly demodulate the SSB signal. In this case, it wouldn't have
mattered whether you had an RF or IF gain control, or which one you used
if you had both.

Michael