B i l l E v e r h a r t wrote:

IF shift allows continuous adjustment of the passband, rather than just
selecting upper or lower. You could knock down interference 2KHz below
the desired station without deleting the entire lower sideband. Or,
while monitoring a SSB station.

Could you knock out the 2KHz interference with a notch filter as well?

You can knock out a tone with a notch filter (but it won't escape triggering
the AGC; a notch filter is taken as audio processing).

You can knock out 2 kHz offset SSB with a brick-wall audio filter, if it's
offset in the direction of the sideband (2 kHz higher for USB); though in the
case of 2 kHz you'll be left with fairly muddy audio in the remaining 0-2kHz.
Nothing much you can do in audio for AM, or SSB offset in the other direction.

I use the passband tuning on the R8B to pick up the full audio of broadcast
stations if there's nothing in the adjacent channel and it's worth the trouble,
using (say) upper sideband synch detection and offset the IF to the upper side.

The synch detection keeps the audio from distorting even though the carrier
is nearly out of the passband, and so you can reach to the high audio frequencies
with the wide 6kHz filter leaning way to one side. Ordinary AM mode would distort
as the carrier amplitude fell.
--
Ron Hardin


On the internet, nobody knows you're a jerk.