Liberals for Guns wrote:
Can someone help me understand something about IF vs synch. I've read
that IF shifting can get rid of an interference that is occurring
slightly lower or higher than the desired frequency. So, if you've
got noise within the filter range and it's on the lower side of the
frequency than you simply shift everything up so the noise is out of
the "window". My question is that I'm not sure why you just couldn't
use sync in to get rid of the interference. By just listening to the
upper sideband the noise wouldn't be there. Right? Do I need to pay
for an advanced feature like IF shift when I could get away with
simply using a sync detector function?

"DX Ace" is right: a sync detector only works on AM signals. Really, it
doesn't by itself allow you to select one sideband or the other either;
that's a function of filter bandwidth options. A sync detector that
receives *both* sidebands is very much possible and worth doing, as it
would reduce selective fading problems.

(that said, any receiver I'm aware of with a sync detector does allow
selecting which sideband you use, and as you noted, that's worth doing too)

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.

That said, in practice I rarely use the IF shift in my receiver...
--
Doug Smith W9WI
Pleasant View (Nashville), TN EM66
http://www.w9wi.com