I agree with the above posts...........they are right on the money. About
that advertisement.........I did see something like that with one of the
Eton radios (was it the S-350?). I think, unless they are using an I.F. much
higher than 455kHz, they are advertising the design deficiency as a merit,
instead of what it really is. You would need quite a bit of selectivity in
the stages ahead of the mixer in order to provide adequate image rejection.
An interesting point.....instead of going to a double conversion scheme in
the Zenith R-7000 (not to be confused with the American made Royal 7000) the
designer chose to continue with a single conversion scheme but changed the
I.F. to 10.7MHz for all tuning ranges. Not a bad radio.

Pete

"Korbin Dallas" wrote in message
news
On Sun, 13 Nov 2005 12:05:46 -0500, Larry wrote:

What am I missing here. Although my background is in electronics and
electrical engineering, I've specialized in power rather than
communications
for thirty years. My scant and no doubt obsolete communications theory
always held that for great short-wave reception, double or even triple
conversion receivers were the norm. Now I see advertised, SW radios with
"... highly sensitive and selective latest state of the art single
conversion analog tuner circuitry....". What breakthrough has made single
conversion so state of the art?

DSP -


--
Korbin Dallas
The name was changed to protect the guilty.