Al Arduengo wrote:

Does anyone have any experience to verify that a portable that has
syncronous detection (7600G) does (not) perform noriceably better than
one that does not have it? More specifically, would a newbie notice
any difference?

It depends what you're listening to and the quality of the synch
detection.

Some synch detectors generate additional noise with weak signals
(the 7600G[R] being an example, so SD isn't useful with weak signals
on it) but work fine with non-weak signals. The 2010 is one that works
fine on both, perhaps shutting itself down discreetly before
the noise point. So there's that aspect: do you need SD on weak
signals only? Or will you get something out of strong signal SD.

Everybody will notice the improvement that SD gives on distant
AM stations at night, particularly around the dark side of twilight,
against selective fading; which means not that the signal becomes
weak, but that the carrier fades below the level needed to support
detection of the sidebands which have not faded, and you get strong
audio distortion, just as if you had way-detuned the station. SD
prevents that distortion completely. This effect is almost
always noticeable on shortwave broadcasters transmitting from
near the auroral belt, eg. the Sackville relay of lots of broadcasters
like Radio Japan (6145 kHz at 00:00 UTC); they're extremely strong
almost all the time, but wildly distorted half the time without SD.

In addition, if it's selectable-sideband SD (which the 7600G[R] has),
you can get away from an adjacent broadcaster's splatter by picking
the opposite sideband to listen to, and some get rid of some heterodynes
as well.

So SD cleans up the audio a _lot_ on hard signals, and if you don't get
SD you'll wish often that you had gotten it. The reverse is not true;
you could go for a similarly priced YB-400 which has nicer audio than
the 7600G[R] but you will wish you had SD sometimes; if you get the
7600G[R] you won't wish you had gotten the YB-400 sometimes, because
you get used to the audio and you don't get used to distortion.

If you just listen to local stations, the YB-400 would be better
for its audio though. Local stations don't have any fading, let
alone selective fading.
--
Ron Hardin


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