RadioBanter - View Single Post - possible fix of rumble synch satellit 700

Mark Zenier · September 14th 06, 06:58 PM posted to rec.radio.shortwave

In article ,
Telamon wrote:
In article . com,
wrote:

Here is the article I found form newsgroup that mention about the way
to eliminate the rumbling noise of synch detector . I hope someone can
study it and give a conclusion on the improvement made be these
modification.

Snip

Some radio stations are off frequency. Use a mode that injects a fixed
receiver local oscillator frequency like CW mode to zero beat the
receiver to the target signal then switch back to sync AM.

And, from a dimly remembered article in QEX many years back, a lot of
shortwave broadcast transmitters have a lot of phase noise. (Speculation:
probably those high effiency transistorized class D ones). Put a
noisy carrier into the servo loop, and the output of the phase detector
will need just the right filters to not carry that through to the VCO.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)