[BC] Heterodyne flutter (was: X-Banders)

[WFIFeng@aol.com]

In a message dated 07/12/2005 11:08:26 AM Eastern Daylight Time, 
reader at oldradio.com writes:

> For example, if
>  Willie zero-beated 1500 WFIF's carrier to WTOP's, I'm sure it would help
>  WFIF gain a few extra miles of useable coverage during "critical hours"
>  when WTOP's skywave is strong.

Because of where I live, WFIF's and WTOP's carriers are almost equal most 
days in the winter at or near sunset. Thus, the heterodyne effect is quite 
pronounced. I have set our carrier to around 5Hz above WTOP's.

I tried zero-beating. Once. It's *far* worse, because you have instances 
where the carriers are out-of-phase for up to several minutes at a time, and it 
sounds positively horrific. The 5Hz flutter is much better on the ears than 
that, and it is low enough in freq, that most radios won't even pass it thru the 
audio stages. A lower frequency will start to affect the AGC, and can sound 
quite nasty as well. 5hz seems to be the best compromise between the audible 
artifacts of a faster heterodyne, and the phasing effects of the carrier 
cancellation/AGC at lower freqs.

Even if WTOP were synced to GPS, and I did the same, there would be dramatic 
phase-shift effects caused by the ionospheric reflection of the WTOP signal. 
We'd be back to square one.

Based on my 18 years of working at WFIF, the 5Hz heterodyne really is the 
best way to deal with it. Of course, the *ultimate* answer for us would be to buy 
them out and either shut them down or power 'em down like was done to WOWO. 
We ain't got that kind'a dough, though. <G>

Willie...