At 02:10 AM 2/18/2007 -0500, you wrote:
>Bill,
>A Wobbler, when heard in its more energetic form sounds like a shaken
>sheet of metal.
>They appear to originate on Cuban AM broadcast stations and when
>strong can be heard interfering with other stations on the same
>channel, at times even usually dominate ones.
>It is not believed they are jamming, but rather the result of
>deteriorating and malfunctioning transmitters, possibly helped along
>with an unstable power grid.
>When you have a spare moment, you can get a notion of the Wobbler at
>the web site; link in my signature.
>Curt
>-------
>W. Curt Deegan
>Boca Raton, (southeast) Florida
>http://ScooterHound.com/WWWR/wobbler
>
Group,
The Wobbler on 1100 is truly bizarre!
It looks like the variation is caused by incipient oscillator failure. As the
frequency varies, it shifts the tuning and loading on the power amps.
That varies the voltage applied to the oscillator. A feedback condition.
Note that some extremes of frequency variation, the frequency has
rapid variations on it...as though the bass component of the modulation
frequency is FMing the signal briefly.
I don't think that external power variations have a thing to do with it.
A grid that unstable would constantly be losing sychronization among
generators on the high-voltage tielines. That would trip breakers and
cause very frequent blackouts.
73 de Charles
-----
Charles A Taylor, WD4INP
Greenville, North Carolina
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