Re: [IRCA] Wobblers and a possible explanation

["W. Curt Deegan" <WWWR@xxxxxxxxxxxxx>]

Charles,

A very interesting suggestion as to Wobbler cause.

I'm listening to an Xtreme 1100 Wobbler right now at 10:07 pm ET, Feb 
17 2007 (0307Z).  I have audio from WTAM Cleveland, OH, on 1100, but 
a weaker carrier on 1098.01 kHz, which could account for the 
Wobbler.  It is generally accepted that many Cuban transmitters are 
old and in ill repair.  This would all certainly seem to meet your 
suggested criteria.

Conditions tonight are such that audio from Radio Cadena Habana is 
not being heard, though in the past it usually has been.  The next 
time RCH is in strong and Wobbling, I'll be better able to determine 
it's carrier frequency without doubt.

Your suggestion is possibly the best proposed Wobbler cause so 
far.  Previously, the combination of bad power regulation and old 
equipment had seemed the most likely culprits, but still with no 
technical explanation of why they would cause a Wobbler.  You may 
have added that missing element.

Thanks,
Curt
-------
W. Curt Deegan
Boca Raton, (southeast) Florida
http://ScooterHound.com/WWWR/wobbler



At 09:25 AM 2/17/2007, you wrote:


>I see a possible causes for the Wobblers.
>
>It's common among tube-type transmitters that, when the oscillator tube
>reaches the end of its useful life (when the transconductance drops below X
>micro-mhos), the inherent feedback inside the transmitter will cause the
>transmitter to "take off" and oscillate at some frequency near the assigned
>frequency. The station will sound about normal, but the carrier frequency
>will be a few kHz off and "wobbulate," or vary with a frequency-modulated
>characteristic caused mainly by bass components of the audio modulation.
>
>If the 1100 Wobbler kicks down at its extreme frequency deviations, betcha
>it'll pop up FMing a few kHz from 1100.
>
>Jest mah opinion. Take it or leave it, sez I.
>
>Charles
>
>
>         -----
>Charles A Taylor, WD4INP
>Greenville, North Carolina


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