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Bob,
Thanks for taking the time to try to explain this to me. I think I now know what it is you are suggesting. If I have not again missed the point, I would agree this could be a possible source of the Wobbler.
Let me presume to boil down your detailed explanation into what is almost certainly an inadequate simplification.
In its barest form a transmitter is an oscillator to generate the fixed frequency carrier signal, a modulator to impress the audio envelope upon the carrier, and an amplifier to juice it all up and shoot it out the antenna, with a few odds and ends thrown in to make it all seem worthy of a college degree for having designed it..
What I hear you suggesting is that at transmitter sites where Wobblers seem to originate, it is not just the oscillator that is generating the carrier signal, but extraneous signals from other paraphernalia in the transmission facility that are introducing off frequency signals along with the desire one, which then are fed through the modulation and amplification steps and blasted into my unsuspecting radio.
Whether these undesirable MW frequencies come from satellite or T1 equipment, is less the point than the fact that shoddy equipment installation and maintenance allows extraneous signals, whatever their source, to affect the broadcast signal. And the wobbling is the end result.
I hope I have not taken so many liberties in reducing this to my level of understanding that I have again missed the point. Does this sum up what you are saying?
-------Original Message-------
Date: 06/09/05 09:47:45
Subject: [IRCA] Bob Foxworth's theory of Wobbler partially dissected right before your eyes
Curt,
Here goes an attempt an an explanation:
T-1 bundle of frequencies are downlinked along with the beacon signal.
Signal frequency and local oscillator signal in effect downlinked
together. Demuxer locks on to beacon signal (which is, I think, just a
carrier) and resultant inside demuxer is a group of frequencies which
could be inside MW BCB except they are confined to the demuxer. I think
there's a tap point brought out at back of demuxer and you could
actually connect a BCB receiver to tap point and tune through T-1 spectrum.
I think.
I think you're right so far. Anyway, at the output of the demuxer which
(I think) again can be a spectrum inside MW BCB but which typically
extends way beyond either way, you have the spectrum. The spectrum is
further decoded/demodulated by a T-1 receiver that "sees" the downverted
spectrum and then further breaks it down to audio or computer-type data
package or most anything.
I think.
Data package goes to server, or something. Also, I think that when any
T-1 subchannels is inactive, it is cut off at the uplink station. The
frequencies carried by a satellite are a complex mixture of all kinds of
T-1 carriers. Any single carrier comes out of the total budget for the
download transmitter. Remember, that satellite is up there and depends
on solar cells and whatnot to power it up. Spectrum and power are precious.
When any carrier in the T-1 spectrum goes down (for the outlined
economic purposes), that channel on the final demodulator, its AGC rises
(or falls) and the inactive channel can then let through all kinds of
junk generated inside the final demodulator.
I think.
That channel goes to the BCB transmitter as AF modulation. But some MW
frequency junk can get through to the transmitter and get put on the air.
I think.
I've been through three/four classes on specific demux receivers.
Modems. Learned the receiver well enough to be dangerous. Now, almost 2
years later it all is starting to fade out on my mental facilities. My
AGC rises (falls) and junk starts coming through. And I foist it off on
you as the output of someone who knows but really just knows just enough
to make myself a real dangerous individual.
Feedback?
Charles
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Charles A & Leonor L Taylor
Greenville, North Carolina
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