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Re: AO-10



Keith, Stacey,
I've found, over the last two weekends, the FM'ing to be very noticable on CW 
but not really a problem on SSB.  On CW, the tone has a distinct "warble."  
On SSB, I have at times noted the frequency shift, but it is hardly 
noticeable--especially compared to the deep QSB.  Go ahead and try it out.  

What we need is some sort of practical protocol for timing transmissions 
between the deep fades--something like the EME'ers use.  
Maybe we could use "beat" time :-)    (I'm only kidding)

73,
Jerry, K5OE

> >The notes on AO-10 say not to use the sat if the beacon is FMing. What 
does 
>  >FMing sound like?
>  >
>  >Keith
>  
>  It's a shift in transponder output frequency caused by variations in
>  available/utilized voltage/power at the transponder.  In its current
>  condition, AO-10 is rotating very slowly, and probably wobbling some as
>  well.  If you go to an unused portion of the passband and send a CW signal
>  on the uplink, listen to your sideband tone on the downlink and you'll hear
>  it drift up and down over a minute or so....that's a form of FM'ing,
>  probably due to variable power from the solar panels caused by variations
>  in illumination, or maybe in the functional state of the very old panels.
>  Of course, if someone else loads the transponder with a heavy signal during
>  your experiment, you may hear a freq. shift then as well.  At times I've
>  heard high power CW signals elsewhere in the passband that I can copy by
>  listening to the frequency shift of the beacon tone!
>  
>  The considerations about not utilizing AO-10 during FM'ing are more
>  theoretical than real.  Certainly, if you key a signal to the transponder
>  while listening to the beacon and you hear a marked drop/shift in the
>  beacon signal, then conditions are really marginal and you should wait for
>  improvement.  However, I would not let the relatively mild FM'ing now being
>  experienced as AO-10's illumination improves deter you from using it.  Have
>  fun. 
>  
>  
>  -- 
>   ________________________________________________________________________ 
>   Stacey E. Mills, W4SM    WWW: 	http://www.cstone.net/~w4sm/ham1.html 
>     Charlottesville, VA	  PGP key:	
http://www.cstone.net/~w4sm/key.asc    	
>  

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