[AMPS] IMD

Ron D. Rossi rrossi@btv.ibm.com
Mon, 17 Sep 2001 16:52:01 -0400




>>>Rich Measures said:
> > >
> > //  Few AB1-grid driven. or AB2-GG amplifiers have as much distortion as 
> > modern transceivers.  Many of the dirty signals that I hear seemingly 
> > involve operator ignorance and/or over-exuberance.  
> > 
Steven Katz responded tongue in cheek:
> 	::You mean the, "damn the torpedoes, all knobs to right!" theory of
> operation is not the correct one?  Darn...-WB2WIK/6>...

Ian White responded:
>
>Good point. It emphasizes that the performance of an amplifier is a
>combination of several things: 
>
>* The tube(s)
>* The circuit configuration
>* The power supply 
>* The operator who tunes, loads and drives it.

Folks,

I have a question. I tune for max power out with min grid I and plate I no 
greater than ICAS spec. I seem to remember someone recently stating that 
adjusting the load just to the point of the power dropping off sharply 
increases IMD performance with only a slight loss of power out.

The three posters suggest there is a method of tuning which improves IMD, but 
fail to state it. Can someone tell me how and more importantly why for someone 
who does not know (a.k.a. me!!)?

I run with my TS-850 set with ALC as prescribed in the manual and compression 
peaking at 10%. The exciter power varies with the efficiency of the amp on a 
particular band (I keep plate current to spec as I don't care to lose a 
transformer to overheating again!!!).

-- 
73 es God Bless de KK1L...ron (kk1l@arrl.net) <><
QTH: Jericho, Vermont
My page: http://www.qsl.net/kk1l



 



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