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[AMPS] parasitic suppressors

To: <amps@contesting.com>
Subject: [AMPS] parasitic suppressors
From: measures@vc.net (Rich Measures)
Date: Thu, 8 Apr 1999 11:13:46 -0700


>Rich says:
>
>       > how come all PA's don't show spurious non harmonically related
>       >>outputs?
>> >
>>?  HF PAs do. 
>
>
>Not this side of the pond, they don't - unless the design is crap and they
>are oscillating. 

?  With the tube not in a state of regeneration, a spectrum analyzer can 
see trains of damped vhf waves coming from the anode-resonant circuit.   
The only requisite is that DC current transients be passing through the 
resonant circuit.  The same phenomenon can be simulated on the workbench 
with a vibroplex key, a vhf resonant circuit, a resistor and a LV source. 
  

> Nor in the ARRL lab reports published in QST. 

?  The ARRL Lab tech. who tested the Ameritron AL-1200 told me that he 
observed intermittent tank spitting that he suspected was caused by an 
intermittent parasite.  This information was not published in QST.  
>
>> One can put a conductance of10mSiemens in parallel with a susceptance
>>  
>And it's still a conductance 10mS or a resistance of 100ohms. The only way
>to  increase the resistance (or decrease the conductance) is to put a
>negative conductance in parallel. 

?  It might be worthwhile to look over Wes' measurements.  

>Since negative conductances require active
>devices, it doesn'r apply. Mind you, if you can find a passive negative
>conductance, your fortune is made...........you won't need PG & E.
>
>>>Rubbish! That's the definition of admittance - the reciprocal of impedance
>> >
>>?  Try it.  Take heed that ye beware of the snare.  
>
>No snare if you do your sums right.
>
?  "nothing is as easy as it looks"  
>
-  cheers, Peter


Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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