[AMPS] Re: Parasitics

[Rich Measures]

>> Date:          Thu, 14 May 1998 01:21:12 -0800
>> From:          Rich Measures <measures@vc.net>
>> Subject:       Re: [AMPS] Re: Parasitics
>
>> >Rich claimed a K5 had parasitics in his 922 because "mistuning and 
>> >misloading can not cause excess tank voltage or arcs. The K5 showed up 
>> >and correct Rich, and said the nichrome Rich sent him was never 
>> >installed. It turned out the cause of the arc was a bad gas discharge 
>> >tube in his lightning arrester.
---------------
Interested in this embarrassment?  See Will's archive for:

From: "David B. Holtkamp (K5KH)" <holtkamp@roadrunner.com>
Newsgroups: rec.radio.amateur.homebrew
Subject: Re: TL922 Arcing/Oscillating? Help with diagnosis?
Date: 30 Nov 1996 22:48:48 GMT
-------------- 
>> Is a bad lightning arrestor breaking down the same thing as deliberate 
>> mistuning?  
>
>Yes, so far as the PA is concerned they are identical. 

The bad lightning arrestor that arced was not in in PA.  It was connected 
in the coax that fed the antenna.  

>That's why I 
>said "mistuning or misloading". 
>
>During a load fault, the PA is no longer properly matched to the 
>load. 

agreed, especially if there is an arc in the antenna tuner or an arc in a 
lightning arrestor in the coax line that feeds the tuner.  

>If, during the mismatched condition, impedance at the tank end 
>of the tube rises. With a high Q resonant tank 

However Pi-network tanks are not resonant at the operating freq. because 
Pi-networks are two L-networks in series, and Pi-L network tanks are 
three L-networks in series.  
>...........


Rich...

R. L. Measures, 805-386-3734, AG6K   


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