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[AMPS] parasitics

To: <amps@contesting.com>
Subject: [AMPS] parasitics
From: km1h@juno.com (km1h@juno.com)
Date: Tue, 21 Apr 1998 21:37:35 EDT
On Tue, 21 Apr 98 11:07:45 -0800 Rich Measures <measures@vc.net> writes:
>>
>>>It seems to me that even a 100% increase in Rs would not make much 
>>>difference in the performance of a VHF parasitic suppressor. 
>>
>>Depends on the amp. The Clipperton L and the Ameritron 811 series do 
>not
>>like much of a value change. The SB-220 is still happy at 100 Ohms.
>>
>The suppressors in the three appear to be quite similar.


I would suspect that answer from someone who has not bothered to actually
look at them.


>>In my case...yes. I have already measured enough of them to see the
>>pattern. Since time is money I cant see wasting it. With Mouser 
>selling
>>5W metal oxides at $ .49 it makes no sense to unwind the L measure 
>the R,
>>rewind the L and put it back in the circuit only to wonder when you 
>will
>>have to do it all over again.  
>>
>Wind, unwind?  I unsolder one end, clip on the DMM.   We are talking 
>maybe half a minute.  If one knows how the resistor was damaged, an 
>instant replay may be avoided -- i.e., if Rs failed from 28MHz 
>operation, 

As I said...how many times do you want to replay the same scene?  I also
doubt the average ham gives a rats ass about the value of his R...he just
wants something that works and not have to stroke his DVM every time his
amp burps. Call Mouser and get a 5W metal oxcide for $.49.  If anyone
really cares then they can mail you the originals to play with.


>>
>>During the debug of a new amp I agree. In a well behaved amp that 
>just
>>went bang I disagree.  Take a 2W carbon and subject it to a 100X 
>overload
>>for a few milliseconds at DC. You will see the same results. 
>
>How does Rs receive a 100x overload in any amplifier, new and old, 
>where 
>Rs is paralleled with an Ls that is a virtual short at HF?

If you continue to live in a parasitic world you will never accept
reality Rich. I dont intend to waste my time in an argument with someone
who can not show proof to support a theory nor accept the possibility of
another idea.
Bent filaments or anything else means absolutely squat unless a "real" 
engineering study  can confirm your "theory". So far I find no support
for it outside of a few that can offer no proof either. Myself , I dont
believe it at all.

73  Carl  KM1H


.   
>>.........


>
>
>cheers
>Rich...
>
>R. L. Measures, 805-386-3734, AG6K   
>
>
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