[AMPS] SB220/SB221

[km1h @ juno.com]

On Wed, 26 Nov 97 16:16:26 -0800 Rich Measures <measures@vc.net> writes:


Lots of SNIPS...not worth repeating

 
>>I did tell you very clearly that the 220 had a problem with VLF 
>>parasitics ...snip...
>
>Indeed you did mention this scenario.  However, it didn't wash because 
>
>there is no VLF resonant circuit in the anode, and the 50uH HV-RFC has 
>
>rather low reactance at VLF..  IMO, the VLF issue looks like yet 
>another 
>rauchian smokescreen.  


So why dont one of you guys prove that one way or another. Set up a
SB-220 at a neutral location and have at it.   Just stop the bull shit
here.


>>> If your amplifier arced mysteriously, it might be interesting to 
>measure 
>>> the resistance of the VHF parasitic suppressor resistor.  
>>
>>Heat any carbon comp resistor to 150-200 degrees C for years and 
>>measure it. Carbon composition resistors change value from long term 
>>temperature exposure, anyone in electronics for a period of time 
>>should know that much.
>>
>True enough, Mr. Rauch, however the suppressor resistors that were 
>being 
>promptly damaged in my amplifier were essentially shorted out by 
>several 
>inches of #16-gauge copper bus-wire - - and the fatal damage was 
>happening during operation at 7.25MHz. 
> 
>>It's pretty darned hot up at the anode connectors. That's why the 
>>resistors change. 
>
>There is a gale of fresh cooling air at that spot in the SB-220.  The 
>changes were typically taking place in less than a minute.  . 
>
>>It matters not what the heat is from, nor can you 
>>tell some time later what did it. All you know is it was heat.

Rich you seem to have a one track mind that everything is parasitics. In
the SB-220 I can see at least 4  reasons for pyrotechnics in the RF deck:
- Parasitics
- Gas
- Mistuning... which will overheat the suppressor resistor and then it is
downhill from there.
- Secondary  VHF reasonance in the tank...even when tuned properly on an
HF band.


Give it a rest please...will you? Tom and I have bitched at length and
will continue to do so at times I am sure;  but we dont continue the same
F/N argument on for years. 

Have a happy Thanksgiving ALL.

73  Carl  KM1H



>Hmmm.  So the changing resistance causes the tune capacitor to 
>intermittently arc over?
>
> .  .  And on the starboard side, passengers can see part of the site 
>of 
>ancient Thebes. Its pharaonic remains include the Great Temple of Amen 
>
>and a massive structure begun by Amenhotep III.  On and on.  
>... ...
>Rich...
>
>R. L. Measures, 805-386-3734, AG6K   
>
>
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