[AMPS] Parasitic suppressors/another question,

[km1h@juno.com]

SNIPPED

>>Simple I believe. The voltage is not an issue in the SB-220 but the
>>current is. I have examined almost 200 bandswitches and amps that 
>have
>>been run hard on 10/11M show a loss of contact tension. 
>
>€  So it is the loss of contact tension that indirectly causes the 
>resistance of the suppressor resistors to substantially increase 
>without 
>showing an outward sign of resistor overheating?


On 10M which comes first, the cart or the horse?

It was agreed by most, (sorry if you were not invited,)  that many common
suppressors do run hot on 10M and extended use will result in an increase
in R.  This in itself does not guarantee the wrath of the parasite god.



>
>>This soon leads to overheating and eventual failure. 
>
>€   only open bandswitch contacts arced.  

Yeah sure. You already stated that the arcs are on 10M. In the SB-220
case that means there are NO open contacts.






>
>>When the rotor heats up it then also
>>transfers heat to the 15M contact. It then becomes a domino effect. 
>>IOTH, those amps that use positive spring loaded contact pressure 
>such as
>>the JV-9000 series do not exhibit that failure mode.
>
>€  The arced AL-82 bandswitch shown in the photo on my Web site is a 
>JV-9000.  



Yep. and I'm the one who sent it to you. But you obviously dont remember
the failure reason.


>>
>>I have modified a few SB-220's with a second output wafer and wired 
>in
>>parallel with a good or rebuilt original. These amps are still used 
>in
>>contests and failures have ceased.
>>
>>No voodoo suppressors, no parasitics.


73  Carl  KM1H


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