[AMPS] SB-220 conundrum

[measures]

>
>Howdy Pete N4ZR and Amp nuts -
>
>I have heard that you can test for VHF parasitics by disconnecting the RF
>input and RF output from your amp and then, with the relay closed (ie, HV
>etc. applied)watch the plate and grid current meters while rotating the
>plate and load controls.
>
>I can see how that would work in some cases but don't know about all cases.
>
I can not see how this stability test would work at frequencies higher 
than HF.  .  To start the most destructive type of parasite (intermittent 
vhf push-push) , a rapid change in anode current is needed.  This 
requirement can be met by switching ZSAC either on or off.  Sometimes a 
vhf parasite can be started by sending high-speed dits.  

later, Lu

-  Rich..., 805.386.3734, www.vcnet.com/measures.  


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