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[AMPS] Bias for SB-220

To: <amps@contesting.com>
Subject: [AMPS] Bias for SB-220
From: measures@vc.net (Rich Measures)
Date: Fri, 4 Jun 1999 12:06:52 -0700


>
>Tom says:
>
>
>>Bunk. The claims that all kinds of splatter is produced are 
>>nonsense, mostly based on not understanding the effects of IMD.
>
>
>Sorry Tom, you're missing the point. My statement is that if you have a signal
> going into the PA and you switch the bias sharply, (we are assuming from cut 
>off, by the way), then you'll effectively pulse modulate it, giving a sinx/x
>
>spectrum. On CW, we call this 'key clicks'.
>
>Now you're saying that there are better ways to implement electronic bias 
>switching than switching to cut off. That is a different argument.
>
?  Peter - - I find it hard to believe that running 5 or so mA of ZSAC is 
going to fully cure this particular distortion problem when the tube 
manufacturer recommends 75mA per bottle for linear operation.  .  
.  The amazing thing to me about RF-bias touters is that they seem to 
cheerfully ignore the fact modern transceivers Already Have a 
delightsomely-right  +LV DC T/R signal wired to a jack at the back that 
gives a positive output which preceeds the RF output  by at least 5mS -- 
a veritiable plenitude of time for high-speed relays to switch.  
>
-  later


Rich...

R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures  


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