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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: Thu, 3 Jun 1999 09:07:02 -0700


>
>Rich wrote:
>
>> ?  How many peak volts on your 'scope?  With "normal" ALC indication,  my
>> TS-440S overshoots to about 120v-p. into 50-ohms.  .  
> 
>The actual pulse lasts less than one mS, eyes can't follow and non-
>storage scopes won't display random one mS pulses that occur 
>right at the leading edge of envelope rise.

?  Oscilloscopes that use a vertical def.  delay line can.  
>
>If you used a FAST peak-storage wattmeter, you would have a 
>clear and accurate indication of overshoot levels. Lacking that, you 
>could use a triggered storage scope triggered off the source at 
>some early stage, and store about a dozen shots of leading edges 
>and find the worse of the batch.
>
?  With an oscilloscope that uses a std.-persistence phosphor CRT, one 
has around 500mS of persistence to see how high the spike went.  My HP 
oscilloscope has a 26kV accelerator, so the trace can be made quite 
bright in order to stretch the persistence.  //  To see an ALC attack 
spike, I set my oscilloccope to trigger at c. 50v, switch on the VOX, and 
speak one word into the microphone.  To confirm the peak voltage 
measurement, I speak again and watch the deflection on the oscilloscope.  
.  .  An easy calc. gives me the peak W into my 49.8 ohm termination.  
For the TS-440, this works out to be c. 144w PEP.  
>
-  cheers, Tom.  


Rich...

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


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