>on 7/10/01 12:03 AM, rick rosner at firstname.lastname@example.org wrote:
>> **** To test ur tuned inputs put a 100 ohm 1/4w carbon
>> composition resistor across the output of the pi-net in question,
>> and put a MFJ-259/B on the input. Simply tweak both caps for
>> flat swr on mfj. repeat for all other tuned inputs.
>I forgot to mention this back when I posted my reply on this topic. It's a
>most excellent suggestion and works well.
/\ But not as well as driving the real cathode with at least half of
the rated anode-I flowing. The g-g cathode is Not a linear resistance.
During most of the positive half of the driving sinewave potential, the
cathode looks like an open circuit. During the negative peak in the
driving sinewave, a g-g cathode is c. 55% of the average cathode
- "Everything is more complicated than it looks. . ." -- Mr. Murphy
>One more suggestion is that you
>leave the tube in the socket and tie the resistor to ground from the cathode
>pins. This way you also take into account the input capacitance in the
>tube. It works very well.
/\ sound idea.
> Just don't power the tube up!
>NA9D (ex: KE9NA)
>Member: ARRL, AMSAT, DXCC, NRA
>"A life lived in fear is a life half lived."
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- R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
FAQ on WWW: http://www.contesting.com/FAQ/amps
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