>
>on 7/10/01 12:03 AM, rick rosner at rar@uniserve.com 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
resistance.
- "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!
>
>73,
>
>Jon
>NA9D
>
>-------------------------------------
>Jon Ogden
>NA9D (ex: KE9NA)
>
>Member: ARRL, AMSAT, DXCC, NRA
>
>http://www.qsl.net/ke9na
>
>"A life lived in fear is a life half lived."
>
>
>--
>FAQ on WWW: http://www.contesting.com/FAQ/amps
>Submissions: amps@contesting.com
>Administrative requests: amps-REQUEST@contesting.com
>Problems: owner-amps@contesting.com
>
>
- R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.
end
--
FAQ on WWW: http://www.contesting.com/FAQ/amps
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
|