Steve Thompson wrote:
>>As I have been told, that is not enough power to place through the pi
>>circuit to get any sort of realistic reading. (That is from the MFJ
>>analyzer)
>
>
>Power level of the test signal is an issue on the input side of a g-g amp,
>but it shouldn't matter on the anode side.
>
You can get a reading by connecting a low-level impedance meter to the
input side of a "hot" amp (all operating voltages applied) but it won't
necessarily represent the impedance at full drive.
You can connect a resistor of the correct value to the input or output
of a cold tube, (no voltages applied) and you can then adjust the input
or output tanks to show 50 ohms at the input/output sockets.
To obtain the correct values of input/output resistance for GG triodes,
the KD9JQ program is very good - http://www.imaxx.net/~kd9jq
That reminds me to ask (will start another thread) if there are data for
Russian tubes?
73 from Ian G3SEK Editor, 'The VHF/UHF DX Book'
'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.com/g3sek
--
FAQ on WWW: http://www.contesting.com/ampsfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|