>
>John, NS1Z, says
>
>
>>I'll concede the pi is back to back Ls but, if it is not resonant at the
>>operating frequency, what is it that everyone is tuning it to....
>
Maximal output and minimal input SWR.
>Firstly, it depends on how you define resonance. When the Q is low, then it
>matters very much which definition you use. The one that is useful when
>applied to all circuits is that the voltage and current at the input are in
>phase.
>
>Especially if there is ANY load reactance, then that's different from the
>sum of the inductive reactances being equal to the sum of the capacitive
>reactances.
>
>So Rich could be right, or he could be wrong, depending on how you look at
>it.
>
>This time, I agree with him.
>
An experiment: optimize/tuneup an amplifier's output tank and input pi
networks for a specific band using a 50 ohm termination on the amplifier.
Shut the amplifier down. Use a dipmeter to measure the resonant
frequencies of the input and output pi-networks. . It may be helpful to
check the dipmeter accuracy with a freq. counter.
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
--
FAQ on WWW: http://www.contesting.com/ampfaq.html
Submissions: amps@contesting.com
Administrative requests: amps-REQUEST@contesting.com
Problems: owner-amps@contesting.com
Search: http://www.contesting.com/km9p/search.htm
|