[AMPS] Load capacitor question.

[2]

>
>Hi,
>
>How should i build the 50ohm output line on my amplifier. I've used this
>formula :
>Z0=138/e-½ log D/d
>when i calculate it for air and with a tube of 20mm inner diameter i get a
>diameter of 8.7mm for the conductor. But is 'air' the way to go ? should i
>use teflon ? what is the dielectric constant of it ?
>i think it's 2 but i'm not shure .

//   2 is correct.  In the last HF amplifier I constructed, I used a 
length of #10 Teflon insulated hookup wire to connect the L-section to 
the output vacuum relays.  The L of this wire is part of the L-section 
inductance.  
photograph at:
http://www.vcnet.com/measures/PBox.top.inside.jpeg
This wire is white, so it not easily seen.  It connects to the vertical L 
in the upper left, travels to the right, turns right and parallels the 
tank L.  The vacuum relays are at the bottom, just out of the photograph.

cheers, Jan

-  R. L. Measures, 805.386.3734,AG6K, www.vcnet.com/measures.  
end


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