I'm building a simple one-tube (circa 1941) QRP rig.
(I've added an isolation xformer, fuse, & 3-wire AC line cord for safety.)
A link of the schematic is here:http://www.bignick.net/temp/1941_QRP_rig.bmp
My question is about the PI filter in the output section.
For some reason, they have placed the DC blocking capacitor AFTER the PI filter.
This means that both tuning capacitors and the tapped inductor are all at the B+ voltage.
In most schematics that I've seen, the blocking capacitor is wired BEFORE the PI network,
(and an RF choke is usually wired from the output of the PI filter to ground.)
Can I move the DC blocking capacitor to a location BEFORE the PI filter without
It would seem to me that the RF would pass thru the 0.001 uF DC blocking capacitor
an on to the filter, but I'm not sure.
For that matter, if I'd like to do some circuit analysis of the PI filter, what input
output impedances would I use for calculations? I would assume that input impedance
would be the plate impedance of the tube, and the output impedance ideally 50 Ohms?