Topband: Plate chokes (Balun thread)

Greg - ZL3IX zl3ix at inet.net.nz
Fri Jan 2 08:32:04 EST 2004


Back in the 80's, when I constructed my homebrew amp, I came up with the
idea of removing the plate coupling cap and using a cathode coupling cap
instead  (cold side of the PI network).  I coupled the output circuit using
a simple 1:1 transformer with enough DC isolation between pri and sec to
keep the HT off the antenna.

I then fed the HT on to the cold side of the PI.   Thus no choke is
required, so the amp can cover any frequency between 1.8 and 30 MHz.

73, and all the best for 2004,

Greg, ZL3IX




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