Good point.
If I lower the swing to 3800 and raise the current to 658mA to keep the
same dissipation, the guesstimated plate load impedance drops to 3610
ohms. Lowering the Q to 10 then puts the loading cap to 923pF @ 1.8mHz,
which works.
(I'm also using 3uH of "lead" inductance left of the PI network to help
mitigate the capacitance issues at higher frequencies. That raises the
load side capacitance requirement slightly on 160M, in case someone
tries to work these numbers)
Thanks,
Jim N7CXI
On 10/21/2013 4:34 AM, Peter Voelpel wrote:
I don´t believe that the anode voltage drops to zero volts at 625mA anode
current.
4KV voltage swing in your calculation is probably too high.
73
Peter
-----Original Message-----
From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Jim Barber
Just to clarify, I used 1.6 for "K", which in Ian's spreadsheet is in
the middle of the range for AB:
Single 8877
4KV
625mA
60% efficiency
"K" factor of 1.6
= 4000 ohms plate load impedance.
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