7.3 PA Bias
7-14
(2) 05P0739 board (PA, FS-2570T)
R26 (Vc ADJ): Collector voltage of the PA on PA-1 board is adjusted by R26 so that the
readout of Vc at output power adjustment is equal to the actual collector voltage. To
adjust R26 on PA-2 board, exchange the connection of J4 and J5 on the TX FIL board.
R33 (Ic ADJ): Collector current of the PA is adjusted by R33 so that the readout of Ic at
output power adjustment is equal to the actual collector current. This adjustment is
made with J2 disconnected on either PA board. The sum of both collector currents is
indicated in the display.
A
+
-
PA BIAS ADJ.
(R16, 200 mA)
PA IN (J2)
Remove the connecter
for BIAS adjustment.
Ic ADJ. (R33)
Vc ADJ.
R26
Fig.7.3.2 250 W PA, 05P0739
PA-1
PA-2
Fig.7.3.3 Location of PA-1 and PA-2
L1
Wire is as short and
heavy as possible.
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