User's Manual

DANIELS

ELECTRONICS LTD.

25W AM Power Amplifier Instruction Manual IM71-AMP3A130-25 4-5

4.3 Control Board Alignment

1. After completion of the amplifier alignment, using the RF Level potentiometer in the

exciter, set the RF output of the power amplifier to 10 watts. LED1 (labeled RF

Power) should be on, otherwise adjust pot R1 until LED1 is just visible. This

threshold may be adjusted to any RF power output level for the AMP-3 (10 –

25W).

2. Disconnect the power amplifier RF output and terminate it with the 3:1 mismatch

load. When activating the exciter, the LED2 (labeled High VSWR) should be on,

otherwise adjust pot R19 until LED2 turns on.

3. Terminate the power amplifier RF output with a 50Ω load. LED2 should be off, if

not, slightly turn the pot R19 counter-clockwise until the LED2 is off and check that

LED2 turns on when the power amplifier RF output is terminated with the 3:1

mismatch load.

4. Disconnect the RF terminal on the load, so that the power amplifier load is open.

Once the exciter is activated, verify that LED3 (labeled Overload) is on and the

power amplifier has no RF output power. If this is not the case, shut down the

exciter, adjust R18 and reactive the exciter. This confirms that antenna VSWR

overload protection works properly.