OM4000 HF POWER AMPLIFIER
1
3
1. Set the multimeter switch to the
HV
position
2.
Set the OPR/STBY switch to the
STBY
position
3.
Press the
ON
button
The amplifier is prepared for operation with the following automatic steps:
The toroidal transformers are switched on step by step.
The cooling blower for the final tube is switched on.
The multi-meter bar graph measures the high voltage; the normal value is
3.3 kV
The WAIT LED lights up
CAUTION
After switching on, please confirm that the blower is operating properly. Air must be
flowing from the ventilating aperture above the tube. If there is any concern, or no air
flow, press the “OFF”-button immediately !
Heating the tube takes about
180 seconds
. After this time the WAIT LED goes out and the
amplifier is ready for operation.
4. Reduce the power output of your transceiver to the
minimum!
5. Switch OPR/STBY to
OPR
position (OPR LED lights up)
6. Choose the
TUNE
position of multi-meter
7. Transmit (mode CW) and increase driver power to
10W
CAUTION
If the input power is higher than 15W and the power amplifier is not correctly tuned, the
safety devices will switch to STBY. After switching the amplifier to STBY, the amplifier
will automatically reset and switch back to OPR mode after abt. 2 seconds.
A tuning table is delivered with the power amplifier. Select a band with band switch and choose
the setting of “TUNE” and “LOAD” according to the table.
NOTE
Delivered tuning table was made for 50 Ohm loading of PA (dummy load). Each amplifier
should have different values depending on used frequency and used type of antenna.
Make
your own table
valid for your real conditions.
