Reflected Power - OM POWER OM2000 HF Instruction Manual

Operation
Operating elements
BAND -
band selector switch (in MHz)
TUNE -
Anode capacitor for tuning, tuning of higher frequencies to "0",
lower frequencies to „100".
LOAD
- Output capacitor tunes antenna load resistance to amplifier.
Capacity is low at „0" and high at "100" on the scale.
OFF -
You switch off the amplifier by pressing this button.
ON -
You switch on the amplifier by pressing this button.
Heating of tube is on and after 3min of delay the amplifier will be
ready for operation.
„OPERATE"you will be ready for operation.
OPR/STBY -
At STBY, if WAIT-LED is on or the amplifier is off your transceiver is in
bypass-mode directly connected to antenna. Maximum 400 Watts !
Bar graph – shows output power .
RF OUTPUT -

REFLECTED POWER

maximum or amplifier switches to STANDBY-mode
bargraph – measerus the currency of the second grid in the range from -20mA to
Ig2
+80mA
HV/IP/TUNE bargraph – measure the anode voltage, anode currency or tuning of the amplifier
TUNING
The OM2000 HF amplifier is operated in class AB. Thus it's possible to obtain a maximum
output power at an excellent linearity. For this purpose the amplifier has to be tuned carefully.
The operation of a mistuned PA will cause malfunctions, the increase of grid current (the GRID-
MAX-LED will light up) and problems with TVI/BCI.
The grid-current is shown with 2 LED diodes. It's normal if the green LED is flashing or may be
shining a little bit during peak operation. If you overload the amplifier the output power increases the
grid current at very small rates and the red GRID-MAX-LED is shining and the safety devices switch
the PA to STBY. You must decrease the output power.
In SSB you will have a good output power if the green LED lights up a bit. The current of screen
grid is measured and shown in a Bar graph indicator. The amplifier has to be tuned in such a
way that the current is between - 20 mA to +50 mA. At currents beyond these values the
operating point will be shifted and IM-products will be rapidly
exceeded, the safety devices will switch the amplifier to STBY mode.
(see photo of front panel)
Bar graph – shows reflected power of the antenna. 350W
-
increased. If a value of + 70mA is