Palstar Commander VHF-1200, Owner'S Manual

Page: 9 / 20

9
CONNECTING YOUR AMPLIFIER
Locate your Commander VHF-1200/2000 so that no equipment is directly above it, as air
expelled from the tube exhaust on top can become quite hot. Allow at least 3 inches clearance
on either side between the unit and other objects or equipment.
Connect the RF OUTPUT of your transceiver to the RF IN connector on the rear of the
VHF-1200/2000 with 50 ohm coax.
Using RG8 or better coax, connect the RF OUT connector on the VHF-1200/2000 to a good
quality thruline Wattmeter, and connect the Wattmeter Output to the antenna, antenna tuner or
dummy load.
Connect the RELAY phono jack on the rear of the VHF-1200/2000 to the Normally Open
(NO) terminal of the RELAY jack on your transceiver. Read the manual that came with your
transceiver to find the proper external connections. On some transceivers, this is not provided,
and an alternate circuit will be required. Always use shielded cable for these connections. The
RELAY jack on the VHF-1200/2000 has positive 12 VDC open circuit on the center pin and
requires the sinking of 55 mA of current when pulled to ground.
Connect the ALC phono jack to the ALC connection on your transceiver using a shielded
cable. Consult your transceiver manual for proper ALC connection details.
Connect a ground lead (as short as possible) from a good earth ground to the GROUND
post on the rear panel.
The 12 VDC jack on the rear panel is an accessory for powering low current 12 VDC de-
vices (less than 100 mA.). Do not connect an external voltage source to the jack.
OPERATING PROCEDURE
After reading this manual and completing the Installation / Preparation Instructions, position
the Commander VHF-1200/2000 front controls as follows:
ON / OFF OFF
OPERATE / STANDBY STANDBY
METER SWITCH Vp (PLATE VOLTAGE)
LOAD 50 - MIDDLE OF RANGE
TUNE MINIMUM CAPACITANCE (POINTER TO LEFT)
After presetting these controls, switch the ON/OFF switch to the ON position. At this time
you will hear the blower running and see an indication of Plate Voltage on the meter, (approx-
imately 2650 VDC)
The 3CPX800A7 used in this amplifier require a warm-up period before RF drive may be
applied, to prevent damage to the tube. A 2 minute warm-up is provided by a solid state timer
circuit. At the end of the warm-up period, the green POWER LED on the front panel illumi-
nates and the unit is ready for operation. Switch the meter switch to the Ip (plate current) posi-
tion.