User's Manual

3300-Watt VHF Low Band Transmitter Chapter 3, Installation and Setup Procedures
335B, Rev. 0 3-7
panels of the VHF amplifier trays, in the
power supply position.
NOTE: If the transmitter does not switch
to Operate when the Operate/Standby
switch is placed in Operate, check that on
the (A12) A/V input and remote interface
assembly an external interlock plug is
connected to J9, with a jumper wired
from pins 21 to 22. If the (A12) A/V
input and remote interface assembly is
not present in your transmitter, check
that an external interlock plug is
connected to J11, with a jumper wired
from pins 23 to 24, on the rear of the
VHF exciter.
With the transmitter in Operate, monitor
the front panel meter of the VHF exciter
tray. In the % Visual Power position, it
should read 100%. If necessary, adjust
the screwdriver adjust power pot on the
front panel of the VHF exciter for 100%.
Check the % Reflected Power position. If
the % Reflected Power is very high,
above 10%, a problem exists with the
output coaxial lines and they will need to
be checked. A center bullet missing from
the coax lines or loose bolts on the
connections can cause this problem.
The gain and phase controls on the front
panels of the individual VHF amplifier
trays were adjusted at the factory to
obtain an output of 100% for the
transmitter and should not need to be
readjusted. The front panel readings on
the individual VHF amplifier trays may
not be the same. Refer to the Test Data
Sheet for the transmitter to compare the
final readings from the factory with the
readings on each of the trays after the
setup. If a reading is off by a significant
amount, refer to the phasing and power
adjustment procedures for the VHF
amplifier trays in Chapter 5, Detailed
Alignment Procedures, of this manual
before trying to make any adjustments.
If a dummy load is connected to the
transmitter, switch the unit to Standby
and switch off the main AC circuit
breaker. Remove the dummy load and
make all of the connections that are
needed to connect the transmitter to the
antenna. Switch the main AC circuit
breaker on and the Operate/Standby
switch to Operate. Adjust the output
power screwdriver pot to achieve an
output of 100%.
If the transmitter is already connected to
the antenna, check that the output is
100%. If necessary, adjust the power
screwdriver pot.
This completes the transmitter setup and
operation procedures for the 335B VHF
low band transmitter. The transmitter
can now be operated normally.
If a problem occurred during the setup
and operation procedures, refer to
Chapter 5, Detailed Alignment
Procedures, of this manual for more
information.