Specifications

5/9/13 888-2857-001 5-21
WARNING: Disconnect primary power prior to servicing.
Section 5 Maintenance and Alignments
Platinum VAX-C Series
STEP 3 Tune output filter (if present) to new frequency. Consult filter test data,
specification sheet, or other manufacturer-supplied information for more
details. Some output filters are band limited and may not be adjustable
across the VHF band. In cases where the filters are band limited a
replacement filter will be required.
!
WARNING:
HARRIS DOES NOT RECOMMEND FIELD TUNING OF FILTERS. CONSULT THE
MANUFACTURER OF THE FILTER BEFORE ATTEMPTING ANY FREQUENCY TUN-
ING OF FILTERS. HARRIS RECOMMENDS ACQUIRING A FILTER TUNED TO THE
FREQUENCY OF CHANGE BEFORE PROCEEDING WITH A FREQUENCY CHANGE.
STEP 4
Use network analyzer to confirm performance of test load, filter,
transmission line and antenna at new frequency.
STEP 5 Use the LCD and front control buttons to navigate to the SETUP
>PFRU>CENTER FREQUENCY menu and enter the new frequency
(MHz). Example: if the desired frequency is 500.5, MHz enter ’500’ as
the center frequency and enter the FREQUENCY OFFSET value as
"500000" (Hz). If the web browser is being used navigate to Tx
Home>Exciter Home>PFRU>Frequency (MHz) and enter the value as a
whole number and decimal. Example: if the desired frequency is 500.50
MHz select the white Frequency box, it will turn light yellow, and then
type in the new value 500.5 and press the enter key. A confirmation box
will open to ask "Are you sure? Press the OK button to proceed.
STEP 6 Press the power down button for 40 seconds.
STEP 7 Use the LCD and control buttons to navigate to
SETUP>XMTR>POWER SETTINGS menu. Adjust the power settings
in this menu to the new levels.
STEP 8 Turn transmitter on.
NOTE:
Steps 9-11 are not absolutely required, the system run at the new desired fre-
quency and will be very close to the desired TX power. If you desire to calibrate
the system follow step 9-11.
STEP 9 Use a calibrated, averaging power wattmeter and a directional coupler
(with known coupling factor) to measure and monitor the transmitter
output power.