Moseley Starlink SL9003Q, User Manual

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Section 5: Module Configuration 5-15
Moseley SL9003Q 602-12016-01 Revision J
CONFIGURE
QAM Radio Launch
RX
Freq
QAM RADIO RX Config
MHz 944.5000
2. Use the cursors to change to the desired frequency. Press ENTER. The unit should
continue to indicate AFC LOCK (green) on the front-panel.
3. The receiver synthesizer AFC voltage will change depending on the frequency
programmed from the front panel. This voltage will typically be between 1.0 Vdc to
2.4 Vdc for the 944 MHz to 952 MHz band. Navigate the LCD screens to monitor the
AFC voltage as follows:
STATUS
QAM Radio Launch
RX
RX
VDC AFC
LO
%
SYNTH LOCK
4.5
100
NOTE : Earlier generations of the SL9003Q required an internal adjustment on the
Receiver Module to center the AFC voltage. These units can be identified when changing the
frequency by 5 MHz will cause the RX AFC to loose lock. With these units the Receiver
Module was placed on an extender card and to access the RX AFC adjustment. Depending
on the “direction” that the frequency was moved, the voltage might read either 0.00 or 9.99
VDC. While monitoring this voltage, you would adjust the RX AFC on the Receive Module
(using a very small flat blade screwdriver) until the voltage read 4.5 +/- .25 VDC.
5.5.3 Measuring Carrier Frequency — TX
Typically it will not be necessary to measure the transmit carrier frequency. Starlink
transmit carrier is derived from a very stable 0.1 ppm OCXO (oven controlled crystal
oscillator) and is factory calibrated to an OCXO reference.
However if it is required to measure the carrier frequency this can be achieved by entering
the factory calibration menu tree:
1. Connect a 30 dB, 5 Watt or greater RF attenuator to the transmitter output.
2. Connect a frequency counter capable of 0.1 ppm (or better) accuracy at 1 GHz to the
RF attenuator.
3. Connect AC power to the SL9003Q transmitter unit.
4. Follow the Factory Calibration menu tree. Navigate to the QAM Modem and enter the
OCXO screen. Enable CW Mode to ON. This will disable modulation on the carrier so
that the carrier frequency can be measured.
5. Measure the frequency. Set the CW Mode to OFF.