User's Manual

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RF Technology T800 Page 18
6.1 Standard Test Condition 6 FIELD ALIGNMENT PROCEDURE
TCXO calibration may be periodically required owing to normal quartz crystal aging. A drift
of 1ppm/year is to be expected.
Each alignment phase assumes that the preceding phase has been successfully carried
out, or
at least that the module is already in properly aligned state with respect to preceding
conditions.
6.1 Standard Test Condition
The following equipment and conditions are assumed unless stated otherwise:
• AF signal generator with 600Ω impedance, 50-3000Hz frequency range, with level set to
387mV RMS.
• Power supply set to 13.8Vdc, with a current capable of >5A.
• RF 50Ω load, 30W rated, return loss <-20dB.
• Jumpers set to factory default positions.
Alignment Frequency
Model Range Align F
T800A 806-830 818MHz
T800B 850-870 860MHz
T800C 928-942 935MHz
6.2 VCO Alignment
1. Select a channel at the center frequency (half way between the highest and lowest
frequencies for the model in question).
2. Disconnect the Audio input (no signal input).
3. Key the PTT line.
4. Measure the voltage between pins 9 and 1 of the test socket (TUNE V), and adjust C99 to
obtain 4.5±0.25V, while the TX LED is ON and the ALARM LED is OFF.
6.3 TCXO Calibration
1. Select a channel at the center frequency (half way between the highest and lowest
frequencies for the model in question).
2. Disconnect the Audio input (no signal input).