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6 Field Alignment Procedure
6.2
VCO Alignment
1.
Select a channel at the centre 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 (TUNEV), and adjust
C99 to obtain 4.5±0.2V, while the TX LED is ON and the ALARM LED is OFF.
6.3 TCXO Calibr ation
1.
Select a channel at the centre 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 carrier frequency at the output connector, and adjust XO1 until the
correct carrier frequency is measured, ±50Hz.
6.4 Modulation Balance
1.
Set RV3 fully CCW (subtone off).
2.
Set RV1 fully CW (maximum deviation)
3.
Set RV2 mid-position
4.
Set JP7 for flat response
5.
Key the transmitter on
6.
Set the audio input to 150Hz, 0dBm.
7.
Measure deviation and adjust RV4 (line Level) for a deviation of 5kHz (2.5kHz
for narrow band transmitters).
8.
Set the audio input to 1.5kHz, 0dBm.
9.
Adjust RV2 (Mod. Bal.) for a deviation of 5kHz (2.5kHz for narrow band
transmitters).
RF Technology T220
6.2 VCO Alignment
Page 19
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