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RF Technology T70/T150 Page 17

6 FIELD ALIGNMENT PROCEDURE 6.1 Standard Test Condition

6 Field Alignment Procedure

The procedures given below may be used to align the transmitter in the field.

Normally, alignment is only required when changing operating frequencies, or after

component replacement.

The procedures below do not constitute an exhaustive test or a complete alignment of

the module, but if successfully carried out are adequate in most circumstances.

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, 25W rated, return loss <-20dB.

• Jumpers set to factory default positions.

Model Range Align F

T70 66-78 74 MHz

T70 70-85 78 MHz

T70 73-88 81 MHz

T150A 136-156 146 MHz

T150A 140-160 150 MHz

T150B 148-168 158 MHz

T150B 154-174 164 MHz

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.

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RF Technology R150 Betriebsanleitung Seite 17