218 Transmitter Fault Finding TP9100 Service Manual
© Tait Electronics Limited May 2005
Frequency Bands
Some fault-diagnosis tasks require programming the radio with the lowest,
center or highest frequency in the radio’s frequency band. The relevant
frequencies for the different bands are listed in Table 10.2. Note that the
following frequency ranges are reserved worldwide for use by distress
beacons:
■ B1 band: 156.8MHz ± 375kHz
■ H5 band: 406.0 to 406.1MHz
Do not
program the radio with any frequency in the above ranges.
Can Removal There are four cans shielding the bulk of the transmitter circuitry:
■ PA BOT can
■ PA LPF BOT can
■ TX CONTROL BOT can
■ PA EX TOP can
To remove any can, first remove the main board from the chassis. Follow the
procedures given in “Disassembly and Reassembly” on page 101.
Can Replacement Replace all cans that have been removed only after repairing the board.
This applies to the B1, H5, and H6 bands. For certain other bands the
transmitter will not operate correctly unless all the cans are fitted.
Table 10.2 Lowest, center and highest frequencies in MHz
Band
Lowest
frequency
Center
frequency
Highest
frequency
B1
H5
H6
136
400
450
155
435
490
174
470
530
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