M8SL2-00-002-812 T854 Initial Tuning and Adjustment C3.9
© Copyright Tait Electronics Limited August 2004. All rights reserved.
3.6 Synthesiser Alignment
1. Ensure that the T854 has been programmed with the required frequencies using
PGM800Win software.
2. Single Channel Select a channel using PGM800Win.
Multichannel Select the middle channel via PGM800Win.
3. Connect a high impedance voltmeter to the long lead of L1 in the VCO (this meas-
ures the synthesiser loop voltage).
4. Key the transmitter by earthing the Tx-Key line.
Single Channel Tune VCO trimmer C6 for a synthesiser loop voltage of
10V.
Multichannel Tune VCO trimmer C6 for a synthesiser loop voltage of
10V on the middle channel.
If there is no middle channel, tune C6 so that the channels
are symmetrically placed around a loop voltage of 10V.
All channels should lie within the upper and lower limits
of 16V and 3V respectively.
Do not attempt to program channels with a greater fre-
quency separation than the specified switching range
(8MHz).
5. Measure the exciter output frequency and adjust the TCXO (=IC700) trimmer if
required.
Caution: This trimmer is susceptible to physical damage. Do not exert a down-
ward force of more than 500g (1lb) when adjusting.
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