Other Setup Considerations - BW Broadcast TX5 FM Broadcast Transmitter Technical Manual

8. Connect as before. Turn the power off to the transmitter, connect your external antenna , reconnect your power
and your on the air!
10. Monitor your total peak deviation with your real world audio material and check with the deviation display that
your peak deviation does not exceed 75 kHz. If you have set up the transmitter as per the instructions in this sec-
tion then you should be within 1 kHz or so of this figure. If your deviation does exceed 75 kHz then adjust the
back panel multiplex control to keep your maximum deviation at 75 kHz.
2.6

OTHER SETUP CONSIDERATIONS

LOOPTHROUGH
The rear panel BNC sockets provide an easy interface to the multiplex path. You can insert an external piece of
equipment between the multiplex output of the internal stereo encoder and the modulator section.
To connect an external piece of equipment consult the external equipments documentation. It should be as easy
as configuring the transmitter as per normal and then simply setting the internal Loopthrough jumper to OFF and
taking the multiplex output to the input of the external equipment and the output of the external equipment back
into the multiplex input socket. If the external equipment is not unity gain you may have to readjust the multiplex
input gain slightly to take account for any gain differences. Most loopthrough designed equipment is unity gain to
make setup and use as simple as possible.
FREQUENCY FINE TUNE ( WARNING, ADVANCED TECHNICIANS ONLY)
While the frequency is controlled by the phase locked loop system, the stability is governed by the stability of the
reference. A quartz crystal is used for the reference for its high stability however component ageing can affect the
frequency slightly over time. The frequency can be finely adjusted via VC1. This provides a small adjustment of
the VCO frequency when locked. This will have been adjusted at factory to the correct setting and the transmit-
ter should remain within 1kHz of the channel required. If however the frequency does move off slightly due to
component ageing then you can adjust VC1 to trim the unmodulated carrier back onto channel. You will need a
frequency counter to monitor the output frequency of the un modulated transmitter when adjusting VC1.
LCD SYSTEM METERING ACCURACY
DISPLAY
POWER SUPPLY
TEMPERATURE
PEAK DEVIATION
RF POWER
BW Broadcast technical manual
Measurement
Volts
Degrees Centigrade
kHz
Watts
Installation and setup
Accuracy
+/-1 Volt
+/-1 Degree
+/-1 kHz
5 %
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