Fixed station installations
Transceiver position
Operating convenience
Air circulation
Proximity of transceiver to antenna
Power supply
The following should be considered when choosing a position for the transceiver.
The transceiver should be placed so that the operator is comfortable and any facilities he
may require can be easily accessed.
Most transceivers rely on air flow around cooling fins to dissipate heat generated by the
transmitter. The mounting position must allow free air flow around these fins.
When using RG-58 coaxial cable from the transceiver to the antenna a cable length of no
more than 30 metres is recommended. Should a run of more than 30 metres be required it is
recommended that a low loss coax such as RG-213 or RG-8 be used.
It is recommended that the transceiver chassis is connected to ground using the bolt on the
rear panel to stop pick-up of unwanted noise from local power supplies and electrical
equipment.
All Barrett transceivers require a supply voltage of 13.8 VDC . In most vehicles or vessels
this is available from the battery, in the case of vehicles with a 24V system a 24V to 12V
converter rated at 25 amps should be used (Barrett P/N BCA90014). In fixed station
installations where 240/220/120/115 VAC mains power is available, a Barrett 922 power
supply should be used. In base station installations where no mains is available a Barrett
901 solar power supply is available.
Note:
Some installations use an AC battery charger to float charge the supply battery.
Battery chargers can produce electrical noise from the rectifier diodes. This noise
causes a static type of interference in the receiver. It may be necessary,
therefore, to switch off the battery charger whilst the transceiver is in use. If float
charging of batteries is required for installations with unreliable ac power supply, it
is recommended that a Barrett 922 be used as this provides a boost and float
charge facility to maintain a battery without the noise problem described above.
BARRETT 950 HF TRANSCEIVER
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