BARRETT 2030 HF SSB TRANSCEIVER
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Marine Installations
General
The Barrett 911 automatic antenna tuner is designed for use in land base station
and maritime HF services. Primarily designed for operation with end-fed un-
balanced antennas such as whips and long-wires, the tuner is built in a waterproof
impact resistant, moulded ABS plastic enclosure.
Antenna selection
The 911 automatic antenna tuner will operate into almost any end-fed antenna with
a length exceeding 2.5 metres, providing an effective ground (earth) is used. The
antenna efficiency will be proportional to the length of the antenna and will be
maximum when the length of the antenna approaches 1/4 wavelength. It is
advisable to limit the wire antenna to 1/4 or 3/4 wavelength at the highest frequency
to be used.
Antenna
On sailing vessels the antenna can either be an insulated backstay or a whip
antenna mounted vertically, usually on the stern. Best performance will be achieved
by using an insulated backstay as the radiating length will be longer than that
available when using a whip. The top insulator on the backstay should be
approximately 300 mm from the mast and the bottom insulator should be at eye
level above the deck. The distance between insulators should be greater than 10
metres and less than 35 metres. A whip antenna is generally used on small to
medium sized power vessels. There are different length whips to suit the vessel
length.
Transceiver and tuner mounting
Select a suitable position in the vessel to mount the transceiver. It should be a
position that is out of the weather and easily accessible to the operator, whilst as
close as practical to the 13.8 V DC power source. Mount the transceiver to a solid
fixing point using the mounting cradle. Make sure there is sufficient space at the
rear of the transceiver to connect the power and antenna cables.
The antenna tuner should be mounted as close to the antenna feed point as
possible. In metal vessels the length of the feeder from the antenna tuner to the
feed-through insulator, inside the vessel, should be kept less than 1 metre.
The antenna feed cable should be a suitable high voltage cable. Care should be
taken to avoid sharp points when terminating the cable to prevent corona
discharges.
The interconnect cable supplied with the antenna tuner should be routed away from
other cables back to the transceiver and connected as indicated in the diagram
overleaf.