waterlock devices which provide an effective way to keep moisure away from
the LNB’s F connector.
The receiver should be unplugged from the a.c. wall receptacle before
connecting or disconnecting the coax cable from the LNB or the receiver. This
eliminates the chance of a short circuit across the coaxial connections.
The connection to the LNB also should be weatherproofed to keep moisture
out. This can be done by flooding the connector with a dielectric silicone sealer
or wrapping the connection with a sticky waterproof compound such as Coax-
Seal. It is also a good idea to use a plastic LNB/feedhorn cover to give your
outdoor electronic components added protection from the elements.
Wiring The Feedhorn
The feedhorn line of the direct burial cable is comprised of three color-coded
22 gauge (or larger) stranded wires. These wires also are shielded and
jacketed. The three wires provide power, pulse, and ground connections for
the feedhorn. Each of these wires connects to corresponding terminals on the
back of the receiver. The wires are color-coded to help identify them when
connecting to the three servo motor wires at the feed (usually red for power,
white for pulse, and black for ground).
A stranded wire is used because it is more flexible and won’t break as easily as
a solid wire. The shield, an aluminum foil wrapped around all three wires,
keeps impulse noises from entering the line and giving false pulses to the
receiver. The receiver uses pulse to keep track of the position of the feedhorn’s
pick-up probe. You therefore can adjust, or “skew”, the position of the probe
and program the optimum polarization for any given satellite transponder into
memory.
The feedhorn’s servo motor rotates the pick-up probe, which swings back and
forth while switching between the horizontally and vertically polarized
transponders (odd and even channels). Keep in mind that there are limits to
the pick-up probe’s clockwise and counter-clockwise movements. The
feedhorn must be aligned on the antenna a that the probe can swing the 90
degrees from horizontal to vertial (or left-hand to right-hand circular)
polarization without reaching the limits of its travel. Several manufacturers
include a directional guide with their feedhorns to show the proper alignment of
the feed when installed on the dish. If you find that you cannot skew the probe
beyond a good picture on both the odd and even channels on all satellites, you
will need to loosen he clamp that holds the feed onto its support and physically
rotate the feedhorn until it is possible to do so.
