8
Power can be supplied from any filtered DC source. An AC to 12VDC
adapter is available from JPS Communications at slight additional cost.
The ANC-4 may be operated directly from the power system of any
12VDC negative ground vehicle.
The MAIN ANT input (J3) connector is a UHF (SO-239) type for use
with coaxial rf cables, such as RG-8 or RG-58. This connector serves as
the rf input from the outside or station antenna system.
The RADIO (J2) connector is also a UHF (SO-239) type for use with
coaxial rf cables, such as RG-8 or RG-58. This connector provides the
output from the antenna to the receiver. When the ANC-4 power is off,
the MAIN ANT is bypassed directly to the RADIO connector.
The NOISE ANTENNA connector on the rear panel (J1) is an RCA
phono jack for connecting the short wire noise antenna or your own noise
antenna to the ANC-4.
This antenna picks up locally generated noise to
the exclusion of desired long distance signals, and is used as a reference
signal which can be varied in magnitude and phase for cancellation of the
local noise. Keep in mind when selecting which noise antenna to use that
you may get deeper noise nulls by having the same polarization on both
the noise antenna and the main antenna.
In either case,
the noise antenna
should be kept as short as possible to provide a good noise null with the
NOISE GAIN control in its mid range.
If sufficient noise cannot be picked up by the noise antenna supplied
with the unit, it may be necessary to install a noise dipole or noise
probe outside to more clearly pick up the noise.
A noise dipole of 3
to 6 feet either side of center, fed with shielded wire or coaxial cable, will
generally suffice. The dipole should be turned broadside (parallel) to the
noise source and should be located 2 to 4 feet above ground, perhaps in
shrubs around the house, but where it can "see" the power lines or other
noise source. This will prevent it from receiving much if any of the
desired signal. After installation, perform the test in the SECTION 2,
ADJUSTING FOR MINIMUM NOISE to be sure that adequate noise
pickup is available from the noise antenna. It is most desirable to have
the matching noise level occur when the NOISE GAIN control is
somewhere in its middle range. Otherwise, the null may be obscured if
it occurs too close to either end of the control.
SECTION 3
CONNECTIONS
POWER
REQUIREMENTS
VEHICULAR
OPERATION
MAIN ANTENNA
INPUT
RADIO INPUT
NOISE ANTENNA
