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security lights, and many other items can be sources of unwanted noise. Plasma televisions
are becoming more popular and are a known generator of unwanted noise interference.
Ground wave noises arriving from a significant distance are vertically polarized. The path
along the earth "filters out" and removes any horizontally polarized signals. Horizontal
electric field components are "short circuited" by the conductive earth as they propagate and
are eliminated.
With the exception of ground wave-propagated noise, receiving antenna polarization effects are not
predictable. It is possible vertically polarized antennas may be quieter than horizontally polarized
antennas. The opposite is also true.
It may be difficult to remove noise with any device when:
Noise and desired signals come from the same direction and elevation angle
Both antennas don’t hear the same noise
The noise source is moving around, or noise sources are coming from several directions at
the same time
Basic Tools Required
5/16", 7/16", 1/2" wrenches or nut drivers, and a 5/8" wrench
# 2 Phillips Head Screw Driver
Active Vertical Antenna Installation
Location
The best place to install your active antennas is where you have the recommended space. Refer to
pages 20-22 for installation information. The two
DXE-ARAV3
receive antennas should be located
a minimum of 1/2-wavelength (at the lowest frequency used) away from any transmit antenna. If
possible, select a location far away from any dwelling where many potential noise sources are
found.
If the receive antennas are located 1/10-wavelength to 1/2-wavelength from a transmitting antenna,
the receive antennas must be powered off at least
5 ms
before transmitting on the transmit antenna.
A sequencer such as the
DXE-TVSU-1A
should be used to ensure the correct transmit-to-receive
switching.
With this close spacing, coupling from nearby transmit antennas or metal structures becomes more
pronounced. At higher frequencies, where the active element length becomes a partial wavelength,
coupling increases further. Placing a
DXE-ARAV3
on the same mast or tower as a Yagi or other
transmitting antenna is not recommended for this reason.
Pay attention to details. The time you spend making a good installation will pay you back many
times with good results.
