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Horizon Antennas
5. Adjustments
Danger: Do not apply RF power to the antenna while anyone is standing
near the antenna. RF burns or electrical shock may occur, causing severe injury
or death.
Equipment. The adjustment process requires Voltage Standing Wave Ratio
(VSWR) measurement. These measurements can be accomplished using most
any antenna analyzer. However, these devices typically generate a very small
signal (less than 0.2W) and may show higher than expected VSWR readings. A
reading of 1.5:1 at the tuned frequency is typical at this low power. The VSWR
readings should decrease once the antenna is used with 10W of power or more.
The VSWR reading on your transceiver will likely show a lower VSWR than a low-
power antenna analyzer.
Cables. Make sure that the coax used for the adjustment process is at least 65
feet long, and that the coax is installed at a 45-degree angle as described on page
11. Do not allow loops or coils in the cable, as this may create an RF choke. The
feedline neither radiates nor acts as a counterpoise for the antenna.
Avoiding Coupling. Due to parasitic coupling, installing your antenna on a
metallic stand may cause the tuned frequencies to differ from those of a permanent
installation. If a non-permanent mounting is required, we recommend our Horizon
non-metallic Quadrastand.
Operation Checklist:
eliminate common problems.
Is your antenna placed at least 30 feet away from other objects such as
buildings, people, trees, etc.? The ends of the antenna arms are very sensitive to
coupling with external objects.
Is your antenna installed such that the arms are at least 24 inches off the
ground? The spacing between the antenna's lower arms and the ground should
be between 24 inches and 30 inches.
Is your coax cable a high-quality RG-8 or RG-8X cable?
If adjustment proves difficult, follow this checklist to
UltraLite
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