40
Installing the Antenna
UltraVoice Remote Interface (UVRI-B)
2. Apply RF power to the antenna at the transmit frequency to be used at that antenna,
and check for the low VSWR while performing each of the following steps.
A. Loosen the setscrew with the Allen key provided and make a slight adjustment to
the aluminum gamma tube for the lowest VSWR (Reflected power).
B. Adjust the gamma link along the driven element for the lowest VSWR.
C. Repeat the above steps until the lowest VSWR is achieved. Reflected power
must be less than 10% of the forward power.
D. Return to the dimensions shown in the antenna instructions, if there is any
trouble achieving a good match. If the element dimensions are incorrect for
the frequency being used, low VSWR may be unattainable. If the VSWR
specification is still unattainable, replace the cable. (A simple ohm meter check
of the cable does not guarantee that the antenna cable is good, due to the DMM
not having the ability to check the cable at high frequencies.) If that does not
take care of the problem, replace the antenna.
Mount Yagi Antenna
See “Figure 8 Yagi Antenna Installation Example” on page 41.
To install the Yagi antenna, do the following:
1. Install antenna, (using installation bracket or equivalent) as high as possible, such
that the antenna cable and obstacles allows, and install on side of pole closest to the
receiving station. Aim antenna at receiving station.
Install a service loop when routing antenna cable.
NOTE
: Objects around the antenna affect the antenna, keep antenna pointed away
from objects.
2. Ensure antenna cable connections are tight. Seal all connection points with heat
shrink or tape and seal with Scotch Coat, or equivalent.
3. Apply RF power to the antenna at the transmit frequency to be used at that antenna,
and check the VSWR (Reflected power). Reflected power must be less than 10% of
the forward power.
If the VSWR specification is unattainable, replace the cable (a simple ohm meter
check of the cable does not guarantee that the antenna cable is good, due to the
DMM not having the ability to check the cable at high frequencies). If that does not
take care of the problem, replace the antenna.
