Federal Signal Corporation YAGI-1, Руководство по установке

Страница: 10 / 18

10
Installing the Antennas
Yagi and Omni Antennas
Federal Signal www.fedsig.com
Mounting the Yagi Antenna
See Figure 1.
To install the Yagi antenna:
1. Install the antenna (using an installation bracket or equivalent) as high as possible,
such as the antenna cable and obstacles allow, and install it on the side of the pole
closest to the receiving station. Aim the antenna at the receiving station. Make sure
the antenna elements are in the vertical direction.
Install a service loop when routing the antenna cable.
NOTE: Objects around the antenna affect the antenna. Keep the antenna pointed
away from objects.
2. Ensure the antenna cable connections are tight. Seal all connection points with heat
shrink or tape and seal with Scotchkote™ 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 ohmmeter
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.
Figure 1 Yagi Antenna Installation Example