Federal Signal Corporation YAGI-1, Installation Manual

Page: 7 / 18

7
Installing the Antennas
Installation Manual
Federal Signal www.fedsig.com
Table 4 Ordering Yagi Antennas
Part Number Frequency
YAGI
-1
136-150
MHz
YAGI
-2
150-174
MHz
YAGI
-10
450-470
MHz
Planning your Antenna System
Proper planning of your antenna system is significantly important. VHF and UHF are
essentially line-of-site frequencies; therefore, radio transmission through a mountain or
the earth in a valley is impossible. Get the antenna as high as possible. Increasing height
by ten feet can make a significant difference and may add miles to the coverage. LMR400
antenna cable length can be up to 200 feet for VHF and 100 feet for UHF. If a longer
antenna cable length is necessary, a higher quality cable is required.
Verify that the antenna height, frequency, location, and the radio system’s ERP (Effective
Radiated Power) are within the site’s FCC license limits. Subtract VSWR loss and cable/
connector insertion losses. To determine ERP, add the antenna’s gain to the radio power
and subtract VSWR loss and cable/connector insertion losses.
Consider the following guidelines:
• Do not have the antenna radiating element touching anything. If too close to an
object, excessive reflected power can occur.
• Place the antennas at least 1.5 feet or more from other objects.
• Separate multiple antennas vertically, not horizontally.
• Antenna cable entering a building requires grounded lightning protection at the
building entry.
Installing the Antennas
INSTALLATION PRECAUTIONS: Radio and antenna installation must conform
to the system’s FCC (or equivalent) license, which specifies the RF frequency,
modulation, RF power, antenna location, and mounting height. Do not operate the
radio system until the installation has been confirmed to comply with the license.
Follow these guidelines:
• Install the antenna above the roofline
• Create the service loop diameter at an 8-inch minimum radius
• Attach a gas discharge suppressor (to interrupt the antenna cable) to the ground plate
mounted to the outside of the building. This properly grounds the antenna shield and
prevents lighting from entering the building.