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3.1 BASE STATION ANTENNA INSTALLATION CHECKLIST
The following suggestions are offered to help those responsible for antenna installations
avoid costly errors in assembly and adjustment. Marti Electronics, Inc. assumes no responsibility for the
installation and performance of antenna systems associated with its equipment. The following
suggestions are not intended to be a complete step–by–step procedure, simply a listing of some of the
most frequently reported errors in antenna system installation.
3.1.1 Antenna Assembly
Follow the manufacturer’s instructions carefully. If no instructions were included with the antenna, call or
write the antenna manufacturer for instructions. Antennas which have phasing or stacking cables must be
assembled care- fully to avoid phase reversal or signal cancellation.
3.1.2 Transmission Line Connector Assembly
Do not use RG–58U or RG–8U cable for RPU station antennas! They have too much loss at VHF and UHF
frequencies. Follow the instructions furnished by the manufacturer when cutting coaxial cable. Inspect the
cable ends for small metal fragments which can short–circuit the line inside the connector assembly. Check
the line for a short– circuit condition after each connector is installed by using an ohmmeter. Pressurized line
should be checked for several days under pressure before installation on a tower to ensure that there are no
leaks in the line or fittings
3.1.3 Moisture Proofing Coax Connectors and Fittings
Extreme care must be exercised with coaxial cable before and after connectors have been installed to ensure
that moisture does not enter the line. Foam dielectric line can take on moisture by absorption which is
difficult to detect and remedy. Therefore, keep the line dry while in storage with ends tightly capped. Coaxial
splices, connectors, and fittings to be located outside should be made mechanically tight, then coated with a
weather–proofing material over at least two layers of vinyl plastic electrical tape. Moisture problems in
antenna systems are usually traced back to connectors which have NOT been properly taped. The Marti K–1
Grounding and Weatherproofing Kit is recommended for use in each new antenna installation.
3.1.4 Location and Grounding of Coaxial Cable
Keep the RPU receiver coaxial cable as far from the broadcast transmitter and its coaxial cable as possible. DO
NOT STRAP RECEIVER CABLE TO THE MAIN ANTENNA CABLE AT ANY POINT. PLACE THE RECEIVER ANTENNA
COAXIAL CABLE ON THE OPPOSITE SIDE OF THE TOWER FROM THE MAIN ANTENNA CABLE. Maintain
maximum separation between these cables at all points, including the distance from tower base to
transmitter building as well as inside the building.
3.1.5 System Grounding
It is essential that the RPU antenna system be properly grounded for safety and proper operation.
3.1.6 Antenna Installation and Adjustment
The polarization of the transmit and receive antennas of the RPU system must be the same! This means that if
the transmitting antenna is vertical, the receiving antenna must also be vertical. Each antenna should be
attached to the tower using the proper side mount or top mount hardware. If an RF wattmeter is available,
each antenna and transmission line can be checked for VSWR when the transmitter is supplying power to it.
The VSWR should be less than 1.5 to 1 (1.5:1). IF THE ANTENNA SYSTEM FAILS TO GIVE THE PREDICTED
SIGNAL STRENGTH LEVEL, THE FOLLOWING ITEMS SHOULD BE CHECKED:
1. Check for correct assembly of antenna.
2. Check that antennas have same polarity.
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