Marti Electronics SRPT-30, User Manual

Page: 22 / 129

8/7/2003
16
ANTENNAS
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 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.
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 carefully to
avoid phase reversal or signal cancellation.
Transmission Line Connector Assembly
Do not use RG-58 U or RG-8 U cable for STL 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.
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 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.
Location and Grounding of Coaxial Cable
Keep the RPU receiver coaxial cable as far from the broadcast transmitter and its coaxial cable as possible.
WARNING
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.