Codan Radio Radio Repeater Systems Training Guide - Manual (Page 40)

TRAINING GUIDE | RADIO REPEATER SYSTEM
Chapter 4: Installation and Maintenance Page 32
h) Mark antenna directions on the inside of buildings so that in the event the antennas are
inadvertently moved they can be returned to the correct azimuth.
i) The repeater station, when complete, should have a record of equipment (on site) and measured
signal levels so that future maintenance technicians will have a standard for reference. A second
copy should be kept on fi le at a different location for convenient reference. A repeater site data
form is shown in Appendix I.
j) Grounds must go directly to ground. In addition, all coaxial cables and drip loops at cable
entrances to the building should not have sharp bends.
k) Guy wires are not recommended. However, if they are used, fl ag them well for better visibility.
l) Vapor corrosion inhibitors placed inside the enclosure are recommended.
MAINTENANCE
With the purchase of good, reliable equipment, maintenance can be held to a minimum. In fact, most
large scale users of mountain-top equipment “service to failure”, rather than having a maintenance
schedule.
Most outages will be caused by catastrophic failure owing to lightning strikes or other weather damage,
by power supply failures, or by interference from others. It is not unknown for a repeater to run for
fi ve to ten years with no attention at all, until the battery supply has to be replaced. However, because
these units are usually in fairly inaccessible locations, it is recommended that for every three repeater
units (VHF or UHF), another repeater unit be held as a spare. With a system of two or more repeaters,
if there is an outage, it is fairly simple to logically determine which transmitter or which receiver is out
at which location. When the repeater itself is the culprit, it is usually not economical to repair it on site.
Having a spare transmitter, repeater and control card carried by the maintenance technician (set up on
the correct frequencies) is much simpler than trying to repair equipment on site.
When on site, however, every effort should be made to bring all equipment up to the original recorded
values by checking transmitter power output and deviation, VSWR of the antenna system(s), duplexer
losses, receiver and transmitter frequencies and receiver sensitivity. Visual inspection of all components
on the site should also be conducted. Ensure that all connectors and clamps are tight and free from
corrosion. Keep the records up to date. Make sure everything is clean and tidy, and before leaving the
site, confi rm that the system operates correctly.