Operation & Maintenance Manual

TELCOSAT RPT 700
Page | 9
Document use is restricted to that described on the cover
3.5 ANTENNA ISOLATION & COAX CABLES
All repeaters require antenna isolation (separation) to prevent the signal from one antenna directly feeding
into the other antenna. If this occurs it is called “oscillation” and your repeater will not work. The usable
gain of your repeater is directly linked to the antenna isolation.
Due to the variations of system layouts and requirements it is not possible to have one procedure that will
suffice every installation. Therefore, we strongly advise that you acquire the services of an RF system
designer to calculate your antenna isolation requirements, or contact Telcosat and we will determine the
antenna isolation requirements that are unique to your installation.
In summary, ensure that your antennas are at the maximum possible distance apart, and where possible
facing away from each other. Under no circumstances should you place antennas in close proximity to
each other.
Coax cables should be low loss 50 ohm, and suitable for the 700 megahertz band frequency.
Antenna connections should be clean and moisture free.
Do not spray lubricant into the connectors as this prevents the signal traveling through the coax.
Use a cleaning solvent that has no oil and does not leave any residue. High quality oil-less contact cleaner
is suitable.
All coax connectors must be water tight and wrapped with water proof tape. Any moisture in the
connectors will degrade or eliminate the signals.
3.6 PREPARING YOUR CELLULAR REPEATER
3.6.1 Installing your Repeater
The Telcosat Repeater weighs in excess of 65 pounds (28.5 Kilograms)
Make sure that your repeater is securely bolted to a suitable support. There are four welded steel tabs on
each corner that must be used to bolt your unit onto a suitable support system. You must use ¼” diameter
grade five steel corrosion resistant bolts with lock washers and securing nuts, a total of 4 bolts and
nuts/lock washers are required.