User's Manual

P-379 Processor
12
Antenna and Tower Recommendations
Your preliminary engineering workgroup should establish your antenna and tower
requirements, both for receiving and transmitting antennas. Construction of sturdy, high
quality antenna/tower systems will pay off in terms of coverage of your service area, the
overall quality and saleability of your radiated signal, and reduced maintenance
expenses. Technalogix provides complete turnkey antenna systems if needed. If your
site is serving as a translator, your receiving antenna should be line of sight to the
originating station, both winter and summer. The foliage will change with season.
Transmitting antennas can enhance or seriously impair the translator output. It is
assumed that one has been selected prior to system installation, but the best-designed
antenna system will function poorly if shortcuts and compromises are used during
installation. Follow the manufacturer’s instructions exactly, along with any engineering
data prepared for the site.
The selection, routing, and length of coaxial cable are extremely important in the
installation. If there is a 3 dB line loss in the cable between your unit’s output and the
transmitting antenna, a 500 watt unit will only deliver 250 watts to the antenna. Buy the
best cable you can obtain, route it via the shortest way to the antenna, and keep it
straight. Do not form it into sharp bends on its way. Do not use any more cable fittings
for the installation than absolutely necessary. All cautions here apply equally to all
coaxial cables in the system - input and output. The better known tower manufacturers
offer complete technical and safety documentation with their towers. Be sure that you
have this information as it regards wind loading, guying, etc. Be absolutely safe and
certain about this aspect as human lives may be at stake.
Shelter Security
The FCC requires that the translator be secure from entry or control by unauthorized
persons, and that any hazardous voltages or other dangers (including most tower bases)
be protected by locks or fences as necessary to protect personnel and prevent
unauthorized tampering or operation. Security of the building further implies that it be
secure from wildlife. Use sturdy construction materials, including sheet metal if
necessary. Holes around conduit, cable, and other similar entry points should be stuffed
with steel wool and caulked to prevent entry of wildlife. Other features of security for your
shelter may include its location with respect to the prevailing wind conditions. Location
leeward of some natural topographical feature will prevent wind damage and snowdrifts.
Check the soil runoff conditions that may slow or hasten wind or water erosion and other
concerns that may be unique to your location
.