Technalogix TAUD-100, Руководство по эксплуатации

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Technalogix Ltd TAUD-1000 Transmitter
VIII-4
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
in line of sight to the originating station all year round. The foliage will change with season.
Transmitting antennas can enhance or seriously impair the transmitter/translator output.
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, your unit will
only deliver half power 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.
Pay attention to radial ice accumulation when designing the transmission system. It is not
uncommon for at least an inch of ice to build up on the tower and antenna. This in turn significantly
increases the weight, cross section, and wind loading of the system.
Attaching the transmission line to the tower is crucial to maintain a safe and reliable operation.
Nylon wire ties and electrical tape will breakdown in the sunlight and ultimately fail, creating a
potentially dangerous situation. It is important to use proper clamps and hoisting grips and also
ensure that the transmission line is grounded to the tower in several locations. When high currents
flow through the tower in the event of lightening strikes, some of that current will through the outer
conductors of the transmission lines. Due to the resistance difference between the steel tower and
copper transmission line, a significant voltage can be developed, often resulting in arcing between
the outer jacket and outer conductor, thus pitting the conductor.
Preventative maintenance is crucial in ensuring that safety is maintained. Specifically, check that
transmission line grounds are tight and are not missing any hardware. Frequently inspect support
clamps or spring hangers. Consider investing in an ice break, if you haven’t already done so, as
shards of falling ice can damage the transmission line – and if it is going to happen, it will happen at
an important time. Check the tower light photocells and conduit.
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. 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. Be absolutely safe and certain about this aspect as human lives may be at
stake.