RC Systems ViewSmart 1600+, Руководство по эксплуатации

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UM-1097
Revision B 126
mounted fiberglass omnidirectional antenna at the base station. Always minimize obstructions between
the gas detector and the base station antenna.
Water-proofing Antenna Connections
Waterproof all outdoor coax connectors using a three-layer sealing process of initial layer of adhesive PVC
tape, followed by a second layer of self-vulcanizing weatherproofing tape, with a final layer of adhesive
PVC tape.
Figure 64 Water-proofing Antenna Connections
Dipole and Collinear Antennas
These antennas are connected to the Radio via a length of coax cable. If the cable is larger than 6mm
diameter (1/4 inch), be aware of sideways tension on the connection. Thick cables have large bending
radii and sideways force on the connector can cause a poor connection.
The polarity of these antennas is the same as the main axis, and they are normally installed vertically.
They can be mounted horizontally (horizontal polarity), however the antenna at the other end of the
wireless link would need to be mounted perfectly parallel for optimum performance. This is very difficult
to achieve over distance. If the antenna is mounted vertically, it is only necessary to mount the other
antennas vertically for optimum “coupling” – this is easy to achieve.
Dipole and collinear antennas provide best performance when installed with at least 1 to 2 wavelengths
clearance of walls or steelwork. The wavelength is based on the frequency:
Wavelength in meters = 300 / frequency in MHz
Wavelength in feet = 1000 / frequency in MHz
Therefore, 900 MHZ antennas require at least 2/3 meter (2 feet) and 2.4GHz 15 cm (6 inches). Antennas
may be mounted with less clearance but radiation will be reduced. If the radio path is short this won’t
matter. It is important the antenna mounting bracket to well connected to “earth” or “ground” for good
lightning surge protection.