User manual

915U-2 Wireless I/O Page 23
Page 23 User Manual
We recommend that the connection be taped, firstly with a layer of PVC Tape, then with
a vulcanising tape such as “3M 23 tape”, and finally with another layer of PVC UV
Stabilised insulating tape. The first layer of tape allows the joint to be easily inspected
when trouble shooting as the vulcanising seal can be easily removed.
Where antennas are mounted on elevated masts, the masts should be effectively
earthed to avoid lightning surges. For high lightning risk areas, surge suppression
devices between the module and the antenna are recommended. If the antenna is not
already shielded from lightning strike by an adjacent earthed structure, a lightning rod
may be installed above the antenna to provide shielding.
Dipole and Collinear antennas.
A collinear antenna transmits the same amount of radio power in all directions - and
they are easy to install and use because they do not need to be aligned to the
destination. The dipole antenna with integral 15 „cable does not require any additional
coaxial cable; however a cable must be used with the collinear antennas.
Collinear and dipole antennas should be mounted vertically, preferably 1 wavelength
away from a wall or mast to obtain maximum range.
Figure 7 – Collinear Antenna mounting