Elpro Technologies 450U-E Wireless Ethernet Modem & Device Server User Manual
12
www.cooperbussmann.com/wirelessresources
Rev Version 1.0.12-Beta7
Antennas
Antennas can be either connected directly to the module connectors or connected via 50 ohm coaxial cable (e.g. RG58
Cellfoil or RG213) terminated with a male SMA coaxial connector. The higher the antenna is mounted, the greater the
transmission range will be, however as the length of coaxial cable increases so do cable losses.
The net gain of an antenna/cable configuration is the gain of the antenna (in dBi) less the loss in the coaxial cable (in dB).
The 450U-E maximum net gain will depend on the licensing regulation for the country of operation and the operating
frequency
Typical antennas gains and losses are:
Antenna
Gain (dBi)
Dipole
2 dBi
Collinear
5 or 8 dBi
Directional (Yagi)
6 15 dBi
Cable Type
Loss (dB per 30 m / 100 ft)
RG58 Cellfoil Cable kits (3m,10m, 20m)
-1dB, -2.5dB, -4.8 dB
RG213 - per 10m (33ft)
-1.8 dB
LDF4-50 per 10m (33ft)
-0.5 dB
The net gain of the antenna/cable configuration is determined by adding the antenna gain and the cable loss.
For example, an 8dBi antenna with 10 meters of Cellfoil (-2.5dB) has a net gain of 5.5dB (8dB 2.5dB).
Installation tips
Connections between the antenna and coaxial cable should be carefully taped
to prevent ingress of moisture. Moisture ingress in the coaxial cable is a
common cause for problems with radio systems, as it greatly increases the
radio losses. We recommend that the connection be taped, firstly with a layer of
another layer of PVC UV Stabilized insulating tape. The first layer of tape allows
the joint to be easily inspected when trouble shooting as the vulcanizing 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,
approved ELPRO surge suppression devices
-SMA-
-N-
en the module and the antenna. If using
non ELPRO surge suppression devices then the devices must have a 'TURN
ON' voltage of less than 90V. 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.
Figure 9 - Vulcanizing Tape