Using with Campbell Scientific Dataloggers
6.4.1 Antenna Supplied by Campbell Scientific
Campbell Scientific can supply various antennas, if required; including a ‘low-
cost’ antenna (see Figure 2, below). This is supplied as part of the standard CS-
GSM/GPRS package.
In areas of high signal strength, the low-cost antenna will be suitable for almost all
applications, either at 900 or 1800 MHz. The antenna, as supplied ‘off the shelf’,
is fitted with a connector which will either directly fit the COM110 modem
transceiver aerial socket or plug into an adaptor that will be supplied. When the
antenna is supplied as part of a weather station or other complete installation,
Campbell Scientific may replace the original connector with a compatible
connector before the system is tested.
In a field installation it is recommended that the cable length between the antenna
and the transceiver is kept as short as possible to reduce the signal loss in the
cable, although, as mentioned above, it is often more advantageous to mount the
antenna higher. In some applications the cable will need to be shortened, and so a
new connector can be installed onto the cable at this time by cutting off the surplus
cable, together with the original connector, and fitting a new connector. Ensure
that all connections are well made, and the connector is secured using a crimping
tool or pliers. The connector which connects to the modem is only suitable for use
in dry environments and so must be protected from direct exposure to water and
precipitation.
Figure 2 ‘Low-cost’ dual-band antenna supplied by Campbell Scientific
The antenna is supplied with a pole mounting adaptor, a `V’ bolt, allowing it to be
fitted to 30-54 mm diameter vertical tubing. If you need to mount antenna onto a
smaller diameter pole, insert some hard packing material between the pole and
bracket. Alternatively, without the adaptor, it can be screwed to a suitable flat
vertical surface. The design of the antenna means that
no ground plane is
required
, thus allowing more flexibility in mounting. Avoid mounting the antenna
close to other vertical metal structures or on flat metal surfaces.
17
