Campbell Scientific RF300-Series DRL VHF/UHF Radio Transceivers - Manual (Page 25)

SECTION 3. RADIOTELEMETRY NETWORK COMPONENTS
3-7
3.2.3 RADIO INSTALLATION
The RF300 Radios are shipped from Campbell
Scientific mounted on a special bracket with a
cable going from the radio to a BNC connector
(see Figure 3-3). The following steps will install
a radio for a field or repeater station.
1. Secure the radio and its bracket using the
four screws from the RF95A Modem's lid.
2. Connect the 10-pin connector (with the red
and black power leads coming out of it) of
the radio/RF modem cable into the radio.
3. Connect the second 10-pin connector of the
cable into the RF modem.
4. Connect the red and black power leads
from the radio cable to the 12V and Ground.
5. Route the BNC end of the antenna cable
through the enclosure conduit. Connect the
cable to the BNC Jack connector secured
on the radio mounting bracket.
3.3 ANTENNAS AND CABLES
Antennas radiate and receive the radio signals.
Each radio in an RF telemetry system must
have an antenna. Coax cable is used to
connect the antenna to the radio.
3.3.1 ANTENNA MOUNTS
Antennas must be mounted above any
surrounding buildings or obstacles. Antennas
must be properly oriented in relationship to the
other antennas for RF communications to work.
Antennas have various mounting options.
Table 3-7 lists mounting specifications for
several common Celwave antennas. Specific
questions regarding antennas can be directed
to Campbell Scientific, Inc. or Celwave.
Celwave's address and phone numbers are:
Celwave
Route 79
Marlboro, NJ 07746
(908) 462-1880 or (800) 321-4700
FAX (908) 462-6919
3.3.2 ANTENNA ORIENTATION
Antennas must be oriented correctly to allow
communication between RF sites. First
determine if your antenna is omnidirectional or
unidirectional.
An omnidirectional antenna will transmit/
receive in a full 360 degree circle. Generally, an
omnidirectional antenna will be a straight
cylindrical rod which is to be mounted vertically
at the top of a tripod.
A unidirectional antenna is designed to
transmit/receive in a particular direction, or in a
specified sector. There are various shapes of
unidirectional antennas. The most common is
the Yagi antenna (see Figure 1-2). The
elements of a Yagi antenna can be mounted
either vertically or horizontally, corresponding to
either vertical or horizontal polarization.
FIGURE 3-4. The PD237 Crossover Plate
Antenna Mount
Normally, all antennas will be mounted with
vertical polarization. Whichever polarization is
used, be sure to keep antennas at all sites
identically polarized.
3.3.3 ANTENNA CABLES AND CONNECTORS
The most common cable type to connect a
radio to the antenna is a coaxial RG-8A/U
cable. Two connectors are required for each
length of cable. The connector for the radio is a
BNC type connector. The connector for the
antenna is usually either a Type-NM or Type-
NF. The BNC, Type-NM, and Type-NF
connectors are shown in Figure 3-6. The Type-
NM (male) connector is for antennas with a
female receptacle, and Type-NF (female) for
antennas with male receptacles.
A Campbell Scientific antenna cable complete
with connectors is specified as either COAX
NM-L or COAX NF-L. COAX NF-L is a coaxial
RG-8A/U cable with a BNC connector on one
end and a Type-NF connector on the other.