Installation OEM6 Family Cards
Chapter 2
OEM6 Family Installation and Operation User Manual Rev 12
29
2.3
Selecting a GNSS Antenna
An active antenna with an LNA is required to boost the power of the incoming signal to compensate for the
line loss between the antenna and the receiver.
NovAtel offers a variety of antennas, including single and dual-frequency, triple-band and wide-band
reference GNSS antennas (refer to our web site:
for details of available
antennas). All antennas include band pass filtering and an LNA. The GNSS antenna chosen depends on the
particular application. Each model offers exceptional phase center stability and a significant measure of
immunity against multipath interference. Each antenna has an environmentally sealed radome and all meet
the European Union’s Restriction of Hazardous Substances (RoHS) and Waste Electrical and Electronic
Equipment (WEEE).
2.3.1
Choosing a Coaxial Cable
An appropriate coaxial cable matches the impedances of the antenna and receiver (50 ohms) and has a line
loss not exceeding 10.0 dB
.
If the limit is exceeded, excessive signal degradation may occur and the receiver
may not meet performance specifications. NovAtel offers several coaxial cables to meet GNSS antenna
interconnection requirements, including:
•
5, 15 and 30 m antenna cable with TNC connectors on both ends (NovAtel part numbers GPS-C006,
GPS-C016 and GPS-C032)
2.3.2
Mounting the GNSS Antenna
After the OEM6 family card is installed in an enclosure, the antenna can be mounted and connected. The
GNSS receiver is designed to operate with any of the NovAtel single, dual and triple-frequency GNSS
antenna models. See
Section 2.3, Selecting a GNSS Antenna
for more information.
When installing the antenna:
•
Choose an antenna location with a clear view of the sky so each satellite above the horizon can be
tracked without obstruction. For more information on RF signal propagation and multipath, refer to
the NovAtel application note
APN-008 Discussions on RF Signal Propagation and Multipath
at
•
Mount the antenna on a secure, stable structure capable of safe operation in the specific
environment.
To select a coaxial cable for the application, consult the NovAtel application note
Equipment Selection and Installation
available at
. Also refer to this
application note if the application requires the use of cable longer than 30 m.
A conversion is required between the OEM617D, OEM628 and OEM638’s MMCX connector or
the OEM615’s and OEM617 MCX connector and the female TNC connector on NovAtel’s
GNSS antennas.
NovAtel recommends using high quality coaxial cables because an impedance mismatch is
possible when using lower quality cables and this produces reflections in the cable that
increases signal loss. Although other high quality antenna cables can be used, the performance
specifications of the OEM6 family receivers are warranted only when used with NovAtel
supplied accessories.
