MPC User Manual Rev 0D 18
Chapter 3 MPC Setup Considerations
3.1 Choose the Right Antenna
The recommended antenna is from the GPS-600 antenna series, which are ideal for all applications. A
Model 600 GPSAntenna provides comparable performance to a choke ring ground plane antenna
while being much lighter and smaller.
When installing the antenna system,
• choose an antenna location that has a clear view of the sky so that each satellite above the
horizon can be tracked without obstruction.
• mount the antenna on a secure, stable structure capable of safe operation in the specific
environment.
The purpose of the GPS antenna is to convert the electromagnetic waves transmitted by the GPS
satellites into RF signals. An active GPS antenna is required for the MPC to function properly; there is
a provision to enable or disable the DC power to the active GPS antenna in case you wish to use an
antenna that has an alternate power source. Please refer to the ANTENNAPOWER command in
Volume 2 of the OEM4 Users’ Guide for details on the command to do this. See List Current
Configuration on Page 63 for information on how to issue commands via the Modulated Precision
Clock website.
An active antenna is required because its low-noise amplifier (LNA) boosts the power of the incoming
signal to compensate for the line loss between the antenna and the Euro4 GPSCard. If the limit of 14
dB of allowable cable loss is exceeded, excessive signal degradation will occur and the GPSCard may
not be able to meet its performance specifications.
NovAtel offers a variety of single and dual-frequency GPSAntenna models. All include band-pass
filtering and an LNA. The GPSAntenna you choose (models 501, 511, 521 and 531 are L1-only;
models 600, 502, 503 and 512 are dual-frequency GPSAntennas) will depend on your particular
application. Each of these models offer exceptional phase-center stability as well as a significant
measure of immunity against multipath interference. Each one has an environmentally-sealed radome.
NovAtel also offers high-quality coaxial cable in standard 5 (Model C005), 15 (Model C015) and 30
m (Model C030) lengths. These come with a TNC male connector at each end. Should your
application require the use of cable longer than 30 m you will find the application note Extended
Length Antenna Cable Runs at our website, http://www.novatel.com
, or you may obtain it from
NovAtel Customer Service directly; see the Customer Service Section at the beginning of this manual.
High-quality coaxial cables should be used because a mismatch in impedance, possible with lower
quality cable, produces reflections in the cable that increase signal loss.
While there may be other coaxial cables and antennas on the market which may also serve the
purpose, please note that the performance specifications of the MPC are warranted only when it is
used with NovAtel-supplied accessories
The Euro4 GPSCard is factory-configured for operation with any of the dual-frequency factory
configured GPSAntenna models, in which case no special wiring is required. The internal antenna
power source of the Euro4 can produce +4.25 to +5.25 V DC at up to 90 mA.
