VBOX 3iSL User Guide
Page 19 of 49
01/12/2011
GPS Antenna
The GPS antenna supplied with a VBOX 3iSL is a 3.5V active antenna. For the best possible signal quality, it is important to maintain a clean connection between
the antenna and a VBOX 3iSL. Before fixing the antenna to a VBOX 3iSL, ensure that there are no dust particles in either connector. Replacement antennae are
available by contacting your VBOX distributor.
The antenna is a magnetic mounting type for quick and simple mounting to the vehicle roof. For optimum GPS signal reception, make sure that the antenna is fitted
to the highest point of the vehicle away from any obstructions that may block satellite reception. The GPS antenna works best with a metal ground plane underneath
(a metallic vehicle roof is perfect for this).
Please also note that when using any GPS equipment, a clear sky view is important. Objects in the surrounding
area such as tall buildings or trees can block the GPS signal causing a reduction in the number of satellites being
tracked, or introducing reflected signals that can decrease the accuracy of the system. Note that clouds and other
atmospheric conditions do not affect a VBOX 3iSL
‟s performance.
GPS antennas require a ground plane to operate correctly. This helps to reduce unwanted reflections of the GPS
signal caused by nearby objects, and usually the metal roof of a vehicle performs this function. However, if a test
requires an antenna to be placed either off the vehicle, or on a vehicle that does not have a metallic roof, a special
ground plane antenna must be used. This has an internal ground plane and can operate perfectly without the need
for mounting on a metal surface. Ground plane antennas are available from your VBOX distributor.
NOTE: VBOX3iSL can struggle with maintaining dual lock if the antennas are placed too close to Roof Bars.
If a poor mounting position cannot be avoided then the use of elevated GPS/GLONASS ground plane
antennas, RLVBACS068 may be required.
