Tall buildings or trees can block GPS signals, causing a reduction in the number and quality of satellites being tracked, leading to inaccurate position measurements and a noisy velocity signal.
Obtaining the best GPS Quality
Placement of the GPS antenna is crucial to the quality of the data recorded by the VBOX Sport. Any metal close to a GPS antenna can disturb the signal in an unpredictable way due to interference from reflections of weak GPS signals.
For the best results, use an external GPS antenna in the centre of a metal roof away from any roof bars or radio antennas. Do not mount the antenna close to the edge of the roof as reflections from the ground may interfere with the signals. If mounting inside the vehicle and using the internal antenna, place the VBOX Sport on the dashboard as far forward as possible in the centre of the windscreen. Avoid the edges as reflections from the A-pillars will cause problems.
Mount the antenna or VBOX Sport as high up as possible and keep above any roll bars. Pieces of metal close to and above an antenna will badly disrupt the GPS signal.
If you are using an external antenna and your vehicle does not have a metal roof, then place the GPS antenna on a flat piece of metal at least 10cm in diameter. If this is not possible, you can use copper or aluminium foil to create a shaped ground plane underneath the antenna. For example, on a fibreglass roof, mount the antenna on top of the roof, and place some adhesive backed metal foil underneath, on the inside of the roof.
Various mounting options are available on our website for the VBOX Sport:
Coldstarting the GPS
If the unit is struggling to acquire satellite lock, a GPS cold-start may be required, this is normally true when the unit hasn’t been used for a long time. To perform a cold-start, press and hold the logging button for 5 seconds.
With a clear view to the sky, the GPS LED should stop flashing in 60s or less.