Getting Started
15
Copyright 2010 by AirNav Systems
permanently on.
White LED (Signal):
The white LED flashes whenever a Mode-S signal is received from an aircraft and decoded with
success. The more this LED flashes the more information is being received by your antenna from
aircraft. In highly congested airspace areas this LED will flash very quickly and it is not unusual in a
busy traffic environment to receive more than 50 Mode-s messages per second. The white LED
Signal cannot be on if the Blue USB is not indicating correctly as above.
Normal Operation:
Under normal operating conditions (hardware connected to your computer, drivers correctly installed
and the Radarbox software running) the green power light will always be on, the blue light will flash
very rapidly when data is being transferred from the receiver to your computer and the white light will
flicker when data is being received from aircraft.
2.3 Antenna Positioning
Antenna Positioning
RadarBox comes with a small magnetic base antenna and this antenna has been selected for its
excellent performance when used with the hardware receiver and AirNav software. Correct positioning
of the antenna is essential in order to gain maximum performance as ADS-B signals are transmitted in
the 1090 MHz Ultra High Frequency band, which is eight times higher than VHF aircraft voice
communications. At this frequency, signals travel by "line of sight" and are affected by any
obstructions such as buildings, trees and hills. This means that if anything comes between you and
the aircraft, then that aircraft will probably not be displayed by RadarBox. In order to achieve
maximum performance and to ensure good range and coverage, the following points should be noted:
· The supplied RadarBox antenna is not intended to be mounted permanently outdoors.
· The antenna should ideally be positioned with a clear view of the sky and clear of obstructions.
· The higher the antenna, the better the performance.
· Performance is enhanced by a "ground-plane" which is simply a metal disk the size of a CD or
larger. Attach the magnetic antenna to the center of the disk
· The longer the feed cable, the poorer the performance.
Whilst RadarBox can work perfectly acceptably with the antenna sitting on a window
ledge, you should always try to find the highest and clearest position. A skylight window
is an ideal location for the antenna. If you have RadarBox installed on a laptop computer,
then you will be able to move the laptop, RadarBox and antenna to find the position that
gives the best performance. An external antenna connected by a long feeder cable can
improve performance, however, the advantage of the high antenna can be completely
overcome by losses in the cable. If you wish to use a long feeder cable, you must use high
quality, low-loss cable. Note that such cable tends to be thick, inflexible and expensive.
A signal pre-amplifier may improve RadarBox performance, however, the amplifier must be capable of
working at 1090 MHz. The performance of a poorly sighted antenna will not be improved by a
pre-amplifier. It is recommended that you experiment with the standard RadarBox antenna before
considering an external antenna and/or a pre amplifier. Moving the antenna only a small distance can
make a significant difference in performance. Remember that height is everything, but not at the
expense of a long 'lossy' feeder cable.
Use the Maximum Range Polar Diagram to see how well you have positioned your antenna. Clear the
polar diagram before starting this test - File | Preferences | General | Clear/Reset Polar Diagram.
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