ROJONE Pty. Ltd – 61 Aero Rd, INGLEBURN NSW 2565 AUSTRALIA
TEL +61 02 9829 1555 FAX 02 9605 8812 EMAIL [email protected]
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6.4
Cellular Telephone ANTENNA
The GSM Telephone Antenna Connector is an SMA Female.
The GSM phone is a Dual Band 850 / 1900 MHz system.
The Cellular antenna provided with the EziTraK™ kit is designed to be mounted on an internal glass
window, plastic window or on the inside of a fibreglass panel.
This Cellular antenna must NOT be mounted to a metal surface as this will severely detune the antenna
and provide poor performance. An alternative antenna such as a half wave or quarter wave vertical may be
used but it must have an Impedance of 50 Ohms and operate at the frequency of your Service Provider,
either
850 MHz, 1900 MHz or both.
If an external antenna is used then it should b e protected from the weather and maintained regularly. If a
coaxial extension cable is used then the cable loss should be minimised so as not to reduce GSM
performance. All antenna installations should be checked and tested regularly and connectors should be
coated in silicon grease or some other sealant.
6.5
GPS ANTENNA
The GPS Antenna Connector is an MCX Female.
DC Output on centre contact is +3VDC. Shield is Ground. Maximum current source is 40 mA.
WARNING: Do NOT short the centre contact to ground or you may damage the Receiver.
The GPS Antenna should be mounted ideally
1.
Out in the open
2.
and On a Ground Plane
3.
and Above other structures
It is not always easy to comply with all of these requirements.
If the GPS antenna needs to be mounted under a surface of some kind then this will possibly degrade the GPS
performance. To help combat this problem it is important to place the antenna on a ground plane when
mounted under a surface. The magnetic mount allows the antenna to attach easily to any ferrous metal ground
plane which should be properly sealed from the environment. Non ferrous ground planes are also suitable for
use. Gluing or attaching a magnet below some non ferrous metal ground planes will allow magnetic mounting.
Be sure to first put the two magnets together, antenna magnet and mounting magnet, and find out which poles
need to face each other.
Ground planes are best when square or circular with the antenna mounted in the centre. A minimum 2 to 4
inches (50 to 100 mm) diameter is recommended. Anything larger than this then the shape is generally of no
concern. Try not to use a corrugated surface on the ground plane as they cause multi-path reflection which
interferes with GPS. Flat grounds are best and cause less reflection. If you have to mount on a corrugated
surface then mount the antenna on a flat metal ground ABOVE the corrugated surface as high as possible. The
two grounds can be electrically connected using a mounting pole if required.
Never mount the antenna under a metal surface. Plastic, wood or fibreglass surfaces are OK but ensure they are
as thin as possible. The thicker the surface the weaker the GPS signal will be. Also try to mount the antenna
about 1 inch (25mm) below the surface. Do NOT mount the antenna hard up against any
surface.