Sharing a GPS antenna

mhayhurst · Occasional Visitor Joined: Feb 25, 2005 Posts: 4

I have SmartNav Trafficmaster in one of our cars but want also to be able to run my TomTom-equipped iPAQ (which I much prefer) as well. I want to be able to use my BT GPS unit. Can I splice into the existing GPS antenna cable (or best of all buy a small adapter/splitter) so it will feed both the SmartNav and the BT units? Will this work?

Mark

DavidW · Posted: Fri Feb 25, 2005 9:48 pm Post subject:

It's very unlikely to work. There's two possible problems.

Firstly, many of these antennas are active - they need a voltage from the GPS receiver to power them. Two power sources on the same cable will cause problems - though this can be overcome.

However, there's a significant chance of the local oscillators of each GPS receiver causing interference to the other receiver if wired to the same antenna. The best thing to do is install two separate antennas, or try the Bluetooth GPS with its internal antenna. You may well find that the Bluetooth GPS is fine without an external antenna.

David

mhayhurst · Occasional Visitor Joined: Feb 25, 2005 Posts: 4

Thanks.

Trouble is I want the BT unit to be stuffed away somewhere under the dash which is why I wanted to run it and the smartnav (which is also under the dash) from one antenna Sad

Mark

Pc-Mobile · Posted: Sat Feb 26, 2005 6:05 am Post subject:

SmartNav Trafficmaster is unlikely to have additional NMEA output which would be the simplest solution to connect to your PDA.

Otherwise, the best solution is to use an external antenna for your BT GPS. The antenna can be near the bottom corner of front/rear screen. It can also be placed under plastic shelf just under fron/rear screen if you want it hidden - where your BT GPS could be placed in the first place unless your screens are coated.
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