GPS Receivers for the TREO 650

I recently borrowed a bluetooth GPS receiver and played with Tom Tom version 6 software. After realising I liked what I saw (and that I wanted a more sensitive GPS receiver) I decided to do some googling. It was surprising how little information there was on GPS systems on the PalmOs... Hopefully the information here will help people in similar trouble.

The GPS I borrowed was a BTGP-38 that was bought very cheaply on ebay. This immediately worked once I chose a nice open spot to test it. I was thinking about buying one of these for myself but didn't like that the fact that the unit didn't have auto-off and I thought I'd try for a more sensitive unit with a better chipset.

I was really keen on the QSTARZ Q818 but had seen posts about problems with palms (vague, no details). The manufacturer didn't know which is a pity as it sounds much better than the BT338 (auto power off AND on for starters).

I bought a GlobalSat BT338 for twice the price of the BTGP-38 and got it working reasonably quickly (but not immediately). It is a more sensitive unit but shorter running time and heavier. It works in many places where the other didn't as it can handle much weaker signals.

Since buying my GPS I have since successfully tried the "Holux GPSlim GR236".

My main tips:

• Pair the bluetooth device first (phones bluetooth configuration). Most (all?) devices use a key of "0000" (four zeros).


• A Palm program will ask you which device you'd like when establishing the connection. If you have not been asked it must either be being remembered (check app config) or something is going wrong (some apps can take a while to prompt for GPS device). Tom Tom 6 in particular is a major "pain in the but-t" (I've taken 30 minutes to get it going at times the first time and I have done it many times...) and for bluetooth devices has no supported way of entering baud rate or choosing the trusted device, stupid, but it will eventually ask (and I think its better not to have the TREO attached to USB cable/cradle)...


• If using a Windows laptop or PDA you will need to create an outgoing COM port to that specific GPS device so when an application wants to communicate with the receiver it will know which trusted device it needs to talk to when esablishing the serial connection.



• If you haven't been asked for (or configured) the baud rate and you are having trouble, then its possible that your application doesn't autodetect it (or is failing to do so). TomTom 6 is buggy in that it has no way of specifying baud rates for the device, what I think worked for me with the BT338 was changing config to a hard wired device, this prompts for baud rate, after entering this correct device to say is a bluetooth device and "Bobs your uncle"... Check GPS doco for correct baud rate (38,400 for the BT338).



• Once a bluetooth session is established (see GPS receiver documentation for what the LEDs mean) I recommend moving to the clearest outdoors location you can find and trying to get the app to work. The GPS receiver will probably not work well indoors, around tall buildings or trees. If that works try walking and/or the car.



• Initial connections can take a very long time. I have seen mention of 5 and 10 minutes. Leave it alone for a while, try to find a test progress or screen which shows satelite information (position/signal strength etc).