One reason for poor reception may be your window film. The heat reflecting films often contain metal particles that block part or maybe most of the signal. Fortunately that is easy to test. If you are in a weak signal area, take the GPS outside your vehicle to see if it improves. There are external antennas available for some GPS units to solve that problem.

There are BIG differences between units. I have had five Garmin units and still have four different units. The oldest will lose the signal in a heavy tree canopy and performs VERY poorly in Bangkok. The newer units have a much more sensitive antenna but there are differences in these also. The old units will not get any signal sitting near a window. The two Nuvi models take a while but do get a signal and the handheld GPSmap 60 Cx will hold the signal anywhere in my house. Both Nuvis lose the signal away from the window.

I have no experience except for Garmin dedicated units. I do have a GPS enabled phone. It is amazingly accurate using AGPS when there are enough GSM towers for the unit to triangulate your position. Without using the Internet "A" portion, the reception is poor. It won't get a signal near my window. When in an area especially near my home in Loei, the AGPS is wildly inaccurate. Out in the open using the GPS without the Internet it is accurate. I have also tested a friend's Nokia and it is no better than my LG phone.

Well.....I also had 2 Garmins and had many problems receiving any satellite signals. Even after installing an external antenna....still the same problem !!!

One of my friends recently let me try his GPS with TOM TOM installed and this works perfectly and I do not need the external antenna.

If you have an iPhone or iPod Touch, you can install TomTom for Thailand from Apps. For the iPod you will need to buy a carkit for use as a gps receiver though.

If you do not have an iPhone or an iPod Touch,just check for another gps receiver that can install TomTom.

Good luck !

I have been using Garmin units (2 different nuvi models) for 2+ years in Thailand, and have never had a problem in getting a satellite fix.

Tom Tom installed? What is that? What kind of GPS unit has Tom Tom installed? As far as I know, the GPS unit acquires the satellite signal regardless of what map you are using. All my Garmins (4) easily get a signal. even the oldest one.

Tjip is talking about a Tom Tom application for smartphones. Most smartphones will use A-GPS to get an initial position fix and in weak signal areas such as under the BTS Skytrain. I also have a couple of Garmin nuvi GPS units that never loose satellite signal while out in the open.

ive been using IGO 08 for a few years now all over thailand , never lets me down .

put on any pna pda unlocked to windows etc

i use the fujitsu loox on my moped lol