Which GPS setting in Tomtom

[eggplant]

Hi all,

New at this but have been doing a lot of reading on this site!

My equipment:
Dell Axim X5
128mb CF card
Tomtom3

and this reciever I got off ebay, I dont know a lot about it but it uses the sirfII chipset (and seems to work well)


Now, I was working away this week and using my new "toy", but I found that sometimes it took AGES for the red light on the reciever to start blinking (indicating it was picking up signals), whereas other times it was a few seconds. After searching, it seems this is probably normal, but I also found that I need to not use the default "tomtom navigator gps" but an alternative, well I've just been sat in the car for a while trying to figure all this out, it does indeed seem that the tomtom gps gives the lowest signal (4 satelites). The other ones I tried were NMEA 0183v2 4800 and SIRF 4800 (I tried this simply because my instructions with the reciever said to use 4800 in the settings), now these two other options both gave 6 satelites, but different ones on the graph, which one should I be using? one setting lights up the leftmost bars in red, the other lit up different ones.

Many thanks

[Hunnymonster]

That looks like a Globalsat BR-305 - so I'd reckon on using NMEA 4800 on COM1 for best results.

The reason it can take extra time to get the first fix is that the receiver caches ephemeris data from the satellites - and it should have a small memory retaining battery/capacitor - if that discharges and it loses the ephemeris data and the date/time it'll take time to reacquire it - more time if you're on the move and interrupt the download by changing direction and losing sight of the satellite it's downloading from.

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