BT-77 signal fluctuates in TTN5.21

voice_of_reason · Regular Visitor Joined: Aug 24, 2004 Posts: 102

Hi all,

I've been using an original TomTom Wireless GPS (silver, MK1) for ages now with TTN5.21 with no problems at all. Good strong signal in the car, always stays rock solid.

I've just bought a new BT-77 (Version 2) GPS unit to give myself a longer battery life. I've paired it with my iPAQ 2210 and am using it on COM8 with no problems (after selecting 'Other Bluetooth Device' option from the TomTom GPS configuration page).

However - my signal now fluctuates constantly, I get anywhere between 0 and 8 satellites, and when the signal does (briefly) even out it sits on around 5 or 6 satellites - much lower than I got on my old TomTom GPS unit. It seems so much more sensitive now. Even passing under a bridge for a fraction of a second makes me completely lose signal (although it comes back again quite quickly), whereas the the old TomTOm unit wouldn't fluctuate at all in the same circumstances.

Same car, same software - so is it the BT-77 that's no good? (not according to what others on the forum have said). Or is it just the driver software for 'Other Bluetooth Device' in TomTom that's not much good?

Anyone else having unstable signals with a BT-77 on TT5.21? Any tips please?

Thanks for your help.

lbendlin · Posted: Thu Jul 06, 2006 4:20 pm Post subject:

we've been warning people since the BT-77 came out. You buy cheap = you buy twice...
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voice_of_reason · Regular Visitor Joined: Aug 24, 2004 Posts: 102

I'll assume that's a GPS unit issue rather than TomTom driver software then.....

iancjc · Posted: Thu Jul 06, 2006 10:12 pm Post subject:

its probably down to the position you have it in the car - I've had a bt-77 for 18 months use it everyday - ;eave it permanenetly powered in the boot with an external antenna on the roof - get 8 - 11 sats normally.

Best 35 quid I've ever spent! BUT I wouldn't have replaced a SSII with one!
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voice_of_reason · Regular Visitor Joined: Aug 24, 2004 Posts: 102

Well, it hasn't caused me any navigation problems as such. When the signal dips, it never really causes me to lose position in TomTom, it just seems a lot more sensitive to surroundings, such as going under bridges or going through wooded areas.

The original TomTom GPS I had served me well, but the battery life is so pitiful it's just not usable any more, and it's such a pain to hard wire into the car to permanently power it (and I'm already using the cigarette lighter to power the PDA). I suppose I could have come up with some kind of wiring configuration to power both the PDA and GPS, but all those cables would have defeated the object of it all being wireless! ;-)

I'm not sure that is related to the position of the BT-77 in the car, because leaving it outside doesn't seem to get me any more than about 6-7 sats either. I'm guessing it's not the unit itself that's at fault, so that's why I wondered whether it was dodgy driver software for the 'Other Bluetooth Device' in TomTom? Seems as though there are plenty of happy customers on th forum though, so perhaps it's just me.....

dougproctor · Posted: Mon Jul 10, 2006 8:53 am Post subject:

I've got a BT-77 and have no problems with it whatsoever. Does exactly what it says on the box. Again, the best £40 I ever spent!
Doug

voice_of_reason · Regular Visitor Joined: Aug 24, 2004 Posts: 102

Thanks for the reply. Like I say, I have no problems really with navigation or losing my position. I just noticed the signal seemed to fluctuate quite a bit and seemed quite sensitive to surroundings (trees, buildings, etc.) Although weirdly enough it still works in my glovebox.

Just wondered how many sats people were getting with TT5.21, and whether the signal was stable or not.

Cheers.

lbendlin · Posted: Mon Jul 10, 2006 2:06 pm Post subject:

As was said before the number of sats is not a function of the program.

There have been cases where a program has screwed up (like earlier versions of TTN5 that got impatient with th receiver and sent it into a cols start loop) but in the vast majority the programs purely take what they get from the receiver.

So the number of sats is a function of the current constellation, the working status of inidividual satellites, your current location, weather conditions, and the receiver. But NOT of the program.
_________________
Lutz

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voice_of_reason · Regular Visitor Joined: Aug 24, 2004 Posts: 102

Thanks for that. Yes, I appreciate the number of satellites is down to the receiver. But I thought it was just feasible that if the GPS driver had any issues with it, it was possible that the TomTom software would report an inconsistent fix, depsite the fact that the GPS unit was receiving a perfectly good signal, i.e. I was wondering if it could be related to the way in which TomTom was interpreting the data sent from the GPS unit.

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