My Nüvi 3490 is less accurate than my 1490...how come? Is it fixable?

**palmtree8** · 10th May 2013, 11:15 PM

Hi everyone...

So far I've had a Nüvi 1490 LMT, and recently purchased a brand new 3490 LMT.

The 3490 is supposed to be a more advanced model, but I've noticed that if I go to the satellite page, its accuracy is a lot worse than my 1490...how can that be??

My 1490 consistently shows 7 to 13 metres of accuracy, whereas the 3490 has 20 to 30 metres (sometimes even 50 to 60 metres!) I've done the "Cold Start" and "Predicted EPH" trick, but it didn't seem to help.
Note: I've always done "apple to apple" comparisons.... (i.e.: always when both units show 5 green signal bars on the top left corner, placed literally side by side.)

Another weird thing I've noticed about the 3490 is that even when I am completely stationery/completely not moving, it *sometimes* shows a (small) amount of speed....between 3 to 5 km/h. My 1490 never does that.......if I'm stationery, then it always shows 0 km/h.

Are there any ways I can tweak the 3490 so it will perform better?

P.S: I have the latest firmware for the 3490, which is 7.90.

**angelozip** · 11th May 2013, 12:17 AM

@Palmatree8, if comparing with other models of GPS and under the same conditions your gps shows significant and negatives differences, even if you have already done the basic procedures, cold start, etc. .., must surely be a hardware problem. How is new and shall be under warranty, send it to the technical assistance.

**palmtree8** · 11th May 2013, 12:21 AM

Originally Posted by angelozip

@Palmatree8, if comparing with other models of GPS and under the same conditions your gps shows significant and negatives differences, even if you have already done the basic procedures, cold start, etc. .., must surely be a hardware problem. How is new and shall be under warranty, send it to the technical assistance.

Ok what's the benchmark value then? To those of you who own a REAL 3490, what is the best accuracy you've ever got? I just tested both units again a few minutes ago. My 3490 didn't go any lower than 10 metres, whereas my 1490 had an amazing 3 metres of accuracy.

**catymag** · 11th May 2013, 12:33 AM

I move these last posts in the other Palmatree8's opened thread , here are off topic .
Please Palmatree8 dont double post in threads
Thanks

**angelozip** · 11th May 2013, 01:07 AM

Originally Posted by palmtree8

Ok what's the benchmark value then? To those of you who own a REAL 3490, what is the best accuracy you've ever got? I just tested both units again a few minutes ago. My 3490 didn't go any lower than 10 metres, whereas my 1490 had an amazing 3 metres of accuracy.

The best reference value in ideal conditions is 3 meters, as shown on your 1490. Remember that these are not absolute values, but a order of magnitude. Either way, your 3490 has problems, most likely hardware, as I said. If you want to go deep do tests with tracklogs as I proposed in the topic of precision of converted 3790, but I would send for assistance or trade it for another, if possible.

**palmtree8** · 11th May 2013, 02:30 AM

What constitutes "ideal conditions"? Clear sky with no clouds? What else?

Could you please explain what you meant by "order of magnitude"?

Not sure if I'll be able to trade it....I bought it used (but good condition) from eBay

**angelozip** · 11th May 2013, 04:02 AM

Originally Posted by palmtree8

What constitutes "ideal conditions"? Clear sky with no clouds? What else?
Could you please explain what you meant by "order of magnitude"?
Not sure if I'll be able to trade it....I bought it used (but good condition) from eBay

Ideal conditions would be in the open sky, without obstacles such as buildings, trees, deep valleys, etc. Order of magnitude that is not an absolute value, only an approximate reference. Anyway the best references is another gps as your 1490.
As you have no way to change it I suggest try a master reset it often solves problems of bad tune. Press and hold the bottom right corner of the screen while turning on your gps, until the warning if "you want to remove all user data?" Answer Yes. Then go to a place of open sky and wait for the complete tune of satellites. Compare then with your 1490.

**palmtree8** · 11th May 2013, 04:24 AM

Originally Posted by angelozip

Ideal conditions would be in the open sky, without obstacles such as buildings, trees, deep valleys, etc. Order of magnitude that is not an absolute value, only an approximate reference. Anyway the best references is another gps as your 1490.
As you have no way to change it I suggest try a master reset it often solves problems of bad tune. Press and hold the bottom right corner of the screen while turning on your gps, until the warning if "you want to remove all user data?" Answer Yes. Then go to a place of open sky and wait for the complete tune of satellites. Compare then with your 1490.

Hmmmmm I didn't mention to you that when I was doing the test, it was done on the 20th floor of my condo, right beside a transparent glass window. I saw 5 green (signal strength) bars though. I don't think the glass window even mattered then...? Or...? (because right beside the 3490 was the 1490, which had 3 metres of accuracy despite the window)

**catymag** · 11th May 2013, 11:26 AM

Green bars or satellites page not always are reliable to measure GPS accuracy as said above by Angelo, if you want for real to check Nuvis' accuracy, enable tracklog, put them "off road" or pedestrian mode and drive a route. After that compare tracks using Mapsource and Google Earth.
We learnt we can have some surprises.
You can see some examples in other thread regarding sats accuracy in converted nuvi 37xx.
Clearing non vol after every firmware flashing is important for good nuvi's operation too.
Some tinted windshields can influence sats reception, normal glasses dont.

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