Steve 90 Posted December 2, 2007 Share Posted December 2, 2007 Just replaced the Garmin 128 in my truck with a garmin plotter running Mapsource. But the GPS seems to be quite a long way out and shows me driving at varying amounts off the road im actually on. Sometimes im on the road, More often im anything up too 30-40feet(at a guess) off it, If I drive along the same piece of road it will leave traces like spagetti along either side of the road. Ive messed with the Map datum and changed it from WGS84 to WGS72 which was slightly better then tried Ordanance survey GB which seemed about the same. Im only guessing the Map datum has anything to do with it so I may be doing the wrong thing as I dont really know what these mean and havn't had chance to read up about it yet. Can anyone give me a few pointers??? Anyone had the same problem and if so how did you solve it??? Many thanks. Steve. Quote Link to comment Share on other sites More sharing options...
Mark90 Posted December 2, 2007 Share Posted December 2, 2007 If I drive along the same piece of road it will leave traces like spagetti along either side of the road. Are you saying that you get tracks either side of the road shown on the map? If it was a datum problem (or a map accuracy problem) you'd expect all tracks to be offset along the same side of the road. When you repeatedly drive the same road do the tracks overlay each other? If not then it looks more like a GPS location accuracy issue. With a good GPS you can tell which side of the road you are on. Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted December 2, 2007 Author Share Posted December 2, 2007 Are you saying that you get tracks either side of the road shown on the map?If it was a datum problem (or a map accuracy problem) you'd expect all tracks to be offset along the same side of the road. When you repeatedly drive the same road do the tracks overlay each other? If not then it looks more like a GPS location accuracy issue. With a good GPS you can tell which side of the road you are on. Good point, They dont overlay each other, Tend to be all over the place but I think mainly to the left of the track im following. As you say a good GPS should be bang on and at the price this should be good!!!!! The PDA i run Memory map on runs exactly on the road all the time and if I repeat a journey it draws the track back over the last. This one's all over the place so as you looks like a GPS accuracy issue! Anyone running a GPSMAP 30063010 had the same problem???? If this is as good as it gets and it can be bettered by a PDA then Garmin can av it back! Quote Link to comment Share on other sites More sharing options...
TOR4x4 Posted December 2, 2007 Share Posted December 2, 2007 If it has one of the white mushroom antenna's i found thet mine was particularly rubbish near trees. The cheap antenna's seem far better. Don't know if you're testing it near trees or not, just a thought. Quote Link to comment Share on other sites More sharing options...
lard Posted December 2, 2007 Share Posted December 2, 2007 If I drive along the same piece of road it will leave traces like spagetti along either side of the road. Many thanks. Steve. i think you need some lager steve to straighten out the spagetti Quote Link to comment Share on other sites More sharing options...
will_warne Posted December 2, 2007 Share Posted December 2, 2007 If it has one of the white mushroom antenna's i found thet mine was particularly rubbish near trees. The cheap antenna's seem far better.Don't know if you're testing it near trees or not, just a thought. I'd also try a differant antenna. Does the 3006 have a built in antenna and, if so, are you using it? I found on my Garmin V that the standard one was hopeless although the smaller of the external ones (it looks like a small, balck computer mouse) works really well and is still pretty accurate even in light tree cover and around steep slopes (I had big problems with this originally). I never liked the idea of the white mushroom ones as they're just asking to be ripped off whereas I never had any problems with the smaller one which was litterally gaffa taped to the roof in a hurry before an event and lasted over a year without coming off. Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted December 2, 2007 Author Share Posted December 2, 2007 If it has one of the white mushroom antenna's i found thet mine was particularly rubbish near trees. The cheap antenna's seem far better.Don't know if you're testing it near trees or not, just a thought. Nowhere near tree's but yes im using the white mushroom antenna. Possibly they ain't great!!!! What did you do with yours Adrian??? What cheap antenna did you use??? The old 128 I have had an antenna that looked the same (white mushroom) but had a coaxial cable to join it to the unit and that seems to work well. The antenna that came with this has a multiple core cable with a signal wire and a positive and negative cable which is not screened so I guess there must be some electronics or booster in the antenna itself. What other antennas are compatable??? Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted December 2, 2007 Author Share Posted December 2, 2007 i think you need some lager steve to straighten out the spagetti Im about to have a few largers, when I have I'll get the Doris to drive me round and see if it looks better!!!!! Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted December 2, 2007 Author Share Posted December 2, 2007 I'd also try a differant antenna. Does the 3006 have a built in antenna and, if so, are you using it? I found on my Garmin V that the standard one was hopeless although the smaller of the external ones (it looks like a small, balck computer mouse) works really well and is still pretty accurate even in light tree cover and around steep slopes (I had big problems with this originally). I never liked the idea of the white mushroom ones as they're just asking to be ripped off whereas I never had any problems with the smaller one which was litterally gaffa taped to the roof in a hurry before an event and lasted over a year without coming off. I have a small black mouse type for my laptop and it seems to work really well, Far better than the Garmin does and for a fraction of the price! Quote Link to comment Share on other sites More sharing options...
will_warne Posted December 2, 2007 Share Posted December 2, 2007 I have a small black mouse type for my laptop and it seems to work really well, Far better than the Garmin does and for a fraction of the price! Garmin do one too. I'd be happy to pop mine in the post for you to test as long as I get it back. I can't remember what mine cost but it wasn't terrible (£50 ish) Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted December 2, 2007 Author Share Posted December 2, 2007 Will, Does it have an end/connector of any sort on the end of the lead and if so what type is it? Quote Link to comment Share on other sites More sharing options...
western Posted December 2, 2007 Share Posted December 2, 2007 I've a Lowe electronics GPS receiver mouse for my Garmin 12XL, IIRC the ends of the lead came with a BNC female connector fitted, similar to the 2nd one down here my other one for the laptop/MM has a USB connector- got that one from ebay. Quote Link to comment Share on other sites More sharing options...
Steve 90 Posted December 2, 2007 Author Share Posted December 2, 2007 Thats the type of connector I have on the 128 but the plotter has a different setup with 5 wires, (signal +, Signal -, Remote, Battery pos and Battery neg if I remember right) so I assume its a completely different antenna. just read on the Garmin web site that The GPS17 (which it is) is supposed to have a 3 meter accuracy! This one would be lucky to manage 30 meters. :angry: Quote Link to comment Share on other sites More sharing options...
88 Special Posted December 3, 2007 Share Posted December 3, 2007 FWIW I am using a Gilsson MCX external antenna on my Garmin GPS60, cost $30, the Garmin antenna was $70. Seems to work well with the USGS maps here in Panama. Don't know if they make one for your unit. The antenna is mounted in the spare tire, it has a magnetic base, I use the simple gps as there is not any map software for my area. Good luck! Quote Link to comment Share on other sites More sharing options...
will_warne Posted December 3, 2007 Share Posted December 3, 2007 Will, Does it have an end/connector of any sort on the end of the lead and if so what type is it? Its a push and twist job. Have a look at Ralph's link - its the 3rd one down (and about half the price I remember it being ) Quote Link to comment Share on other sites More sharing options...
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