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Tips and questions relating to the GPS modules from SFE
#68510
Im not getting very good results with this GPS at the moment i have been logging myself in the car and when i look at the logs sometimes it will log a way point 100 yards off the road that im on.

So when im going down a interstate a nice stright path the gps will not show a nice stright line instead it shows me leaving the interstate at random times so i end up with a zig zag line showing where i went.

I have it set to log every sec.

Is this casued by lack of signal?

I have tired WAAS and it did not make a differance so i assume its not getting a good signal. How many satellites should it be locked on to inorder to get better logging? Usally i get 6 or 8.

Is this the antenna that fits this gps?

http://www.sparkfun.com/commerce/produc ... cts_id=464
By busonerd
#68532
Its a signal issue; its not necessarily how many sats it sees; rather the signal quality of those that its triangulating from.
By z0rr0
#68545
I also get poor signal, but in wooded areas, which is why I bought it. I don't need to map streets :wink:

This is the GPS module that's in the GeoChron:

http://www.sparkfun.com/commerce/produc ... ts_id=8234

It has a MMCX connector. So, the antenna you showed won't go directly to the GeoChron. However, it appears that this product would be ideal for that application:

http://www.sparkfun.com/commerce/produc ... cts_id=285

It uses a bulkhead SMA connector, so you would want to drill a hole in the side of the GeoChron case to install the SMA connector for a professional-looking installation.

Having said all that, I don't know that the antenna you posted will significantly improve signal. It probably will in an automotive application, since it will be above all the shielding of the car, but I doubt it will help me in wooded areas. Does anyone else have input on this? Is there a definitively better external antenna solution here?

TIA
#135070
I've done just as you are hoping to do. I've attached an external antenna to the GeoChron Blue with minimal modifications. I can't vouch for accuracy, as I've yet to get everything working properly, but the antenna fits fine and has good strength in it's magnetic base (to stick to the outside of your car).

This post has photos: viewtopic.php?f=17&t=19914