Modifying a GPS Antenna

Better you contact manufacturer. They WILL give you correct guidance.

I don't suppose your system has a Bluetooth connection? I've been using the Freedom keychain GPS receiver in my car where it sits dangling on the ignition keys and works fine through the car body. I got it about 20% cheaper than shown in the link but it has no external connection apart from the USB charger. Battery life is about 10 hours.

My personal take on the problem as someone who has had both installed GPS in cars and now have a portable (Tom Tom 700) is that your GPS is either defective or badly designed.....sorry to be so negative.

Why do I say that?

1) a good unit has a socket for an external antenna already built into it for difficult situations. Always check this before buying, also check the price of the external antenna that is designed for the unit, it should be cheap, some are very overpriced for no reason. (check also that the maps are new and what a map upgrade costs!)

2) Some cars have a windscreen coating that reduces the Sat signal too much and the antenna needs to be outside. Check on the web for your car and other GPS systems, somebody will complain on the web sure as eggs are eggs...

3) A good system will work even though some layers of metal and or glass. My Tom Tom 700 works even when laid on the floor, face down, under my seat!!!! I found this out accidentally one day when I did not switch it off before placing under my seat where it travels when not in use!!

A disembodied voice came from under me, Trying to guide me back where I had just been to!! Quite a shock in the first instance! My car does have a glass sunroof, but is otherwise steel bodied, the signals were also going through me and through the seat!!!!!

That is a good and sensitive GPS unit......a lot of the cheap ones (and some of the expensive ones too) have relatively bad reception, you need to read up on test scores in magazines, I have never seen a bad report for any Tom Tom up to now......

It is not going to be a simple thing to come up with an exteral GPS antenna unless there is provision for one from the OEM. You a dealing with a fairly weak signal and unless the antenna is designed for that and matched to the input of the receiver you just aren't going to make much of an improvement.

Now if you want to do something simple but silly just get a length of wire, probably 20ga or thereabouts, wind some turns around the OEM GPS antenna and then run the rest up to the bimini frame and run the wire along that. That might improve your reception. If it does you have a chance of coming up with a simple external antenna. If not then you probably have to either get the OEM external antenna or a whole new unit with better reception.

Thanks for the responses. The more I read from you comments the more I believe there is a technical fault with the GPS as it would be reasonable to expect a signal to penitrate through a piece of canvas. As suggested, I will contact the NAVMAN (now NORTHSTAR) technical staff and get their feedback. I will let you know what I find out.

Thanks all,

Maj

Now that is a good response in all areas.

Yes we are waiting to see what comes back

Power to the people and all that!!

Exactly my feelings on the problem!!!

Are you still in guarantee time? If not, see if they have a repair system that gives a fixed cost repair, otherwise you may be paying more for a (bad? Who knows) repair than a new one costs from Tom Tom, or at least a large percentage of the new price....

So be careful and stay lucky....

Hi All,

I took all advise and here is what happened:

First I contacted a NAVMAN (NORTHSTAR) technician in Florida and he said what I was getting for a signal through canvas is expected. He said to adapt an external antenna connector would be costly and without solicitation he added "that's what you get when you buy a cheap item". I didn't say anything as I thought I paid a good amount for the GPS. LOL.

I then tried to induce a signal by wrapping a wire around the antenna and stringing the rest in the superstructure. It worked more like a shield and reduced the signal.

The mechanical non-technical method worked the best. I extended the GPS out and up with a series of crome arms so it was in visual range as well as nearly touching the clear plastic window for sat range.

I let it run for 24 hours and it held a minimum of 8 sats at a minimum strenght of 3 out of 5.

My wife even said it looks good so problem solved.

Thanks again, Maj

The Navman expert was right when he remarked:-

"that's what you get when you buy a cheap item"

This is a clear indication to all concerned NEVER, EVER to buy a Navman!!!!!

That comment was "Straight from the Horse's Mouth" and must therefore be believed!!!

I have had built in GPS's and a Tom Tom portable, the Tom Tom was better in most respects. The new 16:9 Tom Tom is even better, I recently used one, its basically the same as mine but with even better features and screen!!!

I reciently bought a TomTom for my car and have a lot of success with it when travelling. However, I paid a lot more for my NAVMAN.

Thanks for the input.

Maj

We both seem to be convinced that Tom Tom is more for less money......though you do see Navmans in Germany on "Special Offer" for far less than a Tom Tom.....

My Tom Tom new should have been over €600, but buying on Ebay (2 years ago) got it down to €300 or so......mine has the 2GB hard Disk......they have got a lot cheaper generally.....

I bought Tom Tom because it won outright so many comparison tests in different magazines.....