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Waterproof Bluetooth GPS Receiver
sirwin
Thanks for the heads up on that one. I didn't think of that. Fortunately I think I may have a solution. I plan on leaving it installed in the camper of my truck, which fortunately has its own 12 volt system connected to a battery, the truck alternator, and a solar panel. I'm thinking the majority of the time I will be using it will be while I'm driving so the alternator should cover that.

But your question does bring up a good point, do most external antennas basically perform the same? I was thinking of purchasing an external active GPS antenna.

I was planning on permanently mounting the antenna on the roof of the camper so I wanted something small that could handle extended direct sunlight and rain. The one above does say 100% waterproof but I'm not techie enough to understand the rest of the description, and therefore don't know if its "what I need". I don't know what I should be looking for in an external antenna. Any advice or experience with external antennas would be appreciated.
sirwin
Just after I posted the comment above, I did a little googling and found the page below:

Active external GPS Antennas for Garmin, Magellan, & Navman | Gilsson Technologies

They have a list of "features" which I found useful when comparing antennas. Looks like active antennas are definitely something to look for. Signal gain is something to compare.
tcassidy
Before buying all these parts and building a complicated system with a variety of failure points, you should try the basics. Do you know for sure a USB GPS mounted on the dash would not meet your needs?

I did use a Garmin active antenna for quite a while and it was great. However, that was back in the days that I had a Garmin Street Pilot 3 and GPS technology has improved vastly since then. The BU-353 or MTKII based i-Blue GM2 might fulfill your needs without the complication and failure points inherent in the system you are trying to set up. And at a fraction of the cost.

Terry
Ken in Regina
Terry has a good point. While antenna gain versus electrical current draw are good measurements for evaluating the purchase of an external antenna, you really need to ask yourself if you need one.

Let's leave the question of antenna performance begging for a second and look at what you are trying to do: find your way from where you are to where you want to be. This does not need high accuracy or super strong GPS signals. It merely requires that you have adequate reception from three or more satellites. You need just enough accuracy for the navigation component of the software to determine which street/road/highway you are travelling on and roughly where on that road you are at the moment.

As Terry points out, a GPS receiver sitting on the dash will, in the vast majority of cases, get the job done, especially with current technology.

I have an external antenna that I use with my old tech Garmin iQue 3600. In many situations it makes the difference between receiving enough signals to get a location fix or not. It makes the iQue 3600 usable in far more situations than it would otherwise be.

By comparison to my Nuvi 765T, the external antenna makes the old tech iQue 3600 roughly equal to the Nuvi 765T with its internal antenna.

My external antenna is waterproof and magnetic so I could mount it on the outside of the vehicle. I almost never do. It lays on the dash up against the windshield, just where you would likely place a USB receiver for your laptop/netbook. That is sufficient for all but the most obscured locations .. deep canyons in the mountains.

For on-road navigation to get you to where you want to go, you do not need a high degree of accuracy. To illustrate again with my current toys .. my Nuvi 765T has a connector for an external antenna. Just for fun I have connected my external antenna to the Nuvi to see what happens. In all cases it increases the signal strength of the satellites it can already see. In some cases it will even add one or two more satellites that it couldn't grab onto without the external antenna.

In normal conditions here on the flat Canadian Prairies, connecting the external antenna to the Nuvi will pin the satellite signals at the max for all the satellites in view.

But it does not make one tiny bit of difference in getting me where I want to go. The Nuvi or the iQue 3600 will both still get me where I want to go as long as they can see at least three satellite signals of just sufficient strength to get a location fix. They don't even need to have the location fix continuously. As long as I'm travelling on a straight stretch of road and don't have an immediately impending turn, the fix can even be intermittent. It's all good as long as it has a fix during those periods preceding an upcoming turn so it can tell me about it.

If you have other uses, that may change things, of course.

...ken...
sirwin
Just thought I'd finish off the thread. I ended up purchasing a used Holux GPSlim 236 on eBay (as recommended by someone on this thread) along with an external antenna. I installed the antenna on the roof of my camper and the receiver inside a cabinet in the camper. Everything works great.

I have to say I'm VERY impressed with the GPS chip in the GPSlim 236. I heard it was good but I am amazed at how fast it acquires signals (compared to the built-in GPS on my HTC Fuze phone). It's not even in the same ballpark - the receiver stays connected to satellites even when it is inside the cabinet...without the external antenna. Go figure!

The device easily connects to my laptop via Bluetooth so I think I'm good to go. Thanks for all of the tips and advice.

Now onto my next challenge....figuring out how to get the fuze to use the holux gps receiver.
tcassidy
Only one complaint about the Holux GPSlim. I left it in a sunny window too long and the battery deformed somewhat. The unit still works fine but the battery cover won't stay on.

Terry
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