One important feature of TraxPDA is the option to use a standard GPS receiver to download the latitude and longitude of the site when you retrieve the data from the Trax counter. This information is passed on to TraxPro where it is stored in the header of the data file. If you use GIS (Geographic Information System) software in your work then potentially you could use the latitude and longitude information to show the location of the site on a map. Even better, if you use the JMap software from Jamar, then you can automatically place on a study on a street map of your area with a single click of your mouse (click here for more information on JMap).

There are many different GPS receivers available on the market, and with a little bit of work most of them can be made to work with your PDA. Here are a few of our favorites that we have used and liked.

These GPS receivers plug into a Compact Flash (CF) socket on Pocket-PC PDAs. We like them for TraxPDA because they free up the serial port connector on the bottom of the PDA for the Trax cable so you don’t have to swap cables while at the site.

There are several companies that sell them, but some of them look so much alike they probably all are manufactured by one company. No matter, they work well.

You can get an external antenna that plugs into a connector on the side of the module. This antenna has a magnetic mount so it sticks to the top of the car. You don’t need that for TraxPDA normally, but for other applications it might be useful.

Shown here is a CF module and antenna made by Holux Inc. This is one of the lower cost CF GPS modules we have found that also has all of the features we like. We have a couple of these and they work very well.

Here is source to buy the Holux CF GPS 270 unit shown here.

This is a module made by Pharos, another company with a variety of GPS products. It costs about the same as the Holux 270 shown above.

Here is a source for information for the Pharos GPS-CF module and antenna.

If your PDA does not have a Compact Flash slot then you need a GPS receiver that uses a serial port. We don’t like this as much since you have to plug in the GPS receiver to the PDA, collect the GPS data, then plug in the Trax cable to read the counter. This isn’t a bit deal, but it isn’t quite as convenient.

The Holux 210 is currently our favorite GPS receiver if you just need a GPS receiver that connects to a serial port.

It has a good set of features, and yet is still the lowest cost receiver we’ve found. All of the electronics are in the housing that mounts on the roof. The attached cable goes through the window into the car and divides into two cables; one goes to the PDA and the other goes to the cigarette lighter in your car for power for the receiver.

To use this with TraxPro you would drive your vehicle as close to the counter as practical, and then read the GPS data with your PDA. Then get out of the vehicle and read the counter with the PDA. You don’t have to be exactly on top of the counter when you read the GPS data, so normally this will work ok.

You can find out more about the Holux 210 here. This is a review from a company in the UK but you’ll get the idea.

Here is one source to buy this GPS receiver. They buy the units from Holux and put their own name on it, but it is the same receiver. The last time we checked, it was selling for $110, which includes the receiver and a serial cable to go to your computer and a power cable to go to the cigarette adapter in your car.

Another option is to use one of the many hand-held GPS receivers similar to the one shown here. This one is made by Garmin. These receivers have standard serial ports so you can connect them to the PDA if you can find the proper cable. These receivers tend to be more expensive than the other receivers shown on this page since they have keyboards and displays which add to the cost. But you can also use them for other purposes when you aren’t using them for TraxPDA. They work great, and if you have one then there is no need to use anything else.

The trick with these GPS receivers is to find the proper cable(s) to connect the GPS receiver, which usually has a special connector, to your PDA, which has a special connector. You can often get the cable you need from a company called TheSupplyNet. Here is a link to their web site. Enter the type of PDA you have in the search box, then see if they have a GPS cable for your brand of GPS receiver. If you have problems, give us a call and we will try to help.

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