Montana Reflections

(Dreaming of Big Trout)

Matthew Dickerson, Addison Independent, May 27, 1999 (reprinted by permission)

This past weekend a number of hunters took to the woods, and a growing number of them were navigating their way with handheld GPS units. For those of you who have been in hiding for the past few years, GPS stands for Global Positioning Satellites. It is a way to determine your position anywhere on earth using signals from 24 Department of Defense (DoD) satellites.

The basic ability of this technology is rather remarkable. The units simultaneously read signals from up to 12 of these satellites in order to get a fix on their precise location. Since it takes only three satellites to get a position, any additional signals add to the accuracy. Military GPS units can pinpoint their position (latitude, longitude, and altitude) anywhere on the global to within a few millimeters. They can locate the head of a golf tee. Unfortunately, the systems that can do this start at about $10,000.

Commercial handheld units, by contrast, are somewhat less accurate. Fortunately they are also less expensive. The price of introductory models such as the Magellan 300 has dropped down to only about $100. The main reason they are not as accurate as their more expensive counterparts is that the DoD--for security reasons--introduces error into the sattelite signals. Because of this introduced error, the typical handheld GPS unit boasts an accuracy of only about 100 meters. To compensate for the introduced error, the better handheld units do averaging of mulitple readings over time. Walking around my front yard in Bristol, Vermont, my GPS unit was able to get signals from up to 9 sattelites, 6 of which were strong enough to be useful. In practice, most people that I spoke with found that their units were able to lead them to within 30 or 40 feet of the location they were seeking.

In addition to the basic function of telling you where you are, some GPS units have several additional features. For example they can determine your speed and bearing (assuming you are moving). Of greater usefulness, they can store a certain number of landmarks in their memory. With the touch of a button, you can call up any stored landmark and find what direction to go and how far to travel to get there. Some models even keep track of your route and provide navigation in order to backtrack along that route.

Fisherman and sailors were among the first to make use of the technology. If you're out on a lake and get a strike or catch a fish, you can store instantly the location on your GPS unit. Over the past few weeks I've had a chance to test a couple different models.

• The Magellan Blazer 12, which Vermont Field Sports in Middlebury (388-3572) carries for $157.95, was the smallest, fitting easily in a shirt pocket. On 2 AA batteries, it runs about 20 hours providing the basics: current location, speed and bearing, plus the ability to store up to 100 landmarks.
• Jumping to the Magellan Tracker at $270, you get storage for 500 landmarks, several additional navigation screens, a calculator for best fishing and hunting times, a built-in thermometer, a nice screen with 4 scales of gray, and the ability to display on your screen a map showing all landmarks with an area scalable from .2 miles to 320 miles. It runs for 30 continuous hours on 4 batteries, and has an interface that allows connection to a computer.
• Garmin and Lowrance are two other popular manufacturers. The Garmin GPS 12 sells for $200 and provides similar features. The Lowrance Global Nav unit sells for $310 and includes very nice mapping features, a memory of 600 landmarks (the most of any I looked at), and other features comperable to the Tracker. However it was also just a bit bulkier and I found it less intuitive to use.

So what are hunters using them for? The most popular use is to get back to the car. With the touch of a button, you can remember the location of your car (or camp) and then get directions back from anywhere in the woods. Hunters also used them to store their path when tracking a deer. Since you can also enter landmarks by directly typing in the coordinates, some more ambitious explorers are using GPS units to find locations for the first time.

Will it really help you get more deer? Harley Grice wondered just the opposite.

"How many deer are going to be lost in the next few years by hunters who are fooling around with their GPS units? There are too many gadgets in the woods now."

Nonetheless, his wife Marilyn now has a GPS receiver, and she thinks it gives her just a little more confidence to get out in the woods.

"Marilyn is always ready to try new things," Harley laughed. "She rattled antlers 30 years ago before anybody outside Texas was doing it."

Knowing the success Marilyn has had hunting, its hard to argue with anything she does.