BUYING A GPS UNIT

Buying a GPS Unit
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(An excerpt from the book, The Complete Idiot's Guide to Geocaching)

For geocaching, expensive and elaborate gear is not required. More importantly, it should be easy to use, accessible, and durable. Outdoor gear gets seriously abused. Gear can get smashed in bags and packs, rained on, frozen, dropped in an icy river, and so forth. You get the idea. Luckily, most receivers are built to military specs to withstand a lot of electronic killing factors like moisture, dust, and vibration.

Keep your gear longer by securing it with those key-keeper-style coiled lanyards. They are great for attaching receivers, cameras, and radios. If you drop your gear, it may spring back before crashing on the ground. They're great for keeping gear from becoming lost or stolen in wilderness or urban environments.

* Basemap.
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This is highly recommended. The additional cost is marginal, and the increase in the equipment's usefulness is substantial.

* Channels.
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Use a receiver with 12 parallel channels. This should include most manufactured after 1997. Older, single-channel receivers are much slower and may not be as accurate.

* External antenna jack.
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This allows the equipment to be mounted inside a vehicle. It is not always possible to obtain good satellite coverage through a front windshield. Even backpackers will benefit from the ability to safely store the receiver inside a pack with an antenna attached to backpack shoulder straps.

* Interface.
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If using the receiver with a computer, be sure that it includes both data in/out ports, and make sure it's NMEA compatible.

* Memory.
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This is used to load detailed topographic or street-level digital maps into the receiver. Topo maps use up a great deal of memory. Capacity should be at least 8 megabytes, or the receiver should include the ability to accept a memory card for as much memory as needed.

* Power source.
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Use a cigarette lighter power cable whenever possible. If you're only using batteries, make sure to carry spares and use a solar charger for extended field use.

* Rocker keypad.
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Using a receiver without a rocker keypad is like using a computer without a mouse.

* Screen size.
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For visual ease of operation, use a receiver with the largest screen that can be realistically carried. Screen size is measured diagonally. Color is great and helps define map features, although it does burn battery power.

* Waterproof.
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Sooner or later the gear will get submerged. Get gear that is at least water-resistant. Plastic bags and boxes give electronics a little additional protection.

More resources for choosing a GPS unit

* Ask other geocachers in the Groundspeak Forums
http://forums.groundspeak.com/GC/index.php?showforum=11

* Visit gpsinformation.net for guides and reviews.
http://www.gpsinformation.net/

www.geocahing.com