I own a Lowrance Global Map 12, hooked to an antenna permanently mounted in the roof. It only loses the satellites under heavy tree cover, and then only rarely. I'm extremely happy with the programming options and the functions available. It can be hooked to a PC for programming from the Lowrance mapping CD which eliminates the need for expensive cartridges for details. In addition you can choose the details you want to load, and the exact areas you need so that you only use the minimum of memory. Memory is expandable and the multiple (optional) chips can be programmed for different areas in advance. The only downside seems to be that the display is optimized for readability outdoors as a handheld unit, and can be difficult to see at some times in the Hummer. It is a rather large display, bigger than most units in the $400-500 price. My decision to buy this unit was based on the antenna already installed in the truck (I was told that most units must use antennas tuned for that model or brand and this one is only a little bump in the roof), and also the advantage of this unit to be unplugged from the vehicle and used as a hand-held unit for hiking,and a marine unit for fishing and diving.

I've used several Garmin units and have also been very happy with the performance and useability with a laptop PC. The display is very readable in the Hummer and the unit is geared toward vehicle use. If in-vehicle use as an installed accessory is your goal... look at the Garmins, they are great units with lots of options.

Dean Palmer
95HMCS

I have several, and the most sensitive, and most reliable is my Garmin III. I have other Garmin, and other non-Garmin units. The GPS III seems to be the best. Among the APRS guys, the Rockwell card seems to be the best, but I only have one of those, and I really cannot tell you what it does, as it has no readout, and is really quite stupid from a user point of view.

I have a Rockwell that never seemed to have a problem picking up a satellite, even in a parking garage. I just got a Delorme Earthmate that seems to take forever to track and receive data from any available satellite in clear open sky.

The Earthmate seems to be OK, but not as sensitive as the G III. It sure eats batteries, like my Garmin 45. The great thing about it is that it is so inexpensive. Now that it comes with a car adapter, it is even a better deal. A GPS receiver, that is a WORKING GPS receiver for less than $100 is pretty impressive.

I have used my Earthmate all over the country, on the dash boards of all kinds of rental cars. I like it.

The Rockwell works with a Rockwell system onto itself (unless there's an adapter I don't know about to hook it up to a PC for the Delorme software)

My Rockwell card is just a card. It works well. It is a card, with no box, no display, frankly, no nothing. It is the second most sensitive card or unit I have. It was inexpensive, but considering the crap I had to build to make it work, it was not worth the time.

MANY units use the Rockwell engine, the card I have. If your GPS receiver is powered by a Rockwell engine, I am sure it works well.

I am disappointed with my Earthmate, it seems way too "sensitive" to keep a lock on a signal (breathe on it and you lose contact).

It is not "sensitive." It is not as sensitive as the Garmin III. You may be saying it is sensitive to environment, as in it quits under too many trees. Compared to the G III, you may be right. Compared to my Garmin 45, the Earthmate is great.

Do Garmin receivers hook up to a PC?

Yep. Make a cable, or buy a cable. The Garmin puts out several kinds of data, including the "normal" NMEA data format.

--chip
4dr HT

Sam & I use a Garmin III+ GPS, with a hard wired antenna mounted on the roof, had have been very satisfied with it. We have the Garmin MapSource USA Roads & Recreation CD, which is used to provide street level detail to the GPS itself (memory is limited to 1.44 MB at a time, so the map sheets have to be changed out when using it on the road for a long trip, but that is very easy to do). We also use DeLorme Street Atlas 7.0 on a laptop computer when traveling and the DeLorme Hunt'n' Map topo maps when off-road.

We use these maps in pairs. The GPS is used to provide major road and street info for the driver or street level as desired (mounted on the dash above the steering wheel) and a laptop computer is connected (via serial cable). The GPS unit shows the Garmin maps while the computer shows the DeLorme maps (either street or topo). Both the GPS and the laptop display the location pointer when the units are connected in this manner. It's very easy to hook up and also provides lots of other good info, such as locations of fuel stations, places to eat, etc., as we move.

I'm within two/three days of completing the installation of a cellular-communications and navigation platform, with mounting system, in the Hummer and will post pictures on our web site when it's finished. Basically, it consists of the GPS (dash mounted) and the laptop connected via a serial cable. A port replicator is mounted on the top of the doghouse (where cup holders normally are), which is wired for power and sound (verbal instructions from the Street Atlas route tracking). The replicator allows for easy installation and removal of the computer for security purposes. The computer can also be connected, when desired, to either of our cell phones via a cellular-modem cable to provide internet and email access from anywhere that the cell phone can be used.

I must say, however, that there are other good GPS systems available. As I have not used them I have not commented on them.

Henry & Sam
Silver '98 TD Wagon