GPS - Tripmate

GPS's Tripmate by Delorme

Here is a great GPS unit for the cost ($199) that does include the hardware (the GPS receiver) and the mapping software of all the US roads

Here are the technical Specifications of the Delorme Tripmate

Type of Receiver 12 channel GPS L1 C/A code
Cold-start time to fix ~ 3 minutes @ 25 deg.. C
Warm-start to fix ~ 1 minutes @ 35 deg.. C
Temperature range -10 deg. C - +60 deg. C
weight with batteries 9.5 oz.
Battery life ~15 hours under normal operating conditions
Interface RS-232 with NMEA-0183 protocol

Good / Bad (IMHO)

Good:

New Version 5.0, release in Oct. 97

Now talks to you, telling you where and when to turn.
Now street by Street directions
Nicer looking maps
Links with phone book (a great option for on the road)
You can scan in other maps for your display.
Exit information icons, gas stations, and other info.
Night time display (only changes the map colors, okay, but the great)
Power adapter for TripMate is now include, also up the cost to $199.00

Easy to use with just about any laptop computer for mobile use.
Tracks good in most vehicles, but not the Hummer due to angle of the windshield. But is very usable.
Low cost.
small and compact.
Quick to get a fix (once you tell it the state or country you are in)
Cover just about all the roads in the US.

Bad:

Does not come with external power adapter, it is an option. (I have made my own that is power from the laptop's keyboard output) (Ha...new versions now includes this adapter)
No external antenna option - none, Oh... you could go into it and add one but I do not feel the signal quality will be as good).
Not waterproof (for roof mount use) but seem to be built well to keep the water out.
Software lacks a constant display of your bearing, speed heading, and satellite status report.
If you are using a TFT LCD screen, you cannot invert the color display. I found inverting the color great for night time viewing, otherwise the display is too bright, or so dull, it's not easy to read the lettering.
Cannot run as a stand-alone device, no display on it

It has been asked if an external antenna could be added, I say Yes, but I would not do it myself. The unit uses a passive antenna (meaning, no pre amp in the antenna) and added more coax to the antenna would only make for a weaker signal. And a Active antenna would not work either, since it does require about 5 volts that is feed though the antenna lead from a receiver and none is supplied by the Tripmate GPS receiver. In the Hummer I use to place the receiver on the dash right next to the window, for the most part it worked great, until you made a 90 deg. turn or better. That is due to roof of the Hummer blocking it view of the satellites it it had a fix on, but normally with in a minute or less, it will have a new fix more satellites. Option, is to place the bright yellow GPS receiver on the roof, if you do this, be cautious about rain and it getting water inside. It does have a rubber seal and looks like it would work fine out side, but they do not recommend it. If you are going to put on the roof, get a strong flat magnet and bond it to the bottom of the unit and you will have a magnetic mounted GPS unit that you can remove easily.

But should you want to see the insides and where the antenna connects, here it is:

	The little white block with the gold plating is the antenna. It is stuck down in to place with double sided tape, but should you remove it, you will be also removing the ground plain.
	Here is the PC board and the connecting coax to the antenna. The CPU is a Rockwell chip should you want to know.

Above left is where the battery connects. If you jumper pins 2 & 3 (the two towards the center) you can supply the GPS receiver with external power via pin 9 of the 9 pin connector. I made a plug that uses power from my laptop's external keyboard jack, and that is a 5 volt supply. The GPS uses 4 AA batteries or about 6 volts, so running it from a 5 volt source will work just fine. The adapter from Delorme does have a voltage regulator in the cig. lighter plug that will bring the voltage down to about 6 volts..