"Shaun Van Poecke" wrote in
:

Ive seen GPS receivers with serial
or USB connections that plug straight into a laptop, but these things
cost as much as or more than a basic hand held GPS. are they any
better?




http://www.pcmaritime.co.uk/leisure/...eshooting.html

The handheld GPS units are made for NMEA, which is an RS-422 clone using
data that switches between 0V and +5 (or 12, I forget which). A serial
port on your computer is RS-232 standard which switches between -12 and +
12, which is more reliable over long lines as the -12 doesn't get buried
in the noise like 0VDC does, making false data. However, MOST, not all,
serial ports will read RS-422 data fairly reliably.

NMEA is also slower than dirt at 4800 baud, but that's fast enough for
GPS data streams, which are also slower than dirt.

Is your laptop old enough to have a serial port? New ones don't have
them any more as everyone else has gone to USB, up to 2Mbps in ver 2.x.
It just works better and doesn't have those nasty "what speed is this
supposed to be set to by me" problems old serial ports had. USB is
automatic, right down into the operating system, plug n play. It takes
care of itself.

How cheap is cheap? Here's a 20 channel, WAAS-enabled GPS receiver
Froogle at Google lists for $36 that plugs right into the USB port and
folds for storage. Is that cheap enough? It uses the same chipset as
the $150 Garmins and the spec says it will track at -159dbm which is
below the noise level, so I believe impossible....

http://store.luluusa.com/nausbgpsrewi.html
I know someone who is using one of these stuck to the top of his SUV for
Streetmaps. 12 channels, WAAS accurate, same chipset as the rest, nicely
made, simple with a cable for $50, marked down from $199 since the
Chinese took over the market, which is depressed at the moment, flooded
with GPS. I see its only good up to 1000 knots, which might be a problem
for racers...(c;

Get the USB if you're using a laptop and quit screwing around with
handheld nonsense with tiny screens hard to see. You don't need to buy
another computer.

Larry
--
VIRUS ALERT! VISTA has been released!
NOONE will be spared!