Portable computers and GPS

[Steve at]

Stephen,

    Regarding your request for information on portable computers
and GPS systems.  I use a Toshiba 2200SX portable with car
battary adapter for field work.  The normal mains charger
autoselects 110-240 volts so it works in most countries (I use
mine here in Australia and in the US primarily), and the car
adaptor allows extended field use without access to mains power.
Toshiba makes a large range of IBM compatibles, with the upper
range (386 and 486 based models) also running UNIX.  For
Macintosh use, you will need to use the Apple Powerbooks, but I
don't know much about them.

    There seem to be 3 popular GPS systems in use here in
Australia.  We use units sold by Magellan (models 1000 Plus and
5000).  I have one and have used it extensively with no problems.
The unit lacks a direct computer link, but will store 100
"waypoints" (= localities) internally and is repeatable within 2
seconds lat/long.  It is small, robust, runs off batteries
(including both standard and recharable), and floats if you
happen to drop it in water.  The other common models used here
are sold by ProNav and Trimble.  I haven't used them so I can't
say much, but they seem to be basically the same as the Magellan
system.  We purchased our systems from a marine supply house and
they has several models in stock for use to play with, so you may
be able to try before you buy.  I know of one person using the
Sony GPS system, but he has had trouble getting consistantly
repeatable locality results (varaitions of up to several minutes
at the same place over a few days time) and was disappointed with
the mechanical robustness of the system compared to the other
systems listed above (he got it because it was cheaper than other
systems).

    I hope this helps.

                           Steve Shattuck
                           Australian National Insect Collection
                           CSIRO, Entomology
                           Internet: steves at ento.csiro.au

P.S. - Your address (sbsjury at READING.AC.UK) seems to be bouncing.