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I was looking up Trimble just the other day, so my tuppence worth may be of
some value.

It seems that Trimble are a large multinational company who serve the needs
of professionals and businesses who need to know position on land (rather
than at sea). For example, farmers planting crops, forestry, the
construction industry, surveyors.

Trimble's "Pathfinder" service is - as far as I can tell - an attempt to
provide a world-wide service to correct GPS error and so enable a more
precise position (of the order of one foot) to be obtained than is
otherwise achievable with the usual type of GPS receiver. This was
especially useful in the days before the intentional data corruption in the
GPS satellite signal was switched off (March 1st 2000) and before national
mapping agencies started providing their own GPS correction services (WAAP
in the United States for example, where GPS receivers so equipped can also
receive a radio signal giving correction data. In the UK, the Ordnance
Survey have a network of passive "GPS stations" dotted around the country,
over which you can sit your GPS receiver and compare its estimation of
position with that printed on the station, and so obtain a GPS error. The
UK also have an active system called RINEX which seems to operate in much
the same way as Trimble's Pathfinder - except that it is free.) These days,
the Trimble Pathfinder service would appear to be redundant, though
probably still useful in rural third world countries which do not have a
well funded national mapping service. The Trimble website gives a long list
of countries in which they offer their service - though it does not include
Egypt for some reason, which was my interest at the time.

However, I would assume the Trimble GPS device that Jim has should work
without the Pathfinder software bolt-on.

I am intrigued that the GPS comes up with the right date, but the wrong
time, when activated. By the "wrong" time, is it the hours and the minutes
that are wrong, or just the hours? The GPS unit may think it is in a
different time zone than Jim thinks he is in.

On the antenna, Googling "active GPS antenna" will pull up a raft of
antennae for sale at around $15, or less than a tenner in UK currency. The
plug may be a different challenge, but I would assume Trimble would use the
standard BNC, in which case Jim would be home free.

Having got the Trimble GPS to produce some coordinates, Jim can check them
using a sextant and reducing some sights on some celestial objects, so
neatly bringing us back to the subject of this list :-)

Geoffrey Kolbe

At 03:50 20/02/2008, you wrote:
>
>
>I just acquired a Trimble Pathfinder basic GPS device. I have never
>used a GPS before.  This one is more rugged looking and less user
>friendly than the consumer GPS units I have seen. I did a quick
>google for this and found the Trimble site. They say it is not
>supported and it is not Y2K compliant. Does this toll the death nell
>for this device? If not, can someone direct me to a downloadable
>manual? Also, it does not have an antenna. What frequency do GPS
>receivers use? Perhaps I can cut my own antenna. If this is not
>recommended, please direct me to a source for an acceptable antenna.
>
>I am also a short-wave listener and this seems to have an accurate
>clock. As soon as I replaced the batteries and turned it on it
>started up with the correct date, but the incorrect time. How does
>one set this up? It came with 3 each 3.5 inch floppy discs with
>PFINDER Version 3.00 GPS processing software. It also came with a
>data transfer cable that mates with a serial port. I have an adapter
>that will convert USB to Serial and I have access to a 3.5 inch
>floppy to USB adapter. However I bet Version 3.00 will not run on my
>Windows XP. Any recommendations?
>
>I would like to get this thing working again as a GPS navigation
>tool. Short of this I would be happy if I could use it as an accurate
>clock. If anyone has any answers I would be grateful.
>
>Cheers!
>
>Jim
>
>

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