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Re: Amateur Satellites (definition?)



Just a follow up to my earlier posting on our oil spill GPS tracking buoys:

I have had suggestions to try satellite tracking or use balloon elevated
antenna systems.  In researching the project we looked at satellite-based
data collection, but the costs for use of such services is prohibitive
(remember this is not ham radio, but commercial use).  The cheapest mobile
tracker units are in the $5000 range...believe it!  Since we have a
pre-existing communication infrastructure covering Cook Inlet it is more
cost effective to use this using traditional packet radio concepts.  These
are not buoys that spend months on the water like some oceanographic types.
 The are stored on board our response vessels for unplanned and immediate
emergency deployment summer or winter.  They may only in the water for a
few hours or days per year.  They must be durable for throwing over the
side of a workboat or possibly low altitude aircraft dropping.  The
phase-two units weight 60 lbs.  Most of the weight is the aluminum
enclosure (batteries and electronics is only 12 lbs.).  Realize that ships
often require ice breakers to clear a path through this ice!  The buoy is
only 18-inches in diameter by 8-inches tall with a whip antenna and short
GPS stalk.  The antenna is very much at sea-level!

The balloon concept would extend the VHF range of the packet Tx however it
would not likely be easy to deploy in emergency situations or in winter.
Cook Inlet is subject to ice flows and freezing in winter.  My guess the
balloon tethers would be severed rapidly.  Winds aloft can be horrendous up
here!  Also balloons might present a flying hazard!  Arctic ice flows can
be up to 48-inches thick and raft over each other for tens of feet.  It
will be interesting to see if our phase-two design is survivable in these
conditions!

Thanks for your suggestions and input.  The suggestion to try out the buoy
using PC-Sat has appeal.  The VHF radios are not programmable below 150
MHz, however.  Still a 2m HT might be substituted for a test.  I'll give
that one some thought.  The units will not be complete until early summer I
would expect.  We are still awaiting delivery of some of the components.  A
single unit is to be built and tested before the remaining six are started.
 A sea-trial is planned for March on this second prototype.  Maybe I can
get our "in-house" webmaster to add a webpage showing the resulting unit.
The company only has a simple one-page website at present (no I don't know
the url, but try a search on CISPRI).

I thought that the bbs might find this commercial use of APRS interesting.
I've not heard of too many commercial applications yet.  Maybe ours will
help that along.  In any case it has been a fun engineering project for me!

Ed
Alaska Amsat Coord.
Amsat member #3212


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