I'm curious as to the thermal resource beneath me.

I've dug a 500mm deep hole and inserted a tube, 1m long 33mm diameter
2.16mm wall thickness, with caps at both ends.  The tube is straight
plastic pressure piping for water reticulation.  I've set it vertical
using a spirit level before backfilling the hole.

I'm planning a 600mm long tube over the exposed half for blocking
sunlight, with air vents.

How to restrict the thermally induced air flow within the tube?

Is there any value in sensors at different heights?

I'm most familiar with DS1820 series sensors.  Are there any sensors
more suited to this application?

p.s. ground here has not frozen in living memory, winter frosts only
affect grassed areas, and only for a few hours.  Surface can be 65=B0C
to 75=B0C on a calm day in summer.

--=20
James Cameron
http://quozl.linux.org.au/
--=20
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