On 12/19/2010 11:04 AM, donroden@hiwaay.net wrote:
>>> Bare Aluminum if real can make a real good IR reflector.
>
> http://www.engineeringtoolbox.com/emissivity-coefficients-d_447.html
>
>
> Anybody ever see a polished solar hot water collector ?
I once had a number of C-band satellite dishes. One, an 8 footer was
solid Aluminum. It was getting pretty scruffy looking out in the
elements so I decided to paint it. The only suitable paint I had, or so
I thought, was some left over aircraft paint. Now this is some HIGH
gloss stuff that looks like it's had "clear coat" sprayed over it. It
would have been far more expensive to purchase than painting the dish
was worth, but "it was left over".
The finished dish looked great and worked very well. However twice a
year for a couple of days the sun is directly in line with the
geostationary satellites. It's only for a couple of minutes at most.
This normally results in signal loss from that satellite during that
period. It also means the dish, which is really one giant mirror, it
also pointing at the sun with the focus on the LNB. This was one little
detail I had forgotten.
I remember pulling in the driveway and something just didn't look right,
but I couldn't put my finger on it. Then my focus shifted to the
satellite dish. Even from a 100 feet I could see what looked like "some
things" hanging from the LNB. Inspection showed that the heat had
melted the fittings right of the LNB and of course had melted the solder
and completely cooked the LNB
I repainted the dish, but this time it was flat black. Man, did that
dish get hot, but it never melted another LNB. You could feel the heat
from that dish a good 10 feet behind it. BTW that particular dish is
visible in the "Google Earth" image so I know that image hasn't been
updated in quite a while.
73
Roger (K8RI)
> Ever wondered why not ?
>
> Don W4DNR
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