On Sun, 2 Nov 2014 05:30:14 -0000, wrote:

Jeff Liebermann wrote:
On Sat, 01 Nov 2014 18:47:32 -0400, rickman wrote:

I think you are confusing need with practicality. There is nothing to
stop you from making a superconducting antenna. There just isn't a need
for it unless you live in Gareth's world. Hmmm... wasn't that a movie?
Gareth's World?
(...)
I believe there are rather cold temperatures in space. A
superconducting antenna could be used there with *no* supporting
"apparatus".

You don't need to go to outer space to see cryogenic radios in
operation.

You can see space a lot better with a cryogenic radio.

On the ground, cooling the LNB is easy enough but how do you cool the
dish? The LNB is looking at the entire dish, which is sitting there
radiating at ambient temperature. Paint is low emissivity white?

Incidentally, I tried making my own LNB cooling derangement back in
the days of 100K C-band LNB's. Peltier 6 pack beer cooler plumbed
with copper ice maker line and an aquarium pump. The signal would
look great for about 10 minutes, and then slowly fade away. It seems
that cooling also causes water to condense on the "mica" waveguide
window. Add a small heater and fan. When I replaced it with a 25K
LNB, the cooler and fan went away. At least in outer space, there is
no condensation problem.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558