|Subject:||RE: [TowerTalk] URI magic antennas|
|From:||Jim Lux <firstname.lastname@example.org>|
|Date:||Tue, 08 Jun 2004 10:47:26 -0700|
At 12:15 PM 6/8/2004 -0400, Dave Bernstein wrote:
It is no longer necessary to use liquid helium to attain superconductivity. When last I checked, advances with ceramic materials had pushed superconductivity close to liquid nitrogen territory, and the goal of room-temperature superconductivity was still considered a possibility. See http://www.newscientist.com/news/news.jsp?id=ns99991618, for example...
Practically speaking, you don't need superconductivity to improve performance. Just cooling the metal will reduce the resistance, and hence the loss, somewhat. I seem to recall that Cu has about 1/7th the resistance at LN2 (77K) temperatures compared to room temperature. It's roughly linear... Dry Ice (200K?) might get you half or a third of the way there.
Too bad, though, that you can't supercool the earth for some 20 wavelengths around, to reduce that source of loss.
Too bad, also, that reducing resistance isn't the only thing you have to do...
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions and ask for Sherman, W2FLA.
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