The thermal cycling would make a gas "Bag" antenna interesting as the gas expands and contracts with temperature changes.
I like Bob's idea of an array of collinears lying on the moon's surface, since "ground" on the moon must be quite deep due to the lack of moisture.
This makes 2 meters very attractive as a down-link. We could take advantage of the reduced path loss and higher efficiencies in the circuits that 2 meters (or ten meters) has to offer.
I suspect it would be possible to build such antenna that uses a "wound up" spring to unwind the antennas for deployment, like a reverse tape measure that uncoils instead of coils up.
73, Joe kk0sd -----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Gordon JC Pearce Sent: Friday, July 03, 2009 11:41 AM To: amsat-bb@amsat.org Subject: [amsat-bb] Re: The Moon is our Future
On Thu, 2009-07-02 at 18:21 -0500, Gregg Wonderly wrote:
It seems to me that the correct choice is the highest frequency we can get
on
board for at least 24dB at the longest length of antenna that we would be allowed to send up.
Lunar gravity is weaker and there is no wind. So, a collapsible antenna that wouldn't last five minutes in typical Earth weather will be a lot more usable on the Moon.
Maybe something like a telescopic boom with a gas canister or pyro charge to pop the sections out?
Gordon
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