On Tue, 26 Aug 2014 11:35:47 +0100, "gareth"
wrote:

I wonder if there could be a way round
these limitations by emulating the antennae of spacecraft, by
which I mean ingenious ways to fold the whole thing up when
not in use?

I've been working on inflatable antennas and towers for several years.
Unfortunately, I don't have much to show for my efforts. Maybe by
next Field Day.

This is the current incantation of Bosch Aerospace:
http://www.ltaprojects.com
https://www.youtube.com/channel/UC8cxVcsOmrXv1d4aNaXoQCw
They sell on eBay.

For wire antennas, you might look into a tethered aerostat:
https://www.google.com/search?q=aerostat&tbm=isch
Just one problem... vertical HF antennas are not the best because of
the grounding requirements.

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