On Mon, 27 Jan 2014 13:05:08 -0000, "gareth"
wrote:

Taking my lead from the way in which spacecraft unload their antennae
and their solar cells, I wonder if there have been any amateur efforts
into folding antennae to beat planning and zonal limitations?

Unlike the spacecraft, the amateur beams would need a folding-back-up
facility, which together with wind-up-and-tilt-over towers would render the
structure invisble when not in use.

Also inspired by the man-across-the-road who is a Punch-and-Judy man
who has devised a booth that folds up neater than a deck-chair.

Actually, I've been working (very slowly) in a similar solution to the
problem using inflatable antennas and towers. The original concept
was a 20 ft length of plastic shipping tubing, a base plate with valve
and gauge, and a wire over the length of the tubing. The unit is
folded into a box and stored in the trunk of the car. When it's time
to get on the air, a small motorized air pump fills the tube, and
you're ready to go. When done, release the pressure, and fold the
tube back into its box. Later paper designs involved 3 tubes, forming
a tripod arrangement, for more stability and height.

For an antenna, one can either run a wire up the tubing, build an
inflatable Yagi, or balance a Yagi on top. To reduce weight, a ladder
line taped to the outside of the tube should work.

The maximum weight load is simple. Figure out the area of the top of
the tube and multiply by the air pressure. Don't forget to include
the weight of the tubing. If buckling becomes a problem due to top
heaviness, nylon rope guys can be added.

This is not a new concept or anything original. Such inflatable
antennas were built by Bosch Aerospace in the past. The product was
later sold to LTA Projects:
https://www.youtube.com/user/ltaprojects?feature=watch
The problem with their design is that it is designed for heavy duty
paramilitary field use, while mine is intended for occasional light
duty use. It need not be a monster. They also seem to favor a
monopole, while I favor a tripod.

My grand plan was to arrange an all inflatable Field Day for the sole
purpose of getting my picture into QST. However, at my present rate
of progress and level of interest, that's never going to happen.
Perhaps someone else can build it. Don't forget the inflatable Field
Day furnitu
http://www.philippbeisheim.com/sidetable.html

You can also build an inflatable satellite antenna:
https://www.google.com/search?q=inflatable+satellite+antenna&tbm=isch

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