Alan Melia G3NYK wrote:

. . . . .
My other loony idea was to use a balloon, not like Steve does to hold up the
weight of the whole of his 20m vertical (I think), but just to extend the
height of a 15 metre lightweight mast. If the bottom 15m of wire were thick,
supported by the mast, the upper 15m could be quite thin, light wire.

In fact, I only use the balloons to support the top section (typically, 8 m).
This method of increasing the height of the basic vertical means that the
average height of the antenna remains reasonably high when the breeze starts to
blow, because the 'anchor point' for the additional wire is at 12 m above ground
level.

For more details, have a look at:
http://www.cableol.net/alg/radio/136/experi_vert.htm

Regards to all,
Steve GW4ALG