On Mon, 4 Jun 2012 09:53:48 -0700 (PDT), John Cochrane
wrote:

.... text deleted
Again -- the world is full of dipole antennas with physical and
electrical connectors at the base. Why oh why are you not using such
an antenna in this most obvious place for it?

John Cochrane

Per T8's suggestion, I looked at the VDP series 1/2 wave dipole
antennas from Linx;
http://www.linxtechnologies.com/prod...ipole-antenna/

comparing with what appears to be the standard PowerFlarm brick
dipole;
http://www.linxtechnologies.com/prod...ipole-antenna/

the VDP is about 0.7 inch longer, and maybe 10% worse VSWR. Otherwise
the datasheet specs look identical. Both cost under $10.

The big plus is that the very thin flat antenna (with a bottom mount
coax) will be much easier to integrate into our ships. And it will
look much more attractive.

I cut out a cardboard facsimile and was able to fit it to the front
cowling of both a Ventus 2cx and a Ventus C. Not much clearance in the
Ventus 2, but it cleared the canopy by mayb 1/2 inch..

I notice on the Butterfly site that they have a bottom fed antenna
that is cited to have "high performance" with the PowerFlarm.
http://www.butterfly-store.de/en/Ext...FLARM ,i7.htm
Unfortunately, no indication of how tall this antenna is.

To echo John's comment, there has to be a better solution than the
current fat dipole with the center feed coax.

We've come too far and fought too hard to get Flarm into the US
sailplane fleet to let this antenna issue stall widespread acceptance.
If PowerFlarm is to really impact collision statistics, we need to get
nearly 100% fleet penetration. I fear this will not happen with the
fat center-fed dipole. It may work the best, but if it looks ugly or
is difficult to install, we will not get wide fleet penetration.

This is an important issue for the full acceptance of PowerFlarm in
the US !

Bob