It is interesting how a thread diverges from the original question. I
posted this new thread because I had been talking to a former world
champion who has just taken delivery of a Ventus 3M. Schempp-Hirth put
three aerials in the fin: radio, transponder and PowerFlarm apparently
without problems, and they should know. Many of the replies in this thread
have been why this wouldn't work. I originally asked whether it was also
possible to put in an ADS-B aerial. I will be asking Schempps but I thought
I would ask around first.

At 06:38 23 July 2019, wrote:
Actually, putting the Flarm antenna in the vertical stabilizer works
well.
=
Of course, how well I "see" another glider depends on their Flarm
installa=
tion. For example, I "see" K4 and DZ consistently at 8-10 miles. DL and
4A=
F at not more than one mile. 5E and L6 at 4-5 miles.=20

The SZD 55-1 has a battery box at the base of the vertical stabilizer. I
t=
ook the battery out, and put the Flarm in the battery box. The Flarm and
A=
DS-B antenna are mounted in the gap between the rudder and the vertical
fin=
.. The Flarm antenna is located as high as possible but below the metal
com=
ponents of the horizontal stabilizer. The ADS-B antenna is located as
low
=
as possible, but above the mass balance weight. This gives a very short
di=
stance between the Flarm and the antennas. The trick was running the
data
=
cable forward to the Butterfly display. =20

The comm antenna is located in the vertical fin, the transponder antenna
is=
bonded to the inside of the fuselage aft of the main gear. =20

P9