GPS anetenna location OK in baggage area of a fiblerglass glider?

On Tuesday, February 27, 2018 at 4:20:51 PM UTC-8, Matt Herron Jr. wrote:
On Tuesday, February 27, 2018 at 7:16:13 AM UTC-8, Ross wrote:
Not sure how many Discus 2 and Ventus 2 fuses I made, but none of them have a glass turtle deck.
Radio antenna located in the fin which is glass, except the Nimbus 4 where it is located in the rudder.
This however doesn't help your issue

Has anyone tried putting a transponder antenna like the T2glued to the inside the turtle deck? does the antenna require a downward view? 250 watts of RF too close to your head? This would make install on an ASW27 MUCH simpler than a fin or stinger on the outside behind the gear, not to mention more aerodynamic.

Ah no, no and no.

Bad on all counts...

Irradiating yer noggin.

The antenna needs to be as vertical as possible.

You don't want the pilot able to affect it by stacking stuff near it in the luggage area. Like say bottles of RF opaque drinking water.

The carbon fibre spars and rest of the fuselage will block much of the RF. If you don't have a carbon fibre fuselage, go ahead and stick an antenna inside there elsewhere.

Aerodynamics? Uh you flying a world record in an Eta?

But start with... KISS, just follow the glider manufacturers instructions for the transponder antenna install they recommend. The main goal is to have the transponder works as best as it can. Over the last decade or so the major manufacturers have worked this out pretty well. Back in the 1990s some of them had just awful transponder antenna installs.

At the risk of a hanging and in an effort to circle back to the original question ... a recap;

* Most carbon fiber (CF) gliders have a fiberglass (RF transparent) section in the turtledeck. Evidence, picture on the Schelicher page and 27 manual.. YMMV.
* Yes, this glass area can be used for GPS antennas as they are receiving signals from overhead satellites. Think flight recorders. The GPS antenna should be mounted on the surface of the turtledeck for best coverage (not lower on the shelf which will limit receiving signals from GPS satellites nearer to the horizon).
* Antennas that radiate/receive horizontally (FLARM, Xponder, etc) should not be mounted here as the remainder of the CF fuselage will block much of the signal.

May the rebuttals commence.

- John Ω