Any aircraft can be expected to have the transponder antenna stuck amongst equipment in the instrument panel? What RF shielding requirements/standards do you think typical glider cockpit avionics, including all the non-regulated, non-certified devices are built against.

In typical ras fashion somebody asking a reasonable question
has degenerated to nonsense. There are perfectly good documents from glider manufacturers that recommend where/how to install transponder antennas. None describe stuffing it in the instrument panel.