Hi Chris,
After a fair bit of ‘tinkering’ and various antenna fits in various positions over the years, I have just changed over to a pair of PAW ‘Rohan’ external antennas (antennae) fitted under the pod of my flexwing with a laminated aluminium foil ground plane inside the pod. Initial results are showing a significant improvement in range over previous options. A bit dearer, but IMO well worth the extra expenditure!
(Fortunately, when I fitted my transponder, I put its antenna right at the back of the ‘skirt’ so it’s far enough away not to interfere.)
Best Regards
Peter