1. Is the firmware the most recent (6.06)? Yes - good
2. Are your antennas vertical when in flight? Yes - good
3. Did you follow the antenna separation criteria in the manual? I read it and tried to, though there are so many variables it is hard to know what trade offs are more important than others. With so many rules it is almost impossible to obey every rule simultaneously. There are metal parts: the instruments, canopy support brackets, wires, lead weights for nose ballast, nose tow release, and other antennas, etc. - FLARM and GPS antennas, and GPS antennas themselves are fairly close; consider moving them apart.
4. Is the PowerFLARM GPS antenna at least 12" from the other GPS antennas in your system? No, they are about 4inch 96mm apart atop the vario and ASI, I never would have guessed that this would be a related to a reception issue for the Flarm communications. Best I can tell both antennas seem to get along fine and get good reception, they are both for new instruments so I hope that the newer gps antennae interfere with each other less than older generations. Maybe this close placement is something I should test. - both GPS antennas are powered, and active. You might be surprised.
5. Are the connectors correct (RPSMA to FLARM A, SMA to ADS-B)? Yes, factory supplied - good
6. Are the connectors tight? Yes, finger tight, no wrench used - good
7. Have you swapped your antennas from a known good installation set to see if the problem is with them? No, not many other flarm equipped gliders around, and doubt others would appreciate me removing theirs. - this would isolate a fault to your CORE if good antennas don't work.
Do your antennas work in a known good installation? No, have not thought of testing, but with few other flarm targets around except in a large contest that is hard to study. - this would isolate the fault to the antennas.
8. Are your antennas on the glareshield or elsewhere? Yes, see pictures, temporary location on top of glareshield. - location looks ok, perhaps a bit close to the GPS antennas; ADS-B is great. Antennas aren't touching the canopy, are they? They are susceptible to static build-up (very small incoming signals) on dry days.
See PowerFLARM application note rf antennas on cumulus soaring website. I have referred to this but as I mentioned above it is hard to obey all the rules simultaneously so I need advice on what other things to try, other placements and other ideas. - understood
9. When you do the RF analysis, how many flarm/flarm interactions are you seeing? Yes, see page 1 - that's great, some bad results are due to only a few hundred interactions.
Are their installations good (i.e., do they have good RF analysis charts)? There were lots of others, i don’t know how well their installs are done, but at Perry it is a pretty good example of average or the target normal audience that I would fly with. - lots of known good installations there
10. Is your glider carbon fibre, glass, metal, wood? Fiberglass, with metal bits in various places like other gliders. - great, bigger problems with carbon, so that can be
11. Have you shortened your cables to the antenna or GPS? No, they are stock.
Are the antenna wires near any wires which carry large current? Near other instrument power feed lines with 12v, not sure i would call any of that “large current” in this context, but that is a relative term. Nothing draws a lot of amps like an electric motor glider might. - I consider large current a radio at transmit (Becker 1.5 amps)
12. Is there any metal object forward of your FLARM A antenna (eg., compass)? Yes, see other pages -
13. If you are grandfathered, have you installed a FLARM B antenna? What does Grandfathered mean? What were the results? See page 1
The first tranche of COREs/Bricks had rights to IGC, FLARM B, etc. When the newer systems came out, adding a second antenna - FLARM B - required a extra-cost licence (handy for placement in gear well for downward coverage in carbon fuselages).
So:
A - I'd try moving the GPS antennas further apart and away from the FLARM antenna first. Also, check the various coaxial cables for kinks or tight bends. The coax does not appear to be very expensive in the factory supplied cables.
B - If that doesn't work, the 4.72" bottom-fed dipole works well in installations I've seen - also higher transmit gain. The 1/4 wave, which is short and required where glareshield to canopy height is an issue (ASW20 for example) also works very well, but needs a simple ground plane (also higher gain than the original). Each of these is an easier installation, not that expensive (considering the extra range). I gained about 1 km all around with the dipole, and just bought a 1/4 wave, which is shorter, and again has slightly higher gain (every little bit helps with 0.018 watt transmit power - as opposed to a transponder at 175 watts). I use the very short antenna for ADS-B but I don't see much range difference from it. You also get a much shorter and better cable in the Craggy solution. Shorter is better - no coiling of extra-length wire, which is sub-optimal.