Many thanks, Ramy. What you have doesn't seem too different from my set-up, except I have about 8 feet separation between the transponder antenna and the Flarm ADS-B antenna in a fiberglass fuselage ship. Perhaps the 27's carbon fuselage does some helpful attenuation of your own transponder signal?

I look forward to seeing your configuration file. OWNMODEC in my configuration file is set to Aggressive (= 0). I don't know whether this is the default value.

Do other 27/29 owners who are seeing false Mode C alerts have their transponder and Flarm antennas mounted similarly to Ramy's?

-John, Q3

On Friday, July 14, 2017 at 2:14:58 AM UTC-4, Ramy wrote:
1- Both powerflarm antennas in the nose (no carbon in the nose section of my 27a).
2- transponder antenna under the seat pan in front of the stick (so not far from the powerflarm antenna, maybe 3 feet at the most.
3 - configuration file may need to wait until next week or so. BTW I recall there is an option to suppress own transponder more aggressively, I just used the default.

I really never had false alert from my own transponder, no kidding. And my mode C alert is working very well.

Ramy