Hi,
My Trig TT21 also is ADSB OUT capable, but is not connected to a certified GPS source as is required, and therefore is NOT transmitting ADSB OUT. I am sure you would know if yours was connected as it would have cost you about $3000 to have it set up (I was quoted that sort of cost). My Garmin Aera 500 is not a certified GPS source so it could not have been used, I would have had to buy a newer more expensive model.
Much easier and cheaper to buy a Skyecho2 and get the rebate - as I did.
I show up on Flightradar24 due to the transponder. A few days ago I tracked one of my flights and it showed me from under 2000ft after takeoff right the way to my circuit at 2000ft at my destination.
BTW - if you do already have ADSB OUT then don't waste over $1k buying a Skyecho and turning half the functionality off, just buy a PingUSB ADSB IN device from uAvionix for under $400 (under $200 with rebate). All it needs is a small USB powerbank to power it, or connect it to your power accessory slot, and it displays the ADSB IN on your AVPlan/OZRunways.
Cheers,
Neil