Hi Skippy,
I'm still not sure if you have your Trig actually set up and connected to a certified GPS so ADSB OUT is enabled. By default it isn't.
IF it IS set up with ADSB OUT then you would have to disable the ADSB OUT in the Skyecho and just use the ADSB IN with your EFB. This is a big waste of money - you can buy just an ADSB IN device from UAvionix called a PingUSB for about $475 (half that with rebate). This will display ADSB IN on your EFB.
IF you don't have ADSB OUT set up on your transponder then the transponder can still be (and should be, as others have pointed out) turned on as it fulfills a different function from the Skyecho (as outlined previously) by communicating your info to ATC when interrogated.
The Skyecho will broadcast your position etc to other aircraft equipped with ADSB IN directly. Its signal is not that strong, but it is fine for recreational aircraft, in my opinion, as its range is up to about 40NM according to UAvionix. I think that's if you have it positioned in an ideal location - my experience with my Skyecho in my Savannah is about 25NM, but that's still OK for me as I usually have an aircraft displayed on my AVPlan a long time before I spot it visually. (e.g. If my calculations are correct - if 2 aircraft were each travelling at 120kts directly towards each other if they were 20nm apart they would have 5 minutes before colliding, so that's a reasonable time to take evasive action).
HTH
Cheers,
Neil