What is the ADS-B cost, by the time you display the traffic on something?
PowerFLARM can display ADS-B targets and so can many other cheap (non certified) traffic display devices. It's quite simple to do.
For radiating your own position, all Mode-S transponders were certified for ADS-B. Due to lack of equipment, it was usually not tested at all. Garmin charge you money to enable the feature. I've hooked up my Funkwerk TRT800A to my GNS430W and I'm radiating my ADS-B position. However, this was an uphill battle. Nobody at the company had any clue about it and it was basically trial and error on my part that made it work. And then there is even the question whether I can legally enable this feature or not. My view is that I can because it is part of the documented functionality of my STC'ed transponder. What ever is described in the STC'ed installation manual of the transponder can be done.
