The newer ADSB equipment is improving and causing competition that pushes down prices.
The Stratus ESG Transponder costs $3750, comes with an inbuilt GPS and should be easier to install upgrades as it is the same dimensions at a KT76. Even with en Engineering Order and LAME installation should cost about $5k all up. Can't imagine even un-certified equipment would be much cheaper.
The
https://www.pacificavionics.com.au/p...sg-transponder