Hawker Pacific are advertising a small PCAS that actually works anywhere. It interrogates transponder transmissions and displays an alert. There are two models and the larger has an aural alert as well. Made by Zaon, they can be used in any airspace including class G non radar or TCAS instigated transmissions. The Zaon unit can be interfaced with Garmin moving map GPS' to give a pictoral representation on that display as well. Matt, at Hawker Pacific, who is also involved with ADSB matters can give you a better idea than I, a non technophobe can. He is pleased to talk to anyone about Zaon and can be reached on 02 9780 8559 or 1 800 654 983.
This is not an advertisement and I have nothing to gain by bringing this to the attention of a lot of pilots who are concerned about flying mid air collisions. There has also been some misinformation about this unit put on this forum by people with a vested interests in selling another costly concept.
For this reason it is only fair that this misinformation be rectified.
You Tube have a demo,
YouTube - Aviation Consumer Aircraft Traffic Display Demo