Radar spoofing article in AvWeb

This article was quoted in AvWeb this week:
http://www.theaustralian.news.com.au...378061,00.html

"FAA officials have become aware that an electronics boffin, using
a second-hand or 'borrowed' transponder from a small (general aviation)
aircraft connected to a $5 data lead, a $5 aerial and a laptop computer, can
create 10, 20 or even 50 false aircraft on an air traffic controller's
screen," Mr Smith says in a letter to Mr Truss. "This will create total
chaos in the air traffic control system."


It appears the guy would be replacing the serial data stream from the panel
mount with data from a laptop and the transponder "blindly" retransmits
whatever it is told.

I don't see why they couldn't measure a Doppler shift to prove it is a
moving transmitter instead of someone's laptop. Maybe they could software
key the
transponder to a panel mount's serial number like Jepessen does for
databases. That would help with the spoofing.

But isn't the FAA stuck with expensive Primary radars in addition to the new
ADSB ground stations so they can paint a target off aircraft skin instead of
doing away with all of expensive to maintain primary radars?

How is the FAA going to justify not tracking aircraft without electrical
systems and bad guys who don't turn it on to save money?