You don't need OTH radar to detect the aircraft, weather radar can be tweaked to look for the airflow turbulence that every aircraft produces. Military radar can be tuned to longer wavelengths that have a greater detection chance for stealth enabled aircraft. The most serious problem is the skill of the operators, will they recognize a signal as a flock of birds or ground clutter or as an enemy aircraft.
JORN - Quote from my post here
http://forum.juhlin.com/showthread.php?t=4368 (reply #8)
The Jindalee Over The Horizon Radar network AKA JORN (Jindalee Operational Radar Network) had its origins in some 1950s ionospheric testing but also took into account the proof of concept for OTH work done by the USN in the 1950s.
JORN itself was largely developed in a period from 1975 to 1985 and as I understand it, there was a lot of collaborative work between the US and Australia as part of The Technical Cooperation Program (AKA TTCP).
This collaboration came about because Australia could demonstrate that their research was as mature as the US research (and therefore the US would not be burdened with a partner that would contribute little but get all the benefit).
@ Schone - With all that in mind, I would assume that the visitors you had were all part of the ongoing collaboration. You may be interested in this PDF of the overall history of JORN
http://www.dsto.defence.gov.au/attac...izon_radar.pdf