In message , Mary Shafer
writes
Since the NVAF used ground controllers heavily, did they monitor all
the frequencies? I know it's too much for pilots to manage, but a
ground facility should have a little more monitoring capability.

Others (Ed particularly but others too) will have better information,
but falling back on "Clashes" there was a SIGINT centre called 'Teaball'
which did just this: the trouble was getting its messages relayed
through often-flaky radio links and acted upon in a timely manner.

Having a ground-based centre intercept signals, translate them,
correlate them and confirm them, and then get warning to the relevant
aircraft is a non-trivial task even when everyone is amply supplied with
working radios and free frequencies and you've got a complete and
accurate air picture.

Uncertainty over exactly who is where increases the problems. Add in
"protect the source" constraints to hide the fact that you're
successfully eavesdropping from enemy intelligence, and it gets very
tricky indeed. And having busy pilots get vague warnings from "who he?"
doesn't help when they believe they have more immediate threats to their
survival.


Eavesdropping isn't trivial but it's doable. Turning that into immediate
tactical information and communicating it in a usefully timely manner,
is a still a challenge today.

--
When you have to kill a man, it costs nothing to be polite.
W S Churchill

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk