I've got an Icom IC-R2 and my goal is to hear military air/air
conversation
which seems vey difficult. I even have some difficulties listening to
civil
ATC.


I usually only hear commercial pilots, flying close to my position, and i
don't get the replies from the ATC (they're on ground level).

It depends on how high the antennas are. The planes at 30,000 feet will
have a range of 200 or so miles. The towers and planes on the ground will
only have a range of a few miles. This is assuming your antenna is only a
few feet off the ground. If it is 20 feet up you may hear the towers at 10
miles or so.