RadioBanter - View Single Post

August 21st 03, 06:17 AM

In article om,=20
says...
=20
Here is what you're hearing which probably gave the impression
of ATC and the aircraft using two different freq.
=20
This is common at night time where there is less
traffic and less controllers on duty. Since you didn't mention any=20
frequencies I'll use this as an example, this was an actually example of=
=20
someone with the same question who lives in Boston, MA. Lets say=20
you're hearing the ground controller (ATC) on 124.4 but you're hearing=20
the aircraft answering on 118.25. One controller is probably=20
controlling three different sectors. The controller in our example is=20
keying up
the mike and his voice is being broadcast on 120.6, 118.25, 133.0, and
124.4 at the same time. The antenna site for 124.4 is probably near you
as that is the only one you are hearing. The other three antenna sites
are located near the center of the North sector, West sector, and South
sector, too far away from you to hear. So, you might hear Boston say
"Delta 411 decend to one four thousand" on 124.4000. However it was
also broadcast on the three other freqs but you were just too far away
from those antennas to hear it. But now you can hear Delta 411 on
118.25 say "out of 210 for one four thousand Delta 411". You heard the
Deltas reply because he was much higher and in line of site with your
radio. This would give the impression of Duplex but in reality Delta
hear ATC on 118.25.
=20
If you tell us where you're located someone here might be able to help=20
you with local ATC freqs for your area.

=09A great, succinct answer that makes it clear to many of us who may=20
have suspected something like this, but weren't quite smart enough to=20
ask the question in just the right way in order to have it make sense.=20
Hats off to George.

--=20
--
From the sunrise side of Mo-Pac's famous Kirkwood Hill - N 38=B034'53", W=
=20
90=B022'32", 680'
"=A1Y tu madre tambien!"