Do aircraft and folks on the ground talk to each other on 2 different
frequencies? I seem to hear the ground controllers and the actual pilot on
2 separate frequencies talking to each other.

Also, there seem to be a large number of frequencies to listen to regarding
aircraft around here, but which should I concentrate on? I'm just
interested in listening to the planes and the ground controllers and such.

Dave
--
You can talk about us, but you can't talk without us!
US Army Signal Corps!!
www.geocities.com/davidcasey98
Just added Albuquerque Police beat map and
the EDACS frequencies to the site!

Aviation communications are generally Simplex, i.e., you listen and talk
on the same frequency. You should hear both sides of the conversation
on the same frequency.

You can hear inflight aircraft for quite a distance. An aircraft at an
altitude of 3000' above ground level has a line-of-sight distance of ~80
miles. An aircraft at an altitude of 30,000' has a line-of-sight
distance of ~250 miles.

The on-the-ground range of the ground based stations is quite small,
typically a few miles. And, other than tower, stations talking to
inflight aircraft may not be located on the airport.

Walt

David Casey wrote:

Do aircraft and folks on the ground talk to each other on 2 different
frequencies? I seem to hear the ground controllers and the actual pilot on
2 separate frequencies talking to each other.

Also, there seem to be a large number of frequencies to listen to regarding
aircraft around here, but which should I concentrate on? I'm just
interested in listening to the planes and the ground controllers and such.

Dave
--
You can talk about us, but you can't talk without us!
US Army Signal Corps!!
www.geocities.com/davidcasey98
Just added Albuquerque Police beat map and
the EDACS frequencies to the site!

David Casey wrote:
Do aircraft and folks on the ground talk to each other on 2 different
frequencies? I seem to hear the ground controllers and the actual pilot on
2 separate frequencies talking to each other.

Also, there seem to be a large number of frequencies to listen to regarding
aircraft around here, but which should I concentrate on? I'm just
interested in listening to the planes and the ground controllers and such.

Dave

Here is what you're hearing which probably gave the impression
of ATC and the aircraft using two different freq.

This is common at night time where there is less
traffic and less controllers on duty. Since you didn't mention any
frequencies I'll use this as an example, this was an actually example of
someone with the same question who lives in Boston, MA. Lets say
you're hearing the ground controller (ATC) on 124.4 but you're hearing
the aircraft answering on 118.25. One controller is probably
controlling three different sectors. The controller in our example is
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.

If you tell us where you're located someone here might be able to help
you with local ATC freqs for your area.

George
http://www.MilAirComms.com

GeorgeF wrote:


David Casey wrote:
Do aircraft and folks on the ground talk to each other on 2 different
frequencies?

Here is what you're hearing which probably gave the impression
of ATC and the aircraft using two different freq.

This is common at night time where there is less
traffic and less controllers on duty. Since you didn't mention any
frequencies I'll use this as an example, this was an actually example of
someone with the same question who lives in Boston, MA. Lets say
you're hearing the ground controller (ATC) on 124.4 but you're hearing
the aircraft answering on 118.25. One controller is probably
controlling three different sectors. The controller in our example is
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.

Excellent answer! I have also heard the same controller's voice being
transmitted on civilian and military frequencies simultaneously.


If you tell us where you're located someone here might be able to help
you with local ATC freqs for your area.


Another good source of aviation frequencies is www.airnav.com

On Thu, 21 Aug 2003 03:06:46 GMT, Craig Davidson wrote:

Another good source of aviation frequencies is www.airnav.com

Thanks, I'll check it out.

Dave
--
You can talk about us, but you can't talk without us!
US Army Signal Corps!!
www.geocities.com/davidcasey98
Just added Albuquerque Police beat map and
the EDACS frequencies to the site!

Craig Davidson wrote:
GeorgeF wrote:


David Casey wrote:

Do aircraft and folks on the ground talk to each other on 2 different
frequencies?


Here is what you're hearing which probably gave the impression
of ATC and the aircraft using two different freq.

This is common at night time where there is less
traffic and less controllers on duty. Since you didn't mention any
frequencies I'll use this as an example, this was an actually example of
someone with the same question who lives in Boston, MA. Lets say
you're hearing the ground controller (ATC) on 124.4 but you're hearing
the aircraft answering on 118.25. One controller is probably
controlling three different sectors. The controller in our example is
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.


Excellent answer! I have also heard the same controller's voice being
transmitted on civilian and military frequencies simultaneously.

Yes that is normal as well. One reason for that is lets say a Military
aircraft is coming up on an ATC freq, the military aircraft can hear the
controller talking to a civilian plane so the military aircraft will
wait for him to stop talking. Then he knows the freqs are clear. If
ATC didn't do that a military plane could call up on freq however the
same controler would be on the civialian freq talking at the same time
causing ATC to miss the military's call.

George
http://www.MilAirComms.com

On Wed, 20 Aug 2003 22:11:08 -0400, GeorgeF wrote:

[snip to save space]

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.

Makes sense. Thanks!

If you tell us where you're located someone here might be able to help
you with local ATC freqs for your area.

I'm in Albuquerque, New Mexico.

Dave
--
You can talk about us, but you can't talk without us!
US Army Signal Corps!!
www.geocities.com/davidcasey98
Just added Albuquerque Police beat map and
the EDACS frequencies to the site!

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!"