Different frequencies

[gcopter1]

Why is it that both sides of a conversation cannot be heard on one frequency but yet, as soon as that frequency changes, I can hear the aircraft that i could not hear before?

For example, I can hear ATC talking to an aircraft, say, on approach frequency. Then the ATC hands him off to the tower and now I can hear both the pilot and ATC even though the distance from them to my receiver is the same.

 

[qwho]

One reason could be atc has multiple frequencies and you thought he was one one freq but was actually on another. For example the controller sometimes says aircraft xxxxx change to my frequency 125.7.

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[krokus]

Different transmitter locations for the different freqs? I have seen approach & departure controllers using radios at main, or remote, transmitter sites, and the tower/ground controllers using an antenna on the roof of the tower.

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[ShyFlyer]

Another possibility is when a controller is covering more than one sector (or position), they (the controller) is transmitting on two frequencies at the same time.

 

[gcopter1]

One reason could be atc has multiple frequencies and you thought he was one one freq but was actually on another. For example the controller sometimes says aircraft xxxxx change to my frequency 125.7.

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Of course, now I remember, that makes sense. Thanks.

 

[majoco]

Another possibility is when a controller is covering more than one sector (or position), they (the controller) is transmitting on two frequencies at the same time.

Happens here quite frequently in the evenings when most passenger traffic has gone for the night - one controller is covering approach and tower. If one aircraft is in the approach phase then the controller will talk to him on the approach frequency, but he will also hear the same controller talking to the tower aircraft but not the aircraft replies.

 

[PrivatelyJeff]

Happens here quite frequently in the evenings when most passenger traffic has gone for the night - one controller is covering approach and tower. If one aircraft is in the approach phase then the controller will talk to him on the approach frequency, but he will also hear the same controller talking to the tower aircraft but not the aircraft replies.

We have that with my local EMS dispatch. At night they will have one dispatcher covering my county EMS, plus rural EMS/FIRE of the next county and the county after that and sometimes they just patch it all together and other times they won’t.