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Author Topic: Combining freq's, only for TX not RX  (Read 3940 times)
Jonathan_tcu
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« on: August 21, 2005, 04:21:09 PM »

Today is Sunday which means northern Ontario is supposed to monitor 133.72, 128.3, 127.25, and 135.5.  The freq's ARE set up, but apparently, only for transmitting and not receiving.  So, I can only hear pilots within range here locally on 128.3  Does anyone else in other ATC sectors get this problem too? Is it just the contollers who don't want all pilot transmissions duplicating everywhere?
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Lexxx
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« Reply #1 on: August 22, 2005, 10:01:33 AM »

Quote from: Jonathan_tcu
Today is Sunday which means northern Ontario is supposed to monitor 133.72, 128.3, 127.25, and 135.5.  The freq's ARE set up, but apparently, only for transmitting and not receiving.  So, I can only hear pilots within range here locally on 128.3  Does anyone else in other ATC sectors get this problem too? Is it just the contollers who don't want all pilot transmissions duplicating everywhere?


Not sure what your question really is, but it is only the controllers that can "couple" (and that's the correct term) frequencies together. Well, the technicians maintaining the equipment can too of course, and maybe they were doing just that.

Even though you could only hear aircraft on 128.3 on Sunday, the controllers can hear all the aircraft on all the frequencies. If traffic is light, it makes no difference to the controller whether the frequencies are coupled together or not. He can hear and transmit on those four frequencies simultaneously.

The advantage of coupling, (especially when it's busy) is that aircraft on different frequencies can hear each other, and don't usually transmit at the same time making it much easier for the controller.

So, when frequencies are coupled, aircraft transmit on say 135.5. The 135.5 receiver on the ground takes that signal and sends it to the ground based 128.3 transmitter near you, and voila, you hear aircraft that are actually transmitting on 135.5, but you receive them on 128.3.

Now as mentioned, there MAY have been very light traffic, and IF one controller was working all four frequencies and IF no two aircraft transmitted at the same time on different frequencies, the controller would not have been triggered to the fact that the frequencies were not coupled.

There would be absolutely no difference in the service provided. The controller continues to hear all the aircraft, and all the aircraft will hear the controller. The only difference will be that the aircraft will not hear other aircraft on different frequencies, and neither will you.

Make sense?

Cheers
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Jonathan_tcu
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« Reply #2 on: August 22, 2005, 06:43:01 PM »

Yes that I do understand.  Normally, during peak periods 7 am to 8 pm Mon to Fri, 128.3 is coupled with 133.72 for Timmins-Moosonee traffic and then the North Bay 127.25 and Sudbury 135.5 freq's which are coupled to THEIR sectors as well, all couple up to man traffic from the James Bay coast to as far south as just north of Muskoka.  Sometimes, the contollers won't block the coupled incoming transmissions from the other frequencies.  Sometimes the controller will block one or two of them.  After I sent my original message, around 5 o'clock, there was a shift change and that evening  controller opened up all frequencies and all was back to normal.  I do know that when the frequencies split away, I know there ARE other controllers manning the other sectors and not just one controller handling 2 groups of 2 frequencies in 2 separate sectors.
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davolijj
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« Reply #3 on: August 22, 2005, 06:50:39 PM »

Here in the US it is common for controllers to work several frequencies from one position and multicast his transmissions on all of them.  At the same time he will coordinate with the upstream (En Route) facility, and have all his inbound aircraft use only one of his frequencies.  That way he is not missing any aircraft transmissions caused by several aircraft transmitting at the same tme on different frequencies.
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Jonathan_tcu
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« Reply #4 on: August 22, 2005, 06:53:09 PM »

Here's my question that will apply to both Canadian and American airspaces.  Which factor is considered for when controllers couple up frequencies? I know some sectors like mine have set time frames.
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dave
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« Reply #5 on: August 22, 2005, 08:16:03 PM »

Quote from: Jonathan_tcu
Here's my question that will apply to both Canadian and American airspaces.  Which factor is considered for when controllers couple up frequencies? I know some sectors like mine have set time frames.


In the U.S. it is most often done during late night shifts or other times when traffic volume is low.
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LORm
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« Reply #6 on: August 23, 2005, 04:17:28 AM »

Honolulu Center combines frequencies in the late night shift hours, usually around 1900. In the late hours they also provide "clearance for release" before takeoff for aircraft on the ground when the most of the towers close during this time. 119.3, 126.5, 119.5 are three of the last that are coupled in the evening.

I'm not sure about OGG (Kahalui Maui), though, since they are listed as continuously attended. Although lisening, Center does clear them for release on the ground at OGG like the rest of the airports in the state. HNL is the only civilian airport in the state that continously staffs tower, and approach controlers 24-7, unless OGG does as well.
-LorM
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Jonathan_tcu
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« Reply #7 on: August 25, 2005, 06:39:30 AM »

Here's another twist with this freq coupling.  Last night, the controller manning the Timmins sector 128.3 handed off Jazz 7822 to the Sudbury sector on 135.5 and greeted 'so long' to the pilot.  A half hour later, 8:06 pm exactly ( 00h06z) he coupled up the adjacent sector freq's.  This doesn't mean HE manned both sectors separately, does it?  I would assume there WAS someone else manning the Sudbury sector before 8 pm.
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tyketto
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« Reply #8 on: August 25, 2005, 12:01:26 PM »

Quote from: LORm
Honolulu Center combines frequencies in the late night shift hours, usually around 1900. In the late hours they also provide "clearance for release" before takeoff for aircraft on the ground when the most of the towers close during this time. 119.3, 126.5, 119.5 are three of the last that are coupled in the evening.

I'm not sure about OGG (Kahalui Maui), though, since they are listed as continuously attended. Although lisening, Center does clear them for release on the ground at OGG like the rest of the airports in the state. HNL is the only civilian airport in the state that continously staffs tower, and approach controlers 24-7, unless OGG does as well.
-LorM


What they mean here by 'continuously attended', is that someone is always, or will always be available at the field for service (FBO, tiedowns, fuel, etc.) According to AirNav, Tower and Ground at OGG are open from 6am to 11pm local time. Same goes for the TRACON. Anytime afterwards, Center would handle departures/arrivals into OGG, like you said.

BL.
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