Author Topic: kjfk tower - guard freq?  (Read 10260 times)

Offline phil-s

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kjfk tower - guard freq?
« on: October 03, 2009, 09:50:57 PM »
A few days ago a Kalitta was asleep at the wheel in line for takeoff. Tower tried them 3 times, then sounded like he tried them on the guard freq. 121.5 isn't listed as one of the 3 freq's that's monitored on this feed, but maybe it is? Eventually things got straightened out but it left me curious why I would have heard "guard" mentioned unless that freq is included in the feed. Maybe tower was transmitting on the regular frequency saying something like "come up on guard if you can hear this"?



Offline sykocus

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Re: kjfk tower - guard freq?
« Reply #1 on: October 04, 2009, 12:23:22 AM »
The tower could have been "simulcasting". Transmitting on their regular frequencies and guard at the same time.

Offline phil-s

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Re: kjfk tower - guard freq?
« Reply #2 on: October 04, 2009, 07:08:34 AM »
SYKOCUS -- That sounds like the answer. Thanks. Didn't realize they did that.

Now I'm even more curious, what else is "simulcast" used for? Do they transmit ATIS updates that way? Now that I think about it, at JFK I never hear more than one announcement of "ATIS changed to..." even though the feed scans all 3 twr freqs. 

Yet another question: Are the two JFK tower controllers sitting side by side so that they can talk to each other "off-line"? How do they coordinate so that a "simulcast" by one doesn't step on the other?   Wiki has a lovely article on ATC history and ops http://en.wikipedia.org/wiki/Air_traffic_control but nothing on the physical layout or the com links among controllers.

Thanks folks - this site is great.   

Offline dave

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Re: kjfk tower - guard freq?
« Reply #3 on: October 04, 2009, 07:33:22 AM »
I include Guard (121.5) on many of the feeds that LiveATC operates, as do many of the volunteer feeders.  There isn't enough traffic there to interfere with normal traffic on the other frequencies, and there is frequently interesting traffic that would not otherwise be captured.  In the future we may sprinkle some Guard-only feeds around the country and take it off the individual feeds, but that will take some time.

Controllers do not simulcast on Guard.  It is meant to be an emergency frequency and needs to be kept clear.  All facilities monitor Guard but they only transmit when they are looking for an unresponsive aircraft or communicating with an emergency aircraft.

Dave

Offline atcman23

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Re: kjfk tower - guard freq?
« Reply #4 on: October 04, 2009, 10:40:43 AM »
SYKOCUS -- That sounds like the answer. Thanks. Didn't realize they did that.

Now I'm even more curious, what else is "simulcast" used for? Do they transmit ATIS updates that way? Now that I think about it, at JFK I never hear more than one announcement of "ATIS changed to..." even though the feed scans all 3 twr freqs. 

Yet another question: Are the two JFK tower controllers sitting side by side so that they can talk to each other "off-line"? How do they coordinate so that a "simulcast" by one doesn't step on the other?   Wiki has a lovely article on ATC history and ops http://en.wikipedia.org/wiki/Air_traffic_control but nothing on the physical layout or the com links among controllers.

Thanks folks - this site is great.   

Controllers can broadcast on more than one frequency at the same time.  It is only done when necessary.  The ATIS updates you hear may or may not be transmitted by one controller on multiple frequencies.  With the way most of the feeds are set up on this site, it is likely that you are only catching one of the transmissions as each position likely announces the ATIS update at the same time (basically the flight data controller announces the new ATIS code to the controllers and they relay the message on their position (ground, local, etc.)).  At a busy airport, I doubt one controller would simulcast onto all the frequencies with this information as it is likely they would either step on another controller or a pilot.

The controllers do have a particular layout in the tower cab; each layout basically being unique to each tower.  The local and ground controllers are usually within hearing range (may not be next to each other but located close by) and these types of things would be coordinated between the two before they occurred.  One controller would ask the other if they could broadcast on their frequency but at a large airport such as JFK, I think this would be a rarity if it occurs at all.

Offline sykocus

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Re: kjfk tower - guard freq?
« Reply #5 on: October 04, 2009, 12:03:44 PM »
SYKOCUS -- That sounds like the answer. Thanks. Didn't realize they did that.

Now I'm even more curious, what else is "simulcast" used for? Do they transmit ATIS updates that way? Now that I think about it, at JFK I never hear more than one announcement of "ATIS changed to..." even though the feed scans all 3 twr freqs. 

Yet another question: Are the two JFK tower controllers sitting side by side so that they can talk to each other "off-line"? How do they coordinate so that a "simulcast" by one doesn't step on the other?   Wiki has a lovely article on ATC history and ops http://en.wikipedia.org/wiki/Air_traffic_control but nothing on the physical layout or the com links among controllers.

Thanks folks - this site is great.   

To clarify what I said earlier, controllers do not normally simulcast their normal transmissions on guard. I was suggesting that when they went on guard to try and get the connie they simulcasted on their normal freqs as well.

Each control position will have designated frequencies. A frequency is generally only designated to one position. Depending on what they are used for the controller might simulcast all the time or just when it is needed. For example one place I worked had a sector which assigned areas in a MOA (military operations area) and made sure the planes stayed in their area. The pilots would check in on one frequency and then go over another one once they were established in their area. Because they didn't want to be distracted by unnecessary radio chatter we would only simulcast when we needed to talk to one of the planes already in the area. However there are many times when controllers simulcast all the time. One very common example is if a controller is working multiple sectors that are combined because traffic doesn't warrant have them split off. In this case the controller would probably simulcast on all the frequencies designated for the positions they are working.

Offline klkm

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Re: kjfk tower - guard freq?
« Reply #6 on: October 04, 2009, 12:34:50 PM »
I am pretty sure when you push the PTT BOTH (VHF/UHF) on the VSCS for the guard frequency is transmits over your regular frequency as well.  This is likely what happened.  The guard channel has its own push button to transmit over guard, when you push that, it goes over your active frequencies as well.  As the previous poster said you can use simulcasting over multiple frequencies for multiple reasons, usually you do it when positions are combined, and the usable range of the frequency is only so far, in this case you keep aircraft on the separate frequencies (based on where they are in the combined sectors) so they can always hear you. 

Offline phil-s

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Re: kjfk tower - guard freq?
« Reply #7 on: October 05, 2009, 07:33:29 PM »
One specific question, to tie up loose ends:

Dave - Does the KJFK twr feed include the guard freq?

In general, the internal links (data, voice) among controllers is the thing I understand least about how this whole monster works. Anybody know a good online place to read up on it? As it is I'm absorbing it in little dribbles as folks are kind enough to explain specifics. 

Offline dave

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Re: kjfk tower - guard freq?
« Reply #8 on: October 06, 2009, 12:35:06 PM »
One specific question, to tie up loose ends:

Dave - Does the KJFK twr feed include the guard freq?

In general, the internal links (data, voice) among controllers is the thing I understand least about how this whole monster works. Anybody know a good online place to read up on it? As it is I'm absorbing it in little dribbles as folks are kind enough to explain specifics. 

I believe JFK Tower does have Guard programmed in.  I can't check it remotely but we can check next time someone is near the setup.

Offline mklatval

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Re: kjfk tower - guard freq?
« Reply #9 on: October 10, 2009, 02:44:56 PM »
One specific question, to tie up loose ends:

Dave - Does the KJFK twr feed include the guard freq?

In general, the internal links (data, voice) among controllers is the thing I understand least about how this whole monster works. Anybody know a good online place to read up on it? As it is I'm absorbing it in little dribbles as folks are kind enough to explain specifics. 

Anything specific you want to know?

Offline phil-s

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Re: kjfk tower - guard freq?
« Reply #10 on: October 10, 2009, 09:20:04 PM »
Sure -- the strips with info for each a/c. How does that part of the system work? Do they get printed at each controller station at the time the a/c is handed off from the previous controller?  Does the previous controller cause this to happen? If not, what controls the process by which the strips (or the info on them) move from one controller to another?


Offline sykocus

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Re: kjfk tower - guard freq?
« Reply #11 on: October 13, 2009, 10:30:57 PM »
When all goes as it should the information gets passed automatically and a strip is generated before the actual hand off happens. The receiving controller won't take the hand off on an airplane he has no idea about. There use to be a computer system in each center which would receive information from the approaches and towers in their control area as well as other centers. It then decides what sector, approach, tower and/or other center needs that information and sends it there. Now it maybe consolidated somewhat, overall system works the same.

I haven't ever been to a true FAA TRACON so I don't know how many printers the normally have. The approach control I worked when I was in the military only had one printer. The printer was hooked into our FDP computer which received data our host center. When the center's computer had a flight plan that would enter our airspace it would send the info to our FDP computer which would print out the strip. This happened usually 30 mins from the time it was estimated to touch the boundary of our airspace. It was the clearance/flight data controllers job to take each strip and take to the position in the control room that would need it. When a plane passed between control positions inside the facility the strip was physically passed with it. If we had a plane that was leaving our airspace our FPD would send the data to the center's computer and the center's computer would send the data to whoever would need to the information and their FDP would print out the strip, again, about 30 before it hit their boundary.

At a small to medium sized tower there would only be one printer. As the planes moves from taxing to waiting for take off they would get handed to the local controller from the ground controller. I have no idea how it works at a large complex tower like JFK, ATL, DFW, etc. Some of these airports have two local controls some even have two towers.

Most centers don't have strips anymore. They use URET which displays and records the same information electroncially I haven't even seen it yet so can't really describe it, but the back end is probably mostly the same.