novascotian
Member
When in a list of ARTCC freqs some are listed as discrete, what does that mean. For example high discrete....
Discrete frequencies
- Thread starter novascotian
- Start date
- Status
nd5y
Member
As far as I know it means it isn't paired or simulcast.
captkel
Member
Here’s the definition from the FAA:
DISCRETE FREQUENCY- A separate radio frequency for use in direct pilot-controller communications in air traffic control which reduces frequency congestion by controlling the number of aircraft operating on a particular frequency at one time. Discrete frequencies are normally designated for each control sector in en route/terminal ATC facilities.
I do hear discrete artcc frequencies late at night or when it's slow combine with others.
KEL
DISCRETE FREQUENCY- A separate radio frequency for use in direct pilot-controller communications in air traffic control which reduces frequency congestion by controlling the number of aircraft operating on a particular frequency at one time. Discrete frequencies are normally designated for each control sector in en route/terminal ATC facilities.
I do hear discrete artcc frequencies late at night or when it's slow combine with others.
KEL
novascotian
Member
Thanks for the replies, but I am not really sure what that FAA definition means. Since all the ATC comms are between the controller and the individual pilots, then in that regard discrete is no different than non-discrete... or is it saying these are overflow frequencies that some are sent to when it is too busy on the regular ones..... but then you are saying that you hear these late at night when presumably there is less traffic not more... so I am confused...
I've been flying and listening to ATC for years and haven't been able to figure out exactly what the FAA means by these "discrete" frequencies either ?
I've seen frequencies that they use as a primary in a certain area listed as "discrete" while the secondary/overflow frequency is listed as "normal", as well as the other way around.
As an example, the only Boston Center high altitude discrete frequency listed, according the database on this website, is 118.825 (Sector 53 Plattsburgh High), this is a secondary frequency generally only used when the North Atlantic tracks are fairly north sending a lot of traffic to/from Europe through this area, otherwise 135.700 (Sector 52 Montpelier Low/High), also listed as a discrete frequency and transmitted from multiple RCAG's, covers this area.
A little further south in New York Center, they have 125.325 (Sector 56 Kennedy High) listed as a discrete frequency and the sector beside it, 127.175 (Sector 42 East Texas High) listed as non-discrete. Generally, from what I've heard, these sectors are combined with 125.325 the "discrete" frequency used as the primary and the non-discrete 127.175 activated as an overflow/secondary when required.
Also browsing through the FAA daily NFDD messages you will see they are frequently changing the status of ARTCC frequencies from "discrete" to "non-discrete" and vise versa.
eg:
FLORIDA NFDD 239 - 2 12/14/2010
JACKSONVILLE
JACKSONVILLE ARTCC
IDENT ZJX
RCAG
SITE TALLAHASSEE, FL
LATITUDE - 30-29-56.71 N LONGITUDE - 084-19-22.64 W
FREQUENCY 128.625 RECAP
FREQ USE DISCRETE ADDED
ALTITUDE LOW RECAP
So who knows ? It would be interesting to hear the definative answer.
Last edited:
K4DHR
Member
I'll take a swag and say that it means that it is the only frequency assigned to the sector. I looked at the database, and all of the sectors I work at ZME are tagged as discrete. Whereas there are a few sectors in the center that do have two frequencies for one reason or another.
What about ZME Sector 15 HEE (low), the only frequency assigned to this sector is 135.30 and it is listed as "non-discrete" ?
Another example is ZMP Sector 24 Grand Forks (low-high), there are four frequencies assigned to this sector, 132.15, 127.35, 126.10 and 124.20, and they are all listed as "discrete" ?
.
Last edited:
Frequencies actually designated as "overflow" or "workload" or "overload" are rare and hard to find, ZAU has a few, the database here lists 126.850 as "Overload for ZAU26/81/83", another example is 134.20 listed as "Spare Workload Freq NW". Except both these frequencies are listed as "non-discrete".
.
Last edited:
Discrete Definition
Let me try and simplify what I think the FAA means by discrete, and feel free to correct me if this is wrong but, I think they simply mean its a temporarily assigned channel between the pilot and atc. Its temporarily unique to them in order to not clutter up the shared atc frequencies where other traffic is occuring amongs air/ground and/or air/air.
Taking an example of the definition it basically means "1. apart or detached from others; separate; distinct:"
So, they are simply saying they are talking separate from the whole on those frequenies, in my opinion.
Discrete | Define Discrete at Dictionary.com
Let me try and simplify what I think the FAA means by discrete, and feel free to correct me if this is wrong but, I think they simply mean its a temporarily assigned channel between the pilot and atc. Its temporarily unique to them in order to not clutter up the shared atc frequencies where other traffic is occuring amongs air/ground and/or air/air.
Taking an example of the definition it basically means "1. apart or detached from others; separate; distinct:"
So, they are simply saying they are talking separate from the whole on those frequenies, in my opinion.
Discrete | Define Discrete at Dictionary.com
There are many examples of frequenices that are listed as "discrete" that are not temporary. For example the Boston Center Shelton RCAG frequency 134.00 is listed as a "discrete", you can listen to this frequency over at LiveATC, and it's pretty clear that this is the standard frequency that is used for this sector, it's not temporary or a backup. However there are also frequencies that are secondary that are not listed as "discrete" and vice-versa (see examples above).
Last edited:
Hi folks, first post, private pilot with a raggedy ole Piper Dakota I bop around in.
What this means for practical purposes is, a controller will put you on a less populated frequency if he needs to give special instructions to keep the main frequency for an area open.
For example, you're on the line with a Center controller, and he's gotta vector you around a bad Tstorm in your path, because you don't have radar in the airplane and can't see it. He'll say "Piper 67890 switch to my frequency 123.45" and you switch over there, then you and him can speak more freely without everyone else's transmissions butting in.
What this means for practical purposes is, a controller will put you on a less populated frequency if he needs to give special instructions to keep the main frequency for an area open.
For example, you're on the line with a Center controller, and he's gotta vector you around a bad Tstorm in your path, because you don't have radar in the airplane and can't see it. He'll say "Piper 67890 switch to my frequency 123.45" and you switch over there, then you and him can speak more freely without everyone else's transmissions butting in.
doublescan
Member
Thanks xayd , that answers one of about 1200 questions I would like to ask a pilot, haha.
And, I see it's your first post, so I will say "Welcome to RR!"
And, I see it's your first post, so I will say "Welcome to RR!"
That's actually a question! 1200 is the default squawk code for a transponder in an airplane flying VFR (no clearances, fair weather day). 1200 and/or their radio frequency, with a pound or a star maybe, will also be the code for a lot of keypad locks at unattended airports, lol. If you ever feel the need to use their bathroom or sleep on their couch or anything...
That is what it sounds like the FAA definition means. However the frequencies that the FAA list as discrete are not being used this way, a lot of the listed discrete frequencies are clearly the primary frequency being used in the sector. So I still don't understand what criteria the FAA uses for making the distinction ?
The faa prob. Doesnt care how they are listed...
Honestly, other than that reason that I've personally seen used by a controller when I was talking to him, I dunno.
From the pilot's perspective it doesn't matter. They tell us what frequencies to change to and we change to what they tell us. If they mess up and give us the wrong one, we switch back to the previous one like lost children and ask for help.
It might be the reverse.
Discrete may mean "do not use this for special use, this is the designated frequency for this area", and non-discrete frequencies are available for spillover or special use.
Last edited:
I've seen them go both ways (see my examples above). I've been flying for over 30 years (around 14,000 hours) and from a pilots perspective (and ATC geek) I have not been able to figure out what the difference is as they seem to use listed discrete frequencies as both the primary or seconday and vice-versa.
Any chance you remember what area/sector/frequency that was ? large low sectors often use multiple frequencies so it's not uncommon to be switched to a different frequency being used by the same controller just for geographic coverage.
Apparently, as some of the frequency info. they provide is not up to date or accurate either.
Memphis center in central AR the last time I heard such a thing and the only time I've had a controller do that to me personally.
Was a large and growing larger line of Tstorms he was trying to get several of us around between Hot Springs and Russellville as I remember it, but don't remember the frequencies exactly.
Last edited:
From what I can tell there appears to be 4 Memphis low altitude sectors that use 2 separate frequencies, of these 4 sectors, 3 specify one of the 2 frequencies as being discrete, however there is the one sector with two frequencies were both are listed as discrete. All the other Memphis low altitude sectors are single frequency and all are listed as being discrete, except for one.
I'm not familiar with that area, but I suspect that the sectors that do have two frequencies listed use them both for geographic coverage and not as primary/secondary ? Then there is that one sector that uses a non-discrete single frequency while all the others are listed as discrete.
I notice that in addition to frequencies listed as being "discrete" or not there are also some that are listed as "do not publish". I'm wondering then that in this context the "discrete" has something to do with whether or not the frequencies are published on charts ? If you look at an FAA IFR low altitude chart you will see that "discrete" frequencies are shown on the map while those that are not listed as "discrete" are not shown on the charts. Maybe this is what it means and it has nothing to do with actual frequency useage ? Or maybe it's just a coincidence they don't put non-discrete frequencies on low altitude charts ?
Last edited:
- Status
