Question about Frequency "Patching"

Derg

New Arizona, Il Duce/Warlord
Staff member
canadian_atc or anyone else:

A few weeks ago, sitting fat dumb and happy in Maastricht's airspace, ATC asked one of the flights to give him a radio check over another frequency.

When he did, we still heard both ATC and the other aircraft on the original frequency. The non-flying onboard my aircraft notified ATC that they had not actually changed frequencies and Maastricht said something about "frequency patching" or "doubling" or something like that where ATC can broadcast on multiple frequencies and the responding aircraft can be heard over multiple frequencies.

Is this common?
 

Screaming_Emu

Joe Conventional
Nothing to add as far as how they do it, but I think I had this happen on accident the other day. We were talking to washington center, switched to a new frequency, but could still hear the old one. We weren't the only airplane having this problem either...was very strange.
 

Vector4Food

This job would be easier without all the airplanes
We refer to that here as frequency "coupling"

The reasoning behind it is relatively simple. When we combine airspace at "slower" times someone still has to monitor all published frequencies, this has never changed, but before we had coupling, you could be monitoring in my case up to 19 different frequencies, and because of range, have multiple aircraft on up to three or four different freq's, and because they can't hear each other they would step all over each other.

With coupling, we can select which frequencies are "coupled" and through a digital connection, whatever is transmitted/recieved on each frequency is duplicated out any of the coupled frequencies. There is a tiny delay, maybe half a second or so. That way when I have an airplane that's 600 miles away, you can hear when he's talking so it makes for a much safer envrionment.
 

inigo88

Composite-lover
That's pretty neat. "Patching" has been done for a long time in public safety land-mobile radio, but this is the first time I've heard of it being used in ATC. Would definitely help minimize aircraft stepping on each other when ATC is simulcasting on multiple frequencies. Kudos Canada for beating the US to the punch with this. :)
 

Derg

New Arizona, Il Duce/Warlord
Staff member
We refer to that here as frequency "coupling"

The reasoning behind it is relatively simple. When we combine airspace at "slower" times someone still has to monitor all published frequencies, this has never changed, but before we had coupling, you could be monitoring in my case up to 19 different frequencies, and because of range, have multiple aircraft on up to three or four different freq's, and because they can't hear each other they would step all over each other.

With coupling, we can select which frequencies are "coupled" and through a digital connection, whatever is transmitted/recieved on each frequency is duplicated out any of the coupled frequencies. There is a tiny delay, maybe half a second or so. That way when I have an airplane that's 600 miles away, you can hear when he's talking so it makes for a much safer envrionment.
Thanks!

In fact, they call it 'coupling' there as well.

I had written it down but then misplaced my uniform shirt with the note in it.

Not on the jet, of course! :)
 

Cessnaflyer

Wooooooooooooooooooooooooooooooo
Thanks!

In fact, they call it 'coupling' there as well.

I had written it down but then misplaced my uniform shirt with the note in it.

Not on the jet, of course! :)
I hate when the hooker takes my clothes too! ;)
 

Vector4Food

This job would be easier without all the airplanes
Thanks!

In fact, they call it 'coupling' there as well.

I had written it down but then misplaced my uniform shirt with the note in it.

Not on the jet, of course! :)
Nice

I would imagine that within a few years this will be fairly common place. It's as simple as touching each frequency on our panels to turn coupling on or off, sometimes you don't want it in, discreet conversations, stuck mic's etc.

The FAA IIRC ,and someone from that side of the fence can elaborate, is supposed to be phasing this in eventually. I think right now they have other projects of higher priority, not to mention, because of the nature of condensed traffic in the US, I imagine it's less of a priority.

What is funny is when two airplanes that are 600 miles apart try to talk to each other on "company frequency" :) Thinking that they are obviously in range of each other.
 

klkm

Well-Known Member
We have it in the US as well, just isn't used all that often. I find when all the freqs are coupled it causes the freq to break up at times. I do use it if there is a long readback expected on one freq and i expect someone to check in on my other freq, I will turn it on so they won't check on during the readback.
 

Vector4Food

This job would be easier without all the airplanes
We have it in the US as well, just isn't used all that often. I find when all the freqs are coupled it causes the freq to break up at times. I do use it if there is a long readback expected on one freq and i expect someone to check in on my other freq, I will turn it on so they won't check on during the readback.
We had that same issue when it first came, new hardware upgrades, and especially software upgrades have fixed pretty much all of these problems. I've had a tech explain it to me, but I have the attention span of a goldfish when it comes to a lot of that :)
 

Derg

New Arizona, Il Duce/Warlord
Staff member
We had that same issue when it first came, new hardware upgrades, and especially software upgrades have fixed pretty much all of these problems. I've had a tech explain it to me, but I have the attention span of a goldfish when it comes to a lot of that :)
I'll give someone two sentences to capture and hold my attention.

Long-winded people just make me daydream of tacos or crispy, delicious buffalo wings.


Sent from my Colecovision Adam
 

FM_Weasel

Well-Known Member
I wish we had frequency patching at my facility. We run a certain sector combined up almost 100% of the time and there are 3 VHF and 3 UHF frequencies that get pretty active and it's always a word jumble when it starts getting busy (and more so when you through in the land line activity).

Another sector that's often combined has 4 VHF and 4 UHF freqs combined up, with an additional 2 UHF freqs that are monitored on the speaker. I know some places have it much worse but patching would be insanely helpful in these cases.
 

Roger Roger

Paid to sleep, fly for fun
We refer to that here as frequency "coupling"

The reasoning behind it is relatively simple. When we combine airspace at "slower" times someone still has to monitor all published frequencies, this has never changed, but before we had coupling, you could be monitoring in my case up to 19 different frequencies, and because of range, have multiple aircraft on up to three or four different freq's, and because they can't hear each other they would step all over each other.

With coupling, we can select which frequencies are "coupled" and through a digital connection, whatever is transmitted/recieved on each frequency is duplicated out any of the coupled frequencies. There is a tiny delay, maybe half a second or so. That way when I have an airplane that's 600 miles away, you can hear when he's talking so it makes for a much safer envrionment.
That is so cool! I had no idea such a thing existed.
 

inigo88

Composite-lover
That is so cool! I had no idea such a thing existed.
At risk of being the dreaded long-winded guy, I think it basically works like this:

ATC talks to pilots through mountaintop transmitter sites (RCOs/RCAGs). All these sites are linked together (and back to the ATC facility) using point-to-point microwave dishes (those white drum looking things on radio towers). Normally the closest RCO site receives the pilot's transmission and beams it back to the ATC facility via the microwave links. Only with this patching system, the audio is simultaneously beamed to the ATC facility and any other selected RCO tower sites, where it's retransmitted on the patched frequencies. And because all the transmissions literally travel at the speed of light, the resulting delay is pretty small.

Pretty cool!
 

Vector4Food

This job would be easier without all the airplanes
I wish we had frequency patching at my facility. We run a certain sector combined up almost 100% of the time and there are 3 VHF and 3 UHF frequencies that get pretty active and it's always a word jumble when it starts getting busy (and more so when you through in the land line activity).

Another sector that's often combined has 4 VHF and 4 UHF freqs combined up, with an additional 2 UHF freqs that are monitored on the speaker. I know some places have it much worse but patching would be insanely helpful in these cases.
Our UHF's are automatically paired to our VHF frequencies in our panels, there's not even anyway to separate them. To be honest however, it's pretty rare nowadays that a military flight NEEDS to have UHF, but it happens from time to time.
 

Vector4Food

This job would be easier without all the airplanes
At risk of being the dreaded long-winded guy, I think it basically works like this:

ATC talks to pilots through mountaintop transmitter sites (RCOs/RCAGs). All these sites are linked together (and back to the ATC facility) using point-to-point microwave dishes (those white drum looking things on radio towers). Normally the closest RCO site receives the pilot's transmission and beams it back to the ATC facility via the microwave links. Only with this patching system, the audio is simultaneously beamed to the ATC facility and any other selected RCO tower sites, where it's retransmitted on the patched frequencies. And because all the transmissions literally travel at the speed of light, the resulting delay is pretty small.

Pretty cool!
Neat. Interesting to know how it works. ATCers however often don't pay enough attention to how things work... more of the Apple fanboy club motto "It just works"
 

inigo88

Composite-lover
Neat. Interesting to know how it works. ATCers however often don't pay enough attention to how things work... more of the Apple fanboy club motto "It just works"
Haha I hear ya.

One small correction. Since your touchscreen audio panel (VSCS?) acts like the switch that controls the whole system, the audio will go back to the ATC facility first... route through the VSCS and then go back out to all the other RCOs to re-transmit the patch audio. Thanks to radio signals traveling at the speed of light, the delay is still pretty small.
 

Derg

New Arizona, Il Duce/Warlord
Staff member
You mean someone at Southern Jets lets you actually touch the controls and be the pilot flying?
Occasionally.

Wait, at least I FLY a plane rather than make polite suggestions to an autopilot! ;)
 
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