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Saw a news story about possible problems with 5g C-band interfering with commercial/civil aviation. So I looked into what was going on and was mildly surprised and concerned by what the FAA is saying.

An AD is being issued that basically says that at certain locations you can't use your radar altimeter and related system. That seem concerning. 

Here is the proposed AD: https://www.faa.gov/sites/faa.gov/files/2021-12/FRC_Document_AD-2021-01169-T-D.pdf

And here is the part of the AD that really caught my eye:

13629652_ScreenShot2022-01-01at5_22_17PM.thumb.png.5264e7d90a8b58d8d824e4e7171c9192.png

So help me out here. I can't use ILS if there is 5g C-band interference in the area? Wouldn't that mean most metro areas and affect most every flight in those areas during crappy weather? That seems like a pretty steep price to pay just to watch cat videos.

 

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Best way to explain it is that it is like buying a piece of property for $80 billion and finding that it is occupied by squatters who keep taking you to court to stop you from using the property you paid for.

Greater experts than I can debate whether some radio altimeters are insufficiently immune to out-of-band interference. I have heard no evidence of such a thing. But the idea that a valuable chunk of spectrum cannot be put to use because somebody underengineered a device that is licensed to operate in a different band is not only unfair to Verizon and AT&T, but also undermines the FCC’s stewardship of a scarce and precious resource. It’s a freaking mess and I hope that the avionics manufacturers get held accountable.

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12 hours ago, βhyde said:

Saw a news story about possible problems with 5g C-band interfering with commercial/civil aviation. So I looked into what was going on and was mildly surprised and concerned by what the FAA is saying.

An AD is being issued that basically says that at certain locations you can't use your radar altimeter and related system. That seem concerning. 

Here is the proposed AD: https://www.faa.gov/sites/faa.gov/files/2021-12/FRC_Document_AD-2021-01169-T-D.pdf

And here is the part of the AD that really caught my eye:

13629652_ScreenShot2022-01-01at5_22_17PM.thumb.png.5264e7d90a8b58d8d824e4e7171c9192.png

So help me out here. I can't use ILS if there is 5g C-band interference in the area? Wouldn't that mean most metro areas and affect most every flight in those areas during crappy weather? That seems like a pretty steep price to pay just to watch cat videos.

 

Are you flying the type of equipment that is addressed in this AD? And if so are you a Child of the Magenta Line?

If you have a pressure altimeter there is no interference, and from what I understand even the new 787s comes equipped with a pressure altimeter.   Just as the folks flying Etihad 787-10 into Aba Daba Do this past summer that almost screwed the pooch. 

Though, I do find this interesting as just recently LAX bragged about upgrading the terminals to 5G:

https://airportscouncil.org/wp-content/uploads/2019/09/bit-session3-moore.pdf

 

 

 

 

 

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13 hours ago, βhyde said:

Saw a news story about possible problems with 5g C-band interfering with commercial/civil aviation. So I looked into what was going on and was mildly surprised and concerned by what the FAA is saying.

An AD is being issued that basically says that at certain locations you can't use your radar altimeter and related system. That seem concerning. 

Here is the proposed AD: https://www.faa.gov/sites/faa.gov/files/2021-12/FRC_Document_AD-2021-01169-T-D.pdf

And here is the part of the AD that really caught my eye:

13629652_ScreenShot2022-01-01at5_22_17PM.thumb.png.5264e7d90a8b58d8d824e4e7171c9192.png

So help me out here. I can't use ILS if there is 5g C-band interference in the area? Wouldn't that mean most metro areas and affect most every flight in those areas during crappy weather? That seems like a pretty steep price to pay just to watch cat videos.

 

You can use the ILS all you want to, but you can't do any approaches that require a radar altimeter. For me that is no factor, I don't even have one. For airliners that use them for autoland and/or shooting approaches below the standard minimums, this is a huge deal.

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Just now, Ventucky Red said:

Are you flying the type of equipment that is addressed in this AD? And if so are you a Child of the Magenta Line?

If you have a pressure altimeter there is no interference, and from what I understand even the new 787s comes equipped with a pressure altimeter.   Just as the folks flying Etihad 787-10 into Aba Daba Do this past summer that almost screwed the pooch. 

Though, I do find this interesting as just recently LAX bragged about upgrading the terminals to 5G:

https://airportscouncil.org/wp-content/uploads/2019/09/bit-session3-moore.pdf

 

ALL airplanes come with pressure altimeters, that is not the issue. I don't even own a radar altimeter, I won't notice it not working if I don't have it :rolleyes:

The problem is you cannot do certain types of approaches without one, so for one example the minimums to fly an ILS approach are higher without one. I can't do a Cat II or III anyway, so I am used to going elsewhere when the weather gets that low, but airlines count on being able to do II and III and not doing so will disrupt their operations.

https://www.avweb.com/insider/is-a-5g-showdown-looming/

Failure of the radar altimeter is not something to be taken lightly. It not only determines decision height for an instrument approach, it’s the primary source of altitude information for Cat 2 and Cat 3 approaches. If that function can’t be guaranteed, the FAA must regulate that it can’t be used. If there’s even a chance that the cell signals will cause the radar altimeter to fail at a critical moment, which is just about all the time the altimeter is in use, there’s a significant threat to flight safety.

That raises the specter of a ban on Cat 2 and Cat 3 approaches at airports within range of 5G transmitters. On Dec. 5, that will be 46 of the country’s largest metropolitan areas. The mind boggles at the potential consequences given the weather much of the country has been having lately. And within a few years, 5G will be everywhere if the telecoms have their way.

For its part, the FCC says the threat is minimal and it should be up to the aviation industry to deal with the potential interference. Apparently there are ways to harden radar altimeters to shrug off stray cellphone energy and the FCC is of the view that the cost of retrofitting the fleet should be borne by the aircraft operators. That attitude has naturally galvanized aviation into a rare block of unanimity against the rollout.

 

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8 hours ago, Throatwarbler-Mangrove said:

Best way to explain it is that it is like buying a piece of property for $80 billion and finding that it is occupied by squatters who keep taking you to court to stop you from using the property you paid for.

Greater experts than I can debate whether some radio altimeters are insufficiently immune to out-of-band interference. I have heard no evidence of such a thing. But the idea that a valuable chunk of spectrum cannot be put to use because somebody underengineered a device that is licensed to operate in a different band is not only unfair to Verizon and AT&T, but also undermines the FCC’s stewardship of a scarce and precious resource. It’s a freaking mess and I hope that the avionics manufacturers get held accountable.

On the most basic level, this is quite true. If your VHF can't tell channel 15 and channel 16 apart because it sucks, then don't sue me to stop me talking on 15, get a better radio :rolleyes: In real life this is quite tricky, replacing every radar altimeter at once with a new interference-proof version that *does not yet exist* will not be easy or cheap. We have had similar issues with GPS, there have been attempts by companies to use spectrum in such a way that would jam a huge percentage of existing GPS units that so far have not passed. Both radar altimeters and GPS receivers got designed back when there were no neighbors, so they didn't use double-pane glass or even put any locks on the screen doors. Now what was wide-open country is in the middle of the city :o

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59 minutes ago, Ventucky Red said:

Are you flying the type of equipment that is addressed in this AD? And if so are you a Child of the Magenta Line?

If you have a pressure altimeter there is no interference, and from what I understand even the new 787s comes equipped with a pressure altimeter.   Just as the folks flying Etihad 787-10 into Aba Daba Do this past summer that almost screwed the pooch. 

Though, I do find this interesting as just recently LAX bragged about upgrading the terminals to 5G:

https://airportscouncil.org/wp-content/uploads/2019/09/bit-session3-moore.pdf

 

 

 

 

 

Did you watch the Blanoclirio video I posted?  All 30 minutes of it?  It explains the issues clearly and in detail.

I know you fly GA aircraft, but this guy was an Air Force pilot and now flies Boeing triple 7s for a living and he did a lot of research for this video.  For example it isn't just radar altimeters that can experience interference, and it affects commercial aviation far more than GA.  It's a real issue with a lot of ramifications.  It might not cause any competent commercial cockpit crew to crash, but it can cause many problems when many planes on final will have to do a go around because of an instrument glitch right before they land, among other things.

The GA people have no trouble regularly crashing their planes and dying already, and most of them fly VFR with basic instruments anyway. This issue is a big concern for part 121 operations, affecting millions of people.  The 500,000 or so part 91 pilots and their occasional passengers are obviously insignificant compared the number of people flying commercially daily.  

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While I've not yet watched Ed's video.  Didn't we do this whole exact scenario with cell phones when they first became popular? 

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9 hours ago, Throatwarbler-Mangrove said:

But the idea that a valuable chunk of spectrum cannot be put to use because somebody underengineered a device that is licensed to operate in a different band is not only unfair to Verizon and AT&T, but also undermines the FCC’s stewardship of a scarce and precious resource. It’s a freaking mess and I hope that the avionics manufacturers get held accountable.

Your post sounds like all of this is simple and radar altimeters were invented last year.  Radio altimeters were in use long before 5G was a thing, probably long before anybody even thought about 5G for cell phone frequencies.  So are you saying the airlines should be liable just because a relatively new technology suddenly elbows it's way on to the scene and is worth hundreds of billions of dollars in future income and the  airlines can just go pound salt?  Why are it the avionics manufactures at fault for not making allowances for any future possibility?  No profitable company is going to overdesign already complex devices for any future possibility, that's just ludicrous.

How does it undermine the FCCs stewardship?  They control the frequency spectrum however I don't think it's in their charter to allocate new frequencies to newcomers who are paying billions, at the expense of the folks who have been using adjacent frequencies without problems for many years.

As the commercial spectrum frequencies get used more and more, and the useful frequencies aren't in infinite supply, these problems will get worse and worse.  And when the ultimate object is profit, not utility, things will get uglier and uglier.  You are treating this like it's a simple problem and the telecoms should get whatever they want. 

By what you've said here, I am starting to wonder if you don't have some vested interest in the telecom industry, but you don't sound very objective to me.  Are you a Verizon lobbyist?  Do you work in PR for ATT&T?  Because to me you sound like a telecom corporate shill.

If you want to expound on what you said and provide facts and links, to support your view, I am willing to listen.  Otherwise I will stick to my theory.

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2 minutes ago, Windward said:

While I've not yet watched Ed's video.  Didn't we do this whole exact scenario with cell phones when they first became popular? 

Yeah, but not to this extent.  With the huge rise in demand for the communication spectrum, this problem will only get worse and worse.  There are only so many useful frequencies available. Of course at some point new technology will eventually solve the problem, but the demand is growing far faster than the time it takes to develop ground breaking technology.  

It's like the huge amounts of satellites in space today.  When Sputnik was launched in the 1950s, space was empty of man made objects.  The idea that infinite space could get crowded was probably no concern to anyone in the fledgling aero space industry  There is a relatively small amount relatively economical low earth orbit space available and it's getting crowded.  Rocket launches nowadays have to plan trajectories to avoid active and inactive satellites, and old satellites can take years for their orbits to degrade enough to renter the atmosphere.  Remember just recently the ISS had to move to dodge some space junk.  

The demand for more and more useful high tech devices is growing far faster than the ability to find new and innovative ways to economically find room for anything, be it the communication portion of the electromagnetic spectrum, or the available room for space based objects.  The same applies to rare earth elements, and many other things.  Of course an unlimited supply of money for R&D could solve all of the problems, but that's not possible.  To put it in simple terms, it's somewhat analogous to a low income family with 4 rapidly growing teenage boys, trying to keep their kids clothed, let alone in the latest fashions. 

I'm by no means saying I am some kind of genius, but when I was in the 7th grade in the late 1960s, I wrote a paper for a science class about what was modern technology at the time, and mans adaptability, vs the state of the natural world and it's finite resources.  In my closing argument I used the analogy that mankind vs the world we live in was like a kid (mankind) running down a hill pulling a wagon behind him.  At some point on the steep hill (the earth), the inertia of the wagon (technology) would overcome the maximum speed of the kid's ability to run and the wagon would nip at his heels and ultimately cause him to crash and burn.  Little did I know how right I was.  I wish I would have saved my little essay, maybe I was some kind of young prodigy!  :lol:

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1 hour ago, Ed Lada said:

Did you watch the Blanoclirio video I posted?  All 30 minutes of it?  It explains the issues clearly and in detail.

I know you fly GA aircraft, but this guy was an Air Force pilot and now flies Boeing triple 7s for a living and he did a lot of research for this video.  For example it isn't just radar altimeters that can experience interference, and it affects commercial aviation far more than GA.  It's a real issue with a lot of ramifications.  It might not cause any competent commercial cockpit crew to crash, but it can cause many problems when many planes on final will have to do a go around because of an instrument glitch right before they land, among other things.

The GA people have no trouble regularly crashing their planes and dying already, and most of them fly VFR with basic instruments anyway. This issue is a big concern for part 121 operations, affecting millions of people.  The 500,000 or so part 91 pilots and their occasional passengers are obviously insignificant compared the number of people flying commercially daily.  

 

Go read up on the GBAS landing system.

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1 hour ago, Ventucky Red said:

 

Go read up on the GBAS landing system.

GBAS is the old DGPS system using VHF instead of MF datalink. It is a good idea and might one day replace the radar altimeter. If you have a fleet of airplanes, technology that may roll out in the future is not helping when you need something that works next week. In the long run it could be the answer, in the short run it isn't here yet for CAT II/III approaches.

 

* tech note - GPS is only so accurate even when not intentionally degraded. DGPS used fixed stations that obviously knew where they were to broadcast corrections on MF frequencies (about 200-400 KHz). The system worked, but then we got WAAS, which is the same idea but broadcast via satellite. It too works well, but not quite as good as a correction from exactly where you are landing. GBAS is the old DGPS done on VHF with presumably much better corrections.

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31 minutes ago, kent_island_sailor said:

GBAS is the old DGPS system using VHF instead of MF datalink. It is a good idea and might one day replace the radar altimeter. If you have a fleet of airplanes, technology that may roll out in the future is not helping when you need something that works next week. In the long run it could be the answer, in the short run it isn't here yet for CAT II/III approaches.

It is already standard equipment on the 787, 747-8, and an option on the 737 and many of the Airbus family.  Boeing has also stated that many customers are asking for this to be installed on all new aircraft. Additionally, it has already been in use at Newark and Bush International by both Delta and United, not to mention many of the other locations and carriers worldwide.

Cat II and III capability are just around the corner...  I believe it is being tested somewhere in the hinterlands...

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I recall that the FAA prohibited all cell phone and "electronic device" use when cell phones were new.... The idea was that the signals might interfere with navigation systems. Turns out that was all bull shit, the airlines just thought that having a bunch of pretentious assholes yapping in the cabin annoying other passengers might be dangerous to the flight crew....

 So after a few years of debunking, "Airplane mode" was instituted. Mostly, pretentious assholes are texting now, not talking. It's brats with their games on their I-phones that are the biggest annoyance now.

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12 minutes ago, Ventucky Red said:

It is already standard equipment on the 787, 747-8, and an option on the 737 and many of the Airbus family.  Boeing has also stated that many customers are asking for this to be installed on all new aircraft. Additionally, it has already been in use at Newark and Bush International by both Delta and United, not to mention many of the other locations and carriers worldwide.

Cat II and III capability are just around the corner...  I believe it is being tested somewhere in the hinterlands...

Did  you actually watch the video I posted?  It doesn't appear that you did.  Brown is a 777 pilot.  He knows WTF he's talking about and he goes into great detail about the problem.  There is no easy fix for it.  It isn't rocket surgery but isn't kindergarten easy either.  No offense to you, but I think he knows a bit more about this problem than you do and he did a lot of research to make that video.

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15 minutes ago, Ed Lada said:

Did  you actually watch the video I posted?  It doesn't appear that you did.  Brown is a 777 pilot.  He knows WTF he's talking about and he goes into great detail about the problem.  There is no easy fix for it.  It isn't rocket surgery but isn't kindergarten easy either.  No offense to you, but I think he knows a bit more about this problem than you do and he did a lot of research to make that video.

Since the late 90s' the FAA and ICAO have been working on a replacement to the analog navigation systems that were designed and in use long before you and I graced the earth.  When I took my instrument check ride, we were still using ADF/NDB navigation systems and approaches.  They are no longer in existence.   Another question for thought, why are we doing away with many of the VOR stations in the US? Why do we have more and more "tango" routes popping up?  Why does GA aircraft now have a requirement ADS-B?

There was no mention of the new systems coming online in your video - why was that?   You're right he goes into some detail that by the time it might become a problem, the problem no longer exists in favor of the newer systems.

 

 

 

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16 minutes ago, justsomeguy! said:

Not unexpected from the companies that have invested in the spectrum.

Well yeah, they spent many billions acquiring the bandwidth and they want their money back!

Giving the FCC the right to that portion of the spectrum was probably one of the smartest things the government ever did from a financial perspective.  They didn't pay for it and it's become a virtual gold mine.

 

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Question: I'm told that the European Union doesn't think this is a problem. Is that true, and if so why is that?

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2 minutes ago, Ventucky Red said:

There was no mention of the new systems coming online in your video - why was that?   You're right he goes into some detail that by the time it might become a problem, the problem no longer exists in favor of the newer systems.

I watched the video earlier and my short term memory sucks.  But seem to think that I didn't hear what you did (or didn't).  I certainly might be wrong about that.  Maybe when I have a free 30 minutes tomorrow, I'll watch it again keeping in mind what you just said.   But I'll need to re-read your post before I watch it again because I won't remember it tomorrow otherwise.   

This growing old shit really sucks sometimes.

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7 minutes ago, Remodel said:

Question: I'm told that the European Union doesn't think this is a problem. Is that true, and if so why is that?

From my perspective, I don't know.  I keep up with technical things in the US, here not so much.  

I do know that at least in Poland, 5g is not common at all yet.  

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54 minutes ago, Ed Lada said:

they spent many billions acquiring the bandwidth and they want their money back!

Before their customers start lawyering up, I suppose. ;)

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1 hour ago, Remodel said:

Question: I'm told that the European Union doesn't think this is a problem. Is that true, and if so why is that?

Eu 5G Band is a bit farther away from the plane doohickey.

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Any reason the radar altimeters can't have high pass cutoff filters retrofitted? Let's pull a number out of my ass and say it costs $1000 to retrofit and there's 200,000 airliners. We're just not talking about a whole lot of money here.

image.thumb.png.286ecbe1ac84d3f7dd29139ca53646ee.png

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1 hour ago, Olsonist said:

Any reason the radar altimeters can't have high pass cutoff filters retrofitted? Let's pull a number out of my ass and say it costs $1000 to retrofit and there's 200,000 airliners. We're just not talking about a whole lot of money here.

image.thumb.png.286ecbe1ac84d3f7dd29139ca53646ee.png

Changing ANYTHING on an airplane is going to be very expensive and time consuming. $1,000 an airplane would be amazing.

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2 hours ago, kent_island_sailor said:

Changing ANYTHING on an airplane is going to be very expensive and time consuming. $1,000 an airplane would be amazing.

$1,000 is half of 1 first class ticket from Buttfuck Idaho to Greasy spoon Illinois.

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13 hours ago, Ed Lada said:

Your post sounds like all of this is simple and radar altimeters were invented last year.  Radio altimeters were in use long before 5G was a thing, probably long before anybody even thought about 5G for cell phone frequencies.  So are you saying the airlines should be liable just because a relatively new technology suddenly elbows it's way on to the scene and is worth hundreds of billions of dollars in future income and the  airlines can just go pound salt?  Why are it the avionics manufactures at fault for not making allowances for any future possibility?  No profitable company is going to overdesign already complex devices for any future possibility, that's just ludicrous.

How does it undermine the FCCs stewardship?  They control the frequency spectrum however I don't think it's in their charter to allocate new frequencies to newcomers who are paying billions, at the expense of the folks who have been using adjacent frequencies without problems for many years.

As the commercial spectrum frequencies get used more and more, and the useful frequencies aren't in infinite supply, these problems will get worse and worse.  And when the ultimate object is profit, not utility, things will get uglier and uglier.  You are treating this like it's a simple problem and the telecoms should get whatever they want. 

By what you've said here, I am starting to wonder if you don't have some vested interest in the telecom industry, but you don't sound very objective to me.  Are you a Verizon lobbyist?  Do you work in PR for ATT&T?  Because to me you sound like a telecom corporate shill.

If you want to expound on what you said and provide facts and links, to support your view, I am willing to listen.  Otherwise I will stick to my theory.

Let me address the ad hominem first. I am a telecom industry analyst. Over my career I have learned more -- and forgotten more -- about telecom than most people will ever know. I cannot discuss specific clients, but suffice to say that they include mobile operators and manufacturers of mobile infrastructure equipment. I am an objective observer insofar as I am not paid to have a particular opinion on this particular topic. I am not an expert on this topic but do know enough to have an informed opinion. Which is more than others in this thread can claim.

Starting with the basics: the airwaves in the United States, an extremely scarce and valuable resource, are property of the American people, under the stewardship of the FCC and the NTIA. It is the responsibility of the NTIA to allocate frequencies to services, and the FCC to regulate the use of those frequencies. The FCC and NTIA are required to consult with a bunch of federal agencies including the FAA, but they are the experts and have no obligation to accept the recommendations of other agencies.

Until last year, the band from 3.7 to 3.98 MHz was occupied by now-obsolete satellite services. NTIA cannot allow valuable spectrum to remain fallow, and the properties of this particular spectrum make it desirable for mobile communication services. Both agencies conducted notice-and-comment proceedings to reallocate that spectrum (NTIA) and to establish technical rules for the band, and an auction to sell off licenses to mobile carriers to buy out the incumbent users and have unlimited use of said spectrum. Unless the DC Circuit Court finds otherwise, these rulemakings were lawful under the Communications Act and the Administrative Procedures Act.

Verizon, AT&T and T-Mobile bid in good faith in this auction for licenses to use this spectrum at will, subject to the FCC Rules. They have paid (or committed to pay) $80-something Billion to the US Treasury for those licenses. For which the American Public is in turn paying big mobile bills to get advertised speeds.

To the video:   On aviation matters, I defer to Captain B.... Not that he said anything I didn't already know. His statements on engineering matters were factual enough. Where he and I diverges is his claim that the Telecom industry is "encroaching" on those frequencies. Wrong. The Radio Altimeter Service is allocated the band from 4200 MHz to 4400 MHz. Not DC to Daylight and not 3700-3980 MHz. They can't intentionally transmit outside that band and out-of-band transmit power has to roll off at -52dB per kHz. The FCC Rules, unfortunately, do not specify receivers, specifically immunity to out-of-band emissions (I vaguely recall that the European regulations to include a receive mask). The rule is essentially that adjacent band interference is the receiver's problem, not the transmitter's.

image.thumb.png.286ecbe1ac84d3f7dd29139ca53646ee.png

The Radio Altimeter Receive Mask  (green dotted line) is ridiculous. Maybe microwave filters with a higher Q factor were not practical in 1939, but they sure are now. The NTIA and the FCC allocated a generous 220 MHz guard band between the 5G service and the radio altimeter service.  As I understand it, that's 100 MHz more guard band than the European regulators.  It would be poor stewardship of the spectrum to allow more than that 220 MHz to lie fallow because of inadequate receiver design by users of an adjacent band.

It's not as if the avionics manufacturers and the aircraft operators didn't have sufficient warning. This spectrum re-farming has been years in the making. And for RTCA to drop their report only weeks before the mobile operators were to go live with their 5G deployments is at best passive-aggressive.

As to what to do now... Verizon and AT&T have offered to operate at half-power for the next 6 months to give the aviation interests a chance to sort out their mess. They do not see any reason to make more concessions, and I agree with them.  It seems to me that the time should be used to replace older radio altimeters suspected of being susceptible. If I understand correctly (not an aviation expert), the FAA can issue an AD to that effect.

 

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7 hours ago, Throatwarbler-Mangrove said:

Until last year, the band from 3.7 to 3.98 MHz was occupied by now-obsolete satellite services.

 

Are you missing a decimal place or two? I use those frequencies for SSB voice comms and they are still very much in use

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35 minutes ago, Throatwarbler-Mangrove said:

Oops.  I meant GHz.

Another FYI - The 1938 versions of radar altimeters were on 450 MHz, small and cheap(ish) magnetrons were in the future at that point.

Meanwhile AT&T plays hardball:

Telecoms Reject Another 5G Delay, Offer To Modify Airport Deployment (Updated)

January 1, 2022
14
 
 
 
 
 
Screen-Shot-2021-02-25-at-10.30.31-AM-69

Verizon and AT&T say they’ll turn down the power of 5G broadband signals near major airports of their choosing for six months but otherwise the rollout of the much-anticipated system will go ahead as planned on Jan. 5. In a scathing letter to Transportation Secretary Pete Buttigieg and FAA Administrator Steve Dickson released by The Wall Street Journal on Sunday, AT&T CEO John Stankey and Verizon’s Hans Vestberg chided the government officials for what they characterized as an eleventh-hour request to prevent widespread flight restrictions when they’ve had at least a year to prepare for 5G.

(From www.avweb.com/aviation-news/faa-asks-for-another-5g-delay/?MailingID=%CAMPAIGNID%)

This is reminding me of the ADS-B rollout.

FAA to owner of $15,000 airplane: Install ADS-B or park it. You say it costs a significant fraction of what you paid for the entire airplane? Tough shit.

FAA to owner of $15,000,000 737: Install ADS-B or park it. Oh wait, you said that costs too much? Well we can't have THAT now can we? Here is a waiver, you can get around to it years from now. Hey, I retire in 3 years, you got any jobs over there :rolleyes: The 121 operators have gotten used to blowing off issues for another day and getting away with it.

 

 

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23 hours ago, Windward said:

While I've not yet watched Ed's video.  Didn't we do this whole exact scenario with cell phones when they first became popular? 

No - not even slightly. Cell phones back then did not use any frequencies close to anything airplanes use. There were some issues related to using the phones *in the airplanes*, this current issue involves the ground stations.

The problems with planes being used in flight were twofold, there had never been any testing done on numerous two-way radios in use inside an airplane and the cell system itself was not designed to be used by phones that could reach numerous towers at once.

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41 minutes ago, kent_island_sailor said:
FAA to owner of $15,000 airplane: Install ADS-B or park it. You say it costs a significant fraction of what you paid for the entire airplane? Tough shit.

Not always the case regarding ADS-B.  There are still a lot of areas you can fly without it.  Oh! Installing ADS-B on a plane, according to V-ref, you'll get your money back.

As for the Tough Shit part, I agree, the FAA does that a lot.

   
   
   
   
   
 
   

 

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22 minutes ago, Ventucky Red said:

Not always the case regarding ADS-B.  There are still a lot of areas you can fly without it.  Oh! Installing ADS-B on a plane, according to V-ref, you'll get your money back.

As for the Tough Shit part, I agree, the FAA does that a lot.

   
   
   
   
   
 
   

 

NOW the price is down to about $2,000, but it wasn't that long ago it was 5 times that. I recently flew across the country with ADS-B, like AIS once you have it you will never want to not have it.

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2 hours ago, kent_island_sailor said:

NOW the price is down to about $2,000, but it wasn't that long ago it was 5 times that. I recently flew across the country with ADS-B, like AIS once you have it you will never want to not have it.

Sky Beacon was out long before the mandate "hard date" kicked in with a sub $2000 solution.  And if you acted prior to that the FAA kicked $500 back to you. We went with the Stratus, it was a little pricier ($3900 installed) but the transponder was hitting 20 years... it was time.  Nice looking at your iPad/Foreflight and seeing all the traffic out there.

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They are on Top of this

this doing circles over my house for about 1.2 hour

image.thumb.png.57fa6e939b5feb2da9d7ff31b87ca5d2.png

 

 

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If ADS-B is anything like marine AIS, the transponders started out fairly expensive, but within a few years they were sub-$1000.  Now some are under $500.

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46 minutes ago, valis said:

If ADS-B is anything like marine AIS, the transponders started out fairly expensive, but within a few years they were sub-$1000.  Now some are under $500.

Sort of - say 10K to 2K instead of 10K to 0.5K.

In both cases well worth it!

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If the FAA knew the FCC was selling the 5G spectrum for use, why did the FAA not do anything to make sure they would not be affected?

Is this just another Bureaucratic Government Cluster Fuck??

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  • 3 weeks later...

airlines, boeing, and airbus send last minute doom and gloom message to US transport secretary concerned about 5G and aircraft.

https://www.deseret.com/2022/1/18/22889330/5g-airline-flights-damage-what-could-happen

 

a day late and a dollar short as the old saw goes.  Sec Pete Buttage is the same numb-nut who "fixed" the congestion at Long Beach by having ships steam 100 miles offshore and declaring success while the total number of ships backed up continues to grow (currently over 110 ships).

 

5G will start to be turned on later today.

Looks like at&t and verizon will back off for the time being.

https://www.cnbc.com/2022/01/18/5g-deployment-delays-at-airports-on-cancellation-threats.html

Guess even they understand the bad PR if flights are cancelled every time there is fog or bad weather.

 

 

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On 1/3/2022 at 12:54 PM, Meat Wad said:

If the FAA knew the FCC was selling the 5G spectrum for use, why did the FAA not do anything to make sure they would not be affected?

Is this just another Bureaucratic Government Cluster Fuck??

There are lots of scholarly articles out there about this, but I gather the main problem is that the radio altimeters on aircraft (used for instrument approaches and GPWS) were not designed with sufficient input bandwidth filters and run the risk of picking up spurious 5G signals leading to false readings.  It takes time to design, build, certify and install upgraded equipment, which I gather is an additional filter on the input.   

When you modulate a radio signal, you almost always create side band emissions that are higher and lower frequency than the original signal.  The signals "leak" into other frequency ranges.

The problem only affects the US, however, because in Europe they left a bigger guard band between 5G and the aviation frequencies.  

There you have it, in case you didn't read the longer version of this above.

Government cluster-fuck?  I would say industry cluster-fuck, unless you think "failing to regulate industry to force them to do the right thing" is government responsibility. 

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On 1/3/2022 at 1:54 PM, Meat Wad said:

why did the FAA not do anything to make sure they would not be affected?

Maybe the revenues that the FCC stood to gain from 5G outweighed the revenues that the FAA stood to lose from 5G?

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How come Europe has had 5G for over a year now?  Did they carefully position all the towers suitably far enough away from airport frequency needs?

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33 minutes ago, billy backstay said:

How come Europe has had 5G for over a year now?  Did they carefully position all the towers suitably far enough away from airport frequency needs?

They gave the radar altimeter frequencies a bigger guard band than we did ;)

This is actually very interesting, usually the side with less power and money loses despite the law being on their side. In the 50s when ham radio stations on 6 meters interfered with TV channel 2 which is nearby, the TV manufacturers did not get dinged for crappy selectivity, the hams had "quiet hours" imposed on them despite doing nothing wrong. There was never any realistic chance of any other outcome.

This is more two huge $$$$ operations in conflict, Goliath vs. Goliath. Just like with ADS-B, the airlines will delay, screw off, ignore, and procrastinate to the very last second and then cry that they cannot possibly afford to fix their planes. Meanwhile the cell companies are going "We bought it, we own it, not our problem your radios suck".

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3 minutes ago, kent_island_sailor said:

They gave the radar altimeter frequencies a bigger guard band than we did ;)

This is actually very interesting, usually the side with less power and money loses despite the law being on their side. In the 50s when ham radio stations on 6 meters interfered with TV channel 2 which is nearby, the TV manufacturers did not get dinged for crappy selectivity, the hams had "quiet hours" imposed on them despite doing nothing wrong. There was never any realistic chance of any other outcome.

This is more two huge $$$$ operations in conflict, Goliath vs. Goliath. Just like with ADS-B, the airlines will delay, screw off, ignore, and procrastinate to the very last second and then cry that they cannot possibly afford to fix their planes. Meanwhile the cell companies are going "We bought it, we own it, not our problem your radios suck".

It looks to me like a lot of the problem is bleed-over from the 5g transmissions. Don't they have a type requirement to stay within their assigned band?

- DSK

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1 minute ago, Steam Flyer said:

It looks to me like a lot of the problem is bleed-over from the 5g transmissions. Don't they have a type requirement to stay within their assigned band?

- DSK

That is not physically possible. All radios radiate outside of their actual frequency and all receivers pick up signals outside of the one they are actually tuned to. Many of the radar altimeters are an ancient design that worked fine when no one else had a frequency near theirs. EU regulators figured out how big a guard band was needed, the FCC apparently did not and figured the radar altimeters would have to get replaced, tough luck or didn't even think of it.

Think of a Venn diagram:

image.png.0ed87f91ee8bdf720c2000e86db435fe.png

What we have with 5G:

image.png.f9ac67da07e8f0ae5401efab980584f1.png

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5 minutes ago, Steam Flyer said:

It looks to me like a lot of the problem is bleed-over from the 5g transmissions. Don't they have a type requirement to stay within their assigned band?

- DSK

I think the problem is, has been noted, that the radar altimeter receiver does not reject out-of-band signals well.  Before the 5G allocation that adjacent frequency range was used for much lower-power satellite operation so the signals weren't strong enough to cause problems for the RA.  The new 5G signals are much stronger:

radar-altimeter.png

I assume that the 5G signals are properly contained in their band.  I believe they use QAM or similar modern digital modulation techniques and here's no reason for them to have strong out-of-band emissions.

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48 minutes ago, valis said:

I think the problem is, has been noted, that the radar altimeter receiver does not reject out-of-band signals well.  Before the 5G allocation that adjacent frequency range was used for much lower-power satellite operation so the signals weren't strong enough to cause problems for the RA.  The new 5G signals are much stronger:

radar-altimeter.png

I assume that the 5G signals are properly contained in their band.  I believe they use QAM or similar modern digital modulation techniques and here's no reason for them to have strong out-of-band emissions.

image.png.73be72f64e065afd4c0e271edeccbf33.png

 

Sure, the the radar altimeters are supposed to be hearing 4200 to 4400 MHz and if they're too busy listening way over 3700 MHz to tell you where the ground really is, that's a big problem.

I would have expected the power output/freq graph to be more of a bell curve (maybe a hat curve?) but wave mechanics was really one of my poorer subjects. There are obviously limits on how steep you can get the slope from peak output to zero, and the FCC -ought- to know this kind of thing and allocate bands appropriately. And with things like airplane navigation, err on the side of safety... although airlines should not get a pass on using crappy transceivers, either.

Radar freq shifts with the target, how much does this affect these altimeters? You don't want to crash because your radar altimeter is listening to returns between 4200 and 4400, and let's say return from snow, or maybe cactus, drops to 4000.

- DSK

 

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38 minutes ago, Steam Flyer said:

image.png.73be72f64e065afd4c0e271edeccbf33.png

 

I would have expected the power output/freq graph to be more of a bell curve (maybe a hat curve?) but wave mechanics was really one of my poorer subjects. There are obviously limits on how steep you can get the slope from peak output to zero, and the FCC -ought- to know this kind of thing and allocate bands appropriately. And with things like airplane navigation, err on the side of safety... although airlines should not get a pass on using crappy transceivers, either.

Radar freq shifts with the target, how much does this affect these altimeters? You don't want to crash because your radar altimeter is listening to returns between 4200 and 4400, and let's say return from snow, or maybe cactus, drops to 4000.

- DSK

 

I don't know much about the radar altimeters, but is there really any frequency shift?  I believe it's all time-delay stuff.  And I'm far from a wave mechanics expert -- I can barely spell it.

But the emission curve you show is *much* too broad for a 5G signal.  There are many 5G channels in that 3.700 - 3.98 GHz allotment, and each channel uses multiple subcarriers, so the occupied bandwidth of each subcarrier is quite narrow and the shirts of each subcarrier are very steep.  I don't think there is much 5G energy outside of the allotment.

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relying on electronic equipment 100% to prevent Catastrophic events is bad enough

counting on the same to counter known errors and come up with desired information 100%

is a FAIL ... at some point

 

is there anything I can do w my 5G Fone to make all TESLA'S within X distance - slow to 15mph

or play Céline Dion @ Warp Volume ??

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5 hours ago, kent_island_sailor said:

They gave the radar altimeter frequencies a bigger guard band than we did ;)

 

No, actually. The guard band in the US is 220 MHz. If I recall correctly, it is 200 MHz in Australia and it is either 100 or 200 MHz (having a senior moment here) in France.

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5 hours ago, valis said:

I think the problem is, has been noted, that the radar altimeter receiver does not reject out-of-band signals well.  Before the 5G allocation that adjacent frequency range was used for much lower-power satellite operation so the signals weren't strong enough to cause problems for the RA.  The new 5G signals are much stronger:

radar-altimeter.png

I assume that the 5G signals are properly contained in their band.  I believe they use QAM or similar modern digital modulation techniques and here's no reason for them to have strong out-of-band emissions.

Its OFDM in the downlink, OFDMA in the uplink. Energy is spread across the channel. OOB emissions are limited by FCC rules to -40 dBm, effectively below the noise floor.  Also, VZ and AT&T are in the lower part of the band, below 3.7 GHz. T-Mobile can't occupy 3.7-3.98 until next year.

 

image.png.559368edec2c306c810b7fd61cc37153.png

 

 

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7 hours ago, kent_island_sailor said:

They gave the radar altimeter frequencies a bigger guard band than we did ;)

This is actually very interesting, usually the side with less power and money loses despite the law being on their side. In the 50s when ham radio stations on 6 meters interfered with TV channel 2 which is nearby, the TV manufacturers did not get dinged for crappy selectivity, the hams had "quiet hours" imposed on them despite doing nothing wrong. There was never any realistic chance of any other outcome.

This is more two huge $$$$ operations in conflict, Goliath vs. Goliath. Just like with ADS-B, the airlines will delay, screw off, ignore, and procrastinate to the very last second and then cry that they cannot possibly afford to fix their planes. Meanwhile the cell companies are going "We bought it, we own it, not our problem your radios suck".

 

If the FAA owned these frequencies long before 5G was born, how can the government allow 5G to use frequencies that might cause harm to air travel???

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1 hour ago, Throatwarbler-Mangrove said:

Its OFDM in the downlink, OFDMA in the uplink. Energy is spread across the channel. OOB emissions are limited by FCC rules to -40 dBm, effectively below the noise floor.  Also, VZ and AT&T are in the lower part of the band, below 3.7 GHz. T-Mobile can't occupy 3.7-3.98 until next year.

Thanks!

Am I correct in thinking that each of the OFDMA (Orthogonal Frequency Division Multiple Access) subcarriers is itself QAM (Quadrature Amplitude Modulation) or otherwise modulated?

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5 minutes ago, billy backstay said:

If the FAA owned these frequencies long before 5G was born, how can the government allow 5G to use frequencies that might cause harm to air travel???

The FAA didn't "own" the adjacent 5G band.  That had been allocated for satellite service.  And this isn't just FCC, the ITU (International Telecommunications Union) is also involved.  To be honest, I don't know much about how this allocation was changed. 

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Did you hear about the Polak who tried to use ACM64QAM on his AWGN ASDL interface?  His LDPC FEC required a Shannon Limit of  24log(1+P/N) !

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Note to non-geeks:

When a spectrum is assigned to satellites, designers of earthbound equipment on nearby frequencies plan to deal with very week signals from hundreds or thousands of miles away. If said spectrum gets sold to terrestrial customers, now you have strong signals maybe a few yards away.

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47 minutes ago, Grande Mastere Dreade said:

funny thing is that 5g has been implemented outside the US   near airports without  the unmitigated disaster the US airlines have been moaning about

I made the same query a while ago, and I think they said the Euros Use slightly different frequencies.  Scroll back up, to see the reply....

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does all this mean we won't need to Pay for In-Flight WiFi as we will have 5G Cell service

OR Could That have something to do with "The Problem"

Everyone want$ The Money

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20 minutes ago, Elegua said:

I thought this was an interesting infographic. 

 

5G.jpg.b548e7cdefd7b647c7f5aeb0c76edc49.jpg

75c1735d6189c7d229d8097b4f3fdfc0

I think this may be a misleading graphic.

Can't speak for how many seconds before the threshold an airliner pilot has before pushing the go-around button.

Radio engineers don't talk about 2.5X, they talk in decibels (dB). The difference is 4 dB, which sounds a lot less scary when you find out that it is the difference between 28 dBm and 32 dBm of power. Besides, it's 200 MHz away from the band where the radio altimeter is supposed to be operating. Out-of-band emissions for C-Band are below -40 dBm. 

And the French rule about must be down-tilted tells the operators what they're going to do anyway. Why would an operator put an antenna on a tall tower, only to tilt it up? It's supposed to point toward the ground, where the mobile phones are.

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20 minutes ago, Throatwarbler-Mangrove said:

I think this may be a misleading graphic.

Can't speak for how many seconds before the threshold an airliner pilot has before pushing the go-around button.

Radio engineers don't talk about 2.5X, they talk in decibels (dB). The difference is 4 dB, which sounds a lot less scary when you find out that it is the difference between 28 dBm and 32 dBm of power. Besides, it's 200 MHz away from the band where the radio altimeter is supposed to be operating. Out-of-band emissions for C-Band are below -40 dBm. 

And the French rule about must be down-tilted tells the operators what they're going to do anyway. Why would an operator put an antenna on a tall tower, only to tilt it up? It's supposed to point toward the ground, where the mobile phones are.

It's dumbed down for the general public, but the key point is the EU has had not problems with 5G because there are differences in the systems. Most EU airports already use dots to keep the airlines happy. 

Ajit dun messed up selling the wrong thing, specc'd the wrong way while ignoring feedback. Naturally both the buyers and the people impacted are not happy. 

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2 hours ago, Elegua said:

It's dumbed down for the general public, but the key point is the EU has had not problems with 5G because there are differences in the systems. Most EU airports already use dots to keep the airlines happy. 

Ajit dun messed up selling the wrong thing, specc'd the wrong way while ignoring feedback. Naturally both the buyers and the people impacted are not happy. 

It's FUD, intended to mislead the general public.

I'm no fan of Ajit Pai either, but in this case the FCC did what they were supposed to. They got a report from the Aerospace Vehicle Systems Institute that raised concerns. They got another report from Alion that reviewed the AVSI report and pointed out that it was badly flawed. AVSI came back with a request for further study. The FCC's engineers (yes, the FCC has engineers)  read both reports and concluded

Quote

We agree with T-Mobile and Alion that the AVSI study does not demonstrate that
harmful interference would likely result under reasonable scenarios (or even reasonably “foreseeable”
scenarios to use the parlance of AVSI). We find the limits we set for the 3.7 GHz Service are sufficient to
protect aeronautical services in the 4.2-4.4 GHz band. Specifically, the technical rules on power and
emission limits we set for the 3.7 GHz Service and the spectral separation of 220 megahertz should offer
all due protection to services in the 4.2-4.4 GHz band. We nonetheless agree with AVSI that further
analysis is warranted on why there may even be a potential for some interference given that well-designed
equipment should not ordinarily receive any significant interference (let alone harmful interference) given
these circumstances. As such, we encourage AVSI and others to participate in the multi-stakeholder
group that we expect industry will set up—and as requested by AVSI itself.
850 We expect the aviation
industry to take account of the RF environment that is evolving below the 3980 MHz band edge and take
appropriate action, if necessary, to ensure protection of such devices.

The FAA, on the other hand, needs a reckoning. First of all, do they approve avionic equipment for flight, and if so, why would they approve a safety-critical system that is so susceptible to out-of-band interference? Did they not test? Second, they knew that the 3.7 GHz spectrum was going to be re-farmed, but did not participate in the FCC's Notice and Comment proceeding to voice their concerns. Then they bypassed the spectrum coordination process, at the last possible moment, with a dramatic public announcement. Finally, their reasoning depends on flawed studies that assume worse than the worst case scenarios.

The buyers and people impacted are not happy? Of course they're not happy. While they've been waiting for the 3.7 GHz band to finally get auctioned off and opened up, T-Mobile has been walking all over them. They spent $80 billion between them with the Treasury, plus another 19 Billion to compensate the satellite guys for clearing the band. They had their big public launches all set. And then the FAA took a dump on their plate so late that Verizon couldn't even postpone its flashy celebrity launch event.  They have every reason to be pissed.

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2 minutes ago, Throatwarbler-Mangrove said:

It's FUD, intended to mislead the general public.

I'm no fan of Ajit Pai either, but in this case the FCC did what they were supposed to. They got a report from the Aerospace Vehicle Systems Institute that raised concerns. They got another report from Alion that reviewed the AVSI report and pointed out that it was badly flawed. AVSI came back with a request for further study. The FCC's engineers (yes, the FCC has engineers)  read both reports and concluded

The FAA, on the other hand, needs a reckoning. First of all, do they approve avionic equipment for flight, and if so, why would they approve a safety-critical system that is so susceptible to out-of-band interference? Did they not test? Second, they knew that the 3.7 GHz spectrum was going to be re-farmed, but did not participate in the FCC's Notice and Comment proceeding to voice their concerns. Then they bypassed the spectrum coordination process, at the last possible moment, with a dramatic public announcement. Finally, their reasoning depends on flawed studies that assume worse than the worst case scenarios.

The buyers and people impacted are not happy? Of course they're not happy. While they've been waiting for the 3.7 GHz band to finally get auctioned off and opened up, T-Mobile has been walking all over them. They spent $80 billion between them with the Treasury, plus another 19 Billion to compensate the satellite guys for clearing the band. They had their big public launches all set. And then the FAA took a dump on their plate so late that Verizon couldn't even postpone its flashy celebrity launch event.  They have every reason to be pissed.

 

If this is true, and I have no reason to think otherwise, then the FAA was asleep at the wheel while 5G was in its infancy?  Who gets the blame for that, at the FAA?

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4 minutes ago, billy backstay said:

 

If this is true, and I have no reason to think otherwise, then the FAA was asleep at the wheel while 5G was in its infancy?  Who gets the blame for that, at the FAA?

I don't pretend to know the FAA.  It's hard enough keeping an eye on the FCC (which is part of my day job). But this, on top of the 737 Max fiasco, calls for a good housecleaning.

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12 minutes ago, Throatwarbler-Mangrove said:

AVSI came back with a request for further study

So what happened to the further study? Other than to tell the FAA to update and re-certify their gear?   Aircraft gear strikes me a bit like medical devices. It often yestertech because of the certification process. 

 

12 minutes ago, Throatwarbler-Mangrove said:

The FAA, on the other hand, needs a reckoning.

True. But you say that like the US Telecom and communication industry has consistently engaged in sound and ethical business practices.  

 

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13 minutes ago, Throatwarbler-Mangrove said:

I don't pretend to know the FAA.  It's hard enough keeping an eye on the FCC (which is part of my day job). But this, on top of the 737 Max fiasco, calls for a good housecleaning.

 

I think they have sorted out the 737 Max, but this 5G can be a major clusterfuck if they don't solve it very soon..

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11 hours ago, Throatwarbler-Mangrove said:

The FAA, on the other hand, needs a reckoning. First of all, do they approve avionic equipment for flight, and if so, why would they approve a safety-critical system that is so susceptible to out-of-band interference?

Radar altimeters date back to 1938. Most versions of them were certified a LONG time ago, long before anything terrestrial was sharing any of these nearby frequencies.

Trivia fact, about 90% of the airplanes in the USA do not have a radar altimeter, but the ones that do carry a lot of people that will complain when diverted to another airport. For anything I do my phone gives vastly superior terrain warnings than any radar set could do, so the lower end of aviation doesn't care about these things, only people wanting to do Cat II or Cat III landings.

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Thanks for the video Ed!!  Great explanation!  The airliners had the frequency first, so it is up to the phone people not to encroach. 

Simple answer, do like Europe and move the 5G transmitters 2 miles from any airport's frequency needs, and turn down the power. 

Voila, problem solved!

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1 hour ago, billy backstay said:

Thanks for the video Ed!!  Great explanation!  The airliners had the frequency first, so it is up to the phone people not to encroach. 

Simple answer, do like Europe and move the 5G transmitters 2 miles from any airport's frequency needs, and turn down the power. 

Voila, problem solved!

I like Juan Brown (Blancolirio).  He does have a dog in this fight, he is a first officer for American Airlines and flies the B777. He is also a former military pilot and owns his own small airplane.  He knows his shit and his videos are always very informative.  

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12 minutes ago, Ed Lada said:

I like Juan Brown (Blancolirio).  He does have a dog in this fight, he is a first officer for American Airlines and flies the B777. He is also a former military pilot and owns his own small airplane.  He knows his shit and his videos are always very informative.  

 

I have watched a few of his videos, they are excellently done!

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1 hour ago, billy backstay said:

Thanks for the video Ed!!  Great explanation!  The airliners had the frequency first, so it is up to the phone people not to encroach. 

Practically speaking in the video Juan Brown is right, this has become the 5G network's problem.  But the airliners did not "have the frequency first".  They are allocated their RA (Radio Altimeter) band and they still have it.  They never had a claim on adjacent bands, and in theory they should have designed their equipment to operate properly regardless of adjacent band activity.

In practice, no equipment is perfect in this regard.  Transmitters have specifications for out-of-band emissions (and many other requirements) and while low, these are not "zero".  More important in this case, receivers usually have some specifications for performance but these are generally less stringent.  The technical problem here is the RA receiver.  It is responding to adjacent-band signals, not in-band spurious signals. (I used to design and test transmitters and receivers).

Finally, it is the job of the FCC and ITU to manage the frequency allocations to avoid this kind of problem.  But read what Mangrove said, apparently the FCC isn't the main screw-up here:

14 hours ago, Throatwarbler-Mangrove said:

It's FUD, intended to mislead the general public.

I'm no fan of Ajit Pai either, but in this case the FCC did what they were supposed to. They got a report from the Aerospace Vehicle Systems Institute that raised concerns. They got another report from Alion that reviewed the AVSI report and pointed out that it was badly flawed. AVSI came back with a request for further study. The FCC's engineers (yes, the FCC has engineers)  read both reports and concluded

The FAA, on the other hand, needs a reckoning. First of all, do they approve avionic equipment for flight, and if so, why would they approve a safety-critical system that is so susceptible to out-of-band interference? Did they not test? Second, they knew that the 3.7 GHz spectrum was going to be re-farmed, but did not participate in the FCC's Notice and Comment proceeding to voice their concerns. Then they bypassed the spectrum coordination process, at the last possible moment, with a dramatic public announcement. Finally, their reasoning depends on flawed studies that assume worse than the worst case scenarios.

The buyers and people impacted are not happy? Of course they're not happy. While they've been waiting for the 3.7 GHz band to finally get auctioned off and opened up, T-Mobile has been walking all over them. They spent $80 billion between them with the Treasury, plus another 19 Billion to compensate the satellite guys for clearing the band. They had their big public launches all set. And then the FAA took a dump on their plate so late that Verizon couldn't even postpone its flashy celebrity launch event.  They have every reason to be pissed.

 

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