There is something weird going on here. Is this a turf battle between FCC and FAA? Does FAA not really have tech experts anymore?
This process has been going since 2011, with lots of input from stakeholders (the usual slow govt process). The FCC carefully studies interference before opening a band up.
The guard band is absolutely ridiculous at 220Mhz - I thought this was a typo when I saw it. Looking at Boeing comments, Boeing had requested a max guard band of 110Mhz and the FCC doubled that.
We have 30 - 40 countries already operating mobile services in this band. I haven't heard of credible reports of interference.
Finally, longstanding RF rules require that your RF equipment operate in its assigned band. The fault here, if any, lies with airlines and aircraft mfgs to update their equipment if needed. That said, I doubt it's needed.
So seriously, there is some weird FAA stuff going on now.
We wonder why the US infrastructure costs so much. Instead of doing some tests in the years that this was in the cards, the FAA is now throwing up all sorts of roadblocks, just as biden gets ready to spend $1.2 trillion on infrastructure.
Seriously, if this is a real issue, have every airline land near a test deployment of C-band, and figure out which altimeters are so pathetic they need a 200Mhz guard band.
Any conversation around the 5g rollout was colour washed from day one. I assume that happened naturally but who knows really. I have seen very very little informative conversation online, mainly because it became something like the current vaccine debate where the middle line is drowned out by the "believers", and the "crazies". I'm not really surprised to see seemingly routine issues go unnoticed until now.
I agree. It is too bad that reasonable, moderate conversation gets drowned out by the true believers and the conspiracy theorists fighting it out.
I don't think 5g is evil but I don't see the technical or economic need for it. Replacing 4G infrastructure that is just a few years old and has plenty of bandwidth doesn't make much sense to me.
That pretty well fits the typical mindset of the past decade. Nobody wants to take risks and build shit, everyone is instead looking for a noble excuse to get their share of money and authority without actually doing any hard work.
Sounds like my current company. Devs have been complaining about how the tooling has become progressively worse but no one with a fat paycheck cares...so it doesn't get done...until something catches fire.
If you make a tool that has been in use for years - long enough that engineers who turned to management are now in senior management position remember using and liking it back int the day - then you can get a good paycheck to maintain it. Of course this assumes that the tool is still relevant 25 years from when you first created it. Note that this is about you creating and maintaining the tool, taking over someone else's tool might work, but is probably seen as a job for a junior developer.
In some cases you can wait for things to get really bad and then be rewarded for saving the day. (I strong oppose this - a good engineer should see problems and fix them before they get that bad)
You can spend 10% of your time maintaining tools so long as the other 90% has great value. Great value means you see the market need and develop the first prototype that demonstrates the idea works (then turn this over to a new team to make production worthy while you go on to invent something else).
You can run numbers to prove that your tool makes a difference. (Some at Facebook can show hundreds of thousands of dollars saved as a result of their tools)
There are probably others - but none are easy to get into.
Many don't because that type of work doesn't directly and obviously drive revenue, doesn't have slick customer-facing UX, and isn't on the radar of product or management. For every shop that actually has their act together there are two that fall into this trap; from what I gather consulting and contracting places in particular are quite prone to this line of thinking since the distinction between billable and non-billable work underscores this further and leads to especially perverse incentive structures.
> Does your company offer fat paychecks for improving internal tooling?
It does. But not to me. There are entire teams with millions of dollars of budget to improve tooling.
But of course they only do what they like. And my management doesn't care enough to bring our complaints to them. Individual engineer complaints are ignored.
I'm on a project with 3 developers and 5(!) project mismanagers. The developers have laptops with 8 GB of RAM, which has to swap 4 GB to disk if they simply open their IDE. When they type or click things, it's like a slide-show.
I raised this with the PMs repeatedly as a significant project risk. Oh... we can't do anything about that they chorused. That's a different department, that's a different budget, etc, etc... Excuse after excuse.
The PM salaries sum to about $1M per annum, but 3 laptops are just too hard for them to organise. Too hard. Can't be done. Just stop asking. Shh. We're busy.
yeah i buy my own ram lol (for my work laptop)
that 100$ will save me years of stress if anything remotely looks like slideshow when it isnt supposed to
Sounds like one of these companies that just got some investor money, hired friends of friends, and are enjoying the ride. There are exactly zero reasons to try and save the sinking ship. If you succeed, they will just hire more buddies over your head. If they fail, you will be scapegoated.
I would say, be nice and polite, take your time learning whatever tech you need to get a better job, prepare for interviews, get an offer, shake hands and move on...
Are you at a large corporation? A government agency? Just curious about what kind of project has more managers than developers. That's an amazing level of waste and incompetence to allow that to even happen.
Worked in defense in a previous life. Spent a lot of time in DC and northern Virginia.
Take any amazing organization that does great things, give it a bunch of money, and have the revenue stream not get impacted by failure. You get rot. You get IBM 1960 vs IBM the 2010s - present horror show. You get Ford in 1920 vs Ford in 1980. And this isn't limited to the private sector. It's a feature of massive organizations where revenue is divorced from success.
The US Federal Government is an utter horror show. It was once an amazingly capable collection of efficient, nimble organizations. It could hire rogues and mavericks when needed, and was able to fire the desk-riders too. It's now a rotted-out shell. Success happens in-spite of, and never because-of, the organizations themselves.
I always invite people to go and work with one of the US Fed contractors or agencies. Go look at their job postings. Look at the energy levels of the team members. It's somewhere between a DMV and a mausoleum. Ask yourself if you honestly think they need more money or just far fewer, far higher paid staff with the same or even less budget. Then ask yourself if these organizations are capable of understanding, let alone governing, complex domains.
Most of these projects were driven by competition with USSR. I.e., push for results under limited resources. With globalization we have eliminated it and are now left to rot, splinter and wait until the competition between the shards of the former empire sparks progress again.
Except, there's also China with superior morale, superior education and superior efficiency, that might have better plans for the resources left behind a fallen empire...
The United States appears to only know how to wage war and even that has been iffy since WWII. China is poised to decimate us. They’ve been playing the long game for decades now. What have we been doing? Enriching defense contractors and having very little to show for it.
Because the general public doesn't care neither about China, nor about institutional accountability. The media diverts their attention towards conveniently picked unquantifiable problems, so they are busy fighting each other over minor differences, while refusing to notice that BOTH sides are being quietly pushed into poverty via the post-2008 economic policies.
(Late, I know -- a comment in this thread was referenced a few days later.) Yeah, 2008 was a banner year for the U.S. economy (not to mention the world economies). The economy was humming along so smoothly that, IIRC, McCain was able to take a vacation from his busy presidential campaign for a little rest and relaxation. And then Obama had to come along and ruin everything. Bummer! :(
The whole “China long game” feels so lazy. Did you forget that this is the same Chinese government that isn’t resilient enough to handle challenges to it (HK, Taiwan, Tibet, Tianimen Square (sp?)) and it’s the same government where Evergrande is happening because local governments in China just feel like reporting numbers because they’re scared that Xi will get mad if they report real numbers instead of “growth forever”.
China also has a huge population problem coming and it’s likely that they have already peaked economically (you’ll notice states like China get much more belligerent and bellicose as they fail ala Russia) and even that is due to government mismanagement.
So, my point is China isn’t some grand strategic master. They are a country with their own problems, likely even worse than most countries because problem exposition is strongly discouraged.
This doesn’t mean that America or any other country doesn’t have problems, but China isn’t particularly special here.
HK democracy for example is seen as such a threat to China that it must defacto invade HK to stop democracy from overthrowing the CCP. Same with these other areas and Chinese involvement.
> HK democracy for example is seen as such a threat to China that it must defacto invade HK to stop democracy from overthrowing the CCP.
Which it has largely done, and moves on. Saying it's not resilient enough to handle the situation seems to be wishful thinking in that case (and is obviously false in the case of Tiananmen Square or Tibet.)
That’s my point. The CCP appears so weak that anything scary must be attacked viciously. Admit no fault. Allow no dissent. If the CCP was stable and strong it wouldn’t need to invade HK. The invasion demonstrates the weakness.
Perhaps not efficiency. Accomplishment. With limited budgets.
I'll take shipbuilding, tank manufacture, aircraft construction, and logistics for World War Two,
from a prior activity of about nil, as an example of accomplishment.
I don't think guaranteed revenue is the problem, it's guaranteed employment.
We tried tying money to success in our education system with No Child Left Behind and it was a disaster. When you have an organization that is struggling to make effective use of their budget, the solution is to replace the ineffective leadership, not decimate their budget and expect them to do better.
Japanese business school philosophy seems to be fire the leaders first, then the followers. It's a sort of 'both' solution spread over a couple of fiscal cycles.
If you ever get bought by a Japanese conglomerate and your boss gets fired, rather than being relieved you should be worried, because you're next if things don't improve. I can't fault that logic, but it does seem to make at least some westerners a little complacent, cross-purposefully.
> The US Federal Government is an utter horror show. It was once an amazingly capable collection of efficient, nimble organizations. It could hire rogues and mavericks when needed, and was able to fire the desk-riders too. It's now a rotted-out shell. Success happens in-spite of, and never because-of, the organizations themselves.
Not sure how this is related to your point about money, but I do think it's cultural. To work in the civil service right is not something our current culture rewards and/or admires. As such, you get a paucity of talent, hustle, and hard workers.
Their overall guard is 200Mhz on each side, so 400Mhz total, and even WITH that guard they are saying they have interference. This is what makes so little sense to me.
You should have an emitter frequency in the 200Hz range? sure, you sweep it, but you shouldn't need a total of 400Mhz for your guard.
To me, the entire article reads like the airlines are using outdated technology but they don't want to foot the bill for updating it. That would also nicely explain why this isn't a problem for the exact same airplanes landing in Europe.
I don't get it. What difference does it make if US delays roll out when many other countries are going ahead already? It's not like Boeing and Airbus planes don't operate in China, for example.
Actually, other countries (like france) did their own tests and threw out the crap from AVSI/RTCA (who have been very shady about disclosing their data).
Japan and other countries do smaller guard bands, some let cell service go within 100Mhz (ie, twice as close).
This is really an indictment of the technical incompetence and lack of planning (over 10 years) of the FAA.
AFAIK only Japan allows operation anywhere close to 4GHz nationwide, everyone else puts limit at 3.8GHz for nationwide licenses, with occasional location limited <4GHz in UK.
The page I had seen claiming the licenses for close to 4GHz band were sold might have mentioned it wasn't really deployed so far (unfortunately lost the link :/)
I was thinking they'd land at something in range of 20Mhz (10% of a full sweep). for guard. That said, the actual sweep is in .1Mhz or less steps isn't it so you should be able to get away with a small guard I think? What is the actual receiver bandwidth?
3500-3600Mhz and 4800-4900Mhz are the closest used frequencies for 5G in China. Much farther away from the frequencies used by the altimeters than the frequencies causing the concern in the US. In Europe the closest frequency being used is 3800Mhz. Again much farther away from the frequencies used by the altimeters.
Can someone with insight into radio technology explain this?
> The 5G network deployment in the U.S. starting on December 5 is in the 3700 to 3800-MHz bands then later in the 3700 to 3980-MHz bands. Radio altimeters use the 4200 to 4400-MHz band. [1].
Are these not sufficiently separated? Can this not be tested easily, by blasting 5G frequencies at a bunch of different planes in test flights? They've had like a decade to do this; I'd expect something more concrete then "concerns about potential interference" at this point.
There is something weird going on at FAA / NTSB etc.
In most radio applications a guard band of 220Mhz is absolutely unheard of.
You would do a guard at 10% of bandwidth lets say. On one side you'd have 5%.
So we are talking 1-2 Mhz?
My understanding was planes already had 2-3 altimeters, with guard band spacing of maybe 5Mhz (ie, planes already have devices blasting signals at frequencies much closer than 200Mhz).
So a guard band of 300Mhz then? What's weird is that I'd expect an altimeter to be on the order of .1 to 2MHz bandwidth max. There's just something wrong in the math here.
Radar altimeters use frequency modulated continuous wave (FMCW) and the bandwidth is 20 to 170 MHz (the larger the chirp, the more accurate it can be).
It's extremely difficult to have a 170 MHz wide filter at 4.3 GHz with a brick wall response out of band.
It's probably more about the safety culture than the technology. This is the same industry that grounded the 737 MAX worldwide for almost two years due to some rare issues that would have been tolerated in almost every other field.
Because radio altimeters have not been required to tolerate interference above a certain threshold within ~10% of their frequency band, the assumption is that they cannot tolerate it until there is something like a decade or two of production-scale experience without any serious issues. Or until all passenger planes have radio altimeters certified for the new stricter requirements. And because the latter costs money, the industry won't do it as long as other options remain.
Not only that, the issue was caused by Boeing cheaping out on quantity of sensors, and then the ‘there is an issue’ light was sold as a safety upgrade. And the reason this was all needed was because Boeing wanted to escape having to recertify pilots for a new type rating.
Road traffic kills over a million people every year, many of them due to various technical and design flaws. People just tolerate those deaths far better than deaths from plane crashes.
Because road traffic deaths are rarely in the hundreds range per event due to preventable criminal negligence. When a bridge collapses and tens of people die, nobody tolerates it.
If you want to liken the 737 MAX’s failures to road traffic, you have to ask yourself if there’d be broad acceptance of shoddily built, fault-intolerant bridges and freeways. Moreover, would that acceptance be greater or lesser if the public knew that engineers believed their designs were flawed?
I think this has much more to do with the fact that people drive cars and not airplanes. Most people have confidence in themselves and not others (cf. George Carlin's joke: "Have you ever noticed that anybody driving slower than you is an idiot, and anyone going faster than you is a maniac?"). So they're happy to make things safer if those changes only affect other people (as in an airplane). But when it comes to the fixes that would do the most to reduce traffic fatalities (e.g., lower speed limits on non-highways, more speed cameras, or perhaps most pertinently technology in cars that would make it more difficult to speed, etc.), those affect you too.
If the MAX had continued to fly without getting to the root cause it would have been a completely different story than the one that we have today, which is bad enough as it is with both Boeing and the FAA owning what they broke.
Those "rare issues" were also caused by a culture of prioritizing profit and speed of development over safety and training. More of those "rare issues" popped up months later.
Safety culture has scored some huge wins in the last 100 years. Decreased auto fatality rates, safer home materials (lead paint & asbestosis), expiration dates on food, reduced second hand smoke rates, hand washing in hospitals. Let’s not snub our nose as people that work to make a safer world.
Modern cars are ridiculously safer compared to older models. I was watching the news yesterday of someone that hit a concrete wall with a partial front-on collision at speed and just walked away. He was being interviewed at the crash site and looked fine, just a little dazed. Decades ago you'd have to have been air-lifted to hospital to have your bones joined back together with titanium plates.
Because there is no evidence of any interference. Boeing and Airbus are requesting something without showing any evidence, which could have been easily detected in a test environment.
You already need multiple radar altimeters on ONE plane much closer physically and spectrum wise than 5G. In busy airports you already have multiple altimeters operating again closely physically.
Anyways, even if there is interference, it's actually boeing that should fix their systems to operate within their assigned band (ie, operate in the middle of the band, and reject signals outside of band). This is radio 101 stuff.
Only one radar altimeter is generally operational at a time (transmitting), due to high bandwidth involved, and latest ICAO working group reports are "we don't know yet if it's safe with current equipment, retrofitting will take years as they can't even start designing new models till interference data is available, and that countries are implementing temporary mitigations in 5G base stations"
That's where we find how technically incompetent ICAO is I suppose?
Something that has been a decade in the making, they haven't been able to conduct basic tests on. I'm a lay person, but can easily think of basic tests that would help resolve this question.
"On a large aircraft two or three altimeter systems are employed and these systems could utilize a frequency offset of 5 MHz to 10 MHz."
Are you sure? That's an almost impossibly high receive bandwidth for an older type of equipment I would think.
I've seen bandwidth ranges of 50Hz to 300Hz (that's Hz not KHz or MHz). This is swept or chirped over a frequency (bigger is better for that - so 200Mhz good and they'd probably want more).
But in terms of a guard, you should be able to guard much tighter than 200Mhz - that's what I'm not understanding - but haven't looked at it closely.
Frequency Modulated Continuous Wave radars used for most civilian radar altimeters sweep most of 200 MHz bandwidth, largest known case is 196 MHz. Transmit power ranges between 0.1 to 100W.[1]
As another commenter mentioned, making a broadband filter for such wide bandwidth is... problematic, and it's one of those devices where you might want to use fixed function rather than SDR.
Europe didn't assign 3.8-3.98GHz band to 5G - outside of limited deployments in UK, the allocation stops at 3.8GHz and the next band starts way further than 200MHz away from end of aviation bands.
The initial deployment of C-Band in the US is from 3.7 to 3.8 GHz leaving a nearly 400 MHz guard band. Anything above 3.8 GHz won't be deployed for nearly two years, after the incumbent satellite operators clear the spectrum.
Probably because there isn't any problem. Though it could also be that 5G in the US is meant to use some different channels / frequencies than elsewhere, as was done in older wireless standards.
Nearly 40 countries have already adopted rules and deployed hundreds of thousands of 5G base stations in the C-Band at similar frequencies and similar power levels—and in some instances, at closer proximity to aviation operations—than 5G will be in the U.S. None of these countries has reported any harmful interference with aviation equipment from these commercial deployments, as the Federal Aviation Administration recently confirmed.[0]
The very nice weasel wording used tries to make it sound like 40 countries approved above 3.8GHz, but the further paragraphs explain that only japan did so, without going into much detail other than the low guard band.
The FAA complaint is about 3.8-3.98GHz, and all other examples involve no frequency allocations above 3.8GHz
Absolutely zero weasel wording. The initial deployment of C-Band in the US is 100 MHz of spectrum from 3.7 to 3.8 GHz. The remainder of the auctioned C-Band from 3.8 to 3.98 cannot be deployed until the incumbent satellite operators clear the band on or before December 2023. For 2 years there will be a 400MHz guard band.
The sibling comments here are also correct of course but keep in mind that 5G, excluding stuff like mmWave, does not prescribe any particular frequency band to use and can work on just about any. Regulators will find some slice of free frequency space somewhere between roughly 1 GHz to 5 GHz and auction it off and then carriers and device manufacturers will make 5G run in that band. The iPhone 13 for example can use literally 30 different 5G bands on the US models.
while the comment above is a complete lunacy, it's very easy to point out that:
* Chips need a power source. If it was easy to find one inside the human body, we wouldn't have so much hassle replacing batteries in heart pacemakers and other implants.
* Sending/receiving radio waves requires antennae of certain physical sizes. Something that can go through a needle wouldn't really make it.
Making these arguments is harder than pressing the "flag" button, but that's the only way of actually reducing the division in our society rather than furthering it.
The 5G you think of is not operating in certain frequencies that FCC wants to open for sale - in fact I found only one mention of nationwide "up to 4GHz" frequency use for 5G, in Japan, with one operator and AFAIK in limited use. UK has some location-limited licenses granted for internal networks.
Assuming the concerns are accurate, wouldn't this have a very simple solution?
5g has a very short range, about ~1000 feet. So the solution, to be very cautious, is easy: just don't put a 5g tower within 1500-2000 feet of an airport.
That aside, I'm highly skeptical of these concerns: for years pretty much all electronics were forced to be turned off for unfounded concerns. I remember having to turn off my CD Walkman on plane. Suffice it to say that in the 90's it has no wireless capabilities of any sort at all.
Maybe there is some other turf war or $$$ issue here?
5G comes in 2 parts, Frequency Range 1 and Frequency Range 2. FR 2 is the 24-53 GHz stuff often referred to as mmWave 5G where vast amounts of bandwidth are available but has trouble with distance due to atmospheric absorption and not being able to pass through pretty much anything solid. FR 1 is roughly 400 MHz to 7 GHz often referred to as sub-6GHz (6-7 is pretty much planned to be eaten by Wi-Fi 6E now) and travels much further, e.g. rural cells are often up to about 5 miles radius from the tower. The majority of 5G deployments at the moment are focusing on FR 1 which is more an upgrade to traditional service not the new type of service hyped by the media cycle. The C-Band discussed in the article sits in the middle of FR 1.
It's easier to get passengers to behave and not cause accidental danger during takeoff and landing by telling them to shut off devices and place them away.
It's much harder to explain that the continuing reason is that during RTO or worse, a crash, your device can turn into deadly projectile killing someone by blunt trauma.
Your projectile idea is unlikely to be the reason, because I am allowed to have a book in my hands during takeoff and landing, and I am allowed to have a Kindle in my hands so long as it is "off." But I am not allowed to have it "on."
It's a compromise, and flight crew does try to use it this way. That said, consumer devices were regularly found to radiate in all kinds of crazy bands, and would not pass requirements for non-interference in aviation, but pass for home/office environment. The planes where you have wifi internet etc. are certified that they won't have issues with home/office rated equipment. Aviation is really a different regulatory domain and a lot of stuff was designed with the idea that there aren't hundreds of unknowable quality transceivers active in the passenger/cargo area.
P.S. The uncompromising option is to pack sedated passengers in pods in racks, and believe me, it's not that uncommon dream among the flight crews.
As someone who has regularly done transatlantic flights I would love the sedated pod in a rack option as a passenger. Actually, in general I would prefer that option to awake in nearly every passenger flight scenario.
I generally am lucky enough on shorter flights to fall asleep sometime around safe climb is achieved and wake up for landing, but transatlantic is a PITA.
For some additional information, the concerns that Boeing and Airbus have are around radar altimeters. These devices are used especially during landing scenarios, especially automated landing scenarios in low visibility weather. The radar altimeter devices that are in the belly of these planes use fairly low wattage power, and are easily overwhelmed by 5g base station equipment that is located on the landing paths of major airports. The concern is that 5g could interfere and render useless automated ILS landing for major airports. This concern also affects helicopters doing automated or assisted landing at helipads on hospitals and other more complicated landing scenarios.
There has been extensive research and testing that led to this conclusion of concern. You can read more about the background from the independent body that did the investigation:
Is there a reason that this is a huge concern in the US while flights not passing over US airspace freely allow the use of 5G equipment including during take off/landing?
What western airlines allow the use of cell phone radios during takeoff and landing? I’ve flown in over a dozen countries, and they all require “airplane mode” at those times.
Maybe about half the passengers actually turn airplane mode on. Or turn it on for their phone, but forget their tablet and smart watch.
It's just theatre. It's there mostly to stop you playing with your phone and pay attention to the flight attendant doing the safety speech. One time, many years ago when phones were literally the size and weight of bricks and avionics weren't prepared for the interference of these new fangled "moveable phones", there may have been a problem with some of them, so the FAA put a rule in.
These days, every single passenger has at least one 4G or 5G device. If this was truly a problem, really truly actually causing radio interference, this wouldn't be allowed. You'd have to walk through an RF detector at the gate, and they would confiscate your devices and put them in a Faraday cage.
Do you know why they don't confiscate your phones?
Because it doesn't matter. It doesn't matter because avionics has had to deal with RF interference from mobile phones for decades, and no commercial plane would be deemed airworthy if it had any such problem!
Famously, some of the victims of the 9/11 hijackings got to make phone calls from the air, and/or received SMS texts notifying them of what happened to the other planes.
> It's just theatre. It's there mostly to stop you playing with your phone and pay attention to the flight attendant doing the safety speech.
They frequently give the safety demonstration before requesting people turn on airplane mode. And besides, there’s no safety demonstration when landing.
> If this was truly a problem, really truly actually causing radio interference, this wouldn't be allowed.
And they would drug and alcohol test pilots before flight, yet you can still read NTSB reports showing toxicology in fatal crashes.
> Famously, some of the victims of the 9/11 hijackings got to make phone calls from the air, and/or received SMS texts notifying them of what happened to the other planes.
Those were satellite phones (or used special ground-based receivers) they weren’t regular cell phones. And they were embedded in your seat-back and presumably certified as being airworthy.
The calls that I recall being reported on used telephones available to flight crew for communications unrelated to flight and possibly made available for crazy prices to passengers.
You generally can't receive cell phone signal at segment of airliner flight except immediately after takeoff and in final stages of landing, due to optimizations involved in providing said signal (directional segment antennas, with attempts to beam-form towards specific terminals in latest versions). In practice I had hard time and required special tricks to keep a call running above 500m AGL and it probably depended on BTS located on hill above my reference point.
My understanding is it's an FAA rule to prevent talking on the phone during flight (as well as listening to crew like you mentioned, etc.), not some kind of theater (which I understand would be an FCC rule, ostensibly to prevent interference).
There actually tends to be avionics interference from mobile devices, especially outside 2.4GHz band (which is a "junk" band because of airliners - unlicensed use of 2.4GHz band exists so that airliners could use microwave ovens).
Airplanes actually aren't tested for mobile phone interference unless the plane is going to explicitly allow use of in-flight wireless internet. Yes, with modern devices, you have much less risk of interference, but interference happened in the past, and the rule stays mostly to lower the amount of loose, hard and heavy devices that become possibly dangerous projectiles in case of Rejected Take-Off or a crash.
After all, it's easier to put a "theatre" on than try to use reason with barely mentally present (on average) and possibly unruly passengers.
The concern is specific to allowed frequencies - if the network doesn't advertise the frequencies involved then your phone is not going to transmit on them.
It seems to me that the plane-based altimeter hardware here is incredibly antiquated; honestly, it seems incredibly vulnerable to jamming and attack scenarios, not just interference from 5G.
Now, it's reasonable for aircraft manufacturers to say "hey, in the absence of guidance, we haven't had the time to improve this hardware, let's ensure that the replacement timetable and the 5G rollout timetable in landing pathways are well coordinated." And if guidance is indeed absent, that's an incredible failure on the part of regulators, and one we should hold them to task for.
But it's another thing entirely to try to say "5G around airports should be restricted indefinitely." The OP article doesn't give enough detail to determine what it actually is that manufacturers are proposing, but one imagines that if a timeline were specified in their proposal, one reasonable enough for the manufacturers to publicize, it would have been reported on.
As a Canadian American flying Lufthansa from Vancouver to Munich direct I was amused to learn that so long as your flight isn't passing over US airspace nobody gives a rats ass about airplane mode and you can happily continue to use data and make calls (using a transmitter on the plane to relay signals I'd assume) for the entire flight including take off and landing.
This seems to be an entirely BS safety concern made up by US regulators for who even knows what reason.
Tests in UK, Australia and Israel pointed at interference exceeding allowed limits, with an accident ("crash" in aviation lingo) being at least partially caused by erroneous data from radio altimeter (in 2009, different source of interference)
My understanding was from the old analog days where the signals could actually be received while at altitude, however, the software tracking phone switching towers wasn't able to keep up with the speed of a plane so no billing could be applied to the calls. The digital signals are not broadcasting up any longer, so signal is not as useable. However, the BS excuse of "interferes with cockpit operations" was such BS they couldn't just say "just kidding".
Urban legend? Maybe? Fun cahoots type of story though.
Urban legend - even in NMT days, the antennas on cell towers were directional and tried to avoid uselessly radiating upwards. Good luck getting usable signal at any flight level of commercial flight. Even if you're low enough, it's not uncommon for calls to drop due to speed (in fact a common problem on higher speed trains, and newer cell networks do include improvements for high speed terminals due to that).
The mobile phone is just the most common device that is required to have its transmitter shut down, and part of that is that what is fine for home/office environment is not fine in aviation environment (different regulatory domains et al) so the easiest way is to mandate shutting down all transmitters then whitelist certain kinds (2.4GHz stuff like Bluetooth tends to get a pass because 2.4GHz is unlicensed due to possible interference from airliner's microwave ovens)
From my knowledge US airlines are the most lax about enforcement. Any data/calls in the flight have to use local base station or wifi calling going over satellite due to mobile signals being simply unavailable, and these days airliner crews consider it mostly a way for harm reduction during takeoff and landing.
Anyway, enforcement ultimately depends on flight crew, and you really don't want to know what's the upper limit of their authority.
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[ 3.3 ms ] story [ 201 ms ] threadThis process has been going since 2011, with lots of input from stakeholders (the usual slow govt process). The FCC carefully studies interference before opening a band up.
The guard band is absolutely ridiculous at 220Mhz - I thought this was a typo when I saw it. Looking at Boeing comments, Boeing had requested a max guard band of 110Mhz and the FCC doubled that.
We have 30 - 40 countries already operating mobile services in this band. I haven't heard of credible reports of interference.
Finally, longstanding RF rules require that your RF equipment operate in its assigned band. The fault here, if any, lies with airlines and aircraft mfgs to update their equipment if needed. That said, I doubt it's needed.
So seriously, there is some weird FAA stuff going on now.
We wonder why the US infrastructure costs so much. Instead of doing some tests in the years that this was in the cards, the FAA is now throwing up all sorts of roadblocks, just as biden gets ready to spend $1.2 trillion on infrastructure.
Seriously, if this is a real issue, have every airline land near a test deployment of C-band, and figure out which altimeters are so pathetic they need a 200Mhz guard band.
I don't think 5g is evil but I don't see the technical or economic need for it. Replacing 4G infrastructure that is just a few years old and has plenty of bandwidth doesn't make much sense to me.
The people who decide your paychecks typically don't understand what you're doing anyways, so I wouldn't worry about that.
If you make a tool that has been in use for years - long enough that engineers who turned to management are now in senior management position remember using and liking it back int the day - then you can get a good paycheck to maintain it. Of course this assumes that the tool is still relevant 25 years from when you first created it. Note that this is about you creating and maintaining the tool, taking over someone else's tool might work, but is probably seen as a job for a junior developer.
In some cases you can wait for things to get really bad and then be rewarded for saving the day. (I strong oppose this - a good engineer should see problems and fix them before they get that bad)
You can spend 10% of your time maintaining tools so long as the other 90% has great value. Great value means you see the market need and develop the first prototype that demonstrates the idea works (then turn this over to a new team to make production worthy while you go on to invent something else).
You can run numbers to prove that your tool makes a difference. (Some at Facebook can show hundreds of thousands of dollars saved as a result of their tools)
There are probably others - but none are easy to get into.
It does. But not to me. There are entire teams with millions of dollars of budget to improve tooling.
But of course they only do what they like. And my management doesn't care enough to bring our complaints to them. Individual engineer complaints are ignored.
I raised this with the PMs repeatedly as a significant project risk. Oh... we can't do anything about that they chorused. That's a different department, that's a different budget, etc, etc... Excuse after excuse.
The PM salaries sum to about $1M per annum, but 3 laptops are just too hard for them to organise. Too hard. Can't be done. Just stop asking. Shh. We're busy.
I would say, be nice and polite, take your time learning whatever tech you need to get a better job, prepare for interviews, get an offer, shake hands and move on...
I once had to do development on a 640x480 resolution screen because those fancy large monitors are “too expensive”. That place had less than 30 staff.
Take any amazing organization that does great things, give it a bunch of money, and have the revenue stream not get impacted by failure. You get rot. You get IBM 1960 vs IBM the 2010s - present horror show. You get Ford in 1920 vs Ford in 1980. And this isn't limited to the private sector. It's a feature of massive organizations where revenue is divorced from success.
The US Federal Government is an utter horror show. It was once an amazingly capable collection of efficient, nimble organizations. It could hire rogues and mavericks when needed, and was able to fire the desk-riders too. It's now a rotted-out shell. Success happens in-spite of, and never because-of, the organizations themselves.
I always invite people to go and work with one of the US Fed contractors or agencies. Go look at their job postings. Look at the energy levels of the team members. It's somewhere between a DMV and a mausoleum. Ask yourself if you honestly think they need more money or just far fewer, far higher paid staff with the same or even less budget. Then ask yourself if these organizations are capable of understanding, let alone governing, complex domains.
I doubt we'd be able to do that today at at least the same efficiency.
Except, there's also China with superior morale, superior education and superior efficiency, that might have better plans for the resources left behind a fallen empire...
China also has a huge population problem coming and it’s likely that they have already peaked economically (you’ll notice states like China get much more belligerent and bellicose as they fail ala Russia) and even that is due to government mismanagement.
So, my point is China isn’t some grand strategic master. They are a country with their own problems, likely even worse than most countries because problem exposition is strongly discouraged.
This doesn’t mean that America or any other country doesn’t have problems, but China isn’t particularly special here.
Uh, what?
Which it has largely done, and moves on. Saying it's not resilient enough to handle the situation seems to be wishful thinking in that case (and is obviously false in the case of Tiananmen Square or Tibet.)
I'll take shipbuilding, tank manufacture, aircraft construction, and logistics for World War Two, from a prior activity of about nil, as an example of accomplishment.
We tried tying money to success in our education system with No Child Left Behind and it was a disaster. When you have an organization that is struggling to make effective use of their budget, the solution is to replace the ineffective leadership, not decimate their budget and expect them to do better.
If you ever get bought by a Japanese conglomerate and your boss gets fired, rather than being relieved you should be worried, because you're next if things don't improve. I can't fault that logic, but it does seem to make at least some westerners a little complacent, cross-purposefully.
Not sure how this is related to your point about money, but I do think it's cultural. To work in the civil service right is not something our current culture rewards and/or admires. As such, you get a paucity of talent, hustle, and hard workers.
Wow. The whole FM radio band spans about 20MHz, less than 1/10th the range of their guard band.
You should have an emitter frequency in the 200Hz range? sure, you sweep it, but you shouldn't need a total of 400Mhz for your guard.
Japan and other countries do smaller guard bands, some let cell service go within 100Mhz (ie, twice as close).
This is really an indictment of the technical incompetence and lack of planning (over 10 years) of the FAA.
I found a research from MNO to use 4.9-5.0GHz for 5G near airport: https://www.soumu.go.jp/main_content/000777475.pdf
tldr: they need 5MHz guard band and emission adjustment for small cell near 5km from airport / for larger cell near 20km from airport.
> The 5G network deployment in the U.S. starting on December 5 is in the 3700 to 3800-MHz bands then later in the 3700 to 3980-MHz bands. Radio altimeters use the 4200 to 4400-MHz band. [1].
Are these not sufficiently separated? Can this not be tested easily, by blasting 5G frequencies at a bunch of different planes in test flights? They've had like a decade to do this; I'd expect something more concrete then "concerns about potential interference" at this point.
[1] https://www.ainonline.com/aviation-news/air-transport/2021-1...
In most radio applications a guard band of 220Mhz is absolutely unheard of.
You would do a guard at 10% of bandwidth lets say. On one side you'd have 5%.
So we are talking 1-2 Mhz?
My understanding was planes already had 2-3 altimeters, with guard band spacing of maybe 5Mhz (ie, planes already have devices blasting signals at frequencies much closer than 200Mhz).
It's extremely difficult to have a 170 MHz wide filter at 4.3 GHz with a brick wall response out of band.
https://www.ntia.doc.gov/files/ntia/publications/compendium/...
Because radio altimeters have not been required to tolerate interference above a certain threshold within ~10% of their frequency band, the assumption is that they cannot tolerate it until there is something like a decade or two of production-scale experience without any serious issues. Or until all passenger planes have radio altimeters certified for the new stricter requirements. And because the latter costs money, the industry won't do it as long as other options remain.
If you want to liken the 737 MAX’s failures to road traffic, you have to ask yourself if there’d be broad acceptance of shoddily built, fault-intolerant bridges and freeways. Moreover, would that acceptance be greater or lesser if the public knew that engineers believed their designs were flawed?
You already need multiple radar altimeters on ONE plane much closer physically and spectrum wise than 5G. In busy airports you already have multiple altimeters operating again closely physically.
Anyways, even if there is interference, it's actually boeing that should fix their systems to operate within their assigned band (ie, operate in the middle of the band, and reject signals outside of band). This is radio 101 stuff.
Something that has been a decade in the making, they haven't been able to conduct basic tests on. I'm a lay person, but can easily think of basic tests that would help resolve this question.
"On a large aircraft two or three altimeter systems are employed and these systems could utilize a frequency offset of 5 MHz to 10 MHz."
Something is rotten with the regulators.
The fact that certain radio systems can utilize low bandwidth does not mean every system is like them.
I've seen bandwidth ranges of 50Hz to 300Hz (that's Hz not KHz or MHz). This is swept or chirped over a frequency (bigger is better for that - so 200Mhz good and they'd probably want more).
But in terms of a guard, you should be able to guard much tighter than 200Mhz - that's what I'm not understanding - but haven't looked at it closely.
As another commenter mentioned, making a broadband filter for such wide bandwidth is... problematic, and it's one of those devices where you might want to use fixed function rather than SDR.
[1] https://www.icao.int/NACC/Documents/Meetings/2018/RPG/RPGITU...
[0] https://ecfsapi.fcc.gov/file/1103192305940/211103%20CTIA%20E...
The FAA complaint is about 3.8-3.98GHz, and all other examples involve no frequency allocations above 3.8GHz
* Chips need a power source. If it was easy to find one inside the human body, we wouldn't have so much hassle replacing batteries in heart pacemakers and other implants.
* Sending/receiving radio waves requires antennae of certain physical sizes. Something that can go through a needle wouldn't really make it.
Making these arguments is harder than pressing the "flag" button, but that's the only way of actually reducing the division in our society rather than furthering it.
* They are trolling/being sarcastic
* They are testing you for loyalty
* They are showing loyalty to someone else
* They truly believe it (many people really do)
If your entire context is a single post in the frustrated ex-innovators' community (pun intended), you just can't tell anymore.
5g has a very short range, about ~1000 feet. So the solution, to be very cautious, is easy: just don't put a 5g tower within 1500-2000 feet of an airport.
That aside, I'm highly skeptical of these concerns: for years pretty much all electronics were forced to be turned off for unfounded concerns. I remember having to turn off my CD Walkman on plane. Suffice it to say that in the 90's it has no wireless capabilities of any sort at all.
Maybe there is some other turf war or $$$ issue here?
It's much harder to explain that the continuing reason is that during RTO or worse, a crash, your device can turn into deadly projectile killing someone by blunt trauma.
P.S. The uncompromising option is to pack sedated passengers in pods in racks, and believe me, it's not that uncommon dream among the flight crews.
I generally am lucky enough on shorter flights to fall asleep sometime around safe climb is achieved and wake up for landing, but transatlantic is a PITA.
There has been extensive research and testing that led to this conclusion of concern. You can read more about the background from the independent body that did the investigation:
https://www.rtca.org/wp-content/uploads/2020/10/SC-239-5G-In...
And here's a great in depth video explaining the concerns from an actual 777 pilot for a major US airline:
https://www.youtube.com/watch?v=942KXXmMJdY
It's just theatre. It's there mostly to stop you playing with your phone and pay attention to the flight attendant doing the safety speech. One time, many years ago when phones were literally the size and weight of bricks and avionics weren't prepared for the interference of these new fangled "moveable phones", there may have been a problem with some of them, so the FAA put a rule in.
These days, every single passenger has at least one 4G or 5G device. If this was truly a problem, really truly actually causing radio interference, this wouldn't be allowed. You'd have to walk through an RF detector at the gate, and they would confiscate your devices and put them in a Faraday cage.
Do you know why they don't confiscate your phones?
Because it doesn't matter. It doesn't matter because avionics has had to deal with RF interference from mobile phones for decades, and no commercial plane would be deemed airworthy if it had any such problem!
Famously, some of the victims of the 9/11 hijackings got to make phone calls from the air, and/or received SMS texts notifying them of what happened to the other planes.
That was TWENTY YEARS AGO!
They frequently give the safety demonstration before requesting people turn on airplane mode. And besides, there’s no safety demonstration when landing.
> If this was truly a problem, really truly actually causing radio interference, this wouldn't be allowed.
And they would drug and alcohol test pilots before flight, yet you can still read NTSB reports showing toxicology in fatal crashes.
> Famously, some of the victims of the 9/11 hijackings got to make phone calls from the air, and/or received SMS texts notifying them of what happened to the other planes.
Those were satellite phones (or used special ground-based receivers) they weren’t regular cell phones. And they were embedded in your seat-back and presumably certified as being airworthy.
What on earth are you talking about?
You generally can't receive cell phone signal at segment of airliner flight except immediately after takeoff and in final stages of landing, due to optimizations involved in providing said signal (directional segment antennas, with attempts to beam-form towards specific terminals in latest versions). In practice I had hard time and required special tricks to keep a call running above 500m AGL and it probably depended on BTS located on hill above my reference point.
My understanding is it's an FAA rule to prevent talking on the phone during flight (as well as listening to crew like you mentioned, etc.), not some kind of theater (which I understand would be an FCC rule, ostensibly to prevent interference).
Airplanes actually aren't tested for mobile phone interference unless the plane is going to explicitly allow use of in-flight wireless internet. Yes, with modern devices, you have much less risk of interference, but interference happened in the past, and the rule stays mostly to lower the amount of loose, hard and heavy devices that become possibly dangerous projectiles in case of Rejected Take-Off or a crash.
After all, it's easier to put a "theatre" on than try to use reason with barely mentally present (on average) and possibly unruly passengers.
Now, it's reasonable for aircraft manufacturers to say "hey, in the absence of guidance, we haven't had the time to improve this hardware, let's ensure that the replacement timetable and the 5G rollout timetable in landing pathways are well coordinated." And if guidance is indeed absent, that's an incredible failure on the part of regulators, and one we should hold them to task for.
But it's another thing entirely to try to say "5G around airports should be restricted indefinitely." The OP article doesn't give enough detail to determine what it actually is that manufacturers are proposing, but one imagines that if a timeline were specified in their proposal, one reasonable enough for the manufacturers to publicize, it would have been reported on.
This seems to be an entirely BS safety concern made up by US regulators for who even knows what reason.
Urban legend? Maybe? Fun cahoots type of story though.
The mobile phone is just the most common device that is required to have its transmitter shut down, and part of that is that what is fine for home/office environment is not fine in aviation environment (different regulatory domains et al) so the easiest way is to mandate shutting down all transmitters then whitelist certain kinds (2.4GHz stuff like Bluetooth tends to get a pass because 2.4GHz is unlicensed due to possible interference from airliner's microwave ovens)
Anyway, enforcement ultimately depends on flight crew, and you really don't want to know what's the upper limit of their authority.