5G

[GeeBee]

MB S class

[A64Pilot]

6 minutes ago, N201MKTurbo said:

I know exactly where that bicyclist got hit. If there were human eyeballs in that car, the bicyclist probably still would have gotten hit. The only people around there that time of night are the homeless. It is at a trail crossing where a dirt path crosses the road. It is a very infrequently used path. There is no crosswalk or signs where that path crosses the road. Nobody rides or hikes there in the middle of the night. The road is cut through a mountain in the middle of town. People usually speed on that road. It is posted 45, but it is not uncommon for cars to go 60+ through there. The road is also very dark. That trail crossing is just past the crest of the road so cars have no visibility of someone crossing and the crosser cannot see oncoming traffic from one direction. You have to be very careful crossing there. I blame the crosser not the driver. The police didn’t even cite the driver (monitor) of the car because they understand the situation. Uber got screwed in that deal.

 

This was some kind of self driving car?

[N201MKTurbo]

3 minutes ago, GeeBee said:

So given all that, why did the Lidar not detect the object?

Because the bike just darted out into the road from behind a rock. The car did detect the bike, it just couldn’t stop in time.

Edited November 6, 2021 by N201MKTurbo

[N201MKTurbo]

1 minute ago, A64Pilot said:

 

This was some kind of self driving car?

Yes, it was an Uber Car.

[EricJ]

6 hours ago, GeeBee said:

So given all that, why did the Lidar not detect the object?

Reporting at the time indicated that the pedestrian was detected, but that the part of the software that should have reacted to it was disabled.   I don't think it was a lidar failure, it was a system failure or a configuration failure.   

 

[GeeBee]

Point is this. No system is foolproof, unless the enviroment that system operates is closely guarded. 

We can regulate the telcomms to maintain their equipment all we want. But, to each cell tower is hundreds of users attached, transmitting with consumer grade equipment back to the tower on similar frequencies and that like the bicyclist crossing the dark road is the wild card in the operating enviroment. If you have ever set down 400,000 pounds at 140 knots in RVR 300 vis, you don't want to trust that little Missy on TikTok in the back of the mini-van traveling by the airport has a tight phone.

[EricJ]

57 minutes ago, GeeBee said:

Point is this. No system is foolproof, unless the enviroment that system operates is closely guarded. 

We can regulate the telcomms to maintain their equipment all we want. But, to each cell tower is hundreds of users attached, transmitting with consumer grade equipment back to the tower on similar frequencies and that like the bicyclist crossing the dark road is the wild card in the operating enviroment. If you have ever set down 400,000 pounds at 140 knots in RVR 300 vis, you don't want to trust that little Missy on TikTok in the back of the mini-van traveling by the airport has a tight phone.

You might be surprised about the manufacturing tolerance and levels of testing that go into cellular equipment and handsets.   Cellular handsets enjoy an economy of scale that allows a *LOT* of engineering to be spent on their development and testing, so they actually have very, very good RF characteristics and system behavior.   This is partly motivated by the fact that a misbehaving handset can do a lot of damage to the operability of a network, so they have a lot of work up front to minimize the likelihood of that happening with fail safes, etc., built into the standards.   Edit:  e.g., the equivalent of a "stuck mic" on a handset would be an enormous problem in a cellular system for all kinds of obvious and non-obvious reasons, or even just bad transmitter interfering with adjacent channels, so this stuff is all very tightly controlled.    I'm not sure what the 5G spectrum in question is used for, whether it is cells or microcells or backhaul or what.   It might not even be handsets in that spectrum, but backhaul or management equipment.

Almost any modern equipment in regulated spectrum is generaly this way, with much, much better spectral management, motivated by the hugely increasing number of wireless devices over the last thirty years and the need to minimize interference.   Advances in the technology have also contributed to much better performance and resilience in the vast majority of systems.

The radar altimeters in question may be of an older vintage with looser specs or just bad performance from aging in marginal implementations, so I think "some of our stuff is old and crappy but important" isn't really a great argument in the bigger scheme of tighter spectral management and sharing all around.

Edited November 6, 2021 by EricJ

[GeeBee]

Are you willing to bet a planeful of lives on it? Keep in mind Turkish 1951 at Schipol, a 737-800 a relatively new airplane, where an erroneous RA caused premature retard of thrust, which resulted in a stall and crash. The consequences of failure here are known an demonstrated. The FAA is absolutely correct here to be suspect of consumer equipment.

[EricJ]

1 minute ago, GeeBee said:

Are you willing to bet a planeful of lives on it? Keep in mind Turkish 1951 at Schipol were an erroneous RA caused premature retard of thrust, which resulted in a stall and crash. The consequences of failure here are known an demonstrated. The FAA is absolutely correct here to be suspect of consumer equipment.

It is not possible, with any technology in any spectrum, to 100% guarantee anything.   The existing radar altimeters could have, and may have, and probably did at one time or other, experience interference from the previous C-band applications that lived next door in the spectrum in question, and all kinds of other applications that all have a finite probability of radiating in unintended ways.   Should a much higher standard be held to 5G, which will already likely be an order of magnitude more reliable for interference mitigation than previous technologies?   Should an entire block of needed spectrum be left fallow because there are some crappy RA units in the field?

If you get in an airplane and rely on anything electronic for anything, or anything mechanical, or that burns fuel or uses energy or moves, you are already spinning the roulette wheels in all of these areas and hoping the statistics play out in your favor once again.  All that can be done is what can be done to minimize risk as much as practical.   Cost/Risk/reward is always a tradeoff, and I don't think this one favors the FAA since pertinent spectrum rules have been in place for decades.   Risk in this case can be mitigated by not using questionable RA units or using other approaches or technologies.   This will have to be done internationally, anyway, as most parts of the world are already using the C-band spectrum in question for 5G, so the only question is whether the FAA will really attempt to lock the US out of spectrum that is already used in essentially the rest of the world for the expected application.   The US is pretty much in the process of getting left behind here.

[GeeBee]

Uh, no. The Canadians have concerns too.

https://www.avweb.com/aviation-news/canada-puts-the-brakes-on-5g-cellular-networks-around-airports/

 

Furthur the RTCA has determine there are risks in its own research. No offense, but I trust the RTCA more than you. Look at page 87.....They call the risk, "extreme"

"However, although the interference impacts for Usage Category 1 only arise in certain scenarios, the extent and safety consequences of those impacts are extreme, as seen in the CAT II/III Instrument Approach Procedure Scenario discussed in Section 8.1 and Section 10.2. "

https://www.rtca.org/wp-content/uploads/2020/10/SC-239-5G-Interference-Assessment-Report_274-20-PMC-2073_accepted_changes.pdf

[PeteMc]

Verizon and AT&T have also put the breaks on rolling out 5G.

https://www.cnet.com/tech/mobile/at-t-and-verizon-agree-to-pause-5g-rollout-over-faa-safety-concerns/?ftag=CAD-04-10aae4g&bhid=26339908233399705146355489002685&mid=13575949&cid=819709498&fbclid=IwAR0phgVxsLyIfAUo0kpMfcxeZCKSqEUCaoNDQ6g6qTeKBttmBdfN9qdTHrs

[EricJ]

57 minutes ago, PeteMc said:

Verizon and AT&T have also put the breaks on rolling out 5G.

https://www.cnet.com/tech/mobile/at-t-and-verizon-agree-to-pause-5g-rollout-over-faa-safety-concerns/?ftag=CAD-04-10aae4g&bhid=26339908233399705146355489002685&mid=13575949&cid=819709498&fbclid=IwAR0phgVxsLyIfAUo0kpMfcxeZCKSqEUCaoNDQ6g6qTeKBttmBdfN9qdTHrs

 

One month so that there are no concerns over the holiday travel period.

3 hours ago, GeeBee said:

Uh, no. The Canadians have concerns too.

https://www.avweb.com/aviation-news/canada-puts-the-brakes-on-5g-cellular-networks-around-airports/

 

Furthur the RTCA has determine there are risks in its own research. No offense, but I trust the RTCA more than you. Look at page 87.....They call the risk, "extreme"

"However, although the interference impacts for Usage Category 1 only arise in certain scenarios, the extent and safety consequences of those impacts are extreme, as seen in the CAT II/III Instrument Approach Procedure Scenario discussed in Section 8.1 and Section 10.2. "

https://www.rtca.org/wp-content/uploads/2020/10/SC-239-5G-Interference-Assessment-Report_274-20-PMC-2073_accepted_changes.pdf

I'm well aware of all of that.   It is a pretty normal progression of the regulatory process.    The fact remains that much of the developed world has already made the jump, the writing is on the wall.

Edited November 7, 2021 by EricJ

[GeeBee]

Do you work in the telcomm industry Eric?

[GeeBee]

There is no question it is needed. The question is implementation.

 

[EricJ]

5 hours ago, GeeBee said:

Do you work in the telcomm industry Eric?

I did for many years.   Still consult occasionally.   This sort of thing was dealt with regularly.

The idea is not to put people at risk, obviously.   As previously mentioned the approaches will likely be NOTAMed out or equipment required to be replaced or something.   Historically when this has happened in other cases sometimes the interested parties for the new application pay for new equipment or other mitigation for affected parties if or when it is determined that the new application would cause problems for incumbent users with equipment that is fully compliant with existing regulations.   I co-founded a company that wound up supplying thousands of installations of replacement equipment paid for by the cellular industry when they displaced legit, licensed point-to-point terrestrial links in US spectrum that they needed in order to have sufficient continuous spectrum for a particular application.   New spectrum was found for the displaced terrestrial links, but the cellular folks paid for everybody to relocate.   It was a very large, expensive, multi-year effort.

In this case the susceptibility appears to be due to receivers that are not fully compliant with out-of-band rejection requirements.   This may be due to old, crappy design or equipment aging or whatever reason, but it is unlikely that a user in particular spectrum (i.e., RA) will prevail against a user of adjacent spectrum that is compliant with regs and practices because the incumbent has deficient equipment.   The safety aspect of the case is crucially important, but the expected mitigation measure will likely not be prevention of the cellular industry from using that spectrum.   There has long been internationally-driven desire to harmonize spectrum allocation globally so that equipment that works in one part of the world will also work in another, and this is important for both RA as well as cellular equipment.   So this isn't a US problem, it is a global problem, and many parts of the world have already decided how to proceed and are actually using more spectrum which includes ALL of the RA spectrum, not just a piece of C-band carved off to the side like the US issue.   There was a day when the US led the way with this stuff, but these days the rest of the world doesn't really need to wait for us any more and often doesn't.   

[GeeBee]

So who pays if an accident results?

[Ragsf15e]

1 hour ago, GeeBee said:

So who pays if an accident results?

The pilots and passengers.  The families.  The airline and their insurance.  
 

While I agree with going slow and making sure we don’t do something dumb, we’re going to use that spectrum.  If it’s now or maybe in a year or maybe two.  Maybe they figure out airliners built before 2000 are susceptible?  Older RAs?  Fine, Standard ILS mins without an RA.  Anything newer deemed compliant, continues ops normal.  Without causing an accident, the economics will eventually fix the problem if there is one.

[GeeBee]

If you think the SWA and AA crew shortages are causing mayhem, wait until you have a day below CAT 1 at say SEA or ATL and see what happens. Saying, "just do CAT l" and dealing with the reality of that restriction are two very different things.

[Ragsf15e]

6 minutes ago, GeeBee said:

If you think the SWA and AA crew shortages are causing mayhem, wait until you have a day below CAT 1 at say SEA or ATL and see what happens. Saying, "just do CAT l" and dealing with the reality of that restriction are two very different things.

I guess I think the airlines will put new RAs in the old airplanes if they find some are susceptible and pass the costs to the customers.

[N201MKTurbo]

It seems like you could build a radar altimeter at the current frequency and make it reject the interference. If you modulated the signal and then used a lock in amplifier to reject any signals that weren’t its own. By varying the delay of the lock in Modulation from the transmission modulation and finding the delay that would produce the largest signal, it would correlate with the propagation delay, indicating the height above the surface.

Just the rambling of a radio geek.

[GeeBee]

On 11/7/2021 at 8:53 PM, Ragsf15e said:

I guess I think the airlines will put new RAs in the old airplanes if they find some are susceptible and pass the costs to the customers.

Doubtful that will happen fast enough to prevent the chaos a CAT I restriction would create. I remember when the 737NGs had to have new tail feathers because the old ones would restrict the airplane to 270 knots after being de-iced. The winter schedule went to excrement and it took over two years to get them all retrofitted.

 

[Ragsf15e]

24 minutes ago, GeeBee said:

Doubtful that will happen fast enough to prevent the chaos a CAT I restriction would create. I remember when the 737NGs had to have new tail feathers because the old ones would restrict the airplane to 270 knots after being de-iced. The winter schedule went to excrement and it took over two years to get them all retrofitted.

 

Yeah, I’m sure you’re right, but I also don’t think we need to hold the 5g spectrum hostage to protect the airlines schedule.  Obviously we shouldn’t disrupt them for no reason, but they’ve had to know this was coming for plenty of time.  A little pain might cause them to make the necessary adjustments.

[GeeBee]

The pain is not theirs. You will fly them because you need to get where you are going, you just get there later. The pain is on the passengers.

 

[Ragsf15e]

14 hours ago, GeeBee said:

The pain is not theirs. You will fly them because you need to get where you are going, you just get there later. The pain is on the passengers.

 

See I get what your saying, but that’s like the tail wagging the dog.  Just because it causes some short term pain for the airlines (and thus ourselves), doesn’t mean we need to hold up the whole spectrum.  The airlines are businesses, they will adapt or fail, and while it seems harsh, that’s ok.  

[GeeBee]

Why is the onus on the airlines alone to solve a problem created by the cell phone companies. Cell phone companies are businesses too, don't they have to "adapt"?