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| 5G versus commercial aircraft Radio Altimeters in the US, wtf? |
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| LaserSteve:
Sorting the wheat from the chaff is difficult on other forumns, but here goes: Dig hard enough in this thread you'll find links to European government studies and tests, and then some calculations by a poster named "satcom_guru" on pprune and the tw/itter platform. FAA ADs re 5G interference Started: 9th Dec 2021 by WillowRun 6-3 On PPRUNE forumn: https://www.pprune.org/rumours-news/644134-faa-ads-re-5g-interference.html All I can tell is Faa/Fcc/CTIA are keeping tech data closely held. CEPT in Europe is not. Band in question is 4.0 to 4.4 Ghz. Cellular band edge in the US is 3.8 Ghz. No one seems to be talking about potential intermod or mixing products either. Ie Aviation Band + 5G = mixing products? Made all the more interesting by the fact that the US ERP per tower sector is twice that of the rest of the world in 5G bands. Most other nations left a larger guardband. Also a "third harmonic" product from the lower edge of 5G has been mentioned. Landing capability most seriously lost under the current US directives is visibility 1/2 mile or less. Steve |
| jmelson:
--- Quote from: LaserSteve on January 20, 2022, 08:57:22 am ---Sorting the wheat from the chaff is difficult on other forumns, but here goes: Dig hard enough in this thread you'll find links to European government studies and tests, and then some calculations by a poster named "satcom_guru" on pprune and the tw/itter platform. --- End quote --- It seems to me (non pilot) that all it takes is a guy with a Cessna (single engine light plane) equipped with a radioaltimeter to shoot a bunch of approaches to places that have 5G sites running, and the answer will be obvious. Either it interferes or it doesn't. I've seen so much crazy stuff online. There was one article stating that all 5G sites have their antennas pointing straight UP! How is that going to work for phones? I know that radioaltimeters are affected by all sorts of stuff, and give momentarily fluctuating readings, and the planes need to deal with that already. If you fly directly over another large aircraft, it will momentarily show the distance between the two planes. It seems that airlines and aircraft makers have NOT done these tests, and are predicting that aircraft will be falling out of the skies. And, the FCC seems to think they have done enough tests to know there will not be an issue. 5G sites run at lower power than 4G and are closer to their users, and transmit intermittently, so it seems aircraft zipping quickly overhead will only see momentary fluctuations, if any. Well, I know nothing, but it seems SOMEBODY doesn't have real data. Jon |
| ve7xen:
--- Quote from: jmelson on January 20, 2022, 06:48:57 pm --- --- Quote from: LaserSteve on January 20, 2022, 08:57:22 am ---Sorting the wheat from the chaff is difficult on other forumns, but here goes: Dig hard enough in this thread you'll find links to European government studies and tests, and then some calculations by a poster named "satcom_guru" on pprune and the tw/itter platform. --- End quote --- It seems to me (non pilot) that all it takes is a guy with a Cessna (single engine light plane) equipped with a radioaltimeter to shoot a bunch of approaches to places that have 5G sites running, and the answer will be obvious. Either it interferes or it doesn't. I've seen so much crazy stuff online. There was one article stating that all 5G sites have their antennas pointing straight UP! How is that going to work for phones? I know that radioaltimeters are affected by all sorts of stuff, and give momentarily fluctuating readings, and the planes need to deal with that already. If you fly directly over another large aircraft, it will momentarily show the distance between the two planes. It seems that airlines and aircraft makers have NOT done these tests, and are predicting that aircraft will be falling out of the skies. And, the FCC seems to think they have done enough tests to know there will not be an issue. 5G sites run at lower power than 4G and are closer to their users, and transmit intermittently, so it seems aircraft zipping quickly overhead will only see momentary fluctuations, if any. Well, I know nothing, but it seems SOMEBODY doesn't have real data. Jon --- End quote --- This kind of empirical data is maybe good enough for a startup elevator pitch or something, but it's not how you do a safety analysis, it doesn't and can't really cover the gamut. They do, after all, still ban cell phone transmitters on aircraft even after all these years of the public completely ignoring the requests to turn their phones off for 10 minutes during takeoff. Now that those transmissions are moving much closer to an important aviation band, you think some small-n of test approaches is going to convince them it's not a problem? What they might do is do the analysis, figure out what the worst case scenarios are, and then fly those scenarios with test articles. If you're flying over another aircraft while on low approach, something has gone seriously procedurally wrong, the airspace under approach paths is controlled. FCC seems to have sided with the mobile carriers who coincidentally just gave them an $81bn payday, shocker. I think the magnitude of the problem is likely overblown, but I also totally understand the pushback here. It's happening far too fast for the massively bureaucratic and risk-averse aviation industry to properly deal with, and is getting rammed down their throats despite it being likely to cost them many millions. |
| Someone:
--- Quote from: ve7xen on January 20, 2022, 07:42:09 pm ---I think the magnitude of the problem is likely overblown, but I also totally understand the pushback here. It's happening far too fast for the massively bureaucratic and risk-averse aviation industry to properly deal with, and is getting rammed down their throats despite it being likely to cost them many millions. --- End quote --- Airport wants control over what happens in its approach path, its simple, they can buy the land! (yes not all airports have the luxury, but at the same time many airports have sold off/leased that same land they want control over). |
| coppercone2:
I think its a good thing that they are taking their time to check stuff. People often claim the FCC is incompetent (hence the cross checking is good.. there are many stories on HAM forums and stuff showing that you might want to double check FCC anything)... All I see is people worrying about really important systems? You need to be really sure about anything airplane related, given all the problems lately. They probobly grounded a buncha clunker planes :-DD |
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