How 5G puts airplanes at risk – an electrical engineer explains

By Prasenjit Mitra

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This guy again. Sigh.

The radio spectrum ranges from 3 hertz to 3,000 gigahertz

Well, I've never heard of 3Hz being RF before, and 3,000 GHz is wrong too. Starting on a high here. He means 20kHz to 300GHz


The portion of the radio spectrum that carries the signals from your phone and other wireless devices is 20 kilohertz to 300 gigahertz.

No, no it is not. That is a crazy wide range, for a start, and just plain wrong for a second. The phone will use wifi, bluetooth, 3G, 4G and 5G cellular, all with their own narrow frequency ranges, all documented everywhere, and none as low as 20Khz (which is audio anyway)


If two wireless signals in the same area use the same frequency, you get garbled noise.

Not with tech like LBT (listen before talk) and other protocols to allow time division of the band. Hmm, time division multiplexing... like TDMA, used for cellphones for years???


The portions of the radio frequency spectrum used by airplanes and cellphone carriers are different. The problem is that airplane altimeters use the 4.2 to 4.4 gigahertz range, while the recently sold – and previously unused – C-band spectrum for wireless carriers ranges from 3.7 to 3.98 gigahertz. It turns out the 0.22 gigahertz difference between the signals may not be quite enough

The .22GHz gap may not be enought, but the entire C-Band is 0.28Ghz and is enough for all this high speed data for everyone, and the airlines altimeters use a 0.20Ghz band for all the measurements, but a 0.22 gap between them is not enough? If the 4.2 to 4.4 radios are sensing data in the 3.7 range, then they are not very good radios.

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It’s a very low power radar, not a radio. It’s less than 1 watt.

So, the radar altimeters must be crap but the 5G cells will be perfect? The guard band is wider also outside the US.

Other countries have limited 5g to about 600 watts. The US 2,000+ watts, but the carriers are reducing to 1,585 watts temporarily around airports.

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It’s nod radio, it’s radar?????

RADAR= Radio Detection and Ranging


so what happens if one plane flies over another, won’t it detect the lower planes signal and get confused too? Seems to me that their system is more primitive than a simple IR remote control and they’re trying to blame 5g as an excuse to fix their clearly genetically dangerous system.

can the current system be confused by a bird flying blow the plane? By a tell building? A lake? (Different reflectivity perhaps)

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Much of what Mat has written above is correct and the author of the article should not be trusted to wire a power plug. Another glaring error:

Whether there will be interference depends on the receivers in the altimeters and their sensitivity.

Selectivity, not sensitivity, two very different things. Broadly speaking the former being the ability of equipment to receive signals at the frequencies they are designed to receive and the latter being the ability to detect weak signals.

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I used to do paperwork and communications with the FAA for some of their AHCs, EFDs, ALTs, etc. With the mistakes, likely there was a game of telephone where the FAA rep asks the consultant at the repair facility for information on the issue. The consultant, engineer, and technician compiled a report and somehow the information could have gotten misconstrued and made it into the article.

Anyway, the problem ALTs are likely more than 30 years old and flight companies are probably panicking to find upgrades to the old equipment that the FAA can allow or trying to find used newer equipment.

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The airlines are shouting "safety!!", and will pay to upgrade their aging and unsafe equipment. They will tell their shareholders it's the fault of those evil telcos. This is a sham.

The airlines will not spend a single cent anywhere they can save it. There's countless documented records of this.

Articles such as this, badly researched and showing almost zero understanding of the issue, are as bad as blatant misinformation.

The author of this story is a Professor at Penn State.

Let that sink in for a moment.

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The airlines are shouting "safety!!", and will pay to upgrade their aging and unsafe equipment.

Sigh. The only place in the entire world this "aging equipment" faces a safety problem is in the US. It is not the age of the equipment or that the aircraft equipment is unsafe. It is because the implementation of 5G in the US is unsafe. The Boeing 777 and 787 are modern airliners both still in production and both have altimeters that are considered unsafe to use in the US. Nowhere else in the world but the US and only because of how the US is implementing 5G. This is not hard to understand.

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Well, I've never heard of 3Hz being RF before, and 3,000 GHz is wrong too. Starting on a high here. He means 20kHz to 300GHz

Please read this:

Quoting from the link above:

Electromagnetic spectrum has various ranges of spectrums. The frequency range between 3Hz to 3000 GHz is known as radio frequency range or RF spectrum. The RF range frequency widely used in modern technology, mainly in telecommunication.

The wide range of this spectrum was used in different transmission technology and application.

Not to get interference between two users, the radio waves are strictly controlled by International Telecommunication Union (IUT).

IUT divide the RF spectrum into the following frequency band:

• Very low frequency rang that is (3-30 kHz), which is used for navigation and sonar.

Further down:

• Ultra high frequency rang that is (300-3000 MHz), which is used for television, navigation, satellite communication, surveillance radar, radiosonde etc

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It's not just airlines. Sigh. It's general aviation and helicopters particularly impacted. There is no such thing as off the shelf fixes. It takes years to have any piece of anything certified to put on or in an aircraft.

The frequency has been used by aviation for decades. It's up to the encroacher to change not, the user already issued and using a frequency.

As Desert Tortoise said, it is't that hard to understand.

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Yes, Desert Tortoise said a lot of things, but I don't see how X-ray frequencies or sonic frequencies have anything at all to do with the subject at hand, which is the 3.7 to 3.98 GHz range.

Discussion of anything not using this frequency, is off topic.

So, I ask, is it possible to modify the avionics and filter those frequencies out? Of course it is possible.

So why not do it?

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Because it would take years to certify them and it is not the fault of the avionics makers.

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Let’s put the shoe on the other foot. Why don’t the carriers change, since the FCC rules are that the encroacher must change, not the user authorized and approved to use it?

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So, I ask, is it possible to modify the avionics and filter those frequencies out? Of course it is possible.

Have you ever integrated avionics on an aircraft? It would be a minimum five year process to design new equipment and put it through all the tests necessary to certify if safe for flight and will cost many hundreds of millions of Dollars per aircraft. These system are integrated into some pretty complex avionics that literally flies the airplane almost to touchdown. Each aircraft will be a separate stand alone integration effort because each aircraft has different control laws and radio transmissions behave differently on each aircraft. And all this effort and expense would only be necessary for the US since the cellular networks of no other nation encroach on these systems.

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but I don't see how X-ray frequencies or sonic frequencies have anything at all to do with the subject at hand, which is the 3.7 to 3.98 GHz range.

You claimed the author of the article was wrong and implied he didn't know what he was talking about but those frequencies you claim are not radio frequencies are by definition part of the RF spectrum just as the author claimed.

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It's likely that the altimeters were built to a spec that was adequate when nobody was using high power transmitters on nearby frequencies. Also, the US 5G output is much higher than the RotW. Combine the two and you might, possibly have a problem.

The fault is that of the FCC and FAA who are regulators and should have policed this to a resolution long before it became a problem. So they should be paying the bill to fix it.

It is a serious crime to endanger an aircraft. The onus is on the 5G providers not to introduce something new into the mix that does this. They could be arrested simply for that. If a plane is downed, the CEOs of all the 5G companies should be facing multiple life sentences.

It is possible that this is a backhanded way of mediating climate change by reducing domestic air travel in the US, much as international air travel has been blocked, car production has been limited (chip shortage), and consumer sales have been suppressed (not enough containers) etc. It's impossible to know one way or the other on that.

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The fault is that of the FCC and FAA 

The FCC and their supporters in Congress basically told the FAA, DoD and NOAA to pound sand. All three agencies complained bitterly since 2019. There is another chunk of bandwidth that was sold to a company called Ligado that has not been put into service yet. The FCC sold Ligado a chunk of bandwidth that overlaps GPS and some military radar bands. When Ligado puts its system into service GPS will be disrupted. Former Defense Secretary Esper complained long and loud but Ligado's owner called Mr. Esper a liar. Every year since a group of Senators on the Senate Armed Services Committee have tried to insert language into the annual National Defense Act that funds the military and every year they are shot down by a larger number of Senators who support Ligado. GPS is used for maritime navigation and for aviation. For a lot of airports the only instrument approach they have is a GPS approach. If GPS is disrupted aviation and marine users will be without any good means to navigate since Omega and Loran are shut down, replaced by GPS. NOAA has been complaining that new 5G bandwidth will interfere with weather satellites that need one very special frequency to measure water vapor in the atmosphere. Without good information on water vapor weather prediction will suffer greatly. The FCC simply ignored NOAA.

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It’s now the Federal Communications Cartel.

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This is a hardware issue. The aircraft equipment needed to be fully compliant in order for the aircraft to be air worthy. It's not that hard to understand. Unfortunately, everyone has their fingers in the pie rather than addressing the problem in an intelligent manner...

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