Thread by @ParkerChomerics

We want to shed some light on what's going on in recent media reports about #5G signal interference and civilian aircraft. So, what are we talking about?

Thread:

All communications equipment like #cell phones, connected home devices and smart watches operate at a specific #radio frequency, meaning the device is designed to send and receive signals only on approved allocated #frequency bands.

For example, you're probably familiar with the #radio in your car. No not your streaming service, your regular ol' trusty radio.

The radio spectrum includes #frequencies from 3 kHz to 300 GHz.

📻 AM radio operates from 535 kHz to 1.6 MHz.
📻 FM radio operates from 88.0 to 108.0 MHz.

In the United States, the @FCC (Federal Communications Agency) monitors and allocates all radio frequency bands for use by any user of transmitters and receivers.

The @NTIAgov serves as the @POTUS' principal adviser on telecommunications policies.

These two federal agencies, the major #telecom carriers and US #airlines have not been able to fully resolve the issue of navigating #5G around airports.

And the reason is because of one important piece of navigational equipment. The last time you flew on vacation, your plane likely landed safely with the help of a radar #altimeter.

A radar altimeter is designed to measure the vertical distance of the aircraft to the ground, known as Above Ground Level (AGL) and is crucial for use in landing in poor weather conditions and low-visibility situations.

It is also essential in automatic landings, or autoland, during which the avionics are responsible for the landing procedure while being overseen by the pilot and crew. Radar #altimeters and other aircraft electronics operate in the frequency range of 4.2-4.4 GHz.

Global #telecom companies have spent the last several years bidding on licenses being auctioned off by the @FCC for the use of specific frequency bands used to carry #5G signals.

One such range of frequencies is known as the C-band and includes frequencies from 3.7 GHz to 4.2 GHz, which puts it pretty close to the frequency range used in radar #altimeters on aircraft. The C-band is important because it is considered a mid-band frequency.

While carriers have had #5G signals in the past, they have either been at lower frequencies (good coverage but slower speeds) or at much higher frequencies (very fast speeds but only small geographic area of coverage).

The concern for the airlines and the @FAANews is that #5G signals from towers close to airports will interfere with radar altimeters and other avionic equipment.

This would lead to device malfunctions, as this creates a safety concern which could potentially ground aircraft across the US.

The FAA and FCC place strict #electromagnetic interference (#EMI) guidelines on transmit/receive equipment, meaning that communication devices must pass testing to ensure that intentional transmitter/receiver will not interfere nor be interfered with by surrounding devices.

This is also true for all non-transmit/receive equipment in the aircraft. These #EMI guidelines apply to nearly all devices, from cell phones to defibrillators, from automotive electronics to military aircraft.

Preventing interference becomes a trickier problem when devices are operating properly, but in overlapping or adjacent frequency ranges.

Eventually the carriers and airlines will come to an agreement that takes risk out of the equation but electromagnetic interference and electromagnetic compatibility will continue to be in the conversation.