ACMA, 5G and Radio Altimetry

[Pearly White]

Some Australian pilots may be aware of the 5G interference thread with a link to this report https://www.rtca.org/wp-content/uploads/2020/10/SC-239-5G-Interference-Assessment-Report_274-20-PMC-2073_accepted_changes.pdf which is rather heavy going, but contains a rather worrying Executive Summary. In short, the tests seem to reveal potential interference between the new US 5G bands and the nearly-adjacent Radio Altimetry band (4.2-4.4GHz).

Does anyone know if the airlines were involved in any representation to ACMA prior to the allocation of the new 5G mobile phone spectrum? Don't get me wrong, I'm not in the anti-5G lobby. But I do like my Radio Altimeter to be reliable, as it's especially useful in the final phases of flight, that bit near the ground. Just wondering if anyone's been checking out the situation what with all the other distractions.

[MickG0105]

Some Australian pilots may be aware of the 5G interference thread with a link to this report https://www.rtca.org/wp-content/uploads/2020/10/SC-239-5G-Interference-Assessment-Report_274-20-PMC-2073_accepted_changes.pdf which is rather heavy going, but contains a rather worrying Executive Summary. In short, the tests seem to reveal potential interference between the new US 5G bands and the nearly-adjacent Radio Altimetry band (4.2-4.4GHz).

Does anyone know if the airlines were involved in any representation to ACMA prior to the allocation of the new 5G mobile phone spectrum? Don't get me wrong, I'm not in the anti-5G lobby. But I do like my Radio Altimeter to be reliable, as it's especially useful in the final phases of flight, that bit near the ground. Just wondering if anyone's been checking out the situation what with all the other distractions.
Probably worth noting that the Australian 5G bands (3.5 - 3.6GHz) are at a lower frequency than the US 5G bands (3.7 - 3.98GHz). There's a short ACMA paper on the topic here (https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.acma.gov.au/sites/default/files/2020-07/Wireless%2520broadband%2520and%2520radio%2520altimeter%2520c ompatibility%2520study.docx&ved=2ahUKEwiFnIThlvrsAhV57XMBHapIDNYQFjADegQICBAB&usg=AOvVaw1ROIuYrtF7TIKmT3csX8Oc).

[TWT]

Ther Australian 5G band of concern is 3.575 - 3.7Ghz.

[lucille]

Read the ACMA paper. Very interesting. And concerning.

Any idea why transmissions or interference from other aircraft’s rad alts don’t appear to draw the same concerns. Also ground based S band weather radar is 2-4 GHz and it’s transmitted at high power, again there seems to be less interest in this.

[Longtimer]

Air travel chaos looms as US keeps 5G altimeter refit deadlineAir travel chaos looms as US keeps 5G altimeter refit deadline - BBC News (https://www.bbc.com/news/world-us-canada-65465512?at_medium=RSS&at_campaign=KARANGA)

[Badengo]

Check the CASA DRS site, 100s of RAD ALT faults.

AD is imminent in the US, bandpass filters being produced now to filter out the 5g noise and to be fitted at the antenna connection to the RAD ALT receiver.

[Tinstaafl]

I work for a US airline now. We've had limits on some of the airports we fly to. The majority are ok - or have at least one runway that's ok - as long as we comply with certain limitations or alternate procedures. A half doz or so have no remedial procedures so visual weather conditions only. We've been having the filters fitted for the last several months. Most of our aircraft have 2x rad alts so to maximise the limited number of filters for airframes we've been disabling the 2nd rad alt and configuring the systems to a single rad. alt. installation so we only need a single filter on the remaining #1 rad. alt.

If only the previous Gov. had set some limits on the frequency auction off for signal strength and orientation near airports this whole mess could have been largely avoided.