Two mobile phone carriers are going head-to-head with government regulators over a request that they postpone turning on 5G service that could send radio altimeters on jetliners into a tizzy. The service is set to be turned on tomorrow unless the carriers back off.
The issue is specific to ATT and Verizon, whose new 5G offering uses a section of spectrum called C-Band; T-Mobile’s in a different spectrum slice. Transportation Secretary Pete Buttigieg and FAA Administrator Steve Dickson last week asked for the delay. Airlines have also filed a request with the FCC to order a delay.
A number of studies have shown that strong signals in that band, which is very close to the one used by radio instruments in the cockpit, could cause incorrect readings on the radio altimeter, which allows pilots to know how close to the ground they are in foggy or cloudy weather, when visual readings can’t work. If they are unable to rely on the instruments, flights would have to be canceled or diverted.
The companies did offer one olive branch: they are willing, for now, to lower the power of their signals to that of 5G systems operating in France, while further studies are undertaken. They argue that if it is safe in France it must be safe here, but it is not clear that the same conditions apply.
UPDATE
In a last-minute overnight move, the two cell companies agreed to wait two more weeks before turning on their new service. When the service begins, towers near airports will operate at lower power for six months.
If no solution is worked out, FAA plans to ban flights relying on radio altimeters from operating at airports affected by full-power towers, including some, like Seattle, San Francisco and Houston that have large numbers of low-visibility take-offs and landing.
UPDATE
Over the past two weeks there has been a serious see-saw back and forth between the FAA and airlines on one side and the FCC and wireless companies Verizon and AT&T on the other over the C-Band 5G issue—and neither side has done a very good job of making the actual issues clear.
And in general, the press has not been much help, perhaps in part because few have taken the effort to understand the actual issue. Even papers as ‘serious’ as the New York Times and the UK’s Telegraph have allowed it to become what appears to be an issue about 5G itself, which it isn’t. The issue is that two carriers are using spectrum that is uncomfortably close to the spectrum used by radio altimeters.
If you’ve ever experienced static on your radio when certain appliances or lights are turned on, or had one radio station bleed into another as you move from one area to another, you can understand why spacing out is needed. And that is the issue that has been missed as articles dismiss the problem because ‘it works in France’ or the like.
All this is preface to a link we are offering to an article in the Irish Independent which carefully explains the ins and outs of C-Band adjacency and power and why the U.S. situation is different to that in France and elsewhere in Europe.