3 ms·

AIUI the European usage of this band only goes up to 3.8GHz (see https://www.everythingrf.com/community/5g-frequency-bands-in-europe https://www.everythingrf.co

AIUI the European usage of this band only goes up to 3.8GHz (see https://www.everythingrf.com/community/5g-frequency-bands-in-europe https://www.everythingrf.com/community/5g-frequency-bands-in... for example), but the FCC auctioned off band space up to 3.98GHz. Aircraft altimeters use the 4.2-4.4GHz band, so the new US allocation nearly halves the band gap. That is what the FAA is worried about.

gruez 5y ago
>halves the band gap. That is what the FAA is worried about. It's worth noting that a band gap of 200mhz is ridiculously wide, at least according to the top comment from the last thread https://news.ycombinator.com/item?id=29642777 https://news.ycombinator.com/item?id=29642777
g_p 5y ago
The UK makes available shared access licences in the 3.8 to 4.2 GHz band. These are power limited and location constrained, to manage interference with satellite earth stations. You can get a license in this band and run your own private 5G network in it. There doesn't appear to be any concern from the UK aviation regulator (the CAA). Perhaps they're able to achieve sufficient spatial separation from airports and their final approach paths, or perhaps they've found there aren't issues with the reduced transmit power available on these shared access licences? Nonetheless, it will be interesting to see if this 200 MHz guard really is insufficient in the US - at a certain point you need to consider if existing equipment needs to be replaced (like with the swapping of 800 and 700 MHz from digital TV to mobile, and the need for some people to put a band-stop filter onto their TV antenna feed to avoid interference from mobile networks).
- PostThisTooFast 5y ago
- sgent 5y ago
  Using this band is only an aviation problem if you're in the middle of an approach (approximately 20 miles from a runway, but not a big circle). Hence the location and power limitations.

gruez 5y ago

>halves the band gap. That is what the FAA is worried about. It's worth noting that a band gap of 200mhz is ridiculously wide, at least according to the top comment from the last thread https://news.ycombinator.com/item?id=29642777 https://news.ycombinator.com/item?id=29642777

g_p 5y ago

The UK makes available shared access licences in the 3.8 to 4.2 GHz band. These are power limited and location constrained, to manage interference with satellite earth stations. You can get a license in this band and run your own private 5G network in it. There doesn't appear to be any concern from the UK aviation regulator (the CAA). Perhaps they're able to achieve sufficient spatial separation from airports and their final approach paths, or perhaps they've found there aren't issues with the reduced transmit power available on these shared access licences? Nonetheless, it will be interesting to see if this 200 MHz guard really is insufficient in the US - at a certain point you need to consider if existing equipment needs to be replaced (like with the swapping of 800 and 700 MHz from digital TV to mobile, and the need for some people to put a band-stop filter onto their TV antenna feed to avoid interference from mobile networks).

PostThisTooFast 5y ago
sgent 5y ago
Using this band is only an aviation problem if you're in the middle of an approach (approximately 20 miles from a runway, but not a big circle). Hence the location and power limitations.