It's also relevant that the spectrum surrounding the 4.2-4.4 range has not been an empty desert. It has been used for satellite downlink since the 60s I think?

Yes, there are surely tons of differences in RF characteristics between the two. But let's be honest. Analysis would have been done decades ago on the impact of spurious emissions from sat downlinks on RAs, so there should be at least a baseline to work from.

Either way this should not be a discussion now. This clearly was discussed early in FCC filings, questions were asked, data was presented, and all these parties signed off.

On Wed, Jan 19, 2022 at 11:13 AM Tom Beecher <beecher@beecher.cc> wrote:

Altimeter Band : 4.2Ghz - 4.4Ghz

VZ and AT&T agreed (long ago) to reduce power and stay inside 3.7Ghz - 3.98Ghz once the full deployment was done, staying 200MHz away from altimeters.

In Japan, they have been running 5G for over a year now up to 4,1Ghz, and restarting again at 4.5Ghz. Only 100MHz of guard on either side of the altimeter band. I think EU is close-ish, but not totally sure.

I can't find a single report or study that has shown radio altimeter issuers in Japan since 5G was turned on there.

Aside from a single study which a LOT of smart people have called out flaws in, there isn't much out there that proves there WILL be interference with altimeters, just a lot of FUD that says it MIGHT. I dunno what the angle is, but this has turned into a shitshow.

On Tue, Jan 18, 2022 at 3:32 PM Michael Thomas <mike@mtcc.com> wrote:

I really don't know anything about it. It seems really late to be having
this fight now, right?

Mike