So in watching this video the title is totally misleading. They said C-band/5G 
in the title. Most of us are going to read that as 5 GHz and the new 6 GHz 
mostly because that’s what we are more used to. 5G in the cellular sense can be 
just about any band as long as is “Fast Speeds”. A good 4G LTE base station now 
can deliver 85 meg or more to a phone without it being 5G in their terms (or it 
is 5GE for enhanced according to AT&T phones and marketing). So that being 
said, this problem is in the band just above the current 3.5/3.65 GHz band. The 
FCC is expanding that band up to the 3.9 GHz portion if I remember correctly. 
This in most WISP minds is the CBRS band. 

 

The good thing about the problem being in this band, base stations have to log 
in to the SASS system to be able to operate. 

 

I see a simple solution to this problem, just map out the flight paths where 
the concern areas are for the airborne RADAR units. This would include any ILS 
corridors from likely 10 nautical miles out from the runway endpoints and I am 
not sure how they set up approach paths for a helipad. I do know from my days 
of filing for tower height clearances, that every one of these flight paths 
there is concerned with are already mapping out by the FAA. Point being these 
are all known areas of high risk. The SAS is a geography aware database system. 
All they need to do is set the database up to not permit any transmitter on the 
concerned frequencies to operate in these approach path areas. They can use 
that study data referenced in the video to create a good buffer for these areas 
based on free space loss as an added measure of safety. I suppose that one 
could also restrict the transmit power in these exclusion areas to a much lower 
level so as not to cause flight radar units interference and permit some level 
of operations.

 

These exclusion rules built in to the SAS would be applicable to both GAA and 
PAL licensed users. I am pretty sure the SAS has this methodology already in 
place for the costal/port areas and real time on air sensing station set up to 
force base stations to turn off or move from frequencies the Navy might be 
using in ports when they are present.  This band was designed to be using it as 
shared spectrum with on air sensing, extending those capabilities to protect 
the aviation system is a trivial task. If the FAA/air industry types knew this 
it would seem like a simple and logical problem to solve. But alas that would 
make it so chicken little can say the sky is falling which seems like the only 
way we communicate in this world anymore.

 

Thank you,

Brian Webster

www.wirelessmapping.com

 

From: AF [mailto:[email protected]] On Behalf Of Jaime Solorza
Sent: Sunday, December 12, 2021 1:14 PM
To: AnimalFarm Microwave Users Group
Subject: Re: [AFMUG] C band 5G vs Radar Altimeters

 

Well I believe Fort Bliss and other radar users around here are getting revenge 
on the 5Ghz DFS users...several wisps are complaining!!! 

Oh well

 

On Sun, Dec 12, 2021, 8:52 AM Tim Hardy <[email protected]> wrote:

Deja Vu all over again. Very similar to the OBE / adjacent channel concerns 
voiced in the 6 GHz unlicensed proceeding. The FCC’s total lack of 
understanding of receiver filtering in even current devices is astounding and 
its fairly clear that money / politics beats physics everyday.





On Dec 11, 2021, at 3:59 PM, Chuck McCown via AF <[email protected]> wrote:

 

I understand the issue now:

https://youtu.be/942KXXmMJdY

 

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