Re: What do you think about this airline vs 5G brouhaha?

[Masataka Ohta]

Jay wrote:

    By adding an LC bandpass filter will add to the propogation delay of 
the receiver.  When the round-trip time of the echo at 1000 feet is only 
2 microseconds, that added delay will throw the RA out of calibration. 


Altitude error by the delay is proportional to wavelength of signal
(in this case, 3 inches or so) and shouldn't be so serious.

> Perhaps the calibration circuitry can deal with this added delay.

According to the following patent filed in 1997:

https://patents.google.com/patent/US6008754A/en
Current radio altimeter calibration technology requires
the radio altimeter to be calibrated by adjusting the
length of the cable connecting the radio altimeter to
its antenna during installation.

old altimeters may have some difficulty to fully calibrate the delay.

Masataka Ohta

Re: What do you think about this airline vs 5G brouhaha?

[Scott McGrath]

Um the Lightsquared monster is back stronger than ever however it has a new
name Ligado Networks

Yes we now have something which everyone agrees will hose every civillian
GPS receiver out there.   But hey thats the user’s problem.

I’m glad i know how to use a sextant….   Perhaps someone will come up with
a low priced INS.   The 747 was the last airliner which used a INS.Of
course a improperly initialized INS was responsible for the Korean Air
shoot down incident….

Of course this will also hose our NTP servers and 802.11ad/ay networks and
any other network kit that uses GPS.

On Wed, Jan 19, 2022 at 9:34 PM Bryan Fields  wrote:

> On 1/18/22 9:03 PM, Brandon Martin wrote:
> > One thing the FCC could potentially do to wipe some egg of their
> > collective faces, here, is mandate that transmitters operating in this
> > newly allocated wireless band face additional scrutiny for spurious
> > emissions in the radio altimeter band as well as the guard band between
> > the two services and a similar bandwidth above the radio altimeter band.
>
> The issue is not one of out of band emissions, but rather close but strong
> signals near the receiver pass band.  This can cause compression of the
> first
> RF amplifier stage and de-sensitize the receiver so it cannot hear the
> intended signal.  I won't get into the physics, but it is difficult to
> realize
> an effective filter that will permit 4200-4400 with low loss and attenuate
> everything else starting at 4200 MHz and down.  The narrower the filter is,
> the higher the loss is. The greater the stopband attenuation is, the more
> elements required and more ripple is present in the pass band.  Now granted
> for avionics, this is doable in the thousands of dollars, but older radar
> altimeters will not have this level of filtering, nor can you slap a
> filter on
> avionics without manufacturer support.
>
> Further complicating this, radar altimeters in the 4200-4400 MHz band are
> frequency modulating continuous wave transmitters.   In this configuration
> the
> frequency is not closed loop controlled, it can be anywhere in the 200 MHz
> band, as it's modulating a free running VCO nominally at 4300 MHz. This is
> a
> non-issue as the transmitter is used for the receiver reference, so they
> are
> locked to the same free-running oscillator.
>
> Only in recent avionics has the receiver been improved via DSP circuits and
> FFT to do real time spectral analysis and pick out the right receive
> signal.
> The older altimeters out there use simple zero crossing counting to
> determine
> the frequency of the strongest signal.  This leaves them open to potential
> interference by strong near band signals. Exasperating this is the poor
> filtering on the RF receiver in 99% of altimeters when dealing with wide
> band
> signals.
>
> So can this LTE at C band work? Yes.
> Will it require upgrades to avionics and standards? Yep.
>
> Last time this sort of change out was needed Sprint/Nextel bought every
> major
> public safety agency new radios.  One could plot the decline of Sprint
> stock
> to an uptick in Motorola stock.
>
> This reminds me of the Lightsquared case where they were using adjacent
> spectrum to GPS for low speed data from satellites, and wanted to add in
> repeaters on the ground, or an ATC/ancillary terrestrial component.
> Sirrus XM
> does this, in tunnels and such and it's just the rather low power repeater
> of
> the same signal from the satellite. Lightsquared wanted this the be a high
> power LTE signal, which wouldn't "fill in" their satellite signal but make
> an
> LTE network they would sell access on.  Do to the proximity to the GPS
> bands
> and the rather poor selectivity of the GPS receiver, it would have
> dramatically limited GPS performance.
>
> The issue here is that Lightsquared was too small.  The establishment
> wireless
> carriers know that commissioners don't work at the FCC for life, and have
> paid
> lobbyists crawling all over capital hill.
> --
> Bryan Fields
>
> 727-409-1194 - Voice
> http://bryanfields.net
>

Re: What do you think about this airline vs 5G brouhaha?

[Jay Hennigan]

On 1/19/22 18:31, Bryan Fields wrote:


The issue is not one of out of band emissions, but rather close but strong
signals near the receiver pass band.  This can cause compression of the first
RF amplifier stage and de-sensitize the receiver so it cannot hear the
intended signal.  I won't get into the physics, but it is difficult to realize
an effective filter that will permit 4200-4400 with low loss and attenuate
everything else starting at 4200 MHz and down. 


It only needs to attenuate from 3980 and down to solve this potential 
problem.



The narrower the filter is,
the higher the loss is. The greater the stopband attenuation is, the more
elements required and more ripple is present in the pass band.  Now granted
for avionics, this is doable in the thousands of dollars, but older radar
altimeters will not have this level of filtering, nor can you slap a filter on
avionics without manufacturer support.


While the passbands are different in these as they're designed to pass 
the C-band satellite signals and reject the radar, C-band filters with 
insertion loss in the 1.4 dB range with 60dB rejection 20 MHz down have 
been available for quite a while.


https://cdn.shopify.com/s/files/1/0529/5806/8919/t/9/assets/eBPF-C-Spec-Sheet.pdf


Further complicating this, radar altimeters in the 4200-4400 MHz band are
frequency modulating continuous wave transmitters.   In this configuration the
frequency is not closed loop controlled, it can be anywhere in the 200 MHz
band, as it's modulating a free running VCO nominally at 4300 MHz. This is a
non-issue as the transmitter is used for the receiver reference, so they are
locked to the same free-running oscillator.


Fair enough, but C-band below 4200 has hardly been a desert all of these 
years. TD-2 was on mountaintops all over the country pushing a couple of 
watts into huge KS-15676 horns with something like 39dB of gain. 4400 
and above is also licensed for mobile use.


The C-band satellite operators, having to deal with extremely weak 
narrowband signals, only have a 20 MHz guard band from the 5G allocation.



Only in recent avionics has the receiver been improved via DSP circuits and
FFT to do real time spectral analysis and pick out the right receive signal.
The older altimeters out there use simple zero crossing counting to determine
the frequency of the strongest signal.  This leaves them open to potential
interference by strong near band signals. Exasperating this is the poor
filtering on the RF receiver in 99% of altimeters when dealing with wide band
signals.


If that's the case, how have they dealt with the signals from other 
aircraft in busy airspace that are operating in the same band all of 
these years?


The poor filtering on the receiver is obviously the issue. However, 
suitable filters have been available for decades, adjacent frequencies 
have been in use for decades, and it isn't the FCC's fault nor the 
cellular carriers' fault that FAA has certified crappy receivers for use 
in mission-critical applications.


Somebody using a crystal set to listen to a 1KW AM station 20 miles away 
isn't going to get very far complaining to FCC about a new 5KW signal 
100 kHz below it and a couple of miles away. That the FAA would certify 
radars with a front-end like a crystal set is the problem.



So can this LTE at C band work? Yes.
Will it require upgrades to avionics and standards? Yep.


If the 5G allocation were shared spectrum with the radar altimeters, I'd 
concede your point. However, it's at least 220 MHz away, over 5% of the 
actual frequency in use.


All of this talk so far is speculation about potential harmful 
interference. Radar altimeters exist. Cell towers exist. Has anyone 
gathered any real world data demonstrating actual interference?


--
Jay Hennigan - j...@west.net
Network Engineering - CCIE #7880
503 897-8550 - WB6RDV

Re: What do you think about this airline vs 5G brouhaha?

[Bryan Fields]

On 1/18/22 9:03 PM, Brandon Martin wrote:
> One thing the FCC could potentially do to wipe some egg of their 
> collective faces, here, is mandate that transmitters operating in this 
> newly allocated wireless band face additional scrutiny for spurious 
> emissions in the radio altimeter band as well as the guard band between 
> the two services and a similar bandwidth above the radio altimeter band. 

The issue is not one of out of band emissions, but rather close but strong
signals near the receiver pass band.  This can cause compression of the first
RF amplifier stage and de-sensitize the receiver so it cannot hear the
intended signal.  I won't get into the physics, but it is difficult to realize
an effective filter that will permit 4200-4400 with low loss and attenuate
everything else starting at 4200 MHz and down.  The narrower the filter is,
the higher the loss is. The greater the stopband attenuation is, the more
elements required and more ripple is present in the pass band.  Now granted
for avionics, this is doable in the thousands of dollars, but older radar
altimeters will not have this level of filtering, nor can you slap a filter on
avionics without manufacturer support.

Further complicating this, radar altimeters in the 4200-4400 MHz band are
frequency modulating continuous wave transmitters.   In this configuration the
frequency is not closed loop controlled, it can be anywhere in the 200 MHz
band, as it's modulating a free running VCO nominally at 4300 MHz. This is a
non-issue as the transmitter is used for the receiver reference, so they are
locked to the same free-running oscillator.

Only in recent avionics has the receiver been improved via DSP circuits and
FFT to do real time spectral analysis and pick out the right receive signal.
The older altimeters out there use simple zero crossing counting to determine
the frequency of the strongest signal.  This leaves them open to potential
interference by strong near band signals. Exasperating this is the poor
filtering on the RF receiver in 99% of altimeters when dealing with wide band
signals.

So can this LTE at C band work? Yes.
Will it require upgrades to avionics and standards? Yep.

Last time this sort of change out was needed Sprint/Nextel bought every major
public safety agency new radios.  One could plot the decline of Sprint stock
to an uptick in Motorola stock.

This reminds me of the Lightsquared case where they were using adjacent
spectrum to GPS for low speed data from satellites, and wanted to add in
repeaters on the ground, or an ATC/ancillary terrestrial component.  Sirrus XM
does this, in tunnels and such and it's just the rather low power repeater of
the same signal from the satellite. Lightsquared wanted this the be a high
power LTE signal, which wouldn't "fill in" their satellite signal but make an
LTE network they would sell access on.  Do to the proximity to the GPS bands
and the rather poor selectivity of the GPS receiver, it would have
dramatically limited GPS performance.

The issue here is that Lightsquared was too small.  The establishment wireless
carriers know that commissioners don't work at the FCC for life, and have paid
lobbyists crawling all over capital hill.
-- 
Bryan Fields

727-409-1194 - Voice
http://bryanfields.net

Re: SOHO IPv6 switches

[Sean Donelan]

On Tue, 18 Jan 2022, Brandon Martin wrote:
The Netgear GS108T is my typical go-to "not a dumb switch".  8 ports for 
about $80.


Make sure you get the v3 if you want most of the modern IPv6 L2 features (you 
also get some very limited L3 capabilities).  The v2 lacks most of them and 
is still readily available on the market.


Thank you for the SOHO switch recommendation.  Ordered the netgear 
GS108Tv3, next-day delivery, and installed it this evening.  The IGMP/MLD 
snooping did its job keeping the excess multicast traffic off the ports 
with legacy IP gear. The netgear also supports ether.type filters, but I 
didn't need to use those filters. Filtering the multicast was enough, to 
keep the port congestion below the legacy 10Mbps (which seemed to be 
closer to 1 Mbps) breaking point.


My newest IPv4 and IPv6 gear is happy.  My ancient stuff is happy.

And most importantly, I didn't need to spend enterprise-grade bucks or 
play ebay gear roulette.

Re: What do you think about this airline vs 5G brouhaha?

[Masataka Ohta]

Tom Beecher wrote:


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.


The important difference is in power. Downlink signal from satellites
is, at the ground, attenuated a lot. Moreover, downlink signal comes
from above an aircraft, though some are scattered by the ground to
the aircraft.


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.


Possible saturation of radar altimeter by 5G signal is caused
by signal power having nothing to do with spurious emission.


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.


True. FCC even doubled guard band.

Masataka Ohta

Re: What do you think about this airline vs 5G brouhaha?

[Jay]

Greetings,

On Wed, 19 Jan 2022, Masataka Ohta wrote:


Jay Hennigan wrote:


Radar receivers are typically some form of direct conversion with
rather good selectivity, synchronized to the frequency of the
transmitted pulse.


No. Direct conversion stage has no inherent frequency
selectivity and is subject to saturation by noise of
any frequency unless the noise is removed in advance.

Selectivity can be enjoyed only after successful
unsaturated conversion, direct or to IF.

But, the solution is to put an LC band pass/stop filter
between an antenna and a receiver, though I have no
idea on the difficulty to obtain FAA/FCC approval to
do so.


   By adding an LC bandpass filter will add to the propogation delay of 
the receiver.  When the round-trip time of the echo at 1000 feet is only 2 
microseconds, that added delay will throw the RA out of calibration. 
Perhaps the calibration circuitry can deal with this added delay.


  --- Jay Nugent  WB8TKL

Re: Coverage of the .to internet outage

[Scott Weeks]

--- sur...@mauigateway.com wrote:
--- j...@baylink.com wrote:
From: "Jay R. Ashworth" 

This piece:

https://www.npr.org/2022/01/18/1073863310/an-undersea-cable-fault-could-cut-tonga-from-the-rest-of-the-world-for-weeks

drills down to this piece with slightly more detail:

https://www.reuters.com/markets/funds/undersea-cable-fault-could-cut-off-tonga-rest-world-weeks-2022-01-18/

I'm told their national carrier is trying to bring in a ground station as 
well, though not whom it will connect to.
--


It's hard to imagine they don't have a lot of Kacific Terminals or other 
satellite connectivity there.

That's what most of the South Pacific uses and all used before the cables were 
laid.  Maybe the journalists
missed that like they miss things when talking about our stuff?
--


PFFT, no sooner than I hit send and the answer comes out of the PICISOC list:

https://www.capacitymedia.com/articles/3830551/dispute-over-57m-impedes-moves-to-re-connect-tonga-to-the-world

"Dispute over $5.7m impedes moves to re-connect Tonga to the world"

"The government has still not paid Kacific for a 15-year deal, signed three 
years ago, to provide satellite back-up 
in just such an eventuality."

"Now Kacific says it is “standing by” to connect the islands and its 105,000 
people, who were cut off by the 
weekend’s volcano."

"owever, company noted that “the previous government was unwilling to perform 
the contract, and it is currently 
subject to arbitration in Singapore”.

Patouraux said: “All we need is to activate that service and perform that 
contract. We are now awaiting instructions. 
We have one simple message for the government of Tonga. We can help. Please get 
in touch.”


Notably: "Getting in touch might be a problem, as both the 827km Tonga Cable 
from Fiji is cut about 37km from the 
cable landing station, and so is the 410km Tonga Domestic Cable Extension, 
which connects the main island with two 
outlying islands to the north.

scott

Re: Coverage of the .to internet outage

[Scott Weeks]

--- j...@baylink.com wrote:
From: "Jay R. Ashworth" 

This piece:

https://www.npr.org/2022/01/18/1073863310/an-undersea-cable-fault-could-cut-tonga-from-the-rest-of-the-world-for-weeks

drills down to this piece with slightly more detail:

https://www.reuters.com/markets/funds/undersea-cable-fault-could-cut-off-tonga-rest-world-weeks-2022-01-18/

I'm told their national carrier is trying to bring in a ground station as 
well, though not whom it will connect to.
--


It's hard to imagine they don't have a lot of Kacific Terminals or other 
satellite connectivity there.

That's what most of the South Pacific uses and all used before the cables were 
laid.  Maybe the journalists
missed that like they miss things when talking about our stuff?

scott

[NANOG-announce] N84 Sneak Peek + Austin Things To Do + Hackathon Registration

[Nanog News]

*NANOG 84 Sneak Peek *
*Get a Preview of our Upcoming Programming *

>From Feb. 14th - 16th, many of the brightest minds in North American
network engineering, operations, and architecture will gather in Austin,
Texas for our next community-wide gathering.

Register now for hours of general sessions, tutorials, keynotes, BoFs, a
Hackathon +  social events. NANOG conferences are all about education and
community.

*Topics include but are not limited to:*

   -  Richard Steenbergen returns to NANOG with an updated "Everything you
   always wanted to know about optical"
   -  RPKI will be discussed from three different viewpoints (policy,
   adoption, deployment)
   - Geoff Huston will talk about DNS "Openness"
   - Keynote Speaker Radia Perlman will address, "How Bad Industry
   Decisions Led to Good Technology Development"
   - New to NANOG speaker Kyle Lyke will talk about the "Effects of
   Electromagnetic Energy on Electronics"

*Also, don't miss our hybrid expo. There will be numerous opportunities to
connect with our community in real-time (online + person). *

*REGISTER NOW * 

*Things To Do + See in Austin*
Time to chase those winter blues away with some boot-scootin' boogie!
Known as a destination for delicious food, great live music, and a lovable
general weirdness - Austin is sure to have something for everyone!

In the moments of R + R, NANOG has collected a list of things to do and see
in this iconic location.

*READ NOW * 

NANOG 84 Hackathon Registration Open
*Dates/Times:*
Friday, February 4, 2022 - Intro/Tutorial/Team Formation
Saturday + Sunday, February 12-13, 2022 - Hacking

*Format:* In-person/Virtual
*Theme:* Giving Back to Open Source

During this Hackathon, we’ve invited the maintainers of several open-source
projects to propose fixes and features for those products that we’ll invite
teams to work on. Project maintainers will provide problem statements and
objectives, and work with teams collaboratively to help teams understand
the respective code bases and help troubleshoot issues.

*REGISTER NOW * 
___
NANOG-announce mailing list
NANOG-announce@nanog.org
https://mailman.nanog.org/mailman/listinfo/nanog-announce

N84 Sneak Peek + Austin Things To Do + Hackathon Registration

[Nanog News]

*NANOG 84 Sneak Peek *
*Get a Preview of our Upcoming Programming *

>From Feb. 14th - 16th, many of the brightest minds in North American
network engineering, operations, and architecture will gather in Austin,
Texas for our next community-wide gathering.

Register now for hours of general sessions, tutorials, keynotes, BoFs, a
Hackathon +  social events. NANOG conferences are all about education and
community.

*Topics include but are not limited to:*

   -  Richard Steenbergen returns to NANOG with an updated "Everything you
   always wanted to know about optical"
   -  RPKI will be discussed from three different viewpoints (policy,
   adoption, deployment)
   - Geoff Huston will talk about DNS "Openness"
   - Keynote Speaker Radia Perlman will address, "How Bad Industry
   Decisions Led to Good Technology Development"
   - New to NANOG speaker Kyle Lyke will talk about the "Effects of
   Electromagnetic Energy on Electronics"

*Also, don't miss our hybrid expo. There will be numerous opportunities to
connect with our community in real-time (online + person). *

*REGISTER NOW * 

*Things To Do + See in Austin*
Time to chase those winter blues away with some boot-scootin' boogie!
Known as a destination for delicious food, great live music, and a lovable
general weirdness - Austin is sure to have something for everyone!

In the moments of R + R, NANOG has collected a list of things to do and see
in this iconic location.

*READ NOW * 

NANOG 84 Hackathon Registration Open
*Dates/Times:*
Friday, February 4, 2022 - Intro/Tutorial/Team Formation
Saturday + Sunday, February 12-13, 2022 - Hacking

*Format:* In-person/Virtual
*Theme:* Giving Back to Open Source

During this Hackathon, we’ve invited the maintainers of several open-source
projects to propose fixes and features for those products that we’ll invite
teams to work on. Project maintainers will provide problem statements and
objectives, and work with teams collaboratively to help teams understand
the respective code bases and help troubleshoot issues.

*REGISTER NOW * 

Re: What do you think about this airline vs 5G brouhaha?

[Nick Hilliard]

nano...@mulligan.org wrote on 19/01/2022 21:57:
If you look at 5G deployments around Japan and Europe, generally they 
are NOT right up next to major airports.


You might want to fact-check this claim.  Most airports have cell towers 
nearby, particularly international airports.


Whatever about Japan, Europe assigned 3300 - 3800 Mhz for 5G, which is a 
good deal further away from the radio altimeter allocation than the US 
5G allocation of 3700 - 4000 MHz.


Nick

Re: What do you think about this airline vs 5G brouhaha?

[nanog08]

Yeah - I'm sure they do and that is my point.  The heads of Verizon and 
ATT are not flying commercial. Their planes are not commercial airlines 
with hundreds of passengers == so they can much more easily just divert...


Geoff


On 1/19/22 15:12, sro...@ronan-online.com wrote:
Considering Verizon has a very sizable fleet of private aircraft, I am 
fairly certain this will happen often.


Shane


On Jan 19, 2022, at 4:59 PM, nano...@mulligan.org wrote:

 Scott - a side note to clarify things...

The 737 Max8 problem was NOT due to lack of testing or 
non-incremental changes.  The system was well tested and put through 
it's paces.  It was a lack of proper pilot training in the aircraft 
and its systems and some carriers choosing to NOT purchase specific 
flight control options.


Full disclosure - my classmate was the Chief Test Pilot for the MAX8 
and another classmate is the current FAA Administrator.


But I digress - sorry...

If you look at 5G deployments around Japan and Europe, generally they 
are NOT right up next to major airports.


I would like to ask ATT and Verizon senior leadership to put their 
loved ones onto a commercial aircraft that is flying into ORD during 
a blizzard on a Zero-Zero landing (the pilots relying on radio 
altimeters) and the 5G network up and running and then ask how 
confident they are that NOTHING will interfere and 5G is perfectly safe.


Geoff

On 1/19/22 14:37, Scott McGrath wrote:
I’m guessing you are not a pilot,  one reason aviation is resistant 
to change is its history is written in blood,    Unlike tech 
aviation is incremental change and painstaking testing and 
documentation of that testing.


When that does not happen we get stuff like the 737 Max debacle

Aviation is the antithesis of ‘Move fast and break things mentality’ 
for a very good reason safety.


On my flying club’s plane every replacement part comes with a 
pedigree which is added to the plane’s maintenance log upon 
installation and the reason for removing the old one recorded


Imagine how much easier our networks would be to maintain if we had 
records down to the last cable tie in the data center.   If there 
was a bug in a SFP+ for instance all of them, when they were 
installed and by who and what supplier they came from was readily 
available sure would make my life easier.


The reasoning behind that massive pile of documents (pilot joke ‘a 
plane is not ready to fly until the weight of the paperwork equals 
the weight of the airplane’) is that if a failure is traced to a 
component all of them can be traced and removed from service.


On a Airbus for instance all the takeoff and landing safety systems 
are tied to the RadAlt.  The EU has strict rules about where the 
c-band can be used as does Japan both use the 120 second rule c-band 
devices not allowed in areas where the the aircraft is in its 
beginning/ending 2 minutes of flight.


So the REST of the world got c-band right the US not so much



On Wed, Jan 19, 2022 at 10:59 AM Dennis Glatting  wrote:

On Tue, 2022-01-18 at 12:29 -0800, Michael Thomas wrote:
>
> I really don't know anything about it. It seems really late to be
> having
> this fight now, right?
>

I worked in aviation as a technologist. Aviation is resistant to
change.
Any change. When you fly older aircraft, be aware that the
software is
old. Very old. As in some of the vendors long ago stopped
supporting the
software kind of old, assuming the vendors still exist.

Aviation didn't wake up one day with the sudden appearance of
5G. They
knew it was comming. They, aviation themselves, are heavily
involved in
standards. Aviation had plenty of time to test, correct, and
protest.

What aviation now wants is a 5G exclusion zone around airports,
or what
I sarcastically call "a technology exclusion zone," which tends
to be
businesses and homes. What is aviation going to do when 6G comes
along?
A new WiFi standard is implemented? Any other unforeseen future
wired/wireless technologies? Or perhaps cell phones should go
back to
Morse Code for aviation's sake?

路‍♂️️


-- 
Dennis Glatting

Numbers Skeptic

Re: What do you think about this airline vs 5G brouhaha?

[sronan]

Considering Verizon has a very sizable fleet of private aircraft, I am fairly 
certain this will happen often.

Shane

> On Jan 19, 2022, at 4:59 PM, nano...@mulligan.org wrote:
> 
>  Scott - a side note to clarify things...  
> 
> The 737 Max8 problem was NOT due to lack of testing or non-incremental 
> changes.  The system was well tested and put through it's paces.  It was a 
> lack of proper pilot training in the aircraft and its systems and some 
> carriers choosing to NOT purchase specific flight control options.
> 
> Full disclosure - my classmate was the Chief Test Pilot for the MAX8 and 
> another classmate is the current FAA Administrator.
> 
> But I digress - sorry...
> 
> If you look at 5G deployments around Japan and Europe, generally they are NOT 
> right up next to major airports.
> 
> I would like to ask ATT and Verizon senior leadership to put their loved ones 
> onto a commercial aircraft that is flying into ORD during a blizzard on a 
> Zero-Zero landing (the pilots relying on radio altimeters) and the 5G network 
> up and running and then ask how confident they are that NOTHING will 
> interfere and 5G is perfectly safe.
> 
> Geoff   
> 
>> On 1/19/22 14:37, Scott McGrath wrote:
>> I’m guessing you are not a pilot,  one reason aviation is resistant to 
>> change is its history is written in blood,Unlike tech aviation is 
>> incremental change and painstaking testing and documentation of that 
>> testing.  
>> 
>> When that does not happen we get stuff like the 737 Max debacle
>> 
>> Aviation is the antithesis of ‘Move fast and break things mentality’ for a 
>> very good reason safety.
>> 
>> On my flying club’s plane every replacement part comes with a pedigree which 
>> is added to the plane’s maintenance log upon installation and the reason for 
>> removing the old one recorded 
>> 
>> Imagine how much easier our networks would be to maintain if we had records 
>> down to the last cable tie in the data center.   If there was a bug in a 
>> SFP+ for instance all of them, when they were installed and by who and what 
>> supplier they came from was readily available sure would make my life 
>> easier. 
>> 
>> The reasoning behind that massive pile of documents (pilot joke ‘a plane is 
>> not ready to fly until the weight of the paperwork equals the weight of the 
>> airplane’) is that if a failure is traced to a component all of them can be 
>> traced and removed from service.
>> 
>> On a Airbus for instance all the takeoff and landing safety systems are tied 
>> to the RadAlt.  The EU has strict rules about where the c-band can be used 
>> as does Japan both use the 120 second rule c-band devices not allowed in 
>> areas where the the aircraft is in its beginning/ending 2 minutes of flight.
>> 
>> So the REST of the world got c-band right the US not so much
>> 
>> 
>> 
>> On Wed, Jan 19, 2022 at 10:59 AM Dennis Glatting  wrote:
>>> On Tue, 2022-01-18 at 12:29 -0800, Michael Thomas wrote:
>>> > 
>>> > I really don't know anything about it. It seems really late to be
>>> > having 
>>> > this fight now, right?
>>> > 
>>> 
>>> I worked in aviation as a technologist. Aviation is resistant to change.
>>> Any change. When you fly older aircraft, be aware that the software is
>>> old. Very old. As in some of the vendors long ago stopped supporting the
>>> software kind of old, assuming the vendors still exist. 
>>> 
>>> Aviation didn't wake up one day with the sudden appearance of 5G. They
>>> knew it was comming. They, aviation themselves, are heavily involved in
>>> standards. Aviation had plenty of time to test, correct, and protest.
>>> 
>>> What aviation now wants is a 5G exclusion zone around airports, or what
>>> I sarcastically call "a technology exclusion zone," which tends to be
>>> businesses and homes. What is aviation going to do when 6G comes along?
>>> A new WiFi standard is implemented? Any other unforeseen future
>>> wired/wireless technologies? Or perhaps cell phones should go back to
>>> Morse Code for aviation's sake?
>>> 
>>> 路‍♂️️
>>> 
>>> 
>>> -- 
>>> Dennis Glatting
>>> Numbers Skeptic
> 

Re: What do you think about this airline vs 5G brouhaha?

[nanog08]

Scott - a side note to clarify things...

The 737 Max8 problem was NOT due to lack of testing or non-incremental 
changes.  The system was well tested and put through it's paces.  It was 
a lack of proper pilot training in the aircraft and its systems and some 
carriers choosing to NOT purchase specific flight control options.


Full disclosure - my classmate was the Chief Test Pilot for the MAX8 and 
another classmate is the current FAA Administrator.


But I digress - sorry...

If you look at 5G deployments around Japan and Europe, generally they 
are NOT right up next to major airports.


I would like to ask ATT and Verizon senior leadership to put their loved 
ones onto a commercial aircraft that is flying into ORD during a 
blizzard on a Zero-Zero landing (the pilots relying on radio altimeters) 
and the 5G network up and running and then ask how confident they are 
that NOTHING will interfere and 5G is perfectly safe.


Geoff

On 1/19/22 14:37, Scott McGrath wrote:
I’m guessing you are not a pilot,  one reason aviation is resistant to 
change is its history is written in blood,    Unlike tech aviation is 
incremental change and painstaking testing and documentation of that 
testing.


When that does not happen we get stuff like the 737 Max debacle

Aviation is the antithesis of ‘Move fast and break things mentality’ 
for a very good reason safety.


On my flying club’s plane every replacement part comes with a pedigree 
which is added to the plane’s maintenance log upon installation and 
the reason for removing the old one recorded


Imagine how much easier our networks would be to maintain if we had 
records down to the last cable tie in the data center.   If there was 
a bug in a SFP+ for instance all of them, when they were installed and 
by who and what supplier they came from was readily available sure 
would make my life easier.


The reasoning behind that massive pile of documents (pilot joke ‘a 
plane is not ready to fly until the weight of the paperwork equals the 
weight of the airplane’) is that if a failure is traced to a component 
all of them can be traced and removed from service.


On a Airbus for instance all the takeoff and landing safety systems 
are tied to the RadAlt.  The EU has strict rules about where the 
c-band can be used as does Japan both use the 120 second rule c-band 
devices not allowed in areas where the the aircraft is in its 
beginning/ending 2 minutes of flight.


So the REST of the world got c-band right the US not so much



On Wed, Jan 19, 2022 at 10:59 AM Dennis Glatting  wrote:

On Tue, 2022-01-18 at 12:29 -0800, Michael Thomas wrote:
>
> I really don't know anything about it. It seems really late to be
> having
> this fight now, right?
>

I worked in aviation as a technologist. Aviation is resistant to
change.
Any change. When you fly older aircraft, be aware that the software is
old. Very old. As in some of the vendors long ago stopped
supporting the
software kind of old, assuming the vendors still exist.

Aviation didn't wake up one day with the sudden appearance of 5G. They
knew it was comming. They, aviation themselves, are heavily
involved in
standards. Aviation had plenty of time to test, correct, and protest.

What aviation now wants is a 5G exclusion zone around airports, or
what
I sarcastically call "a technology exclusion zone," which tends to be
businesses and homes. What is aviation going to do when 6G comes
along?
A new WiFi standard is implemented? Any other unforeseen future
wired/wireless technologies? Or perhaps cell phones should go back to
Morse Code for aviation's sake?

路‍♂️️


-- 
Dennis Glatting

Numbers Skeptic

Re: What do you think about this airline vs 5G brouhaha?

[Scott McGrath]

I’m guessing you are not a pilot,  one reason aviation is resistant to
change is its history is written in blood,Unlike tech aviation is
incremental change and painstaking testing and documentation of that
testing.

When that does not happen we get stuff like the 737 Max debacle

Aviation is the antithesis of ‘Move fast and break things mentality’ for a
very good reason safety.

On my flying club’s plane every replacement part comes with a pedigree
which is added to the plane’s maintenance log upon installation and the
reason for removing the old one recorded

Imagine how much easier our networks would be to maintain if we had records
down to the last cable tie in the data center.   If there was a bug in a
SFP+ for instance all of them, when they were installed and by who and what
supplier they came from was readily available sure would make my life
easier.

The reasoning behind that massive pile of documents (pilot joke ‘a plane is
not ready to fly until the weight of the paperwork equals the weight of the
airplane’) is that if a failure is traced to a component all of them can be
traced and removed from service.

On a Airbus for instance all the takeoff and landing safety systems are
tied to the RadAlt.  The EU has strict rules about where the c-band can be
used as does Japan both use the 120 second rule c-band devices not allowed
in areas where the the aircraft is in its beginning/ending 2 minutes of
flight.

So the REST of the world got c-band right the US not so much



On Wed, Jan 19, 2022 at 10:59 AM Dennis Glatting  wrote:

> On Tue, 2022-01-18 at 12:29 -0800, Michael Thomas wrote:
> >
> > I really don't know anything about it. It seems really late to be
> > having
> > this fight now, right?
> >
>
> I worked in aviation as a technologist. Aviation is resistant to change.
> Any change. When you fly older aircraft, be aware that the software is
> old. Very old. As in some of the vendors long ago stopped supporting the
> software kind of old, assuming the vendors still exist.
>
> Aviation didn't wake up one day with the sudden appearance of 5G. They
> knew it was comming. They, aviation themselves, are heavily involved in
> standards. Aviation had plenty of time to test, correct, and protest.
>
> What aviation now wants is a 5G exclusion zone around airports, or what
> I sarcastically call "a technology exclusion zone," which tends to be
> businesses and homes. What is aviation going to do when 6G comes along?
> A new WiFi standard is implemented? Any other unforeseen future
> wired/wireless technologies? Or perhaps cell phones should go back to
> Morse Code for aviation's sake?
>
> 路‍♂️️
>
>
> --
> Dennis Glatting
> Numbers Skeptic
>

Re: What do you think about this airline vs 5G brouhaha?

[Tom Beecher]

> Jay, one thing you’re missing is that a maximum of 2 (and almost always
1) radar altimeter will be in use per airfield, as one aircraft will be
landing at a time.

I believe that Lady Benjamin may have conflated the radar altimeter on
aircraft with the instrument landing system transmitters.

On Wed, Jan 19, 2022 at 3:52 PM Jay Hennigan  wrote:

> On 1/19/22 01:53, Lady Benjamin Cannon of Glencoe, ASCE wrote:
> > Jay, one thing you’re missing is that a maximum of 2 (and almost always
> 1) radar altimeter will be in use per airfield, as one aircraft will be
> landing at a time.
>
> Really? I was under the impression that radar altimeters were pretty
> much always active during flight. If not, what triggers the "PULL UP -
> TERRAIN" audible warnings that are often heard on CVR recordings just
> before an airplane flies into cumulo-granite weather (mountains) miles
> from an airport?
>
> If in fact they are only used for IFR approach, is there a lockout to
> ensure that the radar is only active on approach? If pilots forget to
> turn them off after landing, does the radar transmitter automatically
> shut itself off?
>
> > Apparently some old gear has trouble with even a 500MHz guard band,
> which I also find astonishingly bad for any time, but a lot of aviation
> tech is truly from another century.
>
> This is absolutely horrible receiver design on equipment critical to
> aviation safety and it's surprising that tighter specs weren't enforced.
> That adjacent spectrum hasn't exactly been silent until now. It's been
> in use for decades going way back to Bell System TD-2 microwave that at
> one point criss-crossed the country.
>
> > They also have main lobes approx 80* wide so they still function when
> the plane is in 40* of bank.
>
> That makes sense.
>
> --
> Jay Hennigan - j...@west.net
> Network Engineering - CCIE #7880
> 503 897-8550 - WB6RDV
>

Re: What do you think about this airline vs 5G brouhaha?

[Jay Hennigan]

On 1/19/22 01:53, Lady Benjamin Cannon of Glencoe, ASCE wrote:

Jay, one thing you’re missing is that a maximum of 2 (and almost always 1) 
radar altimeter will be in use per airfield, as one aircraft will be landing at 
a time.


Really? I was under the impression that radar altimeters were pretty 
much always active during flight. If not, what triggers the "PULL UP - 
TERRAIN" audible warnings that are often heard on CVR recordings just 
before an airplane flies into cumulo-granite weather (mountains) miles 
from an airport?


If in fact they are only used for IFR approach, is there a lockout to 
ensure that the radar is only active on approach? If pilots forget to 
turn them off after landing, does the radar transmitter automatically 
shut itself off?



Apparently some old gear has trouble with even a 500MHz guard band, which I 
also find astonishingly bad for any time, but a lot of aviation tech is truly 
from another century.


This is absolutely horrible receiver design on equipment critical to 
aviation safety and it's surprising that tighter specs weren't enforced. 
That adjacent spectrum hasn't exactly been silent until now. It's been 
in use for decades going way back to Bell System TD-2 microwave that at 
one point criss-crossed the country.



They also have main lobes approx 80* wide so they still function when the plane 
is in 40* of bank.


That makes sense.

--
Jay Hennigan - j...@west.net
Network Engineering - CCIE #7880
503 897-8550 - WB6RDV

What do you think about the "cloudification" of mobile?

[Michael Thomas]

There was an article in the Economist (sorry if it's paywalled) about 
Dish entering the mobile market using an AWS backend. I don't think that 
AWS brings much more than compute for the most part so I don't really 
get why this would be a huge win. A win maybe, but a huge win? I can 
certainly see that not having tons of legacy and accreted inertia is big 
win, but that's true of any disruptor. In the end they still need base 
stations, spectrum, backhaul and all of that to run their network, right?


Am I missing something, or is this mainly hype?

Mike

https://www.economist.com/business/will-the-cloud-business-eat-the-5g-telecoms-industry/21806999

Re: Telia is now Arelion

[Owen DeLong via NANOG]

I think it’s more in the hopes that previously irritated customers might not 
realize they’re once again dealing
with the same schmucks that pissed them off  years back. It helps keep then 
incoming churn of new
customers to replace the churn from other customers rage quitting.


Owen


> On Jan 19, 2022, at 10:20 , james.cut...@consultant.com wrote:
> 
> As in any other company, the Marketing Department has to find some activity 
> to prove their worth. 
> 
>> On Jan 19, 2022, at 1:05 PM, Phineas Walton > > wrote:
>> 
>> Why are all high-tier ISPs always in the market for rebranding?
> 

Re: Telia is now Arelion

[james.cut...@consultant.com]

As in any other company, the Marketing Department has to find some activity to 
prove their worth. 

> On Jan 19, 2022, at 1:05 PM, Phineas Walton  wrote:
> 
> Why are all high-tier ISPs always in the market for rebranding?

Re: Telia is now Arelion

[Bruce H McIntosh]

On 1/19/22 1:05 PM, Phineas Walton wrote:

*[External Email]*

Telia was such a great name; way easier to remember and more phonetic than 
“Arelion”.. we are moving backwards. Why are all high-tier ISPs always in the 
market for rebranding?



They sound like one of the Twelve Colonies of Cobol now. They gonna build a 
Battlestar for the fleet?

--

Bruce H. McIntosh
Network Engineer II
University of Florida Information Technology
b...@ufl.edu
352-273-1066

Re: Telia is now Arelion

[Saku Ytti]

Hey Justin,

> https://www.arelion.com/
>
> 
>
> Since all other work is now complete in the world I should have plenty of 
> time to update documentation, billing, labels, port names, route-maps, 
> contact email addresses, etc.
>
> After watching their marketing video I learned the pronunciation of Arelion 
> is not R-Lion but is actually A-Ray-Lee-On but I may continue thinking of it 
> as R-Lion because it is shorter and it just sounds cooler in my head.

I do appreciate the problems you have in updating the name, however
they didn't change this to spite you, they do not own the rights to
Telia name as a brand and had to change. I hope this brings you some
comfort in this difficult time.
Fun fact, Arelion is a slime covered corpse in WoW, and an existing
legal entity in a market twelve99 (which would have been a great name)
operates in.


-- 
  ++ytti

Re: Telia is now Arelion

[Phineas Walton]

Telia was such a great name; way easier to remember and more phonetic than
“Arelion”.. we are moving backwards. Why are all high-tier ISPs always in
the market for rebranding?

Phin

On Wed, Jan 19, 2022 at 6:00 PM Justin Krejci 
wrote:

> https://www.arelion.com/
>
>
> 
>
> Since all other work is now complete in the world I should have plenty of
> time to update documentation, billing, labels, port names, route-maps,
> contact email addresses, etc.
>
>
> After watching their marketing video I learned the pronunciation of
> Arelion is not *R-Lion* but is actually *A-Ray-Lee-On* but I may continue
> thinking of it as R-Lion because it is shorter and it just sounds cooler in
> my head.
>

Telia is now Arelion

[Justin Krejci]

https://www.arelion.com/




Since all other work is now complete in the world I should have plenty of time 
to update documentation, billing, labels, port names, route-maps, contact email 
addresses, etc.


After watching their marketing video I learned the pronunciation of Arelion is 
not R-Lion but is actually A-Ray-Lee-On but I may continue thinking of it as 
R-Lion because it is shorter and it just sounds cooler in my head.

Re: What do you think about this airline vs 5G brouhaha?

[Keith Stokes]

Being a former satellite downlink/uplink operator I loosely kept up with this 
and had some involvement.

The satellite vendors moved frequencies on some of their customers to make way. 
I forget the full economics and seem to remember one could get reimbursed from 
the FCC for the change.

However there wasn’t as much of an “agreed-upon signoff” as there was “move, go 
off the air or accept interference”. The FCC and telco deal was done no matter 
what.


--

Keith Stokes



On Jan 19, 2022, at 10:22 AM, Tom Beecher 
mailto:beec...@beecher.cc>> wrote:

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 
mailto:beec...@beecher.cc>> wrote:
Altimeter Band : 4.2Ghz - 4.4Ghz

VZ and AT 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 
mailto:m...@mtcc.com>> wrote:

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

Mike

Re: What do you think about this airline vs 5G brouhaha?

[Tom Beecher]

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  wrote:

> Altimeter Band : 4.2Ghz - 4.4Ghz
>
> VZ and AT 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  wrote:
>
>>
>> I really don't know anything about it. It seems really late to be having
>> this fight now, right?
>>
>> Mike
>>
>>

Re: What do you think about this airline vs 5G brouhaha?

[Tom Beecher]

Altimeter Band : 4.2Ghz - 4.4Ghz

VZ and AT 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  wrote:

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

Re: What do you think about this airline vs 5G brouhaha?

[Andy Ringsmuth]

> On Jan 18, 2022, at 4:34 PM, Dennis Glatting  wrote:
> 
> What aviation now wants is a 5G exclusion zone around airports, or what
> I sarcastically call "a technology exclusion zone," which tends to be
> businesses and homes. What is aviation going to do when 6G comes along?
> A new WiFi standard is implemented? Any other unforeseen future
> wired/wireless technologies? Or perhaps cell phones should go back to
> Morse Code for aviation's sake?

Clarity is critical to this discussion.

And as usual, the media is obfuscating it. Probably not deliberately this time, 
but it is happening nonetheless, because the talking heads on TV don’t have the 
remotest understanding of what is actually happening. Not surprising of course.

This isn’t an OMG 5G! thing whatsoever. It is specifically related to a 
frequency band that cell carriers are now able to use, which is adjacent or 
practically adjacent to an existing frequency band used by airplanes to safely 
land. Yeah, 5G is a fancy-schmancy buzz word but that is not really material to 
the conversation.

A ROUGH analogy would be something along the lines of - you buy some property 
and build your dream home there. Across the street is vacant land owned by the 
city, and the city’s comprehensive plan says it is zoned for recreational use 
and they plan to put a park there some day. Years go by and one day you wake up 
to find bulldozers on the empty lot. “Awesome, my grandkids will have a nice 
park now!” you think. And construction continues. As it nears completion, you 
realize “Hmmm, that doesn’t really look like a park.” Further investigation 
uncovers that the city sold the land to a private developer and they are 
building a brothel and strip club across the street, which will bring massive 
amounts of vehicular and pedestrian traffic to what for decades was your quiet 
little street.

You scream and complain to the city council about it. “I built my dream home 
there because YOU said there would be a nice park with playground equipment and 
a fishing pond built there some day!” The city says “Yeah, well, sucks to be 
you. We sold it, tough cookies.”


Of course like any analogy it doesn’t hold up 100 percent, but that’s a way to 
explain it to non-tech folks.


Andy Ringsmuth
5609 Harding Drive
Lincoln, NE 68521-5831
(402) 304-0083
a...@andyring.com

Re: What do you think about this airline vs 5G brouhaha?

[Dennis Glatting]

On Tue, 2022-01-18 at 12:29 -0800, Michael Thomas wrote:
> 
> I really don't know anything about it. It seems really late to be
> having 
> this fight now, right?
> 

I worked in aviation as a technologist. Aviation is resistant to change.
Any change. When you fly older aircraft, be aware that the software is
old. Very old. As in some of the vendors long ago stopped supporting the
software kind of old, assuming the vendors still exist. 

Aviation didn't wake up one day with the sudden appearance of 5G. They
knew it was comming. They, aviation themselves, are heavily involved in
standards. Aviation had plenty of time to test, correct, and protest.

What aviation now wants is a 5G exclusion zone around airports, or what
I sarcastically call "a technology exclusion zone," which tends to be
businesses and homes. What is aviation going to do when 6G comes along?
A new WiFi standard is implemented? Any other unforeseen future
wired/wireless technologies? Or perhaps cell phones should go back to
Morse Code for aviation's sake?

路‍♂️️


-- 
Dennis Glatting
Numbers Skeptic

Re: What do you think about this airline vs 5G brouhaha?

[Lady Benjamin Cannon of Glencoe, ASCE]

Jay, one thing you’re missing is that a maximum of 2 (and almost always 1) 
radar altimeter will be in use per airfield, as one aircraft will be landing at 
a time. 

2 at SFO in good weather. (Where it doesn’t matter if they work). 

Apparently some old gear has trouble with even a 500MHz guard band, which I 
also find astonishingly bad for any time, but a lot of aviation tech is truly 
from another century. 

They also have main lobes approx 80* wide so they still function when the plane 
is in 40* of bank.

Ms. Lady Benjamin PD Cannon of Glencoe, ASCE
6x7 Networks & 6x7 Telecom, LLC 
CEO 
l...@6by7.net
"The only fully end-to-end encrypted global telecommunications company in the 
world.”

FCC License KJ6FJJ

Sent from my iPhone via RFC1149.

> On Jan 18, 2022, at 2:25 PM, Jay Hennigan  wrote:
> 
> On 1/18/22 12:29, Michael Thomas wrote:
>> I really don't know anything about it. It seems really late to be having 
>> this fight now, right?
> 
> From a technical standpoint it seems to me to be a non-issue. There's a 220 
> MHz guard band. 5G signals top out at 3980 MHz and radar altimeters operate 
> between 4200 and 4400 MHz.
> 
> If a signal 220 MHz away is going to interfere, then radar altimeters on 
> other aircraft operating in the same band would clearly be a far greater 
> threat, and those radar altimeter signals will be rather numerous near 
> airports. In other words, if non-correlated signals 220 MHz away are going to 
> interfere, then signals within the same band are going to be a far greater 
> source of interference.
> 
> Radar receivers are typically some form of direct conversion with rather good 
> selectivity, synchronized to the frequency of the transmitted pulse. In 
> addition, radar altimeter antennas are pointed at the ground, perpendicular 
> to the horizon. Cell site antennas by design are aimed more or less toward 
> the horizon, not pointed straight up at the sky.
> 
> There's also an existing FCC mobile allocation from 4400 to 4500 MHz directly 
> adjacent to the aeronautical radar band on the high side with no guard band, 
> yet no complaints about that.
> 
> IMNSHO, the concern that 5G cellular signals will cause airplanes to fall out 
> of the sky has about this >< much more credence than the concern that 5G 
> signals cause coronavirus.
> 
> It shouldn't be that hard to instrument an aircraft with test equipment, buzz 
> a few operating cell towers, and come up with hard data.
> 
> -- 
> Jay Hennigan - j...@west.net
> Network Engineering - CCIE #7880
> 503 897-8550 - WB6RDV

Re: What do you think about this airline vs 5G brouhaha?

[Lady Benjamin Cannon of Glencoe, ASCE]

Let’s be clear, this is not a 5G issue.  LTE in the space spectrum would be an 
issue.  

This is a spectrum issue. Only.

Ms. Lady Benjamin PD Cannon of Glencoe, ASCE
6x7 Networks & 6x7 Telecom, LLC 
CEO 
l...@6by7.net
"The only fully end-to-end encrypted global telecommunications company in the 
world.”

FCC License KJ6FJJ

Sent from my iPhone via RFC1149.

> On Jan 18, 2022, at 2:15 PM, Mel Beckman  wrote:
> 
>  Apples and oranges Michael. The US domestic aviation environment is quite 
> different than even Europe or and especially smaller countries overseas. And 
> how long has 5G been out anyway? I hardly think that’s been available for 
> enough of a safety track record in any country.
> 
> -mel via cell
> 
>>> On Jan 18, 2022, at 2:06 PM, Mel Beckman  wrote:
>>> 
>>  Shane,
>> 
>> Incorrect. Owning spectrum also includes the right to interference-free 
>> operation. And you imply that the FAA and airline industry has done nothing, 
>> when in reality it’s the FCC who has done nothing. the FAA sponsored 
>> extensive engineering tests that demonstrate the interference is a concern, 
>> and they notified all the parties well in advance. The fCC et al chose to do 
>> no research of their own, and are basing all their assumptions on operation 
>> in other countries, which even you must admit can’t really be congruent with 
>> the US.
>> 
>> -mel via cell
>> 
>>> On Jan 18, 2022, at 2:01 PM, sro...@ronan-online.com wrote:
>>> 
>>>  The thing is aviation DOESN’T own this spectrum, they just assumed it 
>>> would always be unused. And they failed to mention it would be a problem 
>>> during the last 5 years of discussion regarding the use of this spectrum.
>>> 
>>> Shane
>>> 
 On Jan 18, 2022, at 4:25 PM, Mel Beckman  wrote:
 
 
 Michael,
 
 Here’s a recent PCmag editorial on the subject, and it seems like many 
 people want to put Internet speed above airline safety:
 
 https://www.pcmag.com/news/faa-goes-in-hard-to-kill-mid-band-5g
 
 This issue definitely impacts network operations for 5G providers, so 
 makes sense to discuss here.
 
 Here’s a comment from a friend of mine who has been both a network 
 engineer and a pilot for United Airlines, posted on the article linked 
 above:
 
 “As a pilot, I can tell you that landing in instrument conditions is by 
 far the most critical flight regime possible, during which the radar 
 altimeter reports are a matter of life and death. There is no alternative 
 technology, such as GPS, with the required accuracy and reliability, to 
 provide approach guidance down to the runway in zero-zero weather, which 
 is what the radar altimeter does. 
 
 The collective tech industry needs to admit that it made a huge blunder 
 when it urged the FCC’s clueless Ajit Pai to “blow off” the clearly 
 demonstrated FAA spectrum conflict. Sorry, passengers, but if you look out 
 your window, you’ll see that aviation owns this spectrum and is entitled 
 to interference-free operation. Replacing all radar altimeters isn’t going 
 to happen in time for 5G anyway — it took more than ten years just to 
 deploy anti-collision technology. So do what you should have done from the 
 beginning: follow the FCC rules of non-interference to existing users, who 
 have clear priority in this case.”
 
 I tend to agree with him, and it looks like the 5G providers and FAA 
 agreed last week to put some buffer safety zones around runway approaches 
 at 50 major airports:
 
 https://www.cnet.com/news/faa-lists-50-airports-getting-temporary-buffer-zones-blocking-new-5g-signals/
 
 
 -mel 
 
> On Jan 18, 2022, at 12:33 PM, Michael Thomas  wrote:
> 
> 
> I really don't know anything about it. It seems really late to be having 
> this fight now, right?
> 
> Mike
> 

Re: What do you think about this airline vs 5G brouhaha?

[Masataka Ohta]

Brandon Martin wrote:

However, as long as your receiver still has adequate dynamic range to 
receive "everything that's there",


That's not saturation.

Saturation means a receiver does not have adequate dynamic range.

With digital processing under saturation, effective number of bits
is reduced. That is, some necessary bits are lost, which is not
"everything that's there".

Masataka Ohta