5G / Radar altimeter fix deadline will be allowed to end

[chrismol1]

Yea here's what the NOTAMs has said for a while now if of interest what it looks like

ILS RWY 01 (SA CAT II), AMDT 11D ... PROCEDURE NA EXC FOR ACFT USING APPROVED ALTERNATIVE METHODS OF
COMPLIANCE DUE TO 5G C-BAND INTERFERENCE PLUS SEE AIRWORTHINESS
DIRECTIVES 2021-23-12, 2021-23-13. 06 OCT 09:01 2022 UNTIL 06 OCT 13:24 2024

AD AP RDO ALTIMETER UNREL. AUTOLAND, HUD TO TOUCHDOWN, ENHANCED FLT VISION SYSTEMS
TO TOUCHDOWN, HEL OPS REQUIRING RDO ALTIMETER DATA TO INCLUDE HOVER AUTOPILOT
MODES AND CAT A/B/PERFORMANCE CLASS TKOF AND LDG NOT AUTHORIZED EXC FOR ACFT
USING APPROVED ALTERNATIVE METHODS OF COMPLIANCE DUE TO 5G C-BAND INTERFERENCE
PLUS SEE AIRWORTHINESS DIRECTIVES 2021-23-12, 2021-23-13. 19 JAN 05:01 2022 UNTIL
19 JAN 05:01 2024

 

[mikewazowski]

A lot of modern cell sites use "antennas" that are actually the entire RF package built into a plastic radome. They run a LAN cable and power, or power over Ethernet, up the tower to the RF package. Saves the RF loss of having the RF amps on the ground and the antennas at the end of the coax.

A small cell or similar could possibly use POE.

The larger antennas with built in radios have a separate power line and use fiber for connectivity. While they save on any RF loss from jumpers, they tend to weigh a lot and are a bear to change. Most sites will use a remote radio solution with a short jumper to a regular antenna.

 

[mmckenna]

Last time we had a broken cell antenna at work, it was before remote radio units. It was 1-5/8" Heliax up from the ground.

The antennas were multiple elements, cross polarized +45º and -45º, multiple feeds for multiple bands/polarizations. They also had a small actuator that that allowed adjusting the antenna pattern up or down depending on the need.

I had some close up photos of it, but those were lost in a freak iPhone incident.

 

[mikewazowski]

Yup, those were the days. Scissor brackets at the top for mechanical downtilt which evolved to manually moved rods which eventually gave way to servo motors. Now we're into beamforming to single out individual subscribers.

 

[MUTNAV]

Joint Statement on the U.S. Proposal to Identify the Use of 5G Mobile Services in the 3300

The State Department is submitting a proposal to the May 2023 Inter-American Telecommunications Commission held in Mexico City, which calls for opening the 3300-3400 MHz band for 5G mobile services

www.defense.gov

Sounds like a lot of organizations trying to make this work.

At the same time, there having the DOD CIO starting to work issues.

Pentagon CIO taking over 5G activities with eye on expanded testing

The Pentagon in late 2020 launched 5G pilots at five military installations — to the tune of $600 million — and has since doubled the experimentation.

www.c4isrnet.com

Thanks
Joel

 

[ctiller]

120 miles is quite far. The radio altimeter is really only used below about 2500 feet or so which is only within about 10 miles of the airport. i'm guessing they reverted back for some other reason.

 

[CapStar362]

No, 120 miles to Atlanta, also, 35 miles to Augusta Regional and 10 miles to Aiken Airport. We get lots of military flights, too. I forgot to add, 45 miles to Columbia, SC airport.

i used to live in Conyers and directly under where West bound traffic for the southern half ( Runway 27L ) would make their crosswind turn.
from my understanding, the 5G issue comes from RALT's having seriously OLD filters and the FAA not working with the FCC to get them to get just newer bandpass filters installed. Those older filters much looser in tolerances to EMI with C-Band 5G getting involved at about what..... 200 MHz apart, those older filters were not spec'ed for such tight tolerances back when most of these aircraft were built.
Now days, that can easily be mitigated with newer filters that would eliminate this issue, but the FAA wont play ball with the FCC and says its their problem and pilots cannot afford new RALT's. They dont need new RALT's, they just need new RF filter components.
But this why Federal Agencies hardly every work together.

 

[MUTNAV]

Update...

Travel warning as 5G rollout means planes could be BANNED from landing

Transportation Secretary Pete Buttigieg said that only planes fitted with the right equipment will be allowed to land when visibility is poor, such as during bad weather due to new 5G cell towers.

www.dailymail.co.uk

Thanks
Joel

 

[CapStar362]

Update...

Travel warning as 5G rollout means planes could be BANNED from landing

Transportation Secretary Pete Buttigieg said that only planes fitted with the right equipment will be allowed to land when visibility is poor, such as during bad weather due to new 5G cell towers.

www.dailymail.co.uk

Thanks
Joel

^ ^ ^ proving my point. Pothole Pete Buttgag needs to light a fire under the FAA. FCC has done MORE than enough to work on this, FAA has simply given the middle finger.


They refuse to work together to solve this, at the expense of the world and FUBAR'ing schedules.

 

[BinaryMode]

I have to wonder about mountain tops with 5G and radio altimeters barfing when planes are trying to clear the summit.

That part of "radar altimeter" so to speak is not. The PFD uses a database to display the elevations around the plane. It's like a Sandel TAWS (Terrain Alert Warning System) As opposed to the radar altimeter called a GPWS (Ground Proximity Warning System) Here's the gauge mostly used in helicopters. ST3400

Not too bad of a price, eh? LOL

 

[MUTNAV]

^ ^ ^ proving my point. Pothole Pete Buttgag needs to light a fire under the FAA. FCC has done MORE than enough to work on this, FAA has simply given the middle finger.


They refuse to work together to solve this, at the expense of the world and FUBAR'ing schedules.

They say it's a supply chain issue...

Thanks
Joel

 

[BinaryMode]

I have seen the news reports on this interference with the use of 5G and it got me to thinking, what if 5G used something like what is used in 5 GHz Wi-Fi called DFS or Dynamic Frequency Selection? Radar and congestion in wireless networks along the coast > Eye Networks

On the other hand, a radar altimeter uses the frequency range of 4.2 to 4.4 GHz.

 

[mmckenna]

FCC looks to be on a path to maybe fix the root cause: poor receiver design.

FCC seeks public-safety input as it explores new approaches to spectrum policies - Urgent Comms

With radio-frequency spectrum a finite resource, the FCC is exploring new methods to assess and manage its use, as reflected in a policy statement and the launching of a proceeding to gather more information about the topic, according to an FCC official. FCC Attorney Advisor Roberto Mussenden...

urgentcomm.com

 

[MUTNAV]

It's great that you found that article , it's sounds like a good step forward for everything.

I think I read it differently though, I read that they want to change how all radios are going to be future proofed, since the spectrum use can change so quickly.

Thanks
Joel

 

[mmckenna]

it's sounds like a good step forward for everything.

Will be interesting to see how far this spreads. I could/should make its way down to LMR radio. If it does, the CCR's are going to need to clean up their acts. The $14.00 radios might cost $20 after this….

 

[RFI-EMI-GUY]

It's great that you found that article , it's sounds like a good step forward for everything.

I think I read it differently though, I read that they want to change how all radios are going to be future proofed, since the spectrum use can change so quickly.

Thanks
Joel

RX Filtering is no mystery to anyone in the industry. However there are degrees of filtering, bandwidths, shape factors, INSERTION LOSS!, and the FCC, being a bunch of lawyers, not engineers has made a lot of harebrained regulatory changes (Should we start with NEXTEL? Or maybe Lightsquared?) without considering the incumbent technology. So it is easy to say, "its those terrible receivers", when in fact it was terrible decision making that created the immediate crisis. What the newcomers like to do is feign innocence and hope the incumbents will pay for their misdeeds. You can bet that emails were pouring into FCC HQ from retired FCC engineers when each of these dumb ideas were tabled.

New Motorola SCR-3000A P25 "Future Proofed" Filtering Package.

 

[RFI-EMI-GUY]

Will be interesting to see how far this spreads. I could/should make its way down to LMR radio. If it does, the CCR's are going to need to clean up their acts. The $14.00 radios might cost $20 after this….

Whenever someone asks about one of those radios I point out they were never tested to TIA-603D. If I had spare time I would love to build a receiver test lab to pummel those receivers with real world signals. As it is my time is limited and I will be happy with using a sledgehammer.

 

[RFI-EMI-GUY]

That part of "radar altimeter" so to speak is not. The PFD uses a database to display the elevations around the plane. It's like a Sandel TAWS (Terrain Alert Warning System) As opposed to the radar altimeter called a GPWS (Ground Proximity Warning System) Here's the gauge mostly used in helicopters. ST3400

Not too bad of a price, eh? LOL

Money well spent. I got a lesson about the predictive nature of that from the Mentour Pilot YT. I will be sure to ask the crew if they have one when I book my next flight.

 

[MUTNAV]

I was hoping more for something along the lines of ensuring that spectrum for (lets say VHF air ) doesn't have a new service adjacent to it that allows 40 Kw of EIRP, Even if the new service has out of band emissions down by 50 Db, it would still cause interference.

Thanks
Joel

 

[RFI-EMI-GUY]

I was hoping more for something along the lines of ensuring that spectrum for (lets say VHF air ) doesn't have a new service adjacent to it that allows 40 Kw of EIRP, Even if the new service has out of band emissions down by 50 Db, it would still cause interference.

Thanks
Joel

That would require FCC lawyers to admit that it isn't entirely the fault of the receiver. The FCC idiots auctioning off spectrum need to consult independent RF engineers in each and every case.