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Cellular data no longer working when airborne

YellerDaisy

Well Known Member
I realize this is a big and probably heated topic. I would be seriously impressed if we could keep this to a technical discussion specific to the mountain west (USA).

In years past, cellular data on Android worked as expected in the very rural/remote areas of the mountain west when within range of a ground antenna (NM, CO, UT, MT, ID, NV, etc.). This was quite useful for sending/receiving texts, looking up data/weather, etc. while enroute. Generally, this was no more than 4,000'-5,000' AGL.

That doesn't seem to be the case any longer - for at least the last six months and I haven't changed phone hardware in a couple of years. I realize that a lot has changed (3G, 46, 5G, our phones, number of ground antennas, etc.) I'm curious to know if there is a reason for this lost functionality. Specifically one that we can do something about - like enabling/disabling something in Android or ??

Google searches like to focus on commercial aircraft travel so have not been helpful.

Maybe already discussed somewhere??
 
I'm interested in the answer to this as well. I have an iPhone and even when I can see a cell tower under me in ultra flat Kansas, quite often there's no signal. I kinda assumed that it was because I was high enough that I was overwhelming it by picking up too many towers at once or maybe changing location fast enough that it's getting confused? I dunno, it would be awesome if there's a fix for that.
 
I know nothing about the principles of cellular radio transmission/reception, but have often wondered if the towers radiate their signals more outward than upward? Seems like the signal degrades more as altitude increases beyond a couple thousand feet.
 
I'm interested in the answer to this as well. I have an iPhone and even when I can see a cell tower under me in ultra flat Kansas, quite often there's no signal. I kinda assumed that it was because I was high enough that I was overwhelming it by picking up too many towers at once or maybe changing location fast enough that it's getting confused? I dunno, it would be awesome if there's a fix for that.
I think as they install more towers to cover the higher usage and better coverage the antennae are aim more downwards so as not to interfere with each other. Here is Canada I find the cell phone coverage typically better than in the USA.
 
my iphone stopped grabbing signals in the air a couple of years ago. carriers don't like this, as your phone is seeing too many towers at once; think maybe it overloads their server connections when running algorythems to determine where to connect. System is based upon seeing several strong signal towers at once, not 100's like when airborne. I remain convinced that either the carriers or the FCC lobbied Apple and android to modify their sw to detect when this is happening and disable connectivity. Because my iphone offers an emergency function at these times, it tells me the OS is doing the blocking and not a lack of signal strength. frustrating, as i used to be able to get text messages out in the air.

When they tell you to turn off your phone on an airline, that is not just an FAA reg, it is an FCC reg for the reasons I mentioned above. The reg requiring phones be shut off in landing or TO phase is an FAA reg from back in the day when we fooloishly thought cell phones messed with elec equipment.
 
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I think as they install more towers to cover the higher usage and better coverage the antennae are aim more downwards so as not to interfere with each other. Here is Canada I find the cell phone coverage typically better than in the USA.
i don't believe these signals arte directional.
 
5G signals are highly directional, and so id bet the change to 5g has a lot to do with this. In fact 5G antennas are actually many antennas, and actually track the user as they move using "beam forming" to direct a low-energy signal directly at the user as they move.
thanks. didn't realize that 5G was different like that. My knowledge is highly dated i suppose. The old stuff was not like that. they were using almost 3 watts at the transmitter.
 
I know everybody hates AI. But here is what google gemini says:

The behavior this pilot is experiencing—where cellular reception in a light aircraft has significantly degraded over the last few years despite using the same hardware—is a known phenomenon in general aviation.

The primary culprit is the massive structural shift in how cellular networks are designed today compared to "years past." There are several technical reasons for this change, as well as a few potential settings or workarounds the pilot can explore.

1. The 3G Shutdown (The Biggest Factor)​

In "years past," remote and rural cell reception relied heavily on 3G networks (like UMTS or CDMA).

  • The 3G Advantage: 3G signals used lower frequency bands, had simpler modulation, and used wider, less directional antenna patterns. Crucially, 3G had a much longer range and was highly resilient to "multi-path interference" (signals bouncing off the ground and aircraft structure). Because 3G was designed to cast a wide net for coverage, its "spillover" vertical signal easily reached aircraft at 4,000–5,000 feet AGL.
  • The Current Reality: Between 2022 and 2024, all major US carriers completely shut down their 3G networks to repurpose that wireless spectrum for 4G LTE and 5G. Once 3G died, the "safety net" for high-altitude rural reception disappeared.

2. Antenna Downtilt and Beamforming in 4G/5G​

Cell phone towers are not designed to shoot signals up into the sky; they are optimized to provide coverage to people and cars on the ground.

  • Mechanical and Electrical Downtilt: To maximize ground coverage and prevent towers from interfering with adjacent towers further away, engineers physically and electronically tilt the antennas downward toward the earth.
  • 4G/5G Sectorization: Modern 4G and 5G networks use highly directional antennas and advanced techniques like "beamforming." Instead of blasting a signal in all directions (including up), 5G towers focus narrow, targeted beams directly at ground-based devices. At 5,000 feet AGL, an aircraft is flying entirely above the main beam of these modern antennas, sitting in a "dead zone."

3. Rapid Tower Handoff and Velocity Issues​

Cell towers are organized into "cells." As you move, your phone connects to one tower, and as the signal weakens, it seamlessly "hands off" to the next.

  • Line of Sight at Altitude: At 5,000 feet AGL, your phone has an unobstructed line of sight to dozens of towers simultaneously, rather than just the one or two you would see on the ground.
  • Handoff Confusion: Because the aircraft is traveling much faster than a car (e.g., 100–150+ knots), and because it can see so many towers at once, the phone tries to connect to multiple towers simultaneously. Modern 4G/5G protocols are highly sensitive to this. The network sees a phone rapidly hopping between towers that are miles apart and will often reject the connection entirely as a security or network-management measure, assuming it is a glitch or an unauthorized device.

4. Frequency Band Shifting​

Modern networks rely heavily on higher frequency bands (like mid-band 5G). Higher frequencies can carry vastly more data, but they have much poorer propagation through the air and terrible penetration through physical objects. The aluminum skin or the composite structure of an aircraft acts as a partial shield (a Faraday cage), easily blocking these weaker, higher-frequency 4G/5G signals.

What the Pilot Can Do (Android Settings & Workarounds)​

While you cannot change physics or carrier tower design, there are a few Android settings and operational tweaks that might help restore some functionality:

1. Force the Phone to "LTE Only" (Disable 5G) 5G is highly directional, uses higher frequencies, and is terrible for aircraft reception. Forcing the phone to stay on 4G LTE can sometimes help, as LTE has slightly better range and broader beam widths.

  • How to do it: Go to Settings > Network & Internet > SIMs > Preferred network type and change it from "5G (recommended)" to LTE (or 4G/3G/2G auto).
2. Turn Off "Network Extenders" or "Roaming" Aggression If the phone is constantly hunting for the absolute fastest partner network, it will drop a weak, usable signal in search of a strong one it can't actually authenticate with.

  • How to do it: In the same Mobile Network settings, try toggling Automatically select network off. This will force the phone to scan and display available networks. If you see your specific carrier, select it manually so the phone stops wasting battery and processing power jumping to others.
3. Use an External LTE Router / Hotspot Instead of relying on the phone's internal antenna inside the cockpit, some pilots use a dedicated battery-powered LTE hotspot (like a MiFi device).

  • These devices often have superior cellular radios compared to phones.
  • If placed in a side window or under a plastic canopy away from the aluminum airframe, it gets a much better line of sight to the ground. The pilot can then connect their Android phone to the hotspot via Wi-Fi.
4. The Ultimate Solution: Satellite Messengers If the pilot's primary goal is sending/receiving texts and looking up basic weather (in-flight ADS-B weather should be handled via an ADS-B In receiver like a Stratux or Sentry anyway), they should move away from cellular entirely.

  • Devices like the Garmin inReach, Spotlight, or ZOLEO pair with an Android phone via Bluetooth and use the Iridium satellite network. They provide 100% reliable text messaging and weather updates anywhere in the mountain west, at any altitude, completely independent of cell towers.
 
I posted this last month in a Starlink thread. On the way home, I had poor reception below 10K.

“Three weeks ago, I flew from central Texas to Colorado at 12,000’. I had cell reception for probably 70% of the flight. About half 5G. I even had a video call with my son. I’ve flown that same route at least 30 times and have never seen cell reception like that. Has something changed?”
 
my iphone stopped grabbing signals in the air a couple of years ago. carriers don't like this, as your phone is seeing too many towers at once; think maybe it overloads their server connections when running algorythems to determine where to connect. System is based upon seeing several strong signal towers at once, not 100's like when airborne. I remain convinced that either the carriers or the FCC lobbied Apple and android to modify their sw to detect when this is happening and disable connectivity. Because my iphone offers an emergency function at these times, it tells me the OS is doing the blocking and not a lack of signal strength. frustrating, as i used to be able to get text messages out in the air.

When they tell you to turn off your phone on an airline, that is not just an FAA reg, it is an FCC reg for the reasons I mentioned above. The reg requiring phones be shut off in landing or TO phase is an FAA reg from back in the day when we fooloishly thought cell phones messed with elec equipment.

2G, and 3G (modulation techniques and frequencies -- 8-PSK, QPSK) did interfere with devices that used adjacent IF in their VFOs. Remember the "brrrrrrrp" - "ratatatatatata" sounds from the FM receiver in your car when you got your Nokia 3310 too close to it?
 
2G, and 3G (modulation techniques and frequencies -- 8-PSK, QPSK) did interfere with devices that used adjacent IF in their VFOs. Remember the "brrrrrrrp" - "ratatatatatata" sounds from the FM receiver in your car when you got your Nokia 3310 too close to it?
Yes, they were very powerfull and tended to bleed over on to other frequecies. I was more referring to that era when they thought the phones were messing with general computer circuits. You couldn't bring a phone into a hospital for years. They thought the same with avionics. I get the concerns with receivers, but never bought into the effects on general electronics.
 
In the not too distant future we will have Starlink "Cellular" service as an option. This will be a full blown satellite based service unlike the current partnership with T-Mobile. SpaceX recently purchased some very useful spectrum that will make this possible (along with their direct to cell satellites). The new v3.0 Starlink satellites scheduled to begin launching next year will significantly improve both their internet service and the upcoming satellite based phone service.
 
In the not too distant future we will have Starlink "Cellular" service as an option. This will be a full blown satellite based service unlike the current partnership with T-Mobile. SpaceX recently purchased some very useful spectrum that will make this possible (along with their direct to cell satellites). The new v3.0 Starlink satellites scheduled to begin launching next year will significantly improve both their internet service and the upcoming satellite based phone service.
I've been following this closely and really hope it's going to be an actual carrier option for smart phones, that would be awesome.
 
In the not too distant future we will have Starlink "Cellular" service as an option. This will be a full blown satellite based service unlike the current partnership with T-Mobile. SpaceX recently purchased some very useful spectrum that will make this possible (along with their direct to cell satellites). The new v3.0 Starlink satellites scheduled to begin launching next year will significantly improve both their internet service and the upcoming satellite based phone service.

"Cataracts formed while you wait"
 
I've been following this closely and really hope it's going to be an actual carrier option for smart phones, that would be awesome.
I agree! I have Starlink internet service and I'm hoping they have some kind of bundling option available when their satellite based phone service is released.
 
I haven’t noticed a difference recently but something interesting I noticed from our multiple flights across the country. Cell coverage out west we constantly get coverage above 10k and in some places up to 14k. East of the Rockies, we consistently loose service above 5k feet. This has been very consistent for us in most states through the years. I always figured it was the direction the antennas were set but have nothing to back it up.

I know there is a big debate about this but my phone is always on Foreflight and used for nothing else in flight. This info is all from my passenger who likes to keep contact with the world!
 
In the areas that I mentioned in the original question, there are no 5G antennas (at least that I can find or are marketed by the carriers). The best suggestion so far seems to be to disable 5G service. I'll give that a try next time I'm out. In addition, the 'Network Operators' -> Select Automatically (disable) looks like it may be interesting given the description of 'roaming aggression'.
 
For the first time, my iPhone today suggested I point it at a satellite for the purpose of sending & receiving text messages. It even showed me where to point. It worked! I was at 3500 feet.
 
Thanks for the explainations people. That AI response seems to make a lot of sense, Dave.

The issue is not just reserved to your Northern Hemisphere neck of the woods because since moving to the 5G network in NZ we have the same frustrations. My overall perspective is that we've gone backwards and are worse off now than we were before. Maybe satelight texting will be our saviour as it becomes more accessible and more affordable, but for now..... arrrrrrgh!
 
I'm interested in the answer to this as well. I have an iPhone and even when I can see a cell tower under me in ultra flat Kansas, quite often there's no signal. I kinda assumed that it was because I was high enough that I was overwhelming it by picking up too many towers at once or maybe changing location fast enough that it's getting confused? I dunno, it would be awesome if there's a fix for that.
cell phone antennas are pointed at the ground, where the customers are. Maybe pointed higher in areas where there are tall buildings, but still they are not omni
 
I know that the OP was talking Android, but the thread seems to be treating all the cell services, so I’ll just throw out that we routinely fly up and down the Owens Valley between Reno and the LA area and over the years our cell coverage has gotten better and better. I haven’t noticed any degradation in the past few months, but will keep my eyes out for it. We can get text and voice at altitudes up FL180 when we are over “civilization” (defined by Hwy 395) and it does drop off out in the boonies (between Bishop and Minden).

Just a data point…..
 
I know that the OP was talking Android, but the thread seems to be treating all the cell services, so I’ll just throw out that we routinely fly up and down the Owens Valley between Reno and the LA area and over the years our cell coverage has gotten better and better. I haven’t noticed any degradation in the past few months, but will keep my eyes out for it. We can get text and voice at altitudes up FL180 when we are over “civilization” (defined by Hwy 395) and it does drop off out in the boonies (between Bishop and Minden).

Just a data point…..
Likewise, I got a surprising amount of service between 11k and 17k over CO and WY last weekend. Not quite free of interruption but decent
 
Yes, they were very powerfull and tended to bleed over on to other frequecies. I was more referring to that era when they thought the phones were messing with general computer circuits. You couldn't bring a phone into a hospital for years. They thought the same with avionics. I get the concerns with receivers, but never bought into the effects on general electronics.

This is kind of true. Many things changed. First, everybody started carrying a radio with them so products that had poor shielding were regarded as poor. Remember when your toaster would buzz right before the call came in? Poor shielding. New stuff has much better shielding and noise tolerance.

Another thing that changed is that modern cell phones negotiate tx power with the tower. This is to prevent bleeding into other cells and battery life. Your phone only transmits at levels good enough.

This is why when you are out of cell phone range your phone burns through battery. It’s using max tx power looking for a tower.

As for 5G I disable it. The higher the frequency the higher the data rate the more line of sight. I’d rather get better service and have my phone download faster than I need than have poor service and have my phone download way faster than I need.

If 5G is disabled and I’m below 4k I can usually still get a signal, but the real answer is Starlink. Too bad they screwed up the plans
 
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ive built cell sites for 20 years. we put downtilt on antennas to optimize to ground. lower frequency bands will travel further than high bands. so if your phone is running B2 (1900) vs B12 (850) you will get different levels of signal from the same tower.
I’m far from an expert, but this lends to what I was told. Different carriers are on different bands, and some frequencies travel further than others. So “5G” is not the same 5G from carrier to carrier.

I’m retired, so no longer receive the 24/7 barrage of texts and emails as when I working. Now I don’t pay attention to texts - nor worry about connectivity. If I was still working, I’d have to be hooked to Starlink. There was little meaning to the phrase “off duty”! 😝😂
 
I’m far from an expert, but this lends to what I was told. Different carriers are on different bands, and some frequencies travel further than others. So “5G” is not the same 5G from carrier to carrier.

I’m retired, so no longer receive the 24/7 barrage of texts and emails as when I working. Now I don’t pay attention to texts - nor worry about connectivity. If I was still working, I’d have to be hooked to Starlink. There was little meaning to the phrase “off duty”! 😝😂
you can be on one carrier and hit several different frequency bands on one tower. for att we would generally deploy upto 6 different frequency bands on one site.
 
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