I have seen a billion posts and differing opionions about this -

I am using a Mavic 2 Pro w/Smart Controller to inspect buildings that have cell towers mounted on the buildings.

I am told by other Drone Pilots that do Cell Tower Inpections for a living - that "NO the cell towers would not interfere with my Mavic 2 Pro/Smart Controller. How else could we use our DJI Drone to inspect them?"


But I am finding a ton of forum posts and videos from people saying YES - the cell towers can interfere with my Mavic 2 Pro/Smart Controller.

Does anyone out there have a definitive YES or NO on this?
Would appreciate hearing from you!
thanks

Does anyone out there have a definitive YES or NO on this?
Who are you going to believe .. the people that actually do it or some forum turkeys who have no idea but don't bother that they are spreading myths and misinformation?

Labroides Posted at 5-25 07:41
Does anyone out there have a definitive YES or NO on this?
Who are you going to believe .. the people that actually do it or some forum turkeys who have no idea but don't bother that they are spreading myths and misinformation?

Well what's "bothersome" is that people posting in this DJI Forum are reporting cell phone tower interference - so why are they saying that if it didn't happen to them? I'm just trying to be sure.

Marleyman Posted at 5-25 07:43
Well what's "bothersome" is that people posting in this DJI Forum are reporting cell phone tower interference - so why are they saying that if it didn't happen to them? I'm just trying to be sure.

That's the nature of forums.
You get lots of people who will guess or post something they heard somewhere.
Misinformation is as common as accurate information.

Labroides Posted at 5-25 07:45
That's the nature of forums.
You get lots of people who will guess or post something they heard somewhere.
Misinformation is as common as accurate information.

I agree with you....so you yourself don't know the answer to my question?

Marleyman Posted at 5-25 07:47
I agree with you....so you yourself don't know the answer to my question?

I know .... but if you read my first post you'd know what I think.

Flying too close to a cell tower while you are too far away with your remote can cause signal problems. The closer your remote to drone is, the more you can get away with flying close to cell towers. Every transmitter swamps other frequencies near and even far away from the indented resonance frequency at very close range. It also depends on the quality, transmission power and sensitivity of your TX/RX equipment. How the transmission protocol handles interferences plays a role as well.  

You might find this article of interest.  

https://thelegaldrone.com/electr ... -flying-your-drone/

Cell towers do not transmit on the same frequency band as we use, not even close. User Falcoc refers to a principle called Front End Overload, but in my experience, the receivers in the aircraft are well enough designed to not suffer from this effect. I have done circular flights around high power microwave communication towers and never got any interference. Most times the problem is as Labroides says, these reports come from technically ignorant posters.

Geebax Posted at 5-25 15:59
Cell towers do not transmit on the same frequency band as we use, not even close. User Falcoc refers to a principle called Front End Overload, but in my experience, the receivers in the aircraft are well enough designed to not suffer from this effect. I have done circular flights around high power microwave communication towers and never got any interference. Most times the problem is as Labroides says, these reports come from technically ignorant posters.

I thought he was describing the frequency doubling and tripling (2nd and 3rd harmonics)?

Whereas Front End Overload involves too strong a signal being further amplified by front end of receiver to point, the signal (radio channel / frequency) desired is lost amongst over amplification noise of neighboring signals.

What you are asking about is "Bleed Over".  Transmitters designed or set  to transmit on specific frequencies, which also (unwantingly) transmit at greatly reduced power on neighboring frequencies.  

One article discussing Cellular LTE "Bleed Over" to lower frequencies of which are higher channels in TV band.
https://www.techhive.com/article ... or-tv-antennas.html

DowntownRDB Posted at 5-25 09:56
You might find this article of interest.  

https://thelegaldrone.com/electromagnetic-interference-when-flying-your-drone/

Nice . . .it has been many many years since I have seen the name SURE,  they have made some of the best microphones, I favored the Controlled Magnetic, when I was working.  The video brought back much, thank you for listing it for others to see.

HedgeTrimmer Posted at 5-25 17:51
I thought he was describing the frequency doubling and tripling (2nd and 3rd harmonics)?

Whereas Front End Overload involves too strong a signal being further amplified by front end of receiver to point, the signal (radio channel / frequency) desired is lost amongst over amplification noise of neighboring signals.

He could have been, I read it differently I suppose. Either way, modern receiver circuitry tends to be implemented in silicon and is typically very selective, way better than discrete designs of old.

Geebax Posted at 5-25 18:40
He could have been, I read it differently I suppose. Either way, modern receiver circuitry tends to be implemented in silicon and is typically very selective, way better than discrete designs of old.

And often tweak-able via firmware.  Which can quickly bring improvements and fixes without expensive hardware  changes.  On flip, all it takes is a programing error or poorly thought and tested changes to cause problems.

HedgeTrimmer Posted at 5-25 19:37
And often tweak-able via firmware.  Which can quickly bring improvements and fixes without expensive hardware  changes.  On flip, all it takes is a programing error or poorly thought and tested changes to cause problems.

Yes, and that would be on the cards according to my experiences with DJI. Often implement poorly tested software.

Hello there Marleyman. Good day and thank you for reaching out. DJI recommends for you to keep away from the power lines and cell towers if applicable. The DJI drone might picked up magnetic interference from rebar concrete and metal objects / structures and might caused unwanted incident when flying. Thank you.

DJI Stephen Posted at 5-25 20:21
Hello there Marleyman. Good day and thank you for reaching out. DJI recommends for you to keep away from the power lines and cell towers if applicable. The DJI drone might picked up magnetic interference from rebar concrete and metal objects / structures and might caused unwanted incident when flying. Thank you.

DJI Stephen your reply is what causes my confusion on this topic!
DJI Drones are used to inspect Cell Towers - and you say "DJI recommends that you stay away from Cell Towers...they could interfere with your drone...."
Riddle me this - if DJI drones are used to inspect cell towers by professional drone pilots - why does DJI recommend that you don't fly near cell towers???

Marleyman Posted at 5-26 02:46
DJI Stephen your reply is what causes my confusion on this topic!
DJI Drones are used to inspect Cell Towers - and you say "DJI recommends that you stay away from Cell Towers...they could interfere with your drone...."
Riddle me this - if DJI drones are used to inspect cell towers by professional drone pilots - why does DJI recommend that you don't fly near cell towers???

Ignore his post ... it's just misinformation from someone who doesn't even fly a drone.
He's just copying and pasting something he thinks might be relevant.
You'd have to be within a metre of a tower for it to have any effect on your compass and you are unlikely to  be close to any reinforced concrete up there.

Labroides Posted at 5-26 02:58
Ignore his post ... it's just misinformation from someone who doesn't even fly a drone.
He's just copying and pasting something he thinks might be relevant.

Thanks Labroides! Just what I needed to hear

Marleyman Posted at 5-26 02:59
Thanks Labroides! Just what I needed to hear

Unfortunately the moderators in here appear to have no technical knowledge or actual flying experience.

Bob-Mini-2 Posted at 5-25 18:21
Nice . . .it has been many many years since I have seen the name SURE,  they have made some of the best microphones, I favored the Controlled Magnetic, when I was working.  The video brought back much, thank you for listing it for others to see.

You're welcome Bob.  Hope you are having a great week.

DowntownRDB Posted at 5-26 03:17
You're welcome Bob.  Hope you are having a great week.

You as well, hope you are getting some flying in

Bob-Mini-2 Posted at 5-26 11:54
You as well, hope you are getting some flying in

Thanks Bob.  Having a good but busy week.  Prepping to take my large live aboard boat on an excursion in the Caribbean.  So many items on my "make sure it's ready list" but I'm excited to set out soon.

DowntownRDB Posted at 5-26 12:08
Thanks Bob.  Having a good but busy week.  Prepping to take my large live aboard boat on an excursion in the Caribbean.  So many items on my "make sure it's ready list" but I'm excited to set out soon.

Have a splendid trip . . .

Bob-Mini-2 Posted at 5-26 12:25
Have a splendid trip . . .

Thank you kind sir.  

I did about 50 cell tower inspections with a Mavic 2 Pro with zero issues. Then one day during RTH the drone went out of control, none of my inputs had any effect, and it crashed into the ground. I sent it to DJI and the analysis was that the GPS and flight controller ineffective due to interference. This is from their analysis:

3.       At t=1150.5s, relative height=87.6m, unit started to drifting and was showing signs of compass interference and flight controller issues.
4.       Unit was drifting due to compass interference, prior to impact.
5.       Interference: Electromagnetic interference from other devices or structures, such as metal objects or power lines, can cause the drone's compass to malfunction or give inaccurate readings.

MikeBNA Posted at 3-3 06:08
I did about 50 cell tower inspections with a Mavic 2 Pro with zero issues. Then one day during RTH the drone went out of control, none of my inputs had any effect, and it crashed into the ground. I sent it to DJI and the analysis was that the GPS and flight controller ineffective due to interference. This is from their analysis:

3.       At t=1150.5s, relative height=87.6m, unit started to drifting and was showing signs of compass interference and flight controller issues.

Unfortunately that fragment of information from DJI's analysis people doesn't say what caused the interference.
Assuming it had anything to do with a cell tower is almost certainly a mistake.
How far from the tower were you when the problem appeared?
If you post the flight data, someone might be able to tease out more details than DJI gave you.

MikeBNA Posted at 3-3 06:08
I did about 50 cell tower inspections with a Mavic 2 Pro with zero issues. Then one day during RTH the drone went out of control, none of my inputs had any effect, and it crashed into the ground. I sent it to DJI and the analysis was that the GPS and flight controller ineffective due to interference. This is from their analysis:

3.       At t=1150.5s, relative height=87.6m, unit started to drifting and was showing signs of compass interference and flight controller issues.

Hi there, we managed to find out your case number through your forum account. We noticed that our team tried to call you yesterday but cannot reach you. May I ask if you have any inquiries about the analysis result or your case?

Labroides Posted at 3-3 13:02
Unfortunately that fragment of information from DJI's analysis people doesn't say what caused the interference.
Assuming it had anything to do with a cell tower is almost certainly a mistake.
How far from the tower were you when the problem appeared?

Here is a link to the files I could pull from the drone. I was flying with vHive so the log file formats may be different than DJI. If there is any other file that shows the flight info let me know and I will upload it.
You are saying that the compass interference and flight controller issues, coupled with complete lack of controller input moving the drone was completely coincidental to being 30 feet from a cell tower? That seems highly unlikely. That is one extreme coincidence. I can say for certain that some antennas on cell towers cause issues with GPS lock quality and controller link quality, other pilots see this in the field pretty frequently.

DJI Mindy Posted at 3-4 03:19
Hi there, we managed to find out your case number through your forum account. We noticed that our team tried to call you yesterday but cannot reach you. May I ask if you have any inquiries about the analysis result or your case?

yes, thank you I  received the crash analysis information that was requested.

Dirty Bird Posted at 3-5 16:37
As far as RF signal interference there are no issue with cell towers, even if you fly right up to the antenna.  I have a buddy who does cell tower inspections full time with a pair of Mavic 2 Pros & now a freaking M30 with the IR camera (so jealous).  This is what he does all day & no issues.

The only potential issue might be if the tower itself has become severely magnetized.  This could potentially cause a compass issue if you flew into the distorted magnetic field, but any issue should alleviate as soon as you exit the field.

Interesting video but not really reflective of what a tower inspection would entail. Unless you were counting bird's eggs there. It would be hovering 30 feet horizontally away from the tower center and slowly throttling up/down from the top/bottom  then rolling left or right and repeating until the entire structure was covered. The issue seems to happen most when passing directly in front of one of the RADs and through its field.

MikeBNA Posted at 3-6 13:33
Here is a link to the files I could pull from the drone. I was flying with vHive so the log file formats may be different than DJI. If there is any other file that shows the flight info let me know and I will upload it.
You are saying that the compass interference and flight controller issues, coupled with complete lack of controller input moving the drone was completely coincidental to being 30 feet from a cell tower? That seems highly unlikely. That is one extreme coincidence. I can say for certain that some antennas on cell towers cause issues with GPS lock quality and controller link quality, other pilots see this in the field pretty frequently.

You are saying that the compass interference and flight controller issues, coupled with complete lack of controller input moving the drone was completely coincidental to being 30 feet from a cell tower?
I was suggesting that those things are unlikely to be related to the tower, particularly at a distance of 30 ft.

That seems highly unlikely.
Perhaps the flight data will help to evaluate that and confirm or point to something else.
But I can't access the data yet and I don't know anything about vHave, so I can't be certain.

That is one extreme coincidence. I can say for certain that some antennas on cell towers cause issues with GPS lock quality and controller link quality, other pilots see this in the field pretty frequently.
I tend to be skeptical of what drone pilots think was happening and prefer to see actual data to show what actually happened.
Always happy to check flight data to learn more.

Dirty Bird Posted at 3-6 14:54
That was not an actual tower inspection video.  Just me from 8 years ago flying a P2 Vision+ around cell towers to test if there was any lost of control.  As you can see, the towere had absolutely no effect on the Vision+ & I was near the limits of the bird's range as I circled the towers.  I am familiar with the actual tower inspection procedure as I have assisted my friend perform them on occasion.

My Phantom rarely has issues with interference, they seem like they are built with more resistance to interference than the Mavic 2 series. That is my experience anyway.

In the meantime here are some links from discussing the issue from people who work around it every day.

https://learn.sitesee.io/hc/en-u ... rom-the-cell-tower-

https://www.electronicdesign.com ... for-drones-and-uavs

https://www.applus.com/global/en ... l-tower-inspections

https://www.thedroneu.com/adu-06 ... -tower-inspections/

NATE (National Assoc. Tower Erectors) -This document is being provided as a resource to assist NATE members in preparing to operate UAS safely and legally. NATE, its Board of Directors and the UAS Committee emphasize the importance of additional training specific to UAS operation in the vertical communications infrastructure environment. For example, there should be a thorough understanding of potential radio frequency (RF) interference. RF produced by assets on the tower is capable of compromising communication between a UAS and its corresponding ground controller. Operators should be aware of these potential issues and understand how to mitigate potential safety risk.

MikeBNA Posted at 3-6 13:33
Here is a link to the files I could pull from the drone. I was flying with vHive so the log file formats may be different than DJI. If there is any other file that shows the flight info let me know and I will upload it.
You are saying that the compass interference and flight controller issues, coupled with complete lack of controller input moving the drone was completely coincidental to being 30 feet from a cell tower? That seems highly unlikely. That is one extreme coincidence. I can say for certain that some antennas on cell towers cause issues with GPS lock quality and controller link quality, other pilots see this in the field pretty frequently.

There was good flight data from 3 separate flights, but all were up and down flights that landed safely.
The DJI analysis you quoted mentioned "At t=1150.5s, relative height=87.6m".
The longest of the three flights in the supplied data only went for 1.5 minutes.

If you can find the data for the crash flight, I'd be interested to see it.
I have an idea for what might have caused the compass issue, but would need to see the data to know if it might be relevant.

The issue with the logs is that I wasn't using the DJI GO software, so it wasn't recording to the normal log location. When I sent the drone to DJI they provided more detailed analysis but I am not sure how, or which file the info was pulled from. That is why I uploaded everything I had from that day to google drive. The vHive logs couldn't be recovered, since the software froze up after the crash. Here is the full text from DJI:

FLY046
1.       Unit was in RTH mode as per user command and was working as designed. The unit took off with GPS signal.
2.       The unit was flying with compass interference.
3.       At t=1150.5s, relative height=87.6m, unit started to drifting and was showing signs of compass interference and flight controller issues.
4.       Unit was drifting due to compass interference, prior to impact.
5.       Interference: Electromagnetic interference from other devices or structures, such as metal objects or power lines, can cause the drone's compass to malfunction or give inaccurate readings.

Force impact date: 02-17-2023
Force impact GPS location: 36.6589753, -85.6149148
Activation date: 04-22-2019
SN: 163DG19001RC16

MikeBNA Posted at 3-6 15:48
In the meantime here are some links from discussing the issue from people who work around it every day.

https://learn.sitesee.io/hc/en-us/articles/360051618832-How-can-I-avoid-GPS-interference-due-to-EME-emissions-from-the-cell-tower-

The first 3 docs don't say much and the podcast at 9:45 says ...  

but in all honesty I don't think they are going to have issues .. you can fly very close to cell phone towers  without having interference issues

MikeBNA Posted at 3-6 16:05
The issue with the logs is that I wasn't using the DJI GO software, so it wasn't recording to the normal log location. When I sent the drone to DJI they provided more detailed analysis but I am not sure how, or which file the info was pulled from. That is why I uploaded everything I had from that day to google drive. The vHive logs couldn't be recovered, since the software froze up after the crash. Here is the full text from DJI:

FLY046

It's going to be impossible to tell much about a flight for which no data is available.
But the data that was posted demonstrates that it is possible to fly close to towers without problems.


How close were you to the tower when the incident occurred?
The most common cause of compass issues would be completely unrelated to what you were flying close to, but without the data, it's not possible to confirm whether that was the issue here or not.

Drone was 30 feet from the center of the tower, so 20 feet horizontally from the highest antenna, there were cellular and microwave transmitters present.

MikeBNA Posted at 3-6 17:06
Drone was 30 feet from the center of the tower, so 20 feet horizontally from the highest antenna, there were cellular and microwave transmitters present.

I can't say much except that at 20-30 ft, the towers themselves won't have any effect on the drone's compass.
If they did, you'd have noticed it long before 19 minutes.