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Those cell towers !!
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coco60
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Does anybody knows the average minimal distance that one can fly a P4P away from a cell tower without experiencing control problems ??  Of course different towers can have more or less strong signal emissions.
2017-7-15
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dronestarvision
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It is not the Cellular radio frequencies that you have to worry about because their frequency is a lot lower. It is the microwave radios that might be on the cellular towers that can cause serious interference with your drone. 5.8 Ghz is a very common frequency used for longhaul microwave radio communications. If the cell tower gets the longhaul feed from fiber optics than you might not have any issues at all flying as close as you want.
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JW5255
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You are right.  You never know how much power is coming out of a cell tower, or what is attached to it (e.g. microwave transmitter).  A good rule of thumb would be 1000 meters.  Same would be true for high voltage electrical lines.  The problems occur when the signal strength from the tower or power lines becomes greater than the signal strength of the RC and AC.  Avoid them.  
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JW5255
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dronestarvision Posted at 2017-7-15 13:05
It is not the Cellular radio frequencies that you have to worry about because their frequency is a lot lower. It is the microwave radios that might be on the cellular towers that can cause serious interference with your drone. 5.8 Ghz is a very common frequency used for longhaul microwave radio communications. If the cell tower gets the longhaul feed from fiber optics than you might not have any issues at all flying as close as you want.

Due to EMF harmonics, all transmission towers, high tension lines, etc, should be avoided.  
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dronestarvision
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JW5255 Posted at 2017-7-15 13:17
You are right.  You never know how much power is coming out of a cell tower, or what is attached to it (e.g. microwave transmitter).  A good rule of thumb would be 1000 meters.  Same would be true for high voltage electrical lines.  The problems occur when the signal strength from the tower or power lines becomes greater than the signal strength of the RC and AC.  Avoid them.

Can't say that I agree with your statement about high voltage electrical lines. Flying drones around power lines including high voltage ones causing interference is mostly a myth. This is basically a high voltage field that feeds in and out of the Hoover Dam. As you can see from my video I take off and land in the middle of them with no issues. Is it dangerous and not recommended if you don't know what you are doing? Yes...
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RicardoGray
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dronestarvision Posted at 2017-7-15 13:31
Can't say that I agree with your statement about high voltage electrical lines. Flying drones around power lines including high voltage ones causing interference is mostly a myth. This is basically a high voltage field that feeds in and out of the Hoover Dam. As you can see from my video I take off and land in the middle of them with no issues. Is it dangerous and not recommended if you don't know what you are doing? Yes...

I agree with you! The high voltage lines don't pose a real threat as far as I am concerned either. I have flown around them quite a bit, but like you said, you have to be aware of the wires and your situation. The high voltage lines have never caused me any trouble, but the cell phone/microwave ones are another story. At least the ones I have flown by, it doesn't cause me to lose control, but I will lose signal if I am close or if I am passing by, but my signal will return after I get past them. I have never experienced my drone losing control and acting irradictally. I hope that I am just the lucky one! I can't imagine that feeling.
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JW5255
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RicardoGray Posted at 2017-7-15 13:43
I agree with you! The high voltage lines don't pose a real threat as far as I am concerned either. I have flown around them quite a bit, but like you said, you have to be aware of the wires and your situation. The high voltage lines have never caused me any trouble, but the cell phone/microwave ones are another story. At least the ones I have flown by, it doesn't cause me to lose control, but I will lose signal if I am close or if I am passing by, but my signal will return after I get past them. I have never experienced my drone losing control and acting irradictally. I hope that I am just the lucky one! I can't imagine that feeling.

Good luck you guys !  
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coco60
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RicardoGray Posted at 2017-7-15 13:43
I agree with you! The high voltage lines don't pose a real threat as far as I am concerned either. I have flown around them quite a bit, but like you said, you have to be aware of the wires and your situation. The high voltage lines have never caused me any trouble, but the cell phone/microwave ones are another story. At least the ones I have flown by, it doesn't cause me to lose control, but I will lose signal if I am close or if I am passing by, but my signal will return after I get past them. I have never experienced my drone losing control and acting irradictally. I hope that I am just the lucky one! I can't imagine that feeling.

Power lines dont emit frequencies but magnetic fields that weakens after several meters from the line.
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coco60
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RicardoGray Posted at 2017-7-15 13:43
I agree with you! The high voltage lines don't pose a real threat as far as I am concerned either. I have flown around them quite a bit, but like you said, you have to be aware of the wires and your situation. The high voltage lines have never caused me any trouble, but the cell phone/microwave ones are another story. At least the ones I have flown by, it doesn't cause me to lose control, but I will lose signal if I am close or if I am passing by, but my signal will return after I get past them. I have never experienced my drone losing control and acting irradictally. I hope that I am just the lucky one! I can't imagine that feeling.

I think the main reason why it is better not to fly around power lines not really for drone signal disturbance but rather for risk of collisions as P4P obstacle avoidance system might not see the thin electric cables !
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Labroides
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coco60 Posted at 2017-7-15 14:53
I think the main reason why it is better not to fly around power lines not really for drone signal disturbance but rather for risk of collisions as P4P obstacle avoidance system might not see the thin electric cables !

Before you get close enough for collision risk, you'll probably have compass issues.
Stay 50+ metres away
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JW5255
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coco60 Posted at 2017-7-15 14:44
Power lines dont emit frequencies but magnetic fields that weakens after several meters from the line.

Sure, let us rewrite the laws of physics.  If you knew the answers, why did you bother asking the question
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Aardvark
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coco60 Posted at 2017-7-15 14:44
Power lines dont emit frequencies but magnetic fields that weakens after several meters from the line.

Not forgetting the electric field, and the 400,000 volt (at least some of them) potential difference between the lines and ground.

http://www.industrytap.com/flore ... agnetic-fields/1763
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Dirty Bird
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Cellular towers seem to have absolutely no affect on RC communications.  Even mammoth, multi-transmitter, megawatt towers appear to have no impact.  No interference whatsoever in either of these flights.  First video is a Vision+.  Second is a Mavic.




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Geebax
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Dirty Bird Posted at 2017-7-15 16:42
Ccellular towers seem to have absolutely no affect on RC communications.  Even mammoth, multi-transmitter megawatt towers appear to have mo impact.  No interference whatsoever in either of these flights.  First video is a Vision+.  Second is a Mavic.

https://youtu.be/cNdHMkxLhrY

I agree, I have flown a POI around a heavy-duty communications tower and did not see any effect whatsoever.
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Lectro88
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Remember also... it doesn't matter either.
The cell phone towers, Radio towers, and Transmission power lines have way more power driving their signals. You have at best 15 volt DC before a 10 -15 minute flight and then how much punch does your battery have.
if your lottery ticket is a winner you may want to remember.
These "ideas" are just a myth.
I wish you well. I only been around electrical a little over 30 years.
That doesn't matter either.
Rember
Hot water is on the Right, Cold is on the Left and $hit runs up hill.
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Geebax
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Lectro88 Posted at 2017-7-15 17:03
Remember also... it doesn't matter either.
The cell phone towers, Radio towers, and Transmission power lines have way more power driving their signals. You have at best 15 volt DC before a 10 -15 minute flight and then how much punch does your battery have.
if your lottery ticket is a winner you may want to remember.

'You have at best 15 volt DC before a 10 -15 minute flight and then how much punch does your battery have.'

What does that have to do with the issue? Those towers present little threat to a good radio receiver system, especially when they are not transmitting on the same feequncy as your RC unit, or a harmonic of it.
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Lectro88
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If your frequency is close to that of the towers. And 1 day you may stumble across 1 that is.
The tower can way overpower your frequency. Especially with a battery that is partially discharged.
You may never have any problems.
The risk is there.
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Dirty Bird
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You could also be flying along when a stray cosmic ray from the far reaches of space interferes with your signal causing total loss of aircraft control.  Wandering aimlessly, it might then smash through the window of a nearby hospital, before crashing into the maternity ward & hacking several newborns to pieces.

It could happen...the risk is there.  The only solution is DON'T FLY!  It's for the children...
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Geebax
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Lectro88 Posted at 2017-7-15 17:49
If your frequency is close to that of the towers. And 1 day you may stumble across 1 that is.
The tower can way overpower your frequency. Especially with a battery that is partially discharged.
You may never have any problems.

A little knowledge of RF principles would help you a great deal. The battery level has absolutely nothing to do with the issue.
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dronestarvision
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Dirty Bird Posted at 2017-7-15 16:42
Cellular towers seem to have absolutely no affect on RC communications.  Even mammoth, multi-transmitter, megawatt towers appear to have no impact.  No interference whatsoever in either of these flights.  First video is a Vision+.  Second is a Mavic.

https://youtu.be/cNdHMkxLhrY

It is funny how people still want to talk about stuff they have no clue about, but when we show them videos they still don't want to believe. I have been an RF guy for 20+ years and I have worked with every frequency from VLF to EHF. The cellular frequency band is not even close to the frequency band as the drones we are flying. As for power transmission lines, they actually use drones to inspect transmission lines now.
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Geebax
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dronestarvision Posted at 2017-7-15 21:56
It is funny how people still want to talk about stuff they have no clue about, but when we show them videos they still don't want to believe. I have been an RF guy for 20+ years and I have worked with every frequency from VLF to EHF. The cellular frequency band is not even close to the frequency band as the drones we are flying. As for power transmission lines, they actually use drones to inspect transmission lines now.

Finally, someone with RF experience, but sadly no-one will listen to you because they all prefer to believe their pet urban myths.

'The cellular frequency band is not even close to the frequency band as the drones we are flying. '

Don't let facts get in the way of good old fashion fear-mongering. The only risk is for the receiver in the aircraft, it may suffer from front-end overload, but only if the design of the receiver is quite poor, most decent radio systems these days are protected against it.

'As for power transmission lines, they actually use drones to inspect transmission lines now.'

Yeah, funny about this, isn't it?
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JW5255
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I am sure that Aristotle (384–322 BC) would be proud of the responders and responses on this thread, however; Faraday (1821–1867) I suspect would not.  I shall leave you with your lodestones and hammer of thor and simply say: "Good luck with that!"
2017-7-16
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Seb
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Cool down guys In fact, you're all right in what you say, at least in general. We have two factors that should be considered - possible RF jamming that could block RC link and EM fields that could interfere with onboard electronics.

Some of you are stating that cellular frequencies are different than 2.4 or 5.8 GHz used in RC link. That's of course true, but there is another problem that may arise - if enough RF power of any frequency will enter RF receiver input stage, it will block any reception because of intermodulation distortions. But now every RF input stage is equipped with bandpass filters and they are also much more immune to intermodulation, so this risk is greatly minimized.

Second problem is that every wire and every PCB trace works as an antenna. So RF signals with power high enough may induce electric signals in the wires and traces that may directly interfere with onboard electronics, what could be unpredictable in results and in worst case our bird may fall like a rock. And this is why you're not allowed to bring cell phones to some areas in hospitals, airplanes etc. And again - because of drone internal shielding, using of multilayer PCB with short tracks surrounded by ground planes risk of such interference is greatly reduced.

So in ancient times of first multicopters that was made in our workshops all of the mentioned risks were real. We've used lot of boards, connected with long wires, all of it was completely not shielded. We even interfered with ourselves, seeing interferences from ESCs on our FPV downlink :-) But this is history now - it's more probable that you'll lost your drone by firmware flaw than by RF or EMI interference. However, it's still good idea to know how things work and what may happen when flying near to active transmitting antennas or high voltage lines. It always pose a risk greater than flying far from these objects.
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Rodger8
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I inspect Cell Towers with several providers on the same Tower as many as 6 and they are active during the inspection. I get as close as 2 feet to the antennas and have never had an issue.  I don't know what type of device you are using but, if it is capable of Cellular service, try putting it in "Airplane Mode" while using it with your Phantom.
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Landbo
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Dutch Peter, the man who knows everything, unintentionally demonstrates what happens when you fly in front of an antenna with full blows on the transmitter:   12:13 in the video. Such a blast of SHF may well destroy the entrance of one's drones receiver and at the same time, as here, preventing both the drone electronics from working or even destroy it.

Regards Leif.
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Lectro88
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Thanks Seb.

Cool down guys

In fact, you're all right in what you say, at least in general. We have two factors that should be considered - possible RF jamming that could block RC link and EM fields that could interfere with onboard electronics.


I never claimed be an expert folks. my point about the battery. Our range is couple miles in optimum perfect conditions. ANY obsticles simple as trees or buildings can impair or block “OUR” signal.
we’re talking about a transmission towers. SOME signals can go 50 miles or more. Our little hand helds are nothing to these giants.
I'm glad to have read all the posts. I'm old school. of RC planes 30 yrs ago. And yes technology is much better than my day. I've had a plane on the ground and start randomly moving parts, engine not started yet and I never sent the first command. had this happen in the air several times too, So I have had interference many many times. And am leery being close to strong signals for many reasons.
I too work occasionally at a TV tower. Have helped pull wave guide, the hollow elliptical copper tube that the signal passes through.
The engineers there, now I been doing work with them since the 90's are quick to point out give this room, stand behind this area, don't pass here.
These are clear warnings. some being health. And for me I just am just not willing to run the risk.even now knowing that I could, I guess.

We all have our specialty. Mine is electrical.
I try to respect others in most cases.
Why all the bashing for no really good reason.
I gave my good reason. No you don’t have to agree.  I didn't ask you to.
Dang ease up a little and take it all in.
Almost every one had good points.
Mine is use a little caution, be aware.
Give it time time you probably won't have to ask much longer. I see cell towers and others going to NFZ's too, and their every !@#%&$ where.
One more reason to stay away, Not that you would... But a few strikes is all it will take, and it may just come to make it more difficult on our community.
Just think about it a little bit.

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Lectro88
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Sorry They're everywhere

Not     their.
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RicardoGray
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Dirty Bird Posted at 2017-7-15 16:42
Cellular towers seem to have absolutely no affect on RC communications.  Even mammoth, multi-transmitter, megawatt towers appear to have no impact.  No interference whatsoever in either of these flights.  First video is a Vision+.  Second is a Mavic.

https://youtu.be/cNdHMkxLhrY

Cool videos. I think as long as you are aware of what you are doing, these shots are amazing.
2017-7-16
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Avian UAS
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Seb Posted at 2017-7-16 01:52
Cool down guys  In fact, you're all right in what you say, at least in general. We have two factors that should be considered - possible RF jamming that could block RC link and EM fields that could interfere with onboard electronics.

Some of you are stating that cellular frequencies are different than 2.4 or 5.8 GHz used in RC link. That's of course true, but there is another problem that may arise - if enough RF power of any frequency will enter RF receiver input stage, it will block any reception because of intermodulation distortions. But now every RF input stage is equipped with bandpass filters and they are also much more immune to intermodulation, so this risk is greatly minimized.

This explains our recent experience. After many many cell tower inspections without issue, we recently had Inspire 1 drop from the sky like a rock. Post flight diagnostics show 56% battery at the time of the incident. The only explanation (ruled out bad battery or battery connection) was that the HV antenna array caused a short or malfunction as the drone went dead.. and broken. Our range from the antenna was within 5-7 metres and the drone moved directly in the path of the antenna array... anyone else have experience with similar incidents?
3-7 16:45
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Glenn Goodlett
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I occasionally inspect transmission lines. Never had any issues.

[img]201903/07/170250ovo33oxv0t7t803d.

jpg[/img]
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3-7 17:04
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Labroides
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Avian UAS Posted at 3-7 16:45
This explains our recent experience. After many many cell tower inspections without issue, we recently had Inspire 1 drop from the sky like a rock. Post flight diagnostics show 56% battery at the time of the incident. The only explanation (ruled out bad battery or battery connection) was that the HV antenna array caused a short or malfunction as the drone went dead.. and broken. Our range from the antenna was within 5-7 metres and the drone moved directly in the path of the antenna array... anyone else have experience with similar incidents?

Post flight diagnostics show 56% battery at the time of the incident.
What was the voltage per cell at the end of the flight?
3-7 20:48
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Geebax
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Avian UAS Posted at 3-7 16:45
This explains our recent experience. After many many cell tower inspections without issue, we recently had Inspire 1 drop from the sky like a rock. Post flight diagnostics show 56% battery at the time of the incident. The only explanation (ruled out bad battery or battery connection) was that the HV antenna array caused a short or malfunction as the drone went dead.. and broken. Our range from the antenna was within 5-7 metres and the drone moved directly in the path of the antenna array... anyone else have experience with similar incidents?

'The only explanation (ruled out bad battery or battery connection) was that the HV antenna array caused a short or malfunction as the drone went dead.. and broken.'

No antenna can cause a 'short', it is not possible within the rules of physics. It is more likely the battery terminal voltage dropped to a very low level and caused the aircraft to shut down. The fact that you have performed 'many many' cell tower inspections before without issue shows the radio transmission from the tower had nothing to do with the problem.
3-7 21:47
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CHASCOADMIN
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Not recommending, but I regularly inspect cell towers and fly near HVL's and have never had a problem. One tip is to stay away when it is damp, just rained or a slight drizzle.
3-7 22:08
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