Distance from electricity lines

[Vanjo Grale]

I had to take pictures and video of a house right near some high voltage powerlines - the biggest problem I had was getting initial GPS lock, and it went out once during flight near the lines. No control problems besides that, so long as you can fly with no GPS assistance, you should be able to fly as near them - my closest approach was about 20 feet with my P2V+

 

[rrmccabe]

At distance they effect my range. Its hard to get over them without RTH when I am near my max distance. However flying around them has never caused an issue.

 

[FocusOnMe]

Thanks again for your answers.
I ll try again some day in the same spot and i wiill see if this issue happens again.

 

[N017RW]

Thanks again for your answers.
I ll try again some day in the same spot and i wiill see if this issue happens again.

That's good news.

I wish more folks would try to test out their observations or experiences a time or two before declaring 'this was caused by', or 'was due to', etc.

 

[rrmccabe]

Oh come on @N017RW one time is good enough No such thing as flukes or anomalies.

 

[FocusOnMe]

The truth is that i am afraid to test it again.
As i fly more maybe i ll think about it....
At this time i dont have the courage to try it and make any damage to drone.☺☺☺

 

[RoyVa]

That's right be safe and not sorry. I don't understand when we have been warned and told that strange things CAN happen If our quad gets close to hight voltage lines or cell towers. It doesn't mean it's going to every time. But it is a know fact they can effect the electronics in our units, yet we want to try and say we did it and they are wrong. No so next time may be their loss and they will be the ones shouting from the roof top. For me I'm going to heed the warning and stay away a safe distance just to be SAFE and not chance losing my unit due to scrambling the onboard electronics or computer.
I know that no one has lost an email or word document or anything they were working on due to their computer rebooting for any unknown reason. Well if that quad reboots inflight due to interference where is the info on its flight data or RTH GPS info going.... Could be called a fly a way ya think.

 

[yorlik]

...the magnetic field around them diminishes with distance by the square root....

Not to be picky, but in case anyone wants to repeat some of this stuff to their wife, girlfriend, or SO, the facts should be right to get the points.

The magnetic and Electric field goes down by the CUBE of the distance.

But don't believe me, google something like this if you want:

Calculating how magnetic field strength decreases with distance

Reference https://www.physicsforums.com/threa...ield-strength-decreases-with-distance.754213/

 

[yorlik]

...I leave in Greece and i dont know the exact voltage for the wires. I try to find it out.
I dont mean electric towers....
The only i know is that the electricity company in my country name the cables that i had that issue as "high voltage cables".
I was straight under them on the ground and i tried to take off. But when the P3P released the ground went backwords like crazy and with very high speed. I tried to take it down but it didnt respond.
I was lucky that stoped on a bush and i reached it before crashes any wall.

I do not know if Greece uses DC transmission lines as we do in some places in the USA. If so, know that the magnetic and electric fields are from that wire way up there all the way down to the ground under and around it! The earth is the return conductor in these systems, and the fields are always fully BETWEEN the two conductors.

So probably not a good idea to take off from directly or near under it!

 

[yorlik]

The RF EMI is very low-frequency compared to the microwave frequencies that your Phantom uses. It's that crappy buzzing that you hear on the AM radio and caused by cracked or dirty insulators, which is why power companies need to inspect them from time to time. There's no way you can cause an outage by contacting one of the wires, except that you will be out a Phantom. Even if you were to maneuver between two phases of the wires, the Phantom is too small to provide an arc path.

Steve, my uncle was one of the first ham radio operators in the US. Fantastic guy, rivoting stories from his long life before he passed away around 1985... His first ham call sign was 7GI - ya, no W or K in front back in the early 40's or late 30's. But I digress.... He used a spark gap and morse code key to transmit. Made a spark at low freq....

Anyway, it turns out that an ARC of a loose connection on a power line, even though only 60hz, will happen at both the plus and minus voltage peak, so actually is 120hz most of the time. But it is the energy of the arc itself that makes the RF noise. Yep, it goes from dc all the way up to at least 1ghz! Right up there near our RC and FPV freqs!

Remembering that the energy in the fields goes down by the cube of the distance, this noise is not likely to bother us 20-50m away too bad, assuming it is a nice smallish, low energy arc....

The other thing to remember is both the RC and VPF RECEIVERS have a spec called front end selectivity. This is a spec showing how the radio receiver will respond, or not respond, to off frequency signals. Now comes those arc energy pulses ever 4msec (120 times per sec).... if strong enough, they WILL get into the receiver and block the real signal we want to hear. Is this a big issue? Prob not real big because there are seldom reports on the forums of phantom folks loosing it near power lines. Again, the cube distance reduction is really our friend...

some notes if anyone really interested in reading more about this fascinating topic:

http://www.arrl.org/power-line-noise

http://www.downloads.siemens.com/do...aspx?pos=download&fct=getasset&id1=BTLV_40672

 

[SteveMann]

Steve, my uncle was one of the first ham radio operators in the US. Fantastic guy, rivoting stories from his long life before he passed away around 1985... His first ham call sign was 7GI - ya, no W or K in front back in the early 40's or late 30's. But I digress.... He used a spark gap and morse code key to transmit. Made a spark at low freq....

Anyway, it turns out that an ARC of a loose connection on a power line, even though only 60hz, will happen at both the plus and minus voltage peak, so actually is 120hz most of the time. But it is the energy of the arc itself that makes the RF noise. Yep, it goes from dc all the way up to at least 1ghz! Right up there near our RC and FPV freqs!

Remembering that the energy in the fields goes down by the cube of the distance, this noise is not likely to bother us 20-50m away too bad, assuming it is a nice smallish, low energy arc....

The other thing to remember is both the RC and VPF RECEIVERS have a spec called front end selectivity. This is a spec showing how the radio receiver will respond, or not respond, to off frequency signals. Now comes those arc energy pulses ever 4msec (120 times per sec).... if strong enough, they WILL get into the receiver and block the real signal we want to hear. Is this a big issue? Prob not real big because there are seldom reports on the forums of phantom folks loosing it near power lines. Again, the cube distance reduction is really our friend...

some notes if anyone really interested in reading more about this fascinating topic:

http://www.arrl.org/power-line-noise

http://www.downloads.siemens.com/do...aspx?pos=download&fct=getasset&id1=BTLV_40672

Spark is very low frequency. Your uncle's ham gear probably was in the 300 Meter band (and worth a fortune if it's still around). However with each harmonic doubling of the frequency, the effective power goes down by the square root, so by the time the harmonics of noise get to the microwave frequency range, it's pretty weak.

As I said, the biggest risk to flying near power lines is hitting one.

 

[SteveMann]

DC transmission lines as we do in some places in the USA.

I can only think of one and it was shut off on July 11, 2014. [link]

 

[yorlik]

I can only think of one and it was shut off on July 11, 2014. [link]

Ah, the small towns in progressive NYsticking with their Edison buddy! Can you imagine living in one of those homes in this century? Where would you buy light bulbs? a New refrigerator? furnace? WOW!

But that is not what I was referring to; I was referring to the topic of this thread: high voltage power company transmission lines. Yep, they do exist. Mainly for long runs. They exist all over the world. Longest in China at something like 1,500 miles! We have some Iknow of in CA and AL; not sure where else in the USA.

This is what I referred to with the EMF fields being complete and full strength from the wire up above all the way to the earth below:

https://en.wikipedia.org/wiki/High-voltage_direct_current

And when you consider that NO energy is transferred IN a wire but all is OUTSIDE it in the EMF fields, it adds new meaning to being concerned!

 

[yorlik]

Spark is very low frequency. Your uncle's ham gear probably was in the 300 Meter band (and worth a fortune if it's still around). However with each harmonic doubling of the frequency, the effective power goes down by the square root, so by the time the harmonics of noise get to the microwave frequency range, it's pretty weak.

As I said, the biggest risk to flying near power lines is hitting one.

I agree with your assessment that hitting them is probably the biggest issue.

I have some properties with cell towers on them. On occasion I forget and end up flying a few hundred feet away from them at 150ft altitude or so. I have not YET had any problem, although I do strive to stay farther away.

Ah, I missed your meaning on the square root reduction; sorry. But isn't it all relative? How much reduction is REALLY needed to prevent receiver front end overload and loss of our true signal? Even if the 1Ghz microwave arc noise IS reduced by the square of the harmonic, is it low enough close enough to NOT be an issue?

Obviously most of the time it IS as there are not many reports of actual cases of trouble. But those few that ARE reported show that it is all relative.

 

[N017RW]

I can only think of one and it was shut off on July 11, 2014. [link]

This site doesn't agree with your memory:
http://www.cleanlineenergy.com/technology/hvdc/history

 

[SteveMann]

I agree with your assessment that hitting them is probably the biggest issue.

I have some properties with cell towers on them. On occasion I forget and end up flying a few hundred feet away from them at 150ft altitude or so. I have not YET had any problem, although I do strive to stay farther away.

Ah, I missed your meaning on the square root reduction; sorry. But isn't it all relative? How much reduction is REALLY needed to prevent receiver front end overload and loss of our true signal? Even if the 1Ghz microwave arc noise IS reduced by the square of the harmonic, is it low enough close enough to NOT be an issue?

Obviously most of the time it IS as there are not many reports of actual cases of trouble. But those few that ARE reported show that it is all relative.

The distance to get below the S/N floor of the R/C receiver depends on a lot of variables, but mostly on the ERP of the microwave antenna. But unless the ERP is in the megawatts, you aren't going to "fry" the electronics inside the drone. Even then all that overloading the R/C receiver will accomplish is a lost link which triggers an RTH.

 

[SteveMann]

This site doesn't agree with your memory:
http://www.cleanlineenergy.com/technology/hvdc/history

Very interesting. And surprising, It goes against everything I learned in Electrical Engineering in the past century. DC over long distances is horribly inefficient which is why it had been phased out over the past century. I didn't see anything in the Cleanlineenergy website about why dc? did I miss it?

 

[N017RW]

I have some properties with cell towers on them. On occasion I forget and end up flying a few hundred feet away from them at 150ft altitude or so. I have not YET had any problem, although I do strive to stay farther away.

Unless there is relay or other equipment colocated, which is common, the cell 'portion' of the antenna system or site is typically very low power. This is dependent on the density or distance between the site(s) in a particular area.

In addition the [mobile] antennas are directed down a few degrees towards the intended location of the users- i.e. on the ground.

There are some 'tower' guys around here. Maybe one will chime in to elaborate in more detail.

 

[RichWest]

Very interesting. And surprising, It goes against everything I learned in Electrical Engineering in the past century. DC over long distances is horribly inefficient which is why it had been phased out over the past century. I didn't see anything in the Cleanlineenergy website about why dc? did I miss it?

It's definitely related to economics why AC over DC, but technology is changing that cost model due to increasing demand for greater transmission distances from the renewable perspective. Here's one link I found promoting DC transmission, making a case for - http://www.theenergycollective.com/rogerrethinker/204396/ac-versus-dc-powerlines

A century of education...my-my, you are old....

I've got a mechanical engineering handbook copyrighted circa 1950. I also have an electrical handbook dated 2010, in revision 35 or something. Guess which handbook is still a reliable resource....

 

[yorlik]

Very interesting. And surprising, It goes against everything I learned in Electrical Engineering in the past century. DC over long distances is horribly inefficient which is why it had been phased out over the past century. I didn't see anything in the Cleanlineenergy website about why dc? did I miss it?

yep; check the links I posted above and it explains clearly why it is MORE efficient and lower cost at long distances....