Drones

It's a covert misinformation scheme set up by the government, so that when John Q. Public sees a drone flying around their house, they think, "Oh they must be inspecting our HT wires and poles." When in fact they are inspecting other things and it isn't wires or pole their looking at!

Your "conversation" was between two people neither of which has any experience with inspecting utility high voltage transmission lines and the strength of the fields surrounding them.

Current state of the art involves getting a helicopter close enough to enable a person in an equipotential electrostatic shielding suit to attach to the line and do what ever close-up inspection/live line maintenance that is required. Note that the helicopter doesn't fall out of the sky and the minimal RF energy from the lines doesn't affect the instrumentation or communication gear.

Ask your buddy to investigate the RF field strengths and frequencies involved, you'll be surprised at how relatively low both are.

I am aware of the current manner of inspection. The difference being that the helicopter, is not a tiny electric vehicle, and its electrical systems are quite a ways from the lines. The man in the chainmail suit is also out on a platform, which puts the helicopter even further from the wire than one would expect the whole drone to be. Or, at least as close as I would expect it might need to be.

2) How exactly do you 'harden' these kinds of circuits to withstand this level of interference; especially, since they are flying around, and 'grounding' looks like a lost cause for the most part?
Mu Metal.

"2) How exactly do you 'harden' these kinds of circuits to withstand this level of interference; especially, since they are flying around, and 'grounding' looks like a lost cause for the most part?"

That depends. There is no single bullet to slay RFI or more accurately radiated and conducted susceptibility.

I have some direct and recent experience with that. The short answer is that the designer will use a broad number of techniques to minimize susceptibility.

It's a multi-prone approach, but there are a number of best practices for the PC board layout, the circuit design, the mechanical design, and the frequency band of interest. Even then there are always things that bite you unexpectedly as best practices only take you so far.

Some call it a black art, but it is not. It is simply a problem with a very high degree of complexity and engineers that are well versed in that aspect of theory and design are highly sought after.

Lastly, grounding on an aircraft is typically the aircraft itself. You don't have to have a physical connection with earth ground any more than you do with a car. Either the body of the vehicle is metal or there will be a conductive coating applied to the vehicle body, or a metal cage will be constructed around the electronics to act as a ground plane.

I appreciate your answer very much. I do know that building a Faraday cage is one method of assuaging the RF; but then, the problems becomes, how do you just let in the RF flight control information, and keep out all the white noise, which is thousands of times more powerful?

Power lines are pretty low frequency fields, so all you need to do is filter those out using a number of techniques such as keeping aperture sizes smaller than a fraction of the intended wavelength.

Feedthrough caps are a way of isolating RF fields as are ferrite beads for frequencies generally lower than 100 mHz.

This subject is not something you can wrap up in a few paragraphs. Many specialized courses are available on some of the techniques used and a lot of it can get pretty advanced.

Let's put this into perspective. For EMI to get into your enclosure at levels high enough to be concerned about, you generally want to keep your apertures at lambda over 20 or smaller.

For 60 Hz power, your lambda is . . . . . .

5,000,000 meters.

Therefore, make sure none of the holes in your assembly are larger than 250 kilometers.

The thought might come from the fact, that there can be enough coronal discharge to cause St Elmo's Fire, and then there is the attendant zap & hum; or, perhaps it is the fact that you can build a barn with a roof, which is thirty feet under the wires, and enough field strength can be picked up to illuminate florescent lights, and with coils can power small devices.

By my way of figurin', that is sufficiently high enough to knock a totally 'unhardened' drone out of the sky.

Have you tried an internet search regarding drones being used for lines inspection?

Rather than reinventing the wheel based on personal thoughts and observations you should have a look at what is actually being done in the industry, it may be an eye opener.

An internet search of "lines company drone line inspection" for example produced many useful results for further reading.

Let us know what you come up with.

Here you go

http://cr4.globalspec.com/blogentry/25812/Drones-Take-Over-Hazardous-Line-Work

Tested with a standard off-the-shelf drone, 350kV line at a distance of 1 foot - fine, no control or video issues, no special shielding necessary.

You are comparing apples and oranges. The RF energy output of a clean transmission line is relatively low as its frequency, it usually will have no effect on FCC compliant equipment.

Here's an EPRI (ElEctric Power Research Institute) repeort on equipment for monitoring transmission lines close up and in some cases touching the conductor, no interference noted at bit rates up to 54Mb/s:

http://transsensorsrobots.epri.com/pdf/Tline-Roadmap.pdf

No, actually is not. The issue with 'isolated' or 'floating' electronics is not the strength of the E-field, it is the gradient of that field over the dimension of the device that can induce currents. If the E-field DIFFERENTIAL is low from one end of the device to the other, little problems will occur as a result.

The drone doesn't need to be that close, considering the cameras they utilize.

Although, non-interference kinda makes sense, considering the many, many cell phone and data network electronics/antennae which are mounted on distribution and transmission towers (at least in the US).

Some drones operate in the same bands as those networks...gotta love TDM, PLQM, etc.

We don't use drones. We do use a Go Pro on a stiff stick (don't go there) and do photo inspections of 66kV and 33kV and 11kV pole tops. The Go Pro kit has a tx/rx it. The screen and control unit is back at ground level and is used so that the operator ( and his mate) can move the stick to get a good view of plant on the pole and the pole top.

We don't have problems with SN swamping the transmitter or the circuitry of the camera, or the Wi-Fi unit on the ground.

My guess is that a camera on a stick will be closer to the source than a drone, and that the field strengths will be higher.

Hopefully the operator end of the stick is grounded. (If he or she is not on a floating platform).

I wouldn't touch that with a big stick, stiff or otherwise.

I must say that I am surprised. Ya learn something everyday!

Will signals to and from telecom towers interfere with drones?.

Remembering older days, I'm amazed at how impervious the functionality of the common cell phone is to EMI / RFI.

I don't know enough to do more than speculate that it's possible because of the high frequencies used, well above what you would think of as "radio".

Maybe the solution is compensating or cancelling algorithms in the control system possible at the higher frequencies

Hum, maybe I missed something alone the line? I didn't realize the power companies pumped up the frequencies above standard for HV transmission lines??

We've made cameras for line inspection both from helicopters & from ground vehicles. The cameras are sensitive to the corona (even when it's not visible) & allow rapid scanning of the power lines. No special shielding was required.

I'm looking for investors interested in developing a "drone hunter-seeker" for those of us who do NOT want all these stupid little drones buzzing around all the time. My plan is for it to home in on the comm signal the user is controlling the drone with, triangulate on it then find and disable the drone with an EM pulse or something.

But for right now, I'm just using a slingshot and shooting a little dried dough ball with a long piece of string in it. If I can hit one of the rotors, the string wraps up in the blades and brings it down...

LMAO! I'm thinking of moving to Deer trail, Colorado where they have a bounty on the little bastards

I do like your idea with the dough balls and string!

Some sort of net perhaps?

What about those toy Nerf and Super soaker guns, they're getting pretty powerful nowdays!

a man needs a hobby

You just need a drone-seeking missile powered by an Estes rocket engine.

I'm gonna bring Maxwell's Silver Hammer right down on the first douchebag's head who shoots down or intentionally jams my RC airplane, which is what we used to call them in a sane country...God I miss it. Good thing open carry is free to the public in my state.

The most important side effect of drones is safety and spying on others which could violate privacy of individuals and institutions. The flight path should be limited to private properties for guarding farmlands,security of installations etc.

And yet it is perfectly legal for me to fly my Cessna 500 ft above the terrain here in the U.S. so I can do all the 'spying' I want. I'm not a pilot, nor do I own a Cessna, but that's not the point. If you are outside of your abode, there is no reasonable expectation of privacy. While I would find the harassment of individuals to be reprehensible (e.g. the parparazzi), we citizens of the U.S. take our freedoms very seriously knowing full well that once a freedom is lost, it is lost forever. So I do not support draconian regulation that punishes the majority for the sins of a few.

UN supports draconian legislations in certain countries to harass,drive away from homes,jobs etc the minorities afew of them fight for minorities why US does support those?. Why can't they inform member states no draconian legislation is allowed but leaders should resign if section of people,workers,women etc fight for human rights.

My apologies, I am certain your understanding of English is much, much better than my understanding of your native tongue, but I'm not sure I understand your questions.

It's not just me