Sciencemadness Discussion Board

EMP device for pesky drones

yobbo II - 5-10-2020 at 12:25


Has anyone any knowledge or info. on a EMP generator that could be used to disable drones. (swat them from the sky).
I don't wont anything too exotic using explosives (god forbid!).
I am thinking of a great big HV capacator + coil + aerial (directional would be good).

I don't know anything about the subject.


Twospoons - 5-10-2020 at 12:44

I thought about this as a way to silence my neighbor's stereo late at night.
I would be inclined to try an elliptic horn antenna (wide bandwidth, good directivity) with a spark gap at the feed point. There's a good chance you could cause the microcontroller on the drone to reset or lock up.

wg48temp9 - 5-10-2020 at 12:53

You may be able to do it with a bigish parabolic dish with the magnetron and power supply from a microwave oven, depending on how close the drone is and how much you increase the pulse power of the magnetron or with an array magnetrons.

PS: from my leaky experiments with magnetrons they cause buzzing on near by (about 25m) portable radios and that was without a dish and through a wall of a garage. The oven power supplies pulse the magnetron at about 1:5 so peak power is several kilowatts. That could be increases to 10kW pk or more depending the emission of the filament of the magnetron.

Of cause this is illegal in most countries and potentially dangerous to people so this is just for theory.

[Edited on 10/5/2020 by wg48temp9]

PSS: The small size and ground planes of modern PCBs make them very resistant to EMI but the antenna of the radio is the weak point so its probably very easy to saturate the receiver front end or to even damage it compared to resetting the microcontroller. It could also interfere with wifi or damage wifi receivers as they operate in the same frequency band as microwave ovens.

[Edited on 10/5/2020 by wg48temp9]

unionised - 5-10-2020 at 13:32

This has more style...

wg48temp9 - 5-10-2020 at 13:42

Quote: Originally posted by unionised  
This has more style...

Yes much more style and no collateral damage to people or wifi and probably legal if its above your property.

Twospoons - 5-10-2020 at 14:36

I'd be worried about the birds being injured by the prop blades. Seems rather unethical to me.
Maybe its time to build a drone that attacks other drones. All you'd need to do is drop some string into the victim's props.

yobbo II - 6-10-2020 at 12:06

Unfortunately I don't have any eagles.



MadHatter - 6-10-2020 at 14:20

No birds ? No problem. 12 GAUGE ! :D:D:D

yobbo II - 7-10-2020 at 16:13

Believe it or not! I did actually think of the 12 gauge. I believe it is illegal to shoot down a drown (unless of course by accident).
There is a guy selling a device out there that shoots out a net.

You could probably catch the eagle too:D

I have attached a device that emits EMP. It seems doable to build untill you come at the part what needs a 'fast' spark gap. That's a spark gap in a chamber with H or N gas under pressure. SF6 will do to with less pressure. Not so simple.

It used a fairly ordinary spark gas exciting a tesla coil followed by a pulse shaping line (simple) enough to do if you just use the dimentions given. Then the annoying bit is the 'fast' spark gap and an aerial.
The math is way beyond me but he gives dimensions etc.
The whole thing is put into oil.
How would you get around the 'fast' spark gap bit?

I desire a drone swatter. Will trade 12 gauge........

The file is too big.
Google Thesis-2008-Sarkar

Sulaiman - 8-10-2020 at 01:05

I'd consider a directional antenna and a few watts at 2.4GHz to overload the receiver front end

unionised - 8-10-2020 at 03:27

At least some of the drones are autonomous.
You could try blocking GPS location data.

Heavy Walter - 8-10-2020 at 07:05

Mr Bob Iannini, in his book Electronic Gadgets for the Evil Genious show an EMP gun.

wg48temp9 - 8-10-2020 at 08:08

Quote: Originally posted by yobbo II  


Thanks for the interesting thesis. I have never seen the details of a Tesla coil powered EMP device before. Considering its generating about half a million volts its a compact Tesla coil thanks to the oil insulation and as you stated most of the construction is doable DIY. The spark gap of the Tesla coil perhaps could be ambient air or hydrogen as it does not have to be as fast as the pulse output spark gap.

I wounder if using the 0.5MV in a particle accelerator (an evacuated long tube containing an anode and cathode) what experiments could be done.

PS: Apparently from wiki, Lichtenberg figures created within solid insulating materials uses 25MeV electrons so I guess only 0.5MV will not be sufficient.

330px-Lichtenberg_figure_within_a_acrylic_block.jpg - 23kB

[Edited on 10/8/2020 by wg48temp9]

Sulaiman - 8-10-2020 at 08:11

Have a look on YT for 'herf gun'

Twospoons - 8-10-2020 at 15:05

I still think that the elliptical horn, with a simple air spark gap at the feed end, operating at 25kV or so, would be the simplest thing to try. You're just trying to create broadband noise of high field strength - no need to worry about frequency, or impedance matching or efficiency or high-speed hydrogen spark gaps.
The antenna is just two pieces of metal plate - aluminium is easiest to work with - with a former (plywood?)
25kV is easy too - plenty of examples on the net of devices built from a couple of transistors and an old TV line output transformer (search terms: Royer oscillator, or Mazilli driver)

For comparison a simple EMC susceptibility test we use in electronics is the chattering relay test: a relay is connected so that it interrupts its own coil current, resulting in the thing buzzing continuously, with arcing on the switch contacts. This produces a lot of electrical noise, and is a good thumb-suck test - if this will knock over your electronics you have a problem and need to do a bit more design work!
You really dont need anything fancy to create EMI.

buzzing relay

sodium_stearate - 9-10-2020 at 09:09


Yes, I have observed that very phenomenon you mention!

In a digital logic circuit which has some relay outputs,
I have seen this many times. The tiny spark generated
at the contacts just so happens to be close to the coil.

The coil then acts as a crude antenna. The result is a bunch of
hash and noise which can get back on to the Vcc and GND bus,
and wreak all sorts of havoc to nearby logic.

Usually a little filtering will mitigate this enough to
allow the logic to resume working correctly, unaffected
by the relay noise.

But your observation that this can be used as a simple
crude test is spot on! :)

yobbo II - 11-10-2020 at 11:44

There is a jammer here:

It would be an easy solution if it worked. You need a yagi with it

yobbo II - 11-10-2020 at 12:13

Youtube vid here

looks a bit like the device in the theses

there is an interesting WIFI 'stealing' device here


[Edited on 11-10-2020 by yobbo II]

yobbo II - 19-10-2020 at 05:55

njl - 19-10-2020 at 06:05

I wonder if those deauthors that are so common now could interfere with a wifi controlled drone? I think that as long as they're using the right kind of security protocol you should be able to at least detect the signal.

zed - 19-10-2020 at 18:37

Hnuh? A drone over your property? No problem. Kill it.

I imagine a shotgun would do that nicely.

Not legal to fire a shot-gun within the limits of most cities.

But, I can't imagine a paintball gun would be illegal.

Can you jam a drone frequency? Yes!

Among them, radio frequency (RF) jamming, or jammers, can be used to disrupt the RF signal of the drone, causing it to fail. Generally, this RF-Jamming is either at 2.4Ghz or 5.8Ghz, which are “non-assigned” public frequencies. ... Jammers are effective against drones over several kilometres distance.

I did not write this. Just a quick internet look-up.

[Edited on 20-10-2020 by zed]

pneumatician - 10-1-2021 at 15:12

Ask the Iran how to capture a drone :)

well, police use some shit in aeroports and co.

Some high power laser?

or use all this shit debunkers use to "explain" the dissaperances in Bermuda triangle :) work 100% sure ha ha ha :-DDD