EMP / HERF / Marx Generator

[JLSE]

So im onto a new project and getting back to some fun with HV.
I opened this thread for anybody interested in building a HERF gun.

I have been searching for some good info for the past while and finally hit the jackpot. There is one site in particular that has much on the subject, and will post the links at the bottom.

First off, DO NOT attempt anything in this thread or with high voltage in general if you don't understand the dangers involved.

For my project, I will be using standard low cost 800-1500W microwave ovens. The project I would like to build consists of 4 magnetrons mounted as seen in the pic below. I may just try a single first though, just to get the feel of things.

I found this picture on Google, but im not sure how ideal this design is, though it looks pretty bada$$, it may also be a waste of 4 MT's.

Before starting this project, I am also looking at some of the additional hazards. The beam of RF being the biggest one.

So to start off, lets see how NOT to test the newly acquired HV transformer and magnetron..





Im still wondering if the lack of newer videos is the result of the inability to walk or the excessive dr00ling.


On the other hand, this is more like it, and seems to be a simple, safe, and effective setup..






Now that the do and don't examples are out of the way, onto the good stuff.

The simplest setup which is probably the most effective, and most importantly the cheapest, is using a satellite dish.

At a local surplus type store I frequent called Sayal, a decent dish can be obtained for under 50$. Im sure there are cheaper prices or method of obtaining one.

DO NOT STEAL YOUR NEIGHBORS!! Garbage day is a good start for a freebie.


This is the satellite setup ive found, and looks to be the sure-shot of the bunch, but I am gunning for the waveguide as pictured above ^

For either style of 'gun', it is still going to come back to the magnetron and how the power supply, cap and spark gap are set up.

Now I didn't know that a spark gap was used in HERF, but it makes a lot more sense to me now after thinking about it. Adding a spark gap allows the cap to charge giving nasty short bursts of RF, and from what I gather, this is the goal. I have never heard of doing this with a MT though.

Spark gap setup can be seen in this link..

http://servv89pn0aj.sn.sourcedns.com/~gbpprorg/mil/emp1/emp-19.jpg



Now im going to add to this thread as I proceed with my build. I am still in the middle of acquiring parts (on the cheap), and any input to this project is as always welcome.

I know there are a percentage of HV enthusiasts around these parts, please feel free to chime in with any tips. I am looking for advice based on experience on how to increase the frequency of the MT. It is a complicated process from what I have read, but possible.

As well as the construction of the waveguide, im thinking copper clad boards for the long tunnel and then some copper flashing at the end. Square seems to be the ideal shape for the guide, but what is the sizing based on? I have no experience with directing the energy..


Links:

All the links I have found are on this single page > GBPPR HERF Device

There are also news stories, US Navy test documents, homebuilt HERF's, and some audio clips on the topic.

I mentioned EMP and Marx Generator in the title. I will not really be posting anything on either topic (for now) but all can be found in the link above.

 

[digital_blue]

Not to rain on your parade or anything but playing with microwaves/magnetrons is not a good idea especially if you don't have much experience with it. If the risk of lethal HV and deep thermal burns don't have you worried, you should also consider the kWs of interference the thing will put out...

If you absolutely must build a HERF, I highly recommend that you start with "single pulse" version (powered by discharging HV). This will limit the amount of damage you can do to yourself/other objects compared to a "multi-pulse version" (transformer powered). This will also reduce the thermal stresses on the waveguides and horns.

 

[billg519]

A few years ago, I saw an episode of Mythbusters where they built some super microwave device out of four magnetrons. It was an epic fail. They did not properly couple the output of their magnetrons to the body of their device. If you examine a microwave, there is a waveguide section that channels the microwaves from the output of the magnetron to the oven cavity. You may need to implement this or something similar in order for the magnetrons to function correctly. It's easy to burn the end off the magnetron. Hope you're using scrap microwaves for this.

Marx generators are great too. I made one not so long ago.

Hmmm ... post #808

 

[Benm]

Combining the power of multiple magnetrons is, indeed, pretty tricky. Just shoving them in one box and hoping for the best is pointless - it will not work, and probably damage the magentron tubes.

To combine the power you need circulators (GHz range couplers), if you want to combine 4 tubes you'd need 3 of them. Furthermore, it requires extremely precise 'plumbing' to get the mixing process right... and you need 4 magnetrons that are very close in frequency range to start with, such that they lock eachother in frequency.

All in all, this is a pretty insane amount of work. If you want to do experiments, start with only one magnetron and try to get that focussed enough to disrupt electronics at a fair distance. I've seen a video of a PC rebooting after being fired upon from 10 feet or so... it wasnt damaged permanently, but shows the effect.

But most important: Do not mess around with magnetrons unless you know what you are doing. The input voltages and currents are enough to shock you dead instantly, and if that doesnt get you, a kilowatt of microwaves can do serious damage... imagine putting your hand in a micorwave oven for a minute!

 

[JLSE]

the risk of lethal HV and deep thermal burns don't have you worried, you should also consider the kWs of interference the thing will put out...
.

LOL, I thought that was the whole point :eg:



I don't have experience with microwaves, but do with high voltage. I built my first Tesla coil in my early teens and couldn't even Google it, imagine that

The waveguide for the gun pictured above is actually 4 separate waveguides meeting at the horn, see below pic I couldn't find the URL.

I have CDMA, 3G, etc jammers ranging from 50ft radius to 300ft radius in the high watt range, but for the purpose to which I am building this, a wimpy little jammer just wont cut it. Though if I turn one on in my house, the nearest PC has let out a chime sound indicating a 'completed download' lol, when there was nothing downloading... Just not destructive enough..

I am thinking of replicating the dimensions of the existing waveguides. This should hopefully permit enough distance between the emitter of the MT from the walls of the waveguides. If I make to the same dimension, it will be as close to the manufactured spec most suitable for the MT's.

In the pics in my first post, the satellite dish HERF uses the original waveguide cut away from the oven. I am thinking the same arrangement, and just adding on to that with a thick CU clad board.

I was bit by a 10kV oil ignition transformer when I was younger. It threw me across the room, and is well imbedded in my brain... Something that I wish not to repeat.

I was going to try EMP, but the setup is far more costly on time and $$$ to come even close to the range of a HERF.

With 4X 70$ MW ovens, thats a serious setup for under 300$.

I was going to scrounge up the ovens for this in the trash, but want all parts to work as close to the manufacturers specs. Finding 4 oven that are in prime condition will most likely cost me more in gas than a trip to wallymart..

@BillG519, I saw that episode, IIRC they made the water colder, lol. He didn't really put enough thought into that x4 design IMO. The more work you put into anything will always yield much better results.


Heres the pic of the front for the 4pc waveguide..

 

[digital_blue]

You might want to consider building one that is pulsed instead of quasi-CW. From what I hear, the raw output of a magnetron is capable of melting metal. You should also do some reading into waveguide designs; an improper waveguide could cause the microwave equivalent of SWR and will lead to destruction of your magnetron.

As for interference, please be considerate about your targets; dish it out to people who actually deserve it, not a random passersby.

 

[JLSE]

You might want to consider building one that is pulsed instead of quasi-CW. From what I hear, the raw output of a magnetron is capable of melting metal. You should also do some reading into waveguide designs; an improper waveguide could cause the microwave equivalent of SWR and will lead to destruction of your magnetron.

As for interference, please be considerate about your targets; dish it out to people who actually deserve it, not a random passersby.

Of course my good man! im a bit beyond the whole random thing

I spent most of last night reading as much as I could find. I went from damage to the human body A through Z, seems this freq. has a preference to bones over tissue not that its anymore reassuring.

Im taking all things into consideration on this project, and avoided making one for a long time. I figured it may be best, to be on top of my game before even venturing into building one of these.

I wasn't even going to post this thread, but figured if anybody else was going to try this, it would be good to have a decent resource other than that youtube video of some meathead with a piece of foil covering half of his vitals.

I have searched on many occasion for good info and finally found some, so the ball is officially rolling.

Thanks for all the input guys, im open to any suggestions, so by all means...


My goal with this is a law abiding one, I would not want to encourage otherwise..
Just always wanted to build one of these puppies.




As for purpose built HERF's. read the below article, pretty funny.




"Whether it's the booming stereo radiating from the next car, a dog barking incessantly, or the neighbor blasting Bon Jovi, noise has enraged most everyone.

Towns have passed laws to deal with it and numerous gadgets have been developed to protect from it. But few have taken their hatred for noise as far as Houston's Barney Vincelette.

A case of mild autism has made him extremely sensitive to noise. Vincelette, who lives in a spaceship-style house, thinks music, especially top 40, rap and rock 'n' roll, "sounds the same way feces smells."

Vincelette used his genius-level IQ and parts of household microwave ovens to develop a makeshift device that uses electromagnetic waves to temporarily jam the circuitry of his neighbors' stereos.

"Many people just assume that you should be able to have this music in your backyard. But it is such an ugly music that it takes over one's life," he said. "That's why I fight back against it."

Vincelette is so sensitive to noise that he's gone as far as shooting and killing a dog that barked nonstop outside his apartment. He paid a $100 fine and was evicted.

"I'm not terribly proud to have done that but I was at the end of my rope," he said. "The way the law was, there was nothing I could do about it and there was no place I could live that didn't have dogs barking all night and all day."

That sensitivity to noise ignites a rage within Vincelette that has turned neighbors into enemies.

Elizabeth Ramirez, who lives in a mobile home next door, said Vincelette likes to "control" her family with his sound-stopping inventions.

Andy and Shirley Snead also have had a dispute. In August 2002, Vincelette, annoyed by the thumping bass from their stereo, rigged truck horns to an air compressor and blared it.

Police issued a disorderly-conduct citation, which carried a hefty fine.

"A policeman told me he heard it a mile away," Vincelette said.

But instead of paying the ticket, he recorded the noise and sent it to a professional musician and personal friend in the Netherlands.



* Remember, this guy is autistic, so be nice. The fact that there were possibly kids in the path of his HERF does not
sit well with me.

The rest is funny though.

 

[KiLLrB]

Hmm I have 2 spare microwaves just collecting dust...

 

[lasersbee]

Send them to Wannaburn..... He'll recycle them...:eg:
No sense sending them to the Garbage Dump.....

Jerry

 

[JLSE]

So another night of intense reading... DigitalBlue was onto something with the A- pulse and B- 1 MT instead of an array of them. Im thinking he has a HERF in his garage

Running MT's close to one another can cancel each other out. Now what I read seemed to apply to both a single 'shared' waveguide, and separated waveguides as well. The term 'locking' seems to re appear in combining MT's, and can be both a undesirable thing and also be favorable.

To achieve higher powers, a MARX Generator is the way to go.

A radar magnetron can also give higher power but are less effective and more of a disruptor than a destroyer :eg:

There are guys also using 'cantennas', but I think I will first go with the following arrangement,

-Horn antenna via copper flashing
-1600W MT or higher if found
-spark gap arrangement on the cap
-brass mesh surrounding the rear and sides of the MT
-brass mesh collar around the emitter (slightly receded)

Even though a horn antenna is quite directional, there seems to still be an issue of rear facing 'leakage' of RF.

Assuming that no exposure would result standing behind the machine is a dangerous thing. Apparently RF will still leak in this direction, so ive thought of the brass mesh placed as a collar slightly receded back from the face of the emitter. This should catch any stray RF from the horn, well at least from hitting behind it. Id avoid anything on the sides of the horn...

PLastics! These can act as a 'lens' and change the direction of the RF. I was surprised to see that this could happen. There are actually ways to shape and even focus the output in ways that seem pretty odd.

This link covers all one needs to know about antennas > Table of Contents - W1GHZ Microwave Antenna Book ONLINE

Though keep in mind that the book is for frequencies other than 2.4ghz, but still for microwaves in general. Im still working on the dimensions I will use for mine.

I also read that the combination of a horn and dish antennas can be used and provide the highest gains. Im still looking for pics of this style, but can picture what it should look like.



If I were to summarize all of that which I have read in the past few days, id start with saying that there are people out there who should not be trying this stuff!

I have read posts made by people who had arching issues, and proceeded to LOOK DOWN THE WAVEGUIDE TO 'SEE' THE PROBLEM!!!!!!!!

Oh and the coup de gras (shaking head vigorously)...

My questions for the guy in the photo would be, who took the pic (friend= sunny side up), how many other bulbs were tested in this fashion, and how far must he have to lean to shut it down..

BTW, does anybody know what a two plate TED HERF waveguide is? I can only find minimum info.. It appears to be the cats a$$ for antennas..


ROFL!! Was reading on this, but didnt realize that it had been done. They call it the 'voice of God' and is a microwave based device that can resonate audio into a human targets head. Anybody hit with the beam will hear it, but a guy beside you would not. This technology has already been exploited for use in advertising, with unsuspecting persons on a US city street were fed audio clips from some show.. Folks, move to Canada while you still can.

http://www.strategypage.com/htmw/htweap/20071217.aspx < "Death Ray Replaced By The Voice of God"

 

[digital_blue]

A magnetron array is still possible; you just need to make sure there isn't any destructive interference going on. If you plan on using a dish type radiator; use an "off centre" mounting instead of a "parabolic" mounting.

As for a horn antenna, you need to design it carefully. An improperly designed horn will cause destructive interference and/or standing wave; this will cause some of the power to be reflected back towards your magnetron.

If you are worried about RF leakage, a simple solution would be a fine copper mesh/cloth. If you're cheap/on a budget, aluminum window screening will work. Since you are opting for a horn, I recommend using some copper solder braid as a "seal" of sorts.

 

[lasersbee]

ROFL!! Was reading on this, but didnt realize that it had been done. They call it the 'voice of God' and is a microwave based device that can resonate audio into a human targets head. Anybody hit with the beam will hear it, but a guy beside you would not. This technology has already been exploited for use in advertising, with unsuspecting persons on a US city street were fed audio clips from some show.. Folks, move to Canada while you still can.

Weapons: Death Ray Replaced By The Voice of God < "Death Ray Replaced By The Voice of God"

The "voice of God" you are referring/linked to is not a Microwave device...
it is a Directed Audio device using standard audio... The trick is in the
Antenna/Speaker (very expensive...I wanted to buy one)...

It allows you to send sound in a Flashlight type directional beam.. If you
are in the beam you hear the sound and 2 feet way (out of the beam) you
hear nothing...

Jerry

 

[JLSE]

The "voice of God" you are referring/linked to is not a Microwave device...
it is a Directed Audio device using standard audio... The trick is in the
Antenna/Speaker (very expensive...I wanted to buy one)...

It allows you to send sound in a Flashlight type directional beam.. If you
are in the beam you hear the sound and 2 feet way (out of the beam) you
hear nothing...

Jerry

I didn't realize that, I had read of one that uses microwaves and assumed it was the same type. It was also referred to as 'voice of God'. example > Patent For Microwave Voice-To-Skull Technology
Or more succinctly put 'voice to skull'.

This one uses modulated microwaves to do the same job.

The speaker system IIRC was called an 'Acoustic heterodyne device'. Since I read another article on these, I also had seen that they make a speaker system for home theater like this, pretty c00l stuff.

Though still a crazy idea to use on the general pop. to advertise, not as scary as a microwave based device.

A magnetron array is still possible; you just need to make sure there isn't any destructive interference going on. If you plan on using a dish type radiator; use an "off centre" mounting instead of a "parabolic" mounting.

As for a horn antenna, you need to design it carefully. An improperly designed horn will cause destructive interference and/or standing wave; this will cause some of the power to be reflected back towards your magnetron.

If you are worried about RF leakage, a simple solution would be a fine copper mesh/cloth. If you're cheap/on a budget, aluminum window screening will work. Since you are opting for a horn, I recommend using some copper solder braid as a "seal" of sorts.

Well to be honest, im still deciding on the antenna. I may go with a dish for the first tryouts, and may do so to cut build time. The thing I do not like about a dish is the size. Though id expect the accuracy and range to be better than a horn. Always a give and take I guess...


Also, if I use the pulse type setup with a spark gap, what should the pulse rate be? And would adding another cap be beneficial to the output?

I know that the MT's filament has to be heated on a continuous basis with the spark gap. From what ive read, it eliminates the 2-3sec delay for it to warm up. In pulse, ive read that keeping the filament hot is the idea. Does this sound about right?




*Edit

Is there a template that is available for a horn style antenna? Wouldn't a 'good' design for one 2.4ghz oven MT be equally as good for another? The difference between oven MT's would be mainly power output with relative frequency no?

I have also read that there are 'dimples' stamped into the OEM waveguides for a reason, would this apply to a DIY version, or would the difference be somewhat negligible?

 

[Benm]

I have read posts made by people who had arching issues, and proceeded to LOOK DOWN THE WAVEGUIDE TO 'SEE' THE PROBLEM!!!!!!!!

Ah well, that is how you get a darwin award

Working with lasers it seems logical not to look down the barrel to diagnose a problem, but microwaves can be quite dangerous to the eyes as well (because of the lack of circulation to keep them cool), even in situations where you could safely hold your hand in the waveguide (obviously not microwave oven power levels, but things like 1 watt for communications).

 

[JLSE]

I would not voluntarily place any part of my body in front of one of these just plugged in, let alone when its on.

As for the eyes, there is just something a tad creepy about boiling the fluid in your eyes.
I do not wish to deal with cataracts or blindness anytime s00n.

Any testing will be done with considerable distance between myself and the unit. I still cant believe the dude in the video in post #1 and how close he is to an exposed MT.

Wonder if there are any annual death statistics for these chuckle heads :thinking:

 

[Benm]

I doubt there are any statistics, they're probably included in 'electrocution' as a category. People actually killed by microwave output would be very rare. I suppose there are a number of hobbiests that require medical attention for radiowave burns, but i'm not sure anyone keeps track.

And, about your picture.. check this one:
Warum das Doppelschwanzmännchen schließlich doch ausgestorben ist