Introduction: Make a Microwave Gun (HERF Gun)

Picture of Make a Microwave Gun (HERF Gun)

There are no instructables on making a HERF gun... until now. I saw one on YouTube and thought to my self "I have to have one" so I made one and here I will show you how. 

-= DANGER: this instructable deals with high voltage and microwave radiation, don't attempt unless you know what you are doing, I take no responsibility=-  

-=just to clear this up, microwaves alone wont give you cancer but it can aid in it=-

Step 1: Health and Safety

Picture of Health and Safety

Microwaves do not have enough energy to chemically change substances by ionization because they are below the level of non-ionizing radiation. The word "radiation"only means that energy can radiate. It dose not mean radioactive in this case but it can. It has not been shown conclusively that microwaves have enough adverse biological effects at low levels. Some but not all studies suggest that long-term exposure may have a carcinogenic effect. This is separate from the risks associated with very high intensity exposure, which can cause heating and burns like any heat source, and not a unique property of microwaves specifically.During World War II, it was observed that individuals in the radiation path of radar installations experienced clicks and buzzing sounds in response to microwave radiation. This microwave auditory effect was thought to be caused by the microwaves inducing an electric current in the hearing centers of the brain. Research by NASA in the 1970s has shown this to be caused by thermal expansion in parts of the inner ear. When injury from exposure to microwaves occurs, it usually results from dielectric heating induced in the body. Exposure to microwave radiation can produce cataracts by this mechanism, because the microwave heating denatures proteins in the crystalline lens of the eye faster than the lens can be cooled by surrounding structures. The lens and cornea of the eye are especially vulnerable because they contain no blood vessels that can carry away heat. Exposure to heavy doses of microwave radiation (as from an oven that has been tampered with to allow operation even with the door open) can produce heat damage in other tissues as well, up to and including serious burns which may not be immediately evident because of the tendency for microwaves to heat deeper tissues with higher moisture content. NEVER get inside a microwave and close the door, you can't always get out!

The guy holding the neon bulb above the magnetron said this-"The photo above is of a neon filled globe being illuminated by the radiation from a 600 watt microwave magnetron. The magnetron makes a nice hand warmer. The funny fringes in the image are caused by the microwave radiation affecting the digital camera."
Mini FAQ:
1. No, it's not dangerous
2. Because I say it isn't
3. Because I've measured.
4. Because I have the equipment.
5. And the know-how.
6. If you think its dangerous then you're wrong.
7. Go play in the freeway. 

Step 2: What You Will Need

Picture of What You Will Need

all the stuff should be from the same microwave (almost everything you'll need can be found in a microwave) or the same model.
1. the high voltage transformer
2. the magnetron
3. the capacitor 
4. the diode
5. a 3 prong cord
6. a switch (optional, there are switches in microwave but probably not suitable for this)
7. a waveguide 
8. a noise filter (optional, I'm only using one cause my microwave had one)

Because the image note feature is currently not working I'm just going to hope you know what the stuff in the pictures are (on this step), on the next steps I will put what would normally be image notes at the bottom of the page.

Step 3: Hook Everything Together

Picture of Hook Everything Together

The microwave im using to make this had a paper in it with schematics of everything so I made one on paint of what we'll need, I'll also include a noise filter if you want to use one. The pins on the filter should be labeled "L" and "N", there should be two of each kind, two for input two for output and a green wire for ground. On the wall socket (in America) the left hole (the larger one) is neutral and the right hole (the smaller one) is live and middle is ground, now that you know this wire the filter. Connect the output to the primary side of the high voltage transformer. There are two secondary windings in the transformer, the small one is called the "heater" and its used for the magnetron heater, these are usually around 3V @ 15A. The larger winding is the high voltage side, it usually has an output of 2kV @ 500mA and will kill you instantly, these are used for producing the microwaves, you will notice theres only one lead wire for this, the other is connected to the iron core. Take the high voltage lead wire and connect it to one side of your capacitor, on the other side connect one of the heater wires, the diode, and a wire to go to the magnetron. the other lead on the diode should be connected to ground as well as the magnetron case and the transformer core.   

The first picture is a schematic with both setups I made on paint.
The second picture is the schematic from the microwave oven.
The third picture is the main setup without the magnetron.
 The last picture is the main setup with the noise filter.

Step 4: The Waveguide

Picture of The Waveguide

You will need a waveguide to direct the microwaves in one direction instead of them just going everywhere. Microwave ovens have a 4" wave length so the waveguide will have to be 4" at the start and then go up at a 35* angle. The waveguide must be made of metal, the waveguide in the microwave should get you to off at a good start as it has the correct dimensions and mounting holes. If you want you could also attach it to a satellite dish but i dont hate one. 

-=the pink insulator at the top of the magnetron is made from beryllium oxide and if crushed and inhaled it can cause an incurable disease in the lungs=-

The first picture shows how waves travel though a waveguide.
The second picture is a magnetron set up on the arm of a satellite dish (not my picture).
The third is the same as the second.
The fourth is something I made in paint.

Step 5: Finshed

Picture of Finshed
In this picture all of the connections are made except the transformer core is not grounded and one of the terminals broke of the transformer so I have to solder that back on, aside from that I just need a waveguide and I'll be done. My parents would freak out if they saw this so I've got to keep it secret and I'll have my uncle watch me play with it so they think I'm being "safe" with it :D my uncle is an engineer, so while they still cant seem to figure out I know what I'm doing they know my uncle dose. 

-=Thats not my video=-

If your wondering, the song is chop suey by system of a down.


JoshF31 (author)2016-06-09

Hi i was wondering why youre feeding the magnetron housing with 2kv dc thru the diode

unlost117. (author)JoshF312016-09-16

He isnt. The magnetron housing is at ground.

SamN2 (author)2016-04-16

could you get a tighter beam or is 35 deg set in stone

zork the destroyer (author)2016-02-09

i made one, but without the waveguide. A lesson to everyone, don't do it without the guide, it screws woth your head and make the lights go wierd throughout the house.

SamN2 (author)zork the destroyer2016-04-16

yea ... you got lucky. the microwaves could blind you if your not careful.

knnemec (author)2016-02-26

Insects do not have enough water content to be affected by microwaves but humans do, especially in places such as eyeballs, brains, hearts and testicles (where your genetic progeny come from). I have only two words for those who would do this WITHOUT knowing EXACTLY what they are doing: DARWIN AWARD. Great research on the safety aspects, it looks like you were quite successful in making the HERF gun and I would love to see your next project.

Kethurston (author)2014-03-31

can you use this to jam a radar gun?

SirCheez (author)2013-07-26

You should warn people about that capacitor.

Grikovien (author)SirCheez2014-03-11

Tampering with anything you know nothing about, without astute caution, is what step 7 is for: "7. Go play in the freeway." ...Same ends...

But people have a hard time learning from their mistakes if they're dead so I agree, it would be good to throw some warnings around, maybe some nice caution-yellow images with silhouette people being vaporized or dismembered. You know, something nice.

richardfireone (author)2013-08-07

Awesomeness! what kind of killing power does this device have at long range? Is it possible to shield yourself or an object from this kind of attacking force? Is microwave radiation effective in submarine environments or dense jungle? Thank you for your precautions and details.

iThinkBig (author)2013-04-23

umm could you redo this one with a step by step for people who don't know how to read schematics?

SirCheez (author)iThinkBig2013-07-26

Learn electronics and how to read schematics. Regardless of what it says, this Instructable IS dangerous: not the radiation, but many other parts are extremely dangerous if you don't know much about electronics. See this comment on another 'ible:

If you can't read schematics, that generally means you don't know much (AKA anything) about electronics (and I think that schematics are pretty self-explanatory anyway). Without knowledge and precautions, you could be smoking and dead before you hit the ground.

panostzom (author)2013-05-10

can i do it without a HVD at all?

amchiavelli (author)2012-02-20

Jimmy Proton...could you put more information about the transformer used in this project , the voltagem of capacitor and the diode, filter etc ...I have a big interest to build this and crash the noises neighboors...thanks for everything!

billbillt (author)amchiavelli2013-04-23

everything you need is contained in the microwave oven

mykiscool (author)2013-01-12

Does the polarity matter for magnetrons?

Jimmy Proton (author)mykiscool2013-01-18

I wouldn't think so

Kamran Shuja (author)2012-12-14

A very intresting web for hobbiest

NV09 (author)2012-08-28

Hey I was just wandering what the exact values for your transformer, diode and Cap are?

granz (author)2012-04-26

Cool instructable, but I believe you are off on your wavelength calculation. Magnetrons produce about 2.45 GHz so that gives you:

(3*10^8 m/s) / (2.45 * 10^9 Hz) = 0.1224 m
0.1224 m / 0.0254 m/inch = 4.821 inches

When I built one a while back I was able to light up a CFL at greater than 8 ft away.

GASSYPOOTS (author)2012-02-22

why kinda files u burn into those cd's with that :D (jk)

Highvoltage1996 (author)2012-01-23

Hey. Really nice intractable. I like this. I have a 700 watt magnetron capacitor transformer ect. To run it. At only 700 watts if a waveguide was applied, would the microwaves radiating be strong enough to have effects on me or other people that would happen to be behind this thing? If this does happen to leak a risky amount how can I stop that and tell where and how powerful the radiation is leaking?
Thanks! Once again like you intractable a lot!

moris_zen (author)2012-01-03

Should my hard really heat up so much even if I am 2 meters away ?
It is nice in the winter but it doesn't heat up all my body only a small part .
Can it be made to better heat the entire body?
Thanks! cool instructable!

Jimmy Proton (author)moris_zen2012-01-03

Are you using this thing to heat up your body???

moris_zen (author)Jimmy Proton2012-01-04

Yep , works nice - I now placed it further away and it heats up all my body evenly .
I checked and 2.5Ghz shouldn't cause cancer (it is none ionizing frequency) and shouldn't cause any damage to the DNA .. I hope wikipedia is correct ..

Jimmy Proton (author)moris_zen2012-01-04

It is true that microwaves cant cause cancer because they are lower than the ionization level required to cause cancer but it can cause blindness, damage cells by over heating and maybe even sterilization... I certainly wouldnt stand in front of the thing just for those few reasons and im sure there are more but i may suggest covering your penis in aluminum foil and were glasses with metal screens that can absorb the microwaves.

moris_zen (author)Jimmy Proton2012-01-07

I guess I wasn't sarcastic enough .. guys - Only a CRAZY person would get close to these extremal strong microwave radiation!!! - I saw the movie on you tube .
Man - there are 4 different interlock mechanism on the microwave preventing leaks in case of damage to the device .
Although my home phone work on same freq 2.4Ghz - it is only 100mW and not 500W (x5000 times more).
I was just joking - need to clarify this in case some layman actually tries it .
Sorry :-)

Jimmy Proton (author)moris_zen2012-01-07

lol well actually some say they are safe to play with unless youre just completely stupid with it but there are people out there that would microwave themselves just to warm

deaks (author)Jimmy Proton2012-01-05

i wish i could "like" this comment.

also, i love the line "NEVER get inside a microwave and close the door, you can't always get out".

rela (author)2011-05-13

So if you scale this up with sheilded protection you could use it as a excavator to do construction like what they use a breaker or rock drill to do.Break rocks in a more uniform manner with 100% accuracy and a done in like minutes.

deaks (author)rela2012-01-05

i think you need something like this to disaggregate rock:

looks breathtaking...

Jimmy Proton (author)rela2011-05-13

Probably not, it would just heat them up (given that they have moisture in them) and may possibly thermal them but I doubt you could make a vary efficient rock crusher out of this.

mossimo3 (author)2011-11-26

I'm curious as to the orientation of the magnetron's antenna in relation to the waveguide. Does it need to be perpendicular to the waveguide (meaning the RF energy radiates perpendicular to the antenna) or can it be in line with the waveguide (meaning the antenna is near-omnidirectional, so orientation is negligible)? The antenna on the magnetron I have has a cylindrical shape, but then tapers off in a conical shape.

Tobor 2.0 (author)2011-07-20

First off how do you tell what to hook up on the capatictor because i cant figure out because it has 4 hookups.

Jimmy Proton (author)Tobor 2.02011-07-20


Tobor 2.0 (author)Jimmy Proton2011-07-27

I can't fully tell what hooks up to what, could you post a schematick showing it all?

Jimmy Proton (author)Tobor 2.02011-07-27

There is a schematic on the next step.

Tobor 2.0 (author)Jimmy Proton2011-07-29

But both of the schematics show the capatictor with only two leads and not the other two.

Jimmy Proton (author)Tobor 2.02011-07-29

I have never seen a microwave cap with four leads and i really dont know what they might be for.

Tobor 2.0 (author)Jimmy Proton2011-07-30

Here let me refrase that, the microwave capacitor has four different little parts coming out that you can hook wires up to on the schematics only two wires are connected and in the picture of yours, three are connected.

Jimmy Proton (author)Tobor 2.02011-07-30

I know what your talking about now, where it shows wires connecting, they connect on the terminals on the capacitor.

Tobor 2.0 (author)Jimmy Proton2011-07-31

Oh, now I think i see what connects to what. the first wire (far left) connects to the magnatron and the diode goes to the ground, the middle wire is from the transformer same as the red wire. If i hadn't lost my magnatron a long time ago I would be building right now, but sense i can't find it i am using the trans. and the cap. for i high voltage rail machine gun. once i find a new microwave oven i'm defenatly building this with one mod so i can have my death ray! muhahahahaha!

Shadetree Engineer (author)2011-06-29

So finally, a way to really go after all the mosquitoes in my yard! Besides chasing around with a hand-held version on an extension cord, what about aiming the waveguide straight up, and have a UV tube suspended on a string above that. The tube will light up from the microwave, attracting mosquitoes to the airspace above the waveguide where they get warmed up and fry. Maybe a pane of glass across the waveguide and a weather-proof enclosure for the rest? Probably a lot quiter than a standard bug zapper.

That probably dont work because they microwave quickly loose their power.

What? You mean the electrical circuit fails? Why?

They spread out as soon as they leave the magnetron.

Oh. You mean the power intensity per cubic-inch drops-off logarithmically? But that would also begin to happen while the energy is passing through the horn.

I looked up what anyone else may have been doing as far as trying to microwave a mosquito or any small flying insect, and it doesn't look like it'll work. The mosquitoes are too small. There's some debate over why. Maybe the size of their body is no good as a receiving antenna, maybe they fly into the dead spots in the radiation pattern.

So it looks like to make my idea work, I'll need a much higher frequency magnetron, with a wavelength of about a millimeter.

I'm not to sure what that first part meant, I'm not that smart. I guess that because they're so small the dont absorb a sufficient amount of radiation to die, an x-ray tube should do the trick. - this site has a nice explanation of what I thought you meant.


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