Hackaday Lazy Afternoons

Lazy Afternoons

ok this is totally unofficial and spur of the moment, but let me explain this tomfoolery.

since i started writing for hackaday and jason has become a father full time (congratulations so much by the way), it’s been a very interesting transition for me and i’m loving all you readers more and more. the tips and comments (good or bad) i truely appreciate and it shows that whether you love or hate the hack of the day, you’re here for good fun hacks.

so…we’re going to try this whole “lazy afternoons” thing. basically, you send in your hack, and during the afternoon, i check my gmail, see what’s up, find an interesting and (here’s the important part) easy to make hack, and post your hack up here for all hackaday readers to try out for themselves. not everyone can afford $600 for an android head, let alone know how to solder even sometimes. that’s ok. the important part is that you’re interested. so i present to you:

the world’s simplest FM radio jammer sent in by [megabite1]
FM Radio Jammer
we’ve all been there before. maybe we’ve even been guilty of it, but there will always be that person with the radio blasting unwanted music at a time that is not convienient for us. don’t get me wrong here, i don’t mind the occasional Run DMC “hard times” at 2am, but sometimes I need that sleep. so with a 100mhz crystal oscillator and a piece of wire acting as an antenna stuck in it, you can properly jam all 100mhz FM stations and apparently possibly the whole FM band. he says these are a bit hard to find, but dig around or try a place like mouser for one. either way, it’s good for some temporary relief when you need peace and quiet.

so until next time hackers, enjoy your lazy afternoon and keep sending in hacks. we love ’em. no worries, hackaday links will return soon.

129 thoughts on “Hackaday Lazy Afternoons

  1. I was wodnering, what old device could happen to use a 100Mhz oscillators? Because I have ton and ton of old hardware that I use to salvage part for that kind of thing.


  2. As much as I like reading about the more expensive and difficult to complete hacks, this is a hack that I can work on without spending too much time, yet still have fun. I like the simple and doable hacks idea :-)

  3. I don’t know about crystals much more then how to solder them when needed, but couldn’t you use the next closest above the range needed like you can for resisters or capacitors?

  4. the oscillator he used from from a 90’s circuit board. will a brand new oscillator have the same effect of jamming all of FM? the ones im looking at are supposed to be very accurate and stable.

  5. I think this lazy afternoons thing is a great idea. I myself am a beginner in DIY and hardware hacking sort of things. I’ve been looking for a place to get start with easier projects, and this idea seems like it would help with that.

  6. Hi there
    To answer some of your questions,
    No you can’t use the next closest in the range like with Rs and Cs. Unless it is _really_ close like 98-102Mhz or something.
    You can power it with a simple 3.3V lithium (coin battery) cell.
    Yes the same principle can be used to jam 802.11x. However, you will never find a crystal that oscillates at 2.4Ghz so the project will be much more complicated.

  7. What do I do once I get this item. I have never done any hack before and i want to start to solder and make this hack. Could someone help me with other supplies i might need, Does this need a battery or somthing? How does it work?

  8. I havnt really ever replied but ive been here for awhile, i have to say I love hackaday and this crap is neat all of it, the jammer and ring are markable new ones, usb batter, infrared camera, hell more than i can name

  9. when i was reseaching jammers and related trouble-makin’ stuff i was refered to this nifty article that explains the theory behind ‘all channel FM transmitting”: http://www.tinaja.com/glib/muse91.pdf

    of course, extending the math to this situation: a 100.0000MHz crystal will indeed have a first harmonic at 100.0000MHz and therefore certainly jam any station transmitting at that frequency…but it would be really really weird for such a high precision crystal to have harmonics/variations that extend from 88 -> 108MHz. so, while i think its a very nifty hack, i’m curious as to whether/how it jams the entire broadcast band…

  10. At ladyada.

    It could be the harmonic rich square wave put in the simple wire antenna somehow is distorted, making the band of noise wider. I also see no decoupling at all, so the wave coming out of it could very well be very distorted with not well defined edges (different harmonics).

    Well you could verify it by using the same setup, with decoupling and without. And then you check the output with a spectrum analyser. Not that i have such equipment lying at home, but at work we develop products that need to be compliant with CE EMC emissions, so i could make a small setup and measure it.

  11. As someone said before, does anyone have any ideas what one of these would be used for in commercial products? (what could i possibly own that has a 100mhz crystal oscillator in it?)

  12. Would it be possible and relatively cheap to make a device that would jam 802.11 wireless signals? I would give so much to have one…when every teacher’s computer in my school runs on wireless…would make school about a billion times more fun. Please help!

  13. I dont know if u under stood me right joe, i was just saying if he got those hack ideas from make, then he should say that he got found out from make. I actually dont care but its sorta lame when u find 2 articles in a role the day after the make article was posted. If your gonna do that try to diperse it more.

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