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TV Jammer?

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Megamox

New Member
My mate's got one, wont tell me how it works !! Whenever he turns it on i lose the picture on my tv, it goes fuzzy. Said he knocked it up in 30mins. Anyone know the principle or how it works, curious.

Thanks
 

electronic mind

New Member
its simple

1) find out the frequency band reserved for T.V broadcasting

2) get an oscillator that produces signals with frequencies blonging to that band

3) amplify the output signal then emit it with a vertical quarter wave antenna

this signal will interfere with the one should be received by the T.V

the principle of jamming is creat a signal around the receiver which has the same frequency of the one should be received and the same or higher power
 

windozeuser

Member
Wouldn't it work better with a direction antenna, such as the sattelite dish, coffee can combo used in wifi.

By the Way, Any Feds(FCC) in this room, I don't plan to build this.

Until you leave :lol:
 

Megamox

New Member
Its just a normal UK terrestrial tv.

This is a picture of what it does.
 

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Agent 009

New Member
My Opinion

Nice display! But that's not a jammer, but a hacker :p ... I mean by that it's not interfering with the TV signal, it's quite replacing it, bc of high power or so. I want you to do a test. Break the connection between the TV and your receiving antenna, and check if you still have the thing... If yes, I think the jammer's got so much power it's being "overwriting" any other signal. If not, it's just interfering with the cable.
 

Agent 009

New Member
I don't know exactly how the TV signal is made, but let's say it's a sine/cosine wave, doing the funny horizontal lines. Your friend should be creating such wave, using oscillators, adders, and multipliers, then the signal is modulated on the carrier frequency of the TV channel, or it can be also modulated over many frequencies, so as no matter what channel u change to, it'll stay jammed. Note that you don't need much power as such (50W :p or more), cause the signal jammer is far closer and powerful, and TV signal are really (sometimes) weak, compared to locally transmitted signals.
 

electronic mind

New Member
Agent 009 said:
I don't know exactly how the TV signal is made, but let's say it's a sine/cosine wave, doing the funny horizontal lines. Your friend should be creating such wave, using oscillators, adders, and multipliers, then the signal is modulated on the carrier frequency of the TV channel, or it can be also modulated over many frequencies, so as no matter what channel u change to, it'll stay jammed. Note that you don't need much power as such (50W :p or more), cause the signal jammer is far closer and powerful, and TV signal are really (sometimes) weak, compared to locally transmitted signals.

thats right
cuz the original T.V signal is weak
all u need is a jamming signal power about 1Watt and it will do it
forgot to say that u need a variable signal as an input to the VCO
so the output signal will sweep the band , ofcourse u have to know the Specifications of that VCO (the relation between the input voltage and the output freq.)
by the way if need to jam the UHF channels u have to get the VCO from an old video recrder.
by the way the trianlge wave as an input to the VCO gives u the best results
 

Megamox

New Member
Im not sure how powerful it is, but it works off a 9v battery and is about the size of a pack of cigarrettes, with a little wire aerial. Not sure of the frequencies it uses but he said something about one oscillator 'gating' another to get the pattern :?:
 

1st Mil-tech

New Member
My wife's battery charger for her wheel chair will interfere, it uses a switching power supply. Creates a plethora of noise shown on the screen.
 

Agent 009

New Member
Megamox said:
Im not sure how powerful it is, but it works off a 9v battery and is about the size of a pack of cigarrettes, with a little wire aerial. Not sure of the frequencies it uses but he said something about one oscillator 'gating' another to get the pattern :?:
9V Batteries can pack a punch :p ... And the thing with two oscillators is (probably) for the horizontal/vertical spreads: u need the signal to give both H and V information...
 

Thunderchild

New Member
Actually i always thought that just asending out a signal on the same frequenzy as that received will cause sufficient havoc. ultimatly just a little lower or higher in frequenzy will produce the effect of a fixed picture of interferance. is this logical ? or am i simplifying. i know my suggestion needs tuning but hey we're only trying to jam it not make pictures and sound come out of it !
 

mstechca

New Member
Personally, I can't see me making a transmitter that will screw a TV up that much, and yes, I did managed to produce random dots on my MOM's TV downstairs :shock: My transmitter was 6 feet away, and was only running off a 9V battery.

For those lines to be happening, someone must be transmitting alot of watts nearby, or your TV is screwed up. Try buying a new TV, and if you get the same problem, try a TV in a neighbours home. If the problem isn't as bad there, then something must be jamming the signal in your home.

Check every electrical appliance in your house.
 

Agent 009

New Member
mstechca said:
Personally, I can't see me making a transmitter that will screw a TV up that much, and yes, I did managed to produce random dots on my MOM's TV downstairs :shock: My transmitter was 6 feet away, and was only running off a 9V battery.

For those lines to be happening, someone must be transmitting alot of watts nearby, or your TV is screwed up. Try buying a new TV, and if you get the same problem, try a TV in a neighbours home. If the problem isn't as bad there, then something must be jamming the signal in your home.

Check every electrical appliance in your house.
mstechca, it's just his friend's jammer gadget, he's got no problem with the TV itself... i guess :p ...
 

JimB

Super Moderator
Most Helpful Member
Agent 009 said:
mstechca said:
Personally, I can't see me making a transmitter that will screw a TV up that much, and yes, I did managed to produce random dots on my MOM's TV downstairs :shock: My transmitter was 6 feet away, and was only running off a 9V battery.

For those lines to be happening, someone must be transmitting alot of watts nearby, or your TV is screwed up. Try buying a new TV, and if you get the same problem, try a TV in a neighbours home. If the problem isn't as bad there, then something must be jamming the signal in your home.

Check every electrical appliance in your house.
mstechca, it's just his friend's jammer gadget, he's got no problem with the TV itself... i guess :p ...

Dont worry about it, he is probably smoking his "organic cigarettes" again. :lol:
 

Megamox

New Member
I coupled the output of a 555 to a VHF oscillator made out of a tank circuit and tuned it to one of the terrestrial television frequencies, not as impressive as my mates but u can sort of see the pattern. The TV sound is also replaced with the tone of the 555.

Megamox
 

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panic mode

Well-Known Member
that looks rather poor... you need rf oscillator and modulate it by signal from 555.
my jammer was literally killing TV-s and then melting their antenas :)

no, i'm just kidding, nothing was damaged but the results looked just
like in picture in earlier post of this tread. line form video was accompanied by really loud noise. you cannot imagine anger levels
of people waching soccer world cup :-D
 

audioguru

Well-Known Member
Most Helpful Member
Joel Rainville said:
You made a guy appear on your TV with just a 555 timer!
Use a Cmos 555 timer and maybe a pretty girl will appear! :lol: :lol:
 
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