Looking to block / jam VHF frequencies.

May 29, 2009 27 Replies

Cross-posted to sci.electronics.repair / misc, as I didn't know which one would be most appropriate.



Anyone know of a RF noise generator / jammer, that could operate in VHF frequencies? Preferably in UK / Europe. Ideally a radius of 20-30 metres . Even a circuit for a home-build may do, although I am lazy :)


Looking for free lodging from the government?

We have a few empty jails in the Netherlands :)

It's for a home project... maybe I shoulda mentioned that :)

You know that that sort of thing is illegal just about everywhere, right?

W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^---------------------------------------------------------------

Hmmm... Well, they had a budget cut, so......

What specific frequency do you wish to jam?

99-100Mhz. I know where that lies in the spectrum, but it is a personal project with my hi-fi.

BTW I made an error in the distance... I meant 2-3 metres not 20-30 and that _would_ have consequences.

In other words, someone in your house is listening to an FM station you don't want them to listen to? Buy an FM modulator meant to play your ipod through your car radio or stereo, set it to the desired frequency, and then place it near the antenna of your receiver. Or is it your neighbor that plays a particular station too loud?

LOL, they are other good applications of this project.

The ipod transmitter may only be good for a few metres, which is fine but what if I wanted it to go further or through a few obstacles (walls etc)? That wouldn't really be up to it??

I thought jamming was illegal, at least in the U.S.

The e-mail address in our reply-to line is reversed in an attempt to minimize spam. Our true address is of the form che...@prodigy.net.

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It is, and the FCC has been getting really harsh with the size of penalties on offenders that do it deliberately.

If you are planning to interfere with a signal transmitted by someone else and meant to be received by someone else, the first step of this is to contact your solicitor; have him describe the process of posting bond.

In the USA, the limit for an unlicenced transmitter is 100mW (0.1 Watt) and it is a criminal act to interfere with someone else's transmission and/or reception. The details are likely similar where you are.

If you want to eliminate ALL radiant energy in a location on YOUR property, this is the standard method:

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(Windows / glass doors will pose a particular challenge.)

You may already have some nutters about who can give you pointers:

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If you then want to introduce radio-frequency signals into that area via a cable / transmission line and *exclude* one part of the spectrum:

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Any NON-passive method will soon involve the authorities.

Try an FM wireless microphone. Some atleast should be adjustable into that range.

You'll be prosecuted for operating an unlicensed transmitter.

Does that help ? Now, what's the real problem ? Neighbours ?

Graham

-- due to the hugely increased level of spam please make the obvious adjustment to my email address

Makes no difference.

Graham

-- due to the hugely increased level of spam please make the obvious adjustment to my email address

So, explain what you want to do ! BTW, distance is related to receiver sensitivity, NOT transmitter output.

Graham

-- due to the hugely increased level of spam please make the obvious adjustment to my email address

You can buy a low power tunable fm transmitter that runs on a 9 volt battery that will block anything from 88 to 108 as long as the source isn't next door.

That's more like it.

It's illegal everywhere, except maybe in Africa or Russia.

W . | ,. w , "Some people are alive only because \|/ \|/ it is illegal to kill them." Perna condita delenda est ---^----^---------------------------------------------------------------

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