better than a phone jammer... how about radio???

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neeb
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better than a phone jammer... how about radio???

Post by neeb » Mon May 06, 2002 10:45 am

any ideas on a radio jammer? i figured a triangular ac bias over a varacter used as the tuning cap may work.
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dacflyer
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Re: better than a phone jammer... how about radio???

Post by dacflyer » Fri May 10, 2002 8:00 pm

i am looking for something to use to temporarly stop these idiots at the stop light with their BOOM systems,,,something that whould induce feedback or like a sharp squeel !
Hmmmmm or a cell phone jammer ! whould be handy too,,

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dacflyer
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Re: better than a phone jammer... how about radio???

Post by dacflyer » Fri May 10, 2002 8:05 pm

i am looking for something to use to temporarly stop these idiots at the stop light with their BOOM systems,,,something that whould induce feedback or like a sharp squeel !
Hmmmmm or a cell phone jammer ! whould be handy too,,

Dean Huster
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Re: better than a phone jammer... how about radio???

Post by Dean Huster » Mon May 13, 2002 6:06 am

Kinda hard to stop most of the kids' car systems since they tend to use "bass tapes" for their signal source rather than the radio. Maybe running them through an MRI machine?<p>Dean
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

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JdOwNj
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Re: better than a phone jammer... how about radio???

Post by JdOwNj » Thu May 16, 2002 6:34 pm

could we add something to their sys that would wipe out cop radios to the beat of their music, thus getting the thugs arrested?

bwts
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Re: better than a phone jammer... how about radio???

Post by bwts » Tue Jun 11, 2002 8:16 am

To jam electro magnetic waves simply build a Faraday cage around the area you want to be free of them. I suggest cladding rooms with microwave doors or wrapping yourself up in copper wire :) B
"Nothing is true, all is permitted" - Hassan i Sabbah

JdOwNj
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Re: better than a phone jammer... how about radio???

Post by JdOwNj » Fri Jun 14, 2002 5:50 pm

Thing is to do it at THEIR expense, not yours..

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jollyrgr
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Re: better than a phone jammer... how about radio???

Post by jollyrgr » Fri Jun 14, 2002 7:41 pm

This may get people angry at me but....<p>Most of these THUMPERS use an external amp to drive their subwoofers. This connection is often made with poor or no shielding from the radio/tape deck (HEAD) to the amp. The amp will seldom receive and rectify (demodulate) an RF signal like old amps did; the engineers have corrected this problem. But what they can't protect against is a slightly more devious scheme.<p>Take two four to five watt RF AM transmitters (read 27 MHz CB) and transmit on two SLIGHTLY different frequencies (less than a full channel apart). What does this do? The RF signal from one transmitter won't cause much concern to the amp; the signal is there (on the cable between the radio/tape unit and amplifier) but does not make it past the input filter. When you add a second RF signal close to the same frequency (read 500 Hz to 1 kHz different) interesting things happen. When two signals are mixed you get the sum and difference of the two signals. If you have one transmitter on 27.185 MHz and another on 27.184 MHz when they mix you get both of the RF signals the sum (54.369 MHz) and difference 1 kHz. And the 1 kHz signal IS within the pass band of most amps! <p>Even more interesting is how many of these THUMPER setups are configured. The audio amp runs at full volume; the signal from the "head" is adjusted as it is fed to the amp to control the volume. The amps are also set to turn on whenever the ignition is on. Thus turning down the volume or turning off the head WILL NOT STOP THE SQUEAL! Should one of the CBs have a SLIDER (SSB users know what I mean) you can now adjust the annoying tone up and down at will.<p>Don't get stupid and put a big antenna on your car; this will be seen. You will want to use two walkie talkie type radios with the rubber ducky antennas.
No trees were harmed in the creation of this message. But billions of electrons, photons, and electromagnetic waves were terribly inconvenienced!

Michael Vickers
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Re: better than a phone jammer... how about radio???

Post by Michael Vickers » Sat Jun 15, 2002 7:38 am

Sounds interesting, but will that be strong enough of a signal for the circuitry to pick up the annoying signal?

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Re: better than a phone jammer... how about radio???

Post by bwts » Sun Jun 30, 2002 6:45 am

Just got this link from EPE's web site for phone jamming http://news.bbc.co.uk/hi/english/sci/te ... 067672.stm
B)
"Nothing is true, all is permitted" - Hassan i Sabbah

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