Waves Converter

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Ron H
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Re: Waves Converter

Power is measured in dB. Frequency is measured in Hz. They are totally independent. You can't convert one to the other.<p>I'm curious who it is you want to jam. If you own a restaurant or a theater or something similar, I'll be sympathetic. Otherwise... if I knew that you were jamming phones in my neighborhood, I'll guarantee you would be getting a visit from your not-so-friendly FCC investigators.<p>Ron

Michael-love-electronics
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Re: Waves Converter

Thanks for explaining but,... I still want to know what is meant by "low power RF of +20dB".???
I want to make a transmitter circuit that transmit +20dB so what frequency can this transmitter transmit.<p>Hope to find the answer despite of anything.<p>Thanks again

greg123
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Re: Waves Converter

The transmitter can technically transmit any frequency you want. The 20 dBm, as already stated, is the amount of power referenced to 1 milliWatt (0.001 W) That is the amount of power...the Decibal Scale is the log of a ratio...<p>To deviate for a second;<p>Power in dB==<p>dB=10log(P/Pref)
to 1 milliWatt
dBm=10log(100 mW/1 mW)
=10log(100)
=20 dBm<p>So no way to convert to Frequency.......<p>Yes...Since 100 mW = 0.1 W That is low power at what ever RF you need.<p>[ December 06, 2002: Message edited by: Greg ]</p>

jollyrgr
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Re: Waves Converter

2) It is known that if a phone is transmitting on frequency X it will be receiving on frequency Y.
3) It is known that the difference between X and Y is 100 MHz in our example. Thus you get: Y = X + 100 MHz.
4) It is also know that if the phone can't here the tower, the call gets dropped. <p>To put it simple, we need to listen for the cell phone to transmit a signal. We then add the "split" frequency to the received signal and transmit this so that the cell phone receives the BOGUS transmitted signal instead of the cell tower signal. Call is dropped. If all of this takes place on the "home" channel, the phone never gets identified by the phone network, thus no calls.<p>
Thus the "jammer" is simply a device that takes in a received signal from the phone, adds the split frequency to the signal, boosts the new signal, and sends it out as a new signal. In theory this is quite simple. This TYPE of circuit is in just about ALL radio frequency receivers (except things like crystal radios, regen receivers, etc.). It is a VERY common circuit called a MIXER/OSCILLATOR.<p>
From what you are posting tells me this. You have found a "black box" that you want to duplicate to jam phones. Based on the specs you posted, I can assume this much: The box RECEIVES a signal at a frequency "X" that is generated by the cell phone. It converts this frequency by the standard cell split, then AMPLIFIES the new signal by +20 dB. It then transmits this new signal so that the cell phone receives the BOGUS signal instead of the intended signal. Thus a dropped call.<p>
Building a jammer at the frequencies used by cell phones is a challenging task. While you MAY be able to get away with making or buying one of these, I would not want to get caught with one. Should a cell tech be troubleshooting a "dead spot" caused by one of these, it is quite easy to track down. (Shows up very readily on a spectrum analyzer.) I'll assume that you are in the US. If caught here this device COULD be considered a TERRORIST device (disrupting cellular infrastructure). In any case it is ILLEGAL to jam cell phones in most developed countries with the only exception I know of being Japan. Canada thought about legalizing these in places like theaters, concert halls, or other places where cell phones are a problem. Can jammers be located? Yes. It is quite easy to find these. Even without a spectrum analyzer if you used a cell receiver and determined that you were receiving a signal OTHER than the correct one from the tower, out would come the Direction Finding (DF) gear. If located you may only have the jammer confiscated. On the other hand you may be fined, jailed, or both. <p>To qoute a well known President, "I feel your pain". If you have this problem in a theater, simply find the manager and have them take care of the problem. I have personally done this. During the first showing of "Attack of The Clones" some idiot left his phone on. He then took a call DURING THE MOVIE! He did not leave the theater, he stayed in his seat! I went to the manager. Even though it was a young high school kid, he knew what to do. The jerk was still on the phone when the manager and I came back! The manager told him to leave, he was throwing him out. The guy first refused. The kid then told him if he did not leave, the police would be called. The PHONE JERK left to cheers of the entire theater!<p>[ December 06, 2002: Message edited by: Jolly Roger ]</p>
No trees were harmed in the creation of this message. But billions of electrons, photons, and electromagnetic waves were terribly inconvenienced!

Michael-love-electronics
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Re: Waves Converter

Thanks very much for this detailed explanation,.. I really appreciate that.
It seems now from what Jolly Roger has said that the frequency received by the cell phone must be first changed by the jammer by adding the split frequency & resend it back to the cell phone.OK
sorry for the following silly Question:
How can I make a transmitter circuit that emitts 20dB or any power I specify.?<p>Thank you all very very much........ <p>[ December 07, 2002: Message edited by: Michael Wahid ]<p>[ December 09, 2002: Message edited by: Michael Wahid ]</p>

Bernius1
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Re: Waves Converter

try A)reading necessary books, taking courses,
and building prototypes, or,
B) http://www.fcc.gov
also look in dictionary under "malicious intent"
Can't we end all posts with a comical quip?

Michael-love-electronics
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Re: Waves Converter

Thanks no_vice for that information,.. You have said what I want to hear,....SO
From where can I get these books, courses & prototypes.???????
please send me links <p>[ December 10, 2002: Message edited by: Michael Wahid ]</p>

greg123
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Re: Waves Converter

Try searches on amazon.com. Better yet, but a copy of nuts and volts mag. and look in their selection of books. They have some RF stuff there.

Michael-love-electronics
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Re: Waves Converter

Thanks for this help but some more deatils will be appreciated.

haklesup
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Re: Waves Converter

Chris Smith
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Re: Waves Converter

Wiping out others is easy, you go dirty, and use the blanket effect. No math, no school needed. <p>I use pulsed laser drivers into semi balanced antennas instead of the diode. <p>A little experimenting and tank like circuits, a terminating resistor, and presto, the FCC is on your door step in hours! <p>Also No body in the neighborhood gets to watch TV, listen to radio, etc., even if they use cable? <p>Guaranteed.

Michael-love-electronics
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Re: Waves Converter

Thanks for this advice but I'll make this jammer for churches to avoid disturbance happened by these cell phones.
So any help will be appreciated.

Michael-love-electronics
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Re: Waves Converter

Hi,...
Any ideas for how can I make a circuit that makes an interferance between to signals one of them is received and the other is generated from this circuit.?
the reeceived signal can be(RF or MW)......?
Tnanks and
HAPPY NEW YEAR

haklesup
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Re: Waves Converter

Michael<p>I didn't mean to be so pessimistic in my last post but I do still favor a low-tech solution here. A roll of "No cell phone" stickers (like the no smoking symbol) strategically stuck in visible places, a few "please turn off cell phone" signs by the door, a verbal reminder during the announcements part of the service and a one time printed hand out explaining the policy and reasons should eventually work. Once everyone understands that it is impolite to leave your phone on in church, you will have voluntary compliance and there will be no risk of legal liability for your church if your "project" should malfunction and blank out the whole neighborhood.<p>Be aware that you may also be jamming essential phone calls to doctors, law enforcement and volunteer firemen which could endanger the lives of others unintentionally. This is why I advocate the voluntary compliance (low-tech) solution. (plus it's illegal)<p>If you really want to know what is involved in the design process, take a look at the Dec02 (#149) issue of Circuit Cellar (may still be in stores) at the "Vector-SOC" project. While this is different, it does have a RF generator, a receiver section and lots of digital signal processing. The article will give you a very good idea of the complete design process you will need to go through. You can also find a PDF on the www.cypress.com website in the application notes section under PSoC since this was a contest winner.<p>I looked around a little and so far have not seen anything very specific to your request yet. Nor have I seen anything describing the theory behind cell phone jamming yet. I suspect that since this is a marketable product, IP owners are still keeping it to themselves.<p>
You can find lots of good background in the app notes for RF Mini-Circuits www.minicircuits.com/application.html
Don't miss the dBm - Volts - Watts converter table. . I also like Maxim-IC www.maxim-ic.com/appnotes10.cfm/ac_pk/38 they have a bunch of cell phone specific app notes at this URL. Try emailing their apps engineer directly for suggestions<p>Explore the legalities of jamming here.
http://www.wirelessnewsfactor.com/perl/story/8116.html
http://www.wirelessnewsfactor.com/perl/story/9856.html
http://www.osopinion.com/perl/story/18479.html (passive blocking)
http://www.longdistanceconnection.com/art2.htm <p>From one article --- A spokeswoman for the FCC reiterated the law — “jamming cellular transmissions are not permitted” in the United States — and said, “I’m not aware of any exceptions to the rules.”<p>What country are you in? The laws vary. But it is illegal in most countries and restricted where it is allowed. Evidently you can sell and own it but you can’t use it. Look in “spy Shop” or “counter- Espionage” stores to buy the equipment. This URL has a small jammer with a 10m range for \$390 and a larger one for \$560. http://www.microelec.com/misc.htm <p>Happy new year
Chris

Michael-love-electronics
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Re: Waves Converter

Hi,...<p>As I said before, This jammer will be used in churches only to avoid disturbance happened by these cells phones, also a note will be written says:"All cell phones will not work in church".
So everyone will enter the church will know that his cell phone won't work.<p>That's why I think that's important.
THANKS

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