Wavebubble working....kinda

The operation of transmitters designed to jam or block wireless communications is a violation of the Communications Act of 1934, as amended ("Act"). See 47 U.S.C. Sections 301, 302a, 333. The Act prohibits any person from willfully or maliciously interfering with the radio communications of any station licensed or authorized under the Act or operated by the U.S. government. 47 U.S.C. Section 333. The manufacture, importation, sale or offer for sale, including advertising, of devices designed to block or jam wireless transmissions is prohibited. 47 U.S.C. Section 302a(b). Parties in violation of these provisions may be subject to the penalties set out in 47 U.S.C. Sections 501-510. Fines for a first offense can range as high as $11,000 for each violation or imprisonment for up to one year, and the device used may also be seized and forfeited to the U.S. government.

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san26141
 
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Joined: Mon Mar 09, 2009 9:36 am

Wavebubble working....kinda

Post by san26141 »

I have been testing my device with multiple cell phones on different carriers and I don't understand what is happening.

1) I can "jam" an iphone both before and during a call.
2) Other carriers I can "jam" while not on a call. If the other cell is already on a call I have difficulty blocking it (roughly 50/50). I have tried both near and far from a cell tower and it behaves the same. I am roughly judging signal strength between the phones by the amount of bars visible in each one. (Which by no means is accurate.)

Any ideas on why a call in progress is more difficult to "disrupt"?

sciguy14
 
Posts: 17
Joined: Fri Jun 12, 2009 3:19 pm

Re: Wavebubble working....kinda

Post by sciguy14 »

I'm having similar problems. I've built 4 wavebubbles, and on all them, GSM phones (like the iphone) jam perfectly, but CDMA phones hardly jam at all...

nux
 
Posts: 23
Joined: Sun Mar 22, 2009 11:48 pm

Re: Wavebubble working....kinda

Post by nux »

sciguy14 wrote:I'm having similar problems. I've built 4 wavebubbles, and on all them, GSM phones (like the iphone) jam perfectly, but CDMA phones hardly jam at all...
Check the frequency that your CDMA operates on, it may be different from the GSM frequencies you are trying to jam. Also, it may not be suited to the antennas that you are using.
Also, CDMA will be harder to jam, it can work at lower SNR's and is more resistant to noise.

cmolson
 
Posts: 47
Joined: Sun Oct 28, 2007 8:22 am

Re: Wavebubble working....kinda

Post by cmolson »

I have been able to jam any CDMA phone (yes very close range). When I say any, I mean I tried 3-4 phones at close range (standing next to the person)

One thing to check as mentioned above is the program you put into the wavebubble, ensure it is set to the correct frequencies.

Also another note,

The wider the frequency you are trying to jam the less range you will have. It takes time to sweep through more frequencies so try only programming in the very specific range you want to jam.

andyman
 
Posts: 14
Joined: Wed May 21, 2008 1:41 am

Re: Wavebubble working....kinda

Post by andyman »

I just completed one of these babies and I am quickly learning that the amp chips can't tolerate much heat from the soldering iron. Fortunetly I have a spectrum analyzer (FSH6 from R&S) and I can see that one amp puts out very little amplitude (maybe 10dBm).. I replaced the amp with a new one soldered the sucker quickly to prevent damage and my signal went up dramatically (30dBm) on the low freq side.

So just because it works doesn't mean it "works".. You should get it tested somehow.


andy

cmolson
 
Posts: 47
Joined: Sun Oct 28, 2007 8:22 am

Re: Wavebubble working....kinda

Post by cmolson »

andyman wrote:I just completed one of these babies and I am quickly learning that the amp chips can't tolerate much heat from the soldering iron. Fortunetly I have a spectrum analyzer (FSH6 from R&S) and I can see that one amp puts out very little amplitude (maybe 10dBm).. I replaced the amp with a new one soldered the sucker quickly to prevent damage and my signal went up dramatically (30dBm) on the low freq side.

So just because it works doesn't mean it "works".. You should get it tested somehow.


andy


Good point, I haven't really tested mine yet for actual power output. I am familiar enough with electronics to debug the digital side (micro-controller, even power supplies) but RF is a little out of my league. Is there any way to test the output using only an oscilloscope?

When you say soldered "quickly" how much time are we talking, I tacked one pin on, then waited for everything to cool down and soldered the other two pads the same way. I put a bit of solder on the first pad, then heat it up, then move the component onto the heated pad, as soon as I see it has a good connection (shiny) i remove the heat.

sciguy14
 
Posts: 17
Joined: Fri Jun 12, 2009 3:19 pm

Re: Wavebubble working....kinda

Post by sciguy14 »

You can test it with an oscilloscope only if it is super fast. We used a 20GHZ oscilloscope hooked up directly to the SMA connections to get an idea of the amplitude.

cmolson
 
Posts: 47
Joined: Sun Oct 28, 2007 8:22 am

Re: Wavebubble working....kinda

Post by cmolson »

My oscilloscope is 2ghz digital agilent. I know to sample a ~2ghz sine wave you need to get 2.5* the frequency If I remember correctly (nyquest?).

Anyways, the scope has a feature which given a repeated wave, will keep sampling, so it is possible to find the maximum amplitude I believe. (It won't be able to find weird glitches or anything, but it kind of acquires samples over more time.

I will try this later once I get it all hooked up again, thanks for the idea.

Once I get the amplitude, how do I find out the power? (I will be googling this as well )

Thanks!

sciguy14
 
Posts: 17
Joined: Fri Jun 12, 2009 3:19 pm

Re: Wavebubble working....kinda

Post by sciguy14 »

The amplitude is pretty much equivalent to the strength of the output.

cmolson
 
Posts: 47
Joined: Sun Oct 28, 2007 8:22 am

Re: Wavebubble working....kinda

Post by cmolson »

What kind of amplitude are you getting (in V?)

Thanks,

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