Re: cell phone jammer

.... oh, I think it would, you certainly are not going to concentrate on
making the vco very narrow bandwidth... low Q tank circuit would be
excellent for this case... and of course if the vco's bandwidth is wide
enough--you would not even have to sweep...
.... I was thinking of a "white noise audio generator" as might keep the
phone so confused would not be able to pull out digital signals...

I don't know--never checked at what range of freqs you would have to
cover to catch all phones... but sweep if vco is not wide enough--don't
if it is...

.... however, if you sweep, you would sweep at a very high speed... the
object does not even have to be to completely block the cell
signal--just cause enough havoc to make it unusable...

John

"Jim Yanik" <jyanik@xxxxxxxxxx> wrote in message
news:Xns9672C8580ED7Fjyanikkuanet@xxxxxxxxxxxxxxxxx
> Dave <nospam@xxxxxxxxxxx> wrote in news:42ab3040@xxxxxxxxxxxxx:
>
>> John Smith wrote:
>>> gesus... that would probably take out the am broadcast band on up...
>>> heck, it might even "jam" sensitive audio amps... now that is going
>>> to
>>> cause some real problems...
>>
>> He did use the word "band limited". I was once surprised when a
>> student
>> of mine built a noise diode source using a 300mW zener (but really
>> its
>> an avalanche process) diode. The noise was detectable at 2.2GHz - the
>> limit of the spectrum analyser.
>>
>> The problem with amplifying noise is that you need big amps, since
>> the
>> power/Hz might be small, but if the bandwidth is large, the total
>> power
>> is high.
>>
>>>
>>> ... not to even mention how in-efficient it is and the power you
>>> would
>>> need to generate enough power to block even one small set of
>>> frequencies--you certainly would start going thorough batteries
>>> quickly... might be best to hook it up to 220V mains!
>>>
>>> John
>
>
>>>>Why not just a diode-based,band-limited white noise fed to an amp?
>>>>You would need one for each cellphone band.
>>>>
>>>>--
>>>>Jim Yanik
>>>>jyanik
>>>>at
>>>>kua.net
>>>
>>>
>>>
>>
>>
>
> Cellphone(CP) bandwidth is fairly small.And with the low power levels
> at
> the hand-held CP,a great amount of power is not needed,all you need is
> a
> noise floor high enough to cover the received signal at the CP,-not at
> the
> cell site.Breaking one side of the 2-way link is all you need.
> You need broadband for CP because of the spread-spectrum methods of
> modulation.
> Sweeping a VCO is not going to affect spread-spectrum transmissions.
>
> --
> Jim Yanik
> jyanik
> at
> kua.net


.

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