[cell phone jammer design, very low power]

classic Classic list List threaded Threaded
9 messages Options
Reply | Threaded
Open this post in threaded view
|

[cell phone jammer design, very low power]

Art-35
Hi all,

I have a consumer device with a built in spy mode via cellular. From the
device, I know it uses 4G and that the signal strength of the cell
signal is not strong (only one bar on the signal strength ICON). I need
to stop this device from communicating (selectively, as needed). The
antenna is in a corner of the device, so literally I only need a 1 inch
range!

I've found and studied existing 'jammers', they work by jamming the
entire cell phone band and have ranges up to 30 feet, or longer. So,
they need to be relatively high power transmitters, typically 1 watt or
higher. They use a VCO with the control voltage being random noise in
order to make the vco sweep across the entire band. I don't need to jam
the entire band, I only need to transmit on the individual frequency
where the cell transmitter sends it control signals. I am aware that the
actual comm frequency can be changed, but I believe the control signal
is a fixed frequency.

I don't need to jam the receive cell band as my device is in a fixed
location, so it always uses the same cell tower. And, the received
signal strength is fairly weak. I only need to jam a single frequency as
there will be no hand off's to other cell nodes or other cell phone
providers-

I cannot open the consumer devices case tio access the cell phone
transceiver directly.

My problem is I can't find a technical description of the 4G protocol
and the receive band for 4G is 75 MHz wide, so I can't scan it easily.
Searches  on the internet are becoming nearly useless for tech topics
and all my searches end up pointing to cell phone providers and agents
trying to sell me a phone-it's useless for my purposes. Can anyone here
suggest a technical website that explains now 4G works, or perhaps a
forum that has technical members rather than sales people??

Please note, I am not trying to design a unit with high power or to wipe
out the entire 4G band at long ranges!!!!

TIA

Art




--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
Reply | Threaded
Open this post in threaded view
|

Re: [cell phone jammer design, very low power]

Denny Esterline-2
Faraday cage?


On Fri, Jul 24, 2020 at 1:05 PM Art <[hidden email]> wrote:

> Hi all,
>
> I have a consumer device with a built in spy mode via cellular. From the
> device, I know it uses 4G and that the signal strength of the cell
> signal is not strong (only one bar on the signal strength ICON). I need
> to stop this device from communicating (selectively, as needed). The
> antenna is in a corner of the device, so literally I only need a 1 inch
> range!
>
> I've found and studied existing 'jammers', they work by jamming the
> entire cell phone band and have ranges up to 30 feet, or longer. So,
> they need to be relatively high power transmitters, typically 1 watt or
> higher. They use a VCO with the control voltage being random noise in
> order to make the vco sweep across the entire band. I don't need to jam
> the entire band, I only need to transmit on the individual frequency
> where the cell transmitter sends it control signals. I am aware that the
> actual comm frequency can be changed, but I believe the control signal
> is a fixed frequency.
>
> I don't need to jam the receive cell band as my device is in a fixed
> location, so it always uses the same cell tower. And, the received
> signal strength is fairly weak. I only need to jam a single frequency as
> there will be no hand off's to other cell nodes or other cell phone
> providers-
>
> I cannot open the consumer devices case tio access the cell phone
> transceiver directly.
>
> My problem is I can't find a technical description of the 4G protocol
> and the receive band for 4G is 75 MHz wide, so I can't scan it easily.
> Searches  on the internet are becoming nearly useless for tech topics
> and all my searches end up pointing to cell phone providers and agents
> trying to sell me a phone-it's useless for my purposes. Can anyone here
> suggest a technical website that explains now 4G works, or perhaps a
> forum that has technical members rather than sales people??
>
> Please note, I am not trying to design a unit with high power or to wipe
> out the entire 4G band at long ranges!!!!
>
> TIA
>
> Art
>
>
>
>
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
Reply | Threaded
Open this post in threaded view
|

Re: [cell phone jammer design, very low power]

Clint Jay
In reply to this post by Art-35
Unfortunately you will need to jam the entire band as these things are
frequency agile and change channels when they can't link, find another
solution.

On Fri, 24 Jul 2020 at 21:05, Art <[hidden email]> wrote:

> Hi all,
>
> I have a consumer device with a built in spy mode via cellular. From the
> device, I know it uses 4G and that the signal strength of the cell
> signal is not strong (only one bar on the signal strength ICON). I need
> to stop this device from communicating (selectively, as needed). The
> antenna is in a corner of the device, so literally I only need a 1 inch
> range!
>
> I've found and studied existing 'jammers', they work by jamming the
> entire cell phone band and have ranges up to 30 feet, or longer. So,
> they need to be relatively high power transmitters, typically 1 watt or
> higher. They use a VCO with the control voltage being random noise in
> order to make the vco sweep across the entire band. I don't need to jam
> the entire band, I only need to transmit on the individual frequency
> where the cell transmitter sends it control signals. I am aware that the
> actual comm frequency can be changed, but I believe the control signal
> is a fixed frequency.
>
> I don't need to jam the receive cell band as my device is in a fixed
> location, so it always uses the same cell tower. And, the received
> signal strength is fairly weak. I only need to jam a single frequency as
> there will be no hand off's to other cell nodes or other cell phone
> providers-
>
> I cannot open the consumer devices case tio access the cell phone
> transceiver directly.
>
> My problem is I can't find a technical description of the 4G protocol
> and the receive band for 4G is 75 MHz wide, so I can't scan it easily.
> Searches  on the internet are becoming nearly useless for tech topics
> and all my searches end up pointing to cell phone providers and agents
> trying to sell me a phone-it's useless for my purposes. Can anyone here
> suggest a technical website that explains now 4G works, or perhaps a
> forum that has technical members rather than sales people??
>
> Please note, I am not trying to design a unit with high power or to wipe
> out the entire 4G band at long ranges!!!!
>
> TIA
>
> Art
>
>
>
>
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>


--
Clint. M0UAW IO83

*No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.*
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
Reply | Threaded
Open this post in threaded view
|

Re: [cell phone jammer design, very low power]

Bob Blick-5
In reply to this post by Art-35
Art, please review the use of topic tags, as yours is incorrectly formed and can result in delay of future messages from you:

http://mailman.mit.edu/mailman/listinfo/piclist

Thanks, Bob
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
Reply | Threaded
Open this post in threaded view
|

Re: [cell phone jammer design, very low power]

David VanHorn-2
Of course this is extremely illegal, and can result in huge fines.
https://www.fcc.gov/general/jammer-enforcement

On Fri, Jul 24, 2020 at 2:49 PM Bob Blick <[hidden email]> wrote:

> Art, please review the use of topic tags, as yours is incorrectly formed
> and can result in delay of future messages from you:
>
> http://mailman.mit.edu/mailman/listinfo/piclist
>
> Thanks, Bob
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
Reply | Threaded
Open this post in threaded view
|

Re: [cell phone jammer design, very low power]

RussellMc
In reply to this post by Art-35
On Sat, 25 Jul 2020 at 08:05, Art <[hidden email]> wrote:

> I have a consumer device with a built in spy mode via cellular. From the
> device, I know it uses 4G and that the signal strength of the cell
> signal is not strong (only one bar on the signal strength ICON). I need
> to stop this device from communicating (selectively, as needed). The
> antenna is in a corner of the device, so literally I only need a 1 inch
> range!


A selective trap at the frequency of interest may work.

If complete RF isolation is acceptable then a "cage".



           Russell


>
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
Reply | Threaded
Open this post in threaded view
|

Re: [cell phone jammer design, very low power]

madscientistatlarge
In reply to this post by David VanHorn-2
Also highly unethical, and it could (and frankly should) get you extended free room and bored.  What if someone needs to call the emergency number while your' pulling this?  Suppose someone DIES because you were futzing around.  If you can't turn it on and off manually, you obviously plan to hide it near the VICTIM.  Really, really sounds like you are planing a serious crime.  At best it's creepy AF.  If you knew anything about electronics you could build your' own that didn't need a cell phone as transmitter.  Are you 5 or do you just have a 5 YR old mentality?


Sent with ProtonMail Secure Email.

‐‐‐‐‐‐‐ Original Message ‐‐‐‐‐‐‐
On Friday, July 24, 2020 2:52 PM, David VanHorn <[hidden email]> wrote:

> Of course this is extremely illegal, and can result in huge fines.
> https://www.fcc.gov/general/jammer-enforcement
>
> On Fri, Jul 24, 2020 at 2:49 PM Bob Blick [hidden email] wrote:
>
> > Art, please review the use of topic tags, as yours is incorrectly formed
> > and can result in delay of future messages from you:
> > http://mailman.mit.edu/mailman/listinfo/piclist
> >
> > Thanks, Bob
> >
> > ------------
> >
> > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
>
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist



--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
Reply | Threaded
Open this post in threaded view
|

Re: [cell phone jammer design, very low power]

Forrest Christian (List Account)
In reply to this post by Art-35
As mentioned by other's building/using a cell phone jammer is illegal in
the US and worse, it's something the FCC has little tolerance for, and
cellular companies (who paid millions and millions of dollars for the use
of the spectrum) have resources to hunt down any such device and turn you
into the FCC.   This is not recommended at all.

The other piece of this is that there are many bands and frequencies used
by cellular companies, and a device typically searches all of them 700Mhz,
850Mhz, 1700 Mhz, 1900Mhz, etc. etc. etc...  So there isn't just one
frequency to jam.

The best option for you is to block the signal using a faraday cage or
something similar as opposed to jamming it.

On Fri, Jul 24, 2020 at 2:12 PM Art <[hidden email]> wrote:

> Hi all,
>
> I have a consumer device with a built in spy mode via cellular. From the
> device, I know it uses 4G and that the signal strength of the cell
> signal is not strong (only one bar on the signal strength ICON). I need
> to stop this device from communicating (selectively, as needed). The
> antenna is in a corner of the device, so literally I only need a 1 inch
> range!
>
> I've found and studied existing 'jammers', they work by jamming the
> entire cell phone band and have ranges up to 30 feet, or longer. So,
> they need to be relatively high power transmitters, typically 1 watt or
> higher. They use a VCO with the control voltage being random noise in
> order to make the vco sweep across the entire band. I don't need to jam
> the entire band, I only need to transmit on the individual frequency
> where the cell transmitter sends it control signals. I am aware that the
> actual comm frequency can be changed, but I believe the control signal
> is a fixed frequency.
>
> I don't need to jam the receive cell band as my device is in a fixed
> location, so it always uses the same cell tower. And, the received
> signal strength is fairly weak. I only need to jam a single frequency as
> there will be no hand off's to other cell nodes or other cell phone
> providers-
>
> I cannot open the consumer devices case tio access the cell phone
> transceiver directly.
>
> My problem is I can't find a technical description of the 4G protocol
> and the receive band for 4G is 75 MHz wide, so I can't scan it easily.
> Searches  on the internet are becoming nearly useless for tech topics
> and all my searches end up pointing to cell phone providers and agents
> trying to sell me a phone-it's useless for my purposes. Can anyone here
> suggest a technical website that explains now 4G works, or perhaps a
> forum that has technical members rather than sales people??
>
> Please note, I am not trying to design a unit with high power or to wipe
> out the entire 4G band at long ranges!!!!
>
> TIA
>
> Art
>
>
>
>
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>


--
- Forrest
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
Reply | Threaded
Open this post in threaded view
|

Re: [cell phone jammer design, very low power]

Richard Prosser
Can you modify it to disconnect the antenna? Or add an external antenna
that can be switched?
RP

On Sat, 25 Jul 2020 at 17:41, Forrest Christian (List Account) <
[hidden email]> wrote:

> As mentioned by other's building/using a cell phone jammer is illegal in
> the US and worse, it's something the FCC has little tolerance for, and
> cellular companies (who paid millions and millions of dollars for the use
> of the spectrum) have resources to hunt down any such device and turn you
> into the FCC.   This is not recommended at all.
>
> The other piece of this is that there are many bands and frequencies used
> by cellular companies, and a device typically searches all of them 700Mhz,
> 850Mhz, 1700 Mhz, 1900Mhz, etc. etc. etc...  So there isn't just one
> frequency to jam.
>
> The best option for you is to block the signal using a faraday cage or
> something similar as opposed to jamming it.
>
> On Fri, Jul 24, 2020 at 2:12 PM Art <[hidden email]> wrote:
>
> > Hi all,
> >
> > I have a consumer device with a built in spy mode via cellular. From the
> > device, I know it uses 4G and that the signal strength of the cell
> > signal is not strong (only one bar on the signal strength ICON). I need
> > to stop this device from communicating (selectively, as needed). The
> > antenna is in a corner of the device, so literally I only need a 1 inch
> > range!
> >
> > I've found and studied existing 'jammers', they work by jamming the
> > entire cell phone band and have ranges up to 30 feet, or longer. So,
> > they need to be relatively high power transmitters, typically 1 watt or
> > higher. They use a VCO with the control voltage being random noise in
> > order to make the vco sweep across the entire band. I don't need to jam
> > the entire band, I only need to transmit on the individual frequency
> > where the cell transmitter sends it control signals. I am aware that the
> > actual comm frequency can be changed, but I believe the control signal
> > is a fixed frequency.
> >
> > I don't need to jam the receive cell band as my device is in a fixed
> > location, so it always uses the same cell tower. And, the received
> > signal strength is fairly weak. I only need to jam a single frequency as
> > there will be no hand off's to other cell nodes or other cell phone
> > providers-
> >
> > I cannot open the consumer devices case tio access the cell phone
> > transceiver directly.
> >
> > My problem is I can't find a technical description of the 4G protocol
> > and the receive band for 4G is 75 MHz wide, so I can't scan it easily.
> > Searches  on the internet are becoming nearly useless for tech topics
> > and all my searches end up pointing to cell phone providers and agents
> > trying to sell me a phone-it's useless for my purposes. Can anyone here
> > suggest a technical website that explains now 4G works, or perhaps a
> > forum that has technical members rather than sales people??
> >
> > Please note, I am not trying to design a unit with high power or to wipe
> > out the entire 4G band at long ranges!!!!
> >
> > TIA
> >
> > Art
> >
> >
> >
> >
> > --
> > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
> >
>
>
> --
> - Forrest
> --
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
--
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist