Modern day phone signal reciever How to do it?

  • #1

Main Question or Discussion Point

I have included a picture of what I would like to be able to make. I know that older phones operate on very specific MHz signals and that the newer ones are 2.4, or 5.8 GHz.
I know there are scanners out there. But the purchase of one could be illegal, right?

So why not make my own, to pick up the signal at my house.

I can see where I would have to find the freq. of my phones here at home.

The phones at my home are wireless, so I would think the voice signals are being sent through the base station out to the other landlines.

Cell phones I imagine would be a more difficult target, I have seen where the freq. Number goes into the ten thousandths place, probably very hard to pinpoint.

With the vast possibilities it would seem that this may be harder than I think, yes?
 

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  • #2
davenn
Science Advisor
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once upon time you could use a scanner to pick up the old 30 to 40 MHz signals between a cordless phone and its basestation.
These days with the use of the higher frequencies 900MHz, 2.4GHz and 5.8GHz it is more common to use digital and or spreadspectrum techniques between the handset and the base station This makes it somewhere between extremely difficult and impossible to be able to decode and recover any audio from the system. Could probably be done with reasonably sofisticated monitoring equip that some govt agencies have access to.

cheers
Dave
 
  • #3
once upon time you could use a scanner to pick up the old 30 to 40 MHz signals between a cordless phone and its basestation.
These days with the use of the higher frequencies 900MHz, 2.4GHz and 5.8GHz it is more common to use digital and or spreadspectrum techniques between the handset and the base station This makes it somewhere between extremely difficult and impossible to be able to decode and recover any audio from the system. Could probably be done with reasonably sofisticated monitoring equip that some govt agencies have access to.

cheers
Dave
It couldn't be that difficult! Electronics are just pieces of metal and plastic!. Those waves could be picked up by something! The phones themselves can! So the electronics on the phones would be the first thing to look at, right?
 
  • #4
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From FCC Rules and Regulations

§ 15.9 Prohibition against eavesdropping.

Except for the operations of law enforcement officers conducted under lawful authority, no person shall use, either directly or indirectly, a device operated pursuant to the provisions of this part for the purpose of overhearing or recording the private conversations of others unless such use is authorized by all of the parties engaging in the conversation.
 
  • #5
f95toli
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It couldn't be that difficult! Electronics are just pieces of metal and plastic!. Those waves could be picked up by something! The phones themselves can! So the electronics on the phones would be the first thing to look at, right?
And how would you "look" at the electronics in a phone?
The days were sophisticated electronics use elementary components such as resistors and transistors are long gone, modern electronics uses ASICs with millions and sometimes billions of components connected together and packad into single chips.
Of course you can get equipment that could do what you want, but you would need to spend hundreds of thousands of dollars (even something a simple as a spectrum analyzer for these frequencies will cost more than $50 000)
 
  • #6
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1
From FCC Rules and Regulations

§ 15.9 Prohibition against eavesdropping.

Except for the operations of law enforcement officers conducted under lawful authority, no person shall use, either directly or indirectly, a device operated pursuant to the provisions of this part for the purpose of overhearing or recording the private conversations of others unless such use is authorized by all of the parties engaging in the conversation.
This probably needs to be re-posted.
 
  • #7
berkeman
Mentor
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Thread closed for illegal activity discussion. Flyingwing12 -- check your PMs.
 

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