How easy is it for some radio hack to modify a receiver to capture cell phone wavelengths?
Are a lot of people listening to my conversations (besides Ashcroft?)
Could I do it easily?
You don’t need to modify anything, just go buy a radio scanner. A few years ago my friends and I used to listen to cellphone and cordless phone conversations all the time. Pretty interesting stuff sometimes.
Modern cellphones all use digital signals which are encrypted, so your average dude with a radio scanner cannot decode them. Cordless phones still use unencrypted analog signals, as far as I know.
Of course such activity is illegal, so we won’t do that, will we?
Yeah - having a scanner is not itself illegal, but wiretapping (which this activity counts as) is illegal.
So don’t do that.
Only illegal in some countries.
Notably, the country hosting this website. So we won’t be advocating that or offering any how-to’s here.
As it happens, it is mostly not correct anyway. Cellphone calls are mostly digital now, and a simple scanner won’t pick up the conversation, just a bunch of encrypted data that then has to be deciphered.
I believe that most State-sanctioned wiretapping of cellphones now happens at the switch.
Are there then computer programs that will decypher cellphone calls?
If they’re digital, then it sound more like my conversations are secure (except, again, for Ashcroft).
Not really. The problem with monitoring digital conversations is twofold. First, the encryption key can be changed on a rotating basis so that both phone and cell site change to the same key at the same time. This isn’t hugely secure, but it will defeat casual monitoring. The second problem is harder, in that many digital systems (including many cordless phones) is what is termed “spread spectrum” Spread spectrum rotates the frequency the signal is being carried on rapidly, in a random pattern, making it next to impossible to monitor. Even analog systems can use spread spectrum.
there was a terrifically entertaining website a couple years back that broadcast signals from vancouver 24/7.
digital technology makes it harder for the average punk to eavesdrop, whilst also making it infinitely easier for big brother.
nothing is secure.
Don’t even need anything fancy (or at least you didn’t used to). I used to listen to phone conversations by turning an old TV to the top end UHF channels, the channels that got taken away from UHF sometime between the '80s and the '90s. I’d only hear one side of the conversation, and typically only a few seconds at a time (they’re be a “squeak” in the signal and then it would go to static, switching to another cell I guess). Haven’t tried it in years though…
I don’t know about cell phones because I don’t know what frequencies they’re on, but (in the U.S.) it is illegal to sell scanners that can pick up anything in the 900-1400 mHz range because that range is used for cordless phones. You can buy mod chips for most name brands of scanners but to use them is, of course, illegal.
My old Bearcat scanner which I use to eavesdrop on the Po-lice and anybody else chatting away over the radio can occasionally pick up really old cordless phones which operated on 700 or 800 mHz but despite the fact that it claims to be a 900 mHz scanner, it doesn’t go that high.
Also, many analog phones are spread-spectrum meaning that they only stay on any one frequency for a very, very short period of time and so you only pick up a second or less of whatever they’re saying.
Anyone more interested in this should check out an entertaining book called I Listen: A Document of Digital Voyeurism which was ‘written’ by a musician/performance artist who goes by the name Spacewurm. It’s a collection of transcriptions of phone conversations he illegally tapped into.
nitpick: That’s MHz, not mHz. Lower case m is milli (1/1000), upper case M is Mega (1000).
I used to have a scanner that could pick up this range, as well as the 800 MHz band for analog cell phones. It was perfectly legal back then. I tried listening to cell phone conversations and was amazed at how boring it was. I can’t imagine why anyone would do it. Even if you had a decoder, it would take a lot of people (or extremely sophisticated voice recognition systems) to sift through those transmissions for information.