I've seen in various Negativland shows how easy it is to build a machine to hack into cellphone conversations...does anyone know exactly how one would construct such a device through radioshack parts, old cellphones, etc? (preferably untracable)

By "hacking" in i take it you mean being able to receive the conversation.

If it's an Analoge transmission then this can be done easily with a scanner that covers Cell-phone frequencies. There are plenty of models you can pick up second hand fairly cheap, that will cover this band. They will also receive analoge cordless phones.

However if its digital transmissions you wish to hear, then unfortunately you won't get out of it real cheap. Uniden have 2 digital scanners but there is nothing you can build with limited electronics experience that will do the job.

just out of curiosity what is negativland?

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Originally posted by RED TEQUILA:
just out of curiosity what is negativland?

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Good question...Must be a Boston thing.

Evesdropping on digital cellphones is pretty complex as compared to analog phones where a few scanners are factory ready to be able to perform such a task.

CDMA (code division multiple access) basically binary code.

Cingular, Verizon, etc.

TDMA (time division multiple access) basically packets of data.

AT&T, etc.

Two types of encription that are common here in the united states.

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Originally posted by I Love Poop:
CDMA (code division multiple access) basically binary code.

Cingular, Verizon, etc.

TDMA (time division multiple access) basically packets of data.

AT&T, etc.

Two types of encription that are common here in the united states.

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CDMA uses the full available spectrum. Individual conversations are encoded with a pseudo-random digital sequence
CDMA is a digital spread-spectrum modulation technique, not a form of encryption.

CDMA digitizes the conversation and tags it with a frequency code. The data is then scattered across the frequency band in a pseudorandom pattern.

The receiving device is instructed to read only the data corresponding to a particular code to reconstruct the signal.

Therefore CDMA is not technically encrypted it is just a method for sending and receiving a digital transmission.

TDMA, or Time Division Multiple Access, is a digital alternative to the analog AMPS, or Advanced Mobile Phone System, cellular service.

TDMA works in a method similar to network packet-switching. It allows a cellular operator to divide the signal into short segments, allowing different conversations to "take turns." This allows three times as many people to use the system than amps.

Listening in on a digital phone call will be similar to decoding a digital pager, with the use of something similar to POCSAG, ie a digital scanner with computer interface and software.

what is the modles on thoes uniden digital radio scanners

Click Here to view Unidens 2 digital capable scanners.

The handheld is the BC250D and the base is the BC785D

They are digital capable scanners but require the add on digital card BCI25D to receive digital transmissions.

thanks for that reply they say that it won't pick up cell and cordless i made a post this morning wondering if it could fixed to thanks again the old bodyman

No they wont receive digital cellphones or digital cordless phones. As you can see from my post above the techniques for their transmission is more complex than standard digital.

However it "may" be possible at a later stage via use of software and patch lead or a modified or aftermarket Digital card.

We will just have to wait and see.

bangbangbooty nice breakdown of CDMA and TDMA.