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Generate AM Radio Broadcasts With Your Monitor
tessellation writes: "Tempest for Eliza is a program that uses your computer monitor
to send out AM radio signals. You can then hear computer
generated music in your radio." Here is your big chance to disrupt free thinking radio programs in your neighborhood.
This isn't the first time something like this has appeared on slashdot. Way back in the day ('99) there was an article about a guy who was using the radio interference from his motherboard to do the same sort of thing.
I used to bulls-eye womp-rats in my pants
For many years during the cold war, the NSA had
been nervous about natural radiations emanating/broadcasted by VDTs and electrical wiring. So much so that many government sites were constructed with TEMPEST safeguards with thick concrete walls, wiremesh shielding and isolated electrical works. Even then, VDTs, type writers, phones, and other electrical devices were never placed close to walls adjacent to the outside of the enclosed space.
Read the Van Eck document.
http://www.shmoo.com/tempest/emr.pdf
Read the TEMPEST page
http://www.eskimo.com/~joelm/tempest.html
With a crappy radio, it had to be fairly close 5 feet to make it out... my monitor doesn't put out that much rf... it's a low-rad type.
Now, putting my ham radio at 5 watts about 10 feet away does interesting things to my monitor, I can tell you that!
"Alcohol, Tobacco, Firearms, and Explosives" should be a convenience store, not a government agency.
It was a car racing game... the sound effects made a kind of sense... except they didnt stop when you crashed the car :)
But I've been in one of Ross Andersons lectures where him and Markus demonstrated tempest working against a laptop. Just using LCD won't protect you, see Here (google cache - page seems to be missing) and Here
Good description of van Eck phreaking in Cryptonomicon by Neal Stephenson or in this article (which is quite a large pdf)
Additionally, line printerss played Jingle Bells . . .
hawk
Oh, there are a few ways to increase the output of your monitor by many watts too. These require the case to be taken off and willingness to turn your screwdriver on parts connected to the B+ chassis (about 2000 volts.) Uplugging the computer during this process is optional. Voiding your monitor's warranty and making it a potential fire hazard is your destiny with this procedure.
Brightness is one good way. Want to vaporize some phosphor off the screen? Well, look at that funny transformer with the thick red wire going to the picture tube's top. No, don't put your fingers under that red cap as you'll discharge 30,000 volts. The capacitance stores enough current that it may jump start your heart into transporter mode to a higher (or lower) place in the heavens. Anyways, look back on the transformer where one or two or more small screwdriver adjustments are provided. One should be the focusing voltage for the electron voltage. All this adjustment will do is make your picture tube require prescription glasses when things get fuzzy. The other adjustment dangerously raises the drive voltages of your homebrew particle accelerator into x-ray producing levels. Enjoy.
The other tasty method to injure personal health is to max out horizontal drive voltage. Your adjustment of choice is on the main circuit board that is a minefield of tempting adjustments. The one I am talking about is an adjustable inductor, when tinkered with will lose the monitor's calibration for the horizontal picture width. Its the one adjustable inductor that stands taller than the rest and its frequency is so high, its design require the turns of wire to be a bundle of stranded wire. Yes, remove the powdered ferrite slug out of this coil. Current will now saturate the picture tube's yoke coils. Electronic devices and radios around the house will now bow to your monitor's new elite status.
There you go. Not only have you voided your monitor's warranty, you have just demonstrated why picture tubes are evil particle accelerators. They should be banned.