How to build your own telephone bug
A Hacker's Information Report Article by Axon
Now, of course, this article is going to display the principle of radio
transmission, as well as showing how to use an alternative power source;
therefore this article is completely educational. You'll even get to
practice soldering! Wheee! (By the way, listening to someone else's
telephone conversation without their permission is against the law, and
it's also mean. Never attempt to bug my telephone. I'll find it as soon
as I pick up the phone. Don't point fingers at me if you get busted for
doing something non-educational with this info...snicker)
The first thing I would recommend to all you crazy hacks is to scroll to
the BOTTOM of this text, and ogle at my Ascii-Schem for how to make this
awesome device. I may put a Gif version of the schematic up on the HIR
Distro site later if i get a whole lot of complaints. Note the parts list
under the schem...jot all those things down, and go to some place to get
them. You may need to special order the transistors, but probably not.
Radio shack might have them, or an equivalent. Just ask and they'll look
through a huge old book to find equivalents.
Now that you have your parts, let's continue... I expect most of you should
be able to assemble it from the schem. you will probably want to etch a
small pc-board (I've fit this project on a board as small as a quarter), or
something. This is REALLY simple.
To make the coil, take the 6 inches of enameled 28 gauge wire, and scrape the
enamel off the ends (1/8 inch is good) and wrap the wire tightly around a
pencil, and carefully remove it, taking care to keep its shape. If it gets
deformed, you are screwed. Redo it.
Since this article is educational, I might as well teach you guys how all
this crap works together to send a fone conversation over the radio waves.
This device is a combination of a high frequency oscillator, and a voice
amplifier. The voice amplifier takes the signal from the phone line, and uses
it to modulate the oscillator, causing a nice clear FM signal. Let's take
a look at what's happening inside out little circuit.
The parts of the bug that makes up the oscillator circuit are Q1, L1, C1, C2,
C3, C4, R2, and R3, and a power supply, which happens to be the phone line
(wow! No batteries or nothing?!) Q1 is Biased into conduction by R2. The
collector of Q1 is attached to L1, and C2, 3, and 4. This array of coil and
capacitors happens to cause an oscillationn ranging between 88MHz and 108 MHz,
depending on how the trimmer capacitor is adjusted. This range of frequencies
is typically known as the FM (frequency Modulation) Band. That's right, the
stuff your FM radio can "hear".
Q2 and R1 make up the Voice amplifier, which is used to amplify the audio
signal, and is then used to modulate the signal that the oscillator is
generating.
Okay, so how do we hook this up, find what frequency it's on, use it, etc?
Well, ya gotta hook it up first. Testing this device requires a phone line,
a phone, and an FM radio that you can have close to the phone. To hook it
up, you have to put it between the phone. This will be hooked up sort of in
series with the phone, and kinda parallel, too.
Green wire: Hook this up to the green line wire on the FAR side of the fone.
Gray wire: Hook this up to the green line wire on the NEAR side of the fone.
Red wire: Attach it to the red wire. IT just needs to make contact. Don't
Cut the red wire, and if you do, twist all three red wires back
together.
green line wire/green bug wire Gray Bug wire Green fone wire|""""""|
---------------*--------|"""""|---------------------*---------------| |
| BUG | | FoNE |
|_____|--| <---RED Bug wire | |
---------------------------------*----------------------------------|______|
To test it, tune to an empty station on your FM radio, one with only static.
pick up the fone your bug is attached to, and then adjust the Trimmer slowly
(preferably with something insulated or plastic) until you hear the dial tone
(or if you wait too long, the "We're Sorry..." message) on the radio. make
sure you aren't touching any of the wires (especially the coil) as this will
slightly change the frequency when you release it. You now have a working
bug. IF you just can't seem to tune it in, check to make sure you don't have
any loose connections or solder bridges. IF that doesn't work, try using
a different empty radio channel.
For permanent installation, you may want to mount it inside a project box,
with one male, and one female RJ-11 jack sticking out so you can just plug
it straight into any normal fone line, or you may consider mounting it INSIDE
a telephone. This device is small enough. As far as the Antenna, I've tried
various things. you may want to make a long wire, or just hook the antenna
wire up to the yellow modular wire (which is used for a second line. This
will not, however, mess up their second line if they have one, just make it
a huge antenna. You may be able to pick up the conversations from as far away
as a quarter mile. Good luck!
Ascii-schem for telephone bug ЙННННННННННННННННННН
by Axon є Legend
Q2МНДДДДДДДДДДДВДДДДДДДДДДДДДДДї ЗДДДДДДДДДДДДДДДДДДД
gray wire ДДДДДДВДДДДДДДДДН№ і і є ййййй = coil
і R1 М» і і є МНН
АД\/\/\/ДДДґ і ЪйййййЩ і є Н№ = transistor
47к і і і L1 .___. і є МН
green wireДДДДДДДДДДДДДДДДДЩ і і \ / і є
R2 і і і і є .___.
Ъ\/\/\/Щ і і і є \ / = Antenna
і270Kк ГДДДДДВ і і є і
і Q1МНДЩ C2БVARIABLE і і є
ГДДДДДДДН№5pF-40pFВ і і є \/\/\/ = resistor
C1 Б МНїЪДДДДЕДДДДДДДДДЩ і є
100pFВ R3 ГЩ C3Б і є Б
red wire ДДДДДДДДДДДДДБДД\/\/\/ДДДБї47pFВ і є В =Capacitor
680к АДДДДБДДДДДДДДДДДДДДДЩ є
ИНННННННННННННННННННН
Resistors Capacitors Transistors
ДДДДДДДДДДДДДДДДДДДДДДїЪДДДДДДДДДДДДДДДДДДДДДДДДДДїЪДДДДДДДДДДДДДДДДДДДДДДДДДДДї
R1 = 47 Ohm ¬Watt 5% ііC1 100pF Cer. іі Q1 2N3904 і
R2 = 270K Ohm ¬Watt 5%ііC2 Trimmer 5-40pF Variableіі Q2 MPSA56 і
R3 = 680 Ohm ¬Watt 5% ііC3 47 pF Cer. іАДДДДДДДДДДДДДДДДДДДДДДДДДДДЩ
ііC4 470 pF Cer. і Coil = 6 inches of 28ga
ДДДДДДДДДДДДДДДДДДДДДДЩАДДДДДДДДДДДДДДДДДДДДДДДДДДЩ enameled wire See
Green, red, gray wires are 22ga solid preferably Previous part of
text for how to make it