Bug

FM surveillance BuG Transmitter

FM surveillance BuG Transmitter

The Circuit shown can transmit voice to exceptionally good range. Tune trimmer to hear the signal to your near radio. Frequency range is 88-108 MHz. Max current consumption is 30mA. You can power the bug with a 9Volt Battery, or you can plug a power supply to feed in 9-12 Volts. ..

1W Linear FM Booster

1W Linear FM Booster

That RF Amplifier is for boosting small fm transmitters and bugs. It use two Philips 2N4427 and its power is about 1Watt. At the output you can drive any linear with BGY133 or BLY87 and so on. Its power supply has to give 500mA current at 12 Volts. More voltage can boost the distance but the transistors will be burned much earlier than usual.! In any case do not exceed the 15Volts. ..

Wireless Bug detector

Wireless Bug detector

This fairly simple circuit makes it possible to place such a wall as a conduit to locate. It is a conduit for power, no water or gas-seeker. The only requirement is that there is tension on the line. The antenna in the table can consist of a simple piece of copper wire. The correct adjustment is done through R7, in order to prevent the buzzer and LEDs still light up even though there is no leadership in the area. ..

Phone line FM transmitter

Phone line FM transmitter

Here is a simple yet very useful circuit which can be used to eavesdrop on a telephone conversation. The circuit can also be used as a wireless telephone amplifier. One important feature of this circuit is that the circuit derives its power directly from the active telephone lines, and thus avoids use of any external battery or other power supplies. This not only saves a lot of space but also money. It consumes very low current from telephone lines without disturbing its performance. The circuit is very tiny and can be built using a single-IC type veroboard that can be easily fitted inside a telephone connection box of 3.75 cm x 5 cm. The circuit consists of two sections, namely, automatic switching section and FM transmitter section...

High Quality FM BUG

High Quality FM BUG

This project requires a high degree of soldering. It uses surface-mount resistors, capacitors transistors and diodes. It can only be assembled on the PC board supplied in the kit as the Latching Circuit is already soldered to the board and the project will not work with substitute components. The Infinity Bug connects across the phone line and takes very little current as most of the circuit is not active when in the "waiting" state. This is called "leeching" and the Infinity Bug is a leech device as it gets its operating current from the phone line. Some phone systems detect as little as 0.5mA and if more than 1mA is drawn from the line, it remains engaged. ..

FM bug circuit

FM bug circuit

This is just one of the many bugging devices available on the eaves-dropping market. The range includes pen and pencil holders, trophies, framed pictures and office furniture with false bottom drawers. These products are readily sold to fledgling companies, eager to nestle into big brother's market. And for a while these bugging devices worked. Few firms knew of their existence, and even less on how to sniff them out. But that has all changed now. If a corporation suspects a leak at any level, the first thing they order is an investigation into security. Not only personnel, but information and electronic security...

FM Bug detector 80 - 150 MHz

FM Bug detector 80 - 150 MHz

This Mini FM Bug Detector is basically a broad-band receiver. It picks up the complete band from below 80Mhz to 150MHz and almost anything that transmits in that band will be detected. If a bug with a sensitive microphone is transmitting nearby, the result will be a feedback whistle. The Bug Detector will not determine the output power of a bug as it is detecting the sensitivity of the microphone. However it will prove the carrier section is working (this is the section that produces the 88MHz frequency) and also the audio section. ..

wireless FM bug

wireless FM bug

This project is a miniature, VHF FM (wideband) Wireless Microphone transmitter of the type that are commonly refered to as BUG's. Note that "BUGS" are illegal but "Wide-Band Frequency Modulation Wireless Microphones" (WBFMWMs) are not, as so many people have told me (including the RSGB!). Besides, the AF sensitivity of this transmitter prevents it from being an effective bug for eaves-dropping! I personally use one of these WBFMWMs plugged into my HF rig headphone socket so that I can "earwig" QSO's and nets when sitting on the toilet, washing the dishes, bringing in the coal, etc. ..

Microphone FM bug transmitter

Microphone FM bug transmitter

This is the basic fm trasmitter that I built. In theory, according to electronics, it shouldn't work but works fine and is very sensitive. It can transmit the signal up to 45 yards (about 40 meters) . A sensitive FM radio can pick up the signal up to 100 yards (80 meters) but I can't see any reason for it. This kind of microphones are also called "spy microphones" but knowing that the battery is bigger than the actual circuit, I can't see any application like that, anyway, this circuit should be used as educational application only...

Making a 900MHz Phone Bug

Making a 900MHz Phone Bug

Today they have moved up to 900MHz. It is not easy to build stuff for 900MHz so in this project I will re-use an old cordless 900MHz phone I found in a container. Since you wont have the same phone as I have, you might think this is not a project for you, Wrong! Read this and you will learn how do identify parts in cordless phones and you can rebuild almost any model. This is a block diagram of an analogue 900MHz cordless phone. The transmitter part is not interesting because we don't want to transmit anything. The RF signal is first filtered and amplified in a 959 MHz filter. The RF signal will then enter a mixer to be down converted to lower frequency. To the mixer you will find a VCO (Voltage Controlled Oscillator). The frequency from the VCO is controlled by a PLL synthesizer. The PLL synthesizer probes the VCO frequency (Fin), and adjust the "PD" voltage until it finds and locks to the programmed frequency. The product out of the mixer will pass a filter (21.4MHz in my case) and then enter a standard FM receiver circuit to demodulate the sound...

50MHz crystal bug

50MHz crystal bug

This bugg is based on my previous 3-transistor transmitter. This bugg unit has many advantage. The transmitter use a crystal 46.515MHz to hold a steady frequency. The frequency can be fine-tuned by some 100kHz. The transmitter can send data and audio-signal with +/- 10kHz FM modulation. The output power is about 10mW into 50 ohm. The crystal I used is a 3:th overtone crystal. The coil L1 is a slug tuned coil. The primary winding is 8 turns and the second winding is 2 turn. The inductance in the primary winding is about 800nH. L1 and C1 should be in resonance at 47MHz. The number of turns is dependent on type of coil you have. You will have best performance when the "ferrite tuning slug" is at the bottom of the CAN, because you will then have the best couppling between the two windings. ..

bug transmitter with PIC16F870 PLL

bug transmitter with PIC16F870 PLL

This frequency of this transmitter is PLL controlled which makes it very stable. The frequency is programmed in digitally way and can be changed very easy. Frequency range is about 50 to 150 MHz and the output power 100mW. The output power is about 100mW and most of the time that is too much. High output power will consume lot of battery time and that is not good. Most of the time you don't need to transmit long distance. The time you want to transmit is more important. The output power is very easy to set and I will explain how to change it to save battery. ..

FM phone BUG with SA615

FM phone BUG with SA615

Many Cordless phones are still analogue and use the frequency from 30-50MHz. The signal is FM-modulated and can easy be picked up with any FM-receiver. I will present a FM-receiver wich can be adjusted within this frequency range. The cordless phones can have different number of channels. In the oldest type you will find a single crystall (one channel). The multi-channel phones uses a synthesizer chip to set a frequency wich is not occupied. The receiver I present is not crystall controlled. The receiving frequency is set manually by a potensiometer. This way you can easy find any signal within the frequency range. ..

400mW FM Bug

400mW FM Bug

Power supply: 12-14 V stab., 100 mA. RF power: 400 mW. Impedance: 50-75 ohm. Frequency range: 87,5-108 MHz. Modulation: wideband FM. Connect the 6 V / 0,1 A bulb to the output and use R1 to tune the right frequency. Maybe you might stretch coils of the L1. Then use C14 and C15 to adjust the highest power (the highest light of the bulb). Then you can connect antenna and audio signal. Adjust R2 until the audio sounds as loud as the other stations. With good antenna (dipole placed outdoor and high) the transmitter has very good coverage range about 500 meters, the maximal coverage range is up to 4 km...

FM transmitter with two 2N3904

FM transmitter with two 2N3904

This circuit uses a small microphone to capture the sound and some transistors to generate radio waves that can be picked up by a FM receiver like a car stereo. The first part is the microphone and some resistors to get it working. Next we have a capacitor and the first transistor, this amplifies the sound from the microphone so that it can be loud enough to work with. The last part, there is a transistor, a coil and some capacitors. This part generates the radio waves and combines them with the sound from the mic to transmit it thru the antenna...

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