Bugs

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

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. ..

High power bug

My FM Wireless Microphone has been a very popular project with beginners and experienced constructors alike. It has been used inside guitars and as the basis of a remote control system. I do however, receive many requests for a higher powered circuit and better microphone sensitivity. Now I can introduce the new FM Wireless Microphone (v5), which also has a better frequency stability, over 1Km range (under ideal conditions) and is good on microphone sensitivity. This has been achieved by adding an RF amplifier buffer (with 10dB gain) and an AF preamplifier to boost the modulation a little...

Telephone line FM Transmitter

Would you like to be able to amplify a phone call so everybody can hear it? Or perhaps you'd like a way to record phone calls for record-keeping purposes. If either idea sounds good to you, then you might want to build the FM Telephone Transmitter describe in this article. It's a simple, yet ingenious device that connects in series with a phone line, "reals" power from the latter, and transmits both sides of a conversation to an FM radio tuned to between 90 and 95 MHz. ..

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. ..

Here is a simple transmitter that when connected to a phone line, will transmit anything on that line (execpt the dial tone) to any FM radio. The frequency can be tuned from 88 to about 94Mhz and the range is about 200 feet. It is extremely easy to build and is therefore a good, useful beginner project...

This circuit is extremely simple, therefore there is less chance of any problems. It can be placed anywhere on the phone line and it will record any conversation on any phone on that line...

My site contains a few low power transmitters of one type or another, but until now no receiver. This circuit can be used to "sweep" an area or room and will indicate if a surveillance device is operative. The problem in making a suitable detector is to get its sensitivity just right; too much and it will respond to radio broadcasts, too little sensitivity and nothing will be heard...