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Bugs (Electronic) & Detectors
Last Updated on: Thursday, June 25, 2015 06:20 AM


Links to electronic circuits, schematics, designs for engineers, hobbyists, students & inventors:

1 transistor FM transmitter / FM bugging device -  No circuit description, schematic only. . .  [CdS Electronic's website]

 

3 Transistor FM Radio Bug -  VOYAGER is a super-sensitive FM Radio microphone developed by Talking  Electronics. The components are all common types of resistors, capacitors and transistors matched so well in this circuit that  amazing  sensitivity and  distance  are obtained. The name VOYAGER was given to it "because it  goes so far". We have re-designed the Board and further matched some components  to  suit  the  needs  of  the  classroom. The result is a superb bug which is compact but powerful, and quite easy to build. . .  [CdS Electronic's website]

 

3m 100 MHz small bug -  . . . 

A 'bug' receiver -  I have had several requests for a miniature, VHF FM (wideband) transmitter of the type that are commonly refered to as BUG's. I personally use one of these plugged into my HF rig headphone socket so I can "earwig" QSO's and nets when sitting on the toilet, washing the dishes, bringing in the coal, etc. I know from experience that this project can be used to stimulate interest in Radio in older children, . . .  [Harry, SM0VPO Email: harold.lythall @ era.ericsson.se]

 

Bug Detector (mini) -  This project is a handy piece of TEST EQUIPMENT. You can never have enough assistance when designing FM bugs. The first thing you need to know after putting a bug together is the fact it is transmitting.
This project gives you this indication. Once you know a bug is transmitting, you can work on getting the best output power and adjusting the frequency to a blank spot on the dial. . . .  [email Colin Mitchell: talking AT tpg.com.au]

Bug Detector with Beep -  This circuit is not open for discussion. Although working perfectly, it was experimental. I will answer no emails in regards to this circuit. If you are looking for a more serious and reliable bug detector, . . . .  [Tony van Roon's circuit]

 

Bug Duster -  For cleaning out those pesky bugging devices:  The Bug Duster is a detector for uncovering RF-based video and audio bugging devices. It has two modes of operation, an All-Band detector suitable for spotting many forms of analog and digital modulation and a "Pseudo-Sinitsa" mode of operation that can detect most forms of modulation, even dead carriers. The Pseudo-Sinitsa mode is based on the Soviet Cold War transmitter hunter called the Sinitsa. That machine used an RF diode to chop the incoming RF at an audio rate, imparting an AM modulation on the carrier. Subsequent filters and an RF amplifier then fed an ordinary AM detector and audio amplifier. The Bug Duster uses two diodes to accomplish nearly the same results. Instead of turning the RF on and off, an analog switch selects the voltage from one of two detector diodes at an audio rate, one diode detecting incoming RF and the other acting as a reference. The result is nearly identical to the old Sinitsa since the reference diode sits at the same voltage the detector diode would drop to if the RF were removed. In fact, an offset voltage may be applied to the reference diode to "dial out" background RF, typically commercial broadcast signals (the 5k potentiometer). . . .  [Charles Wenzel (unless otherwise noted)]

 

Crystal Locked FM Bug -  Producing a crystal locked transmitter is a natural extension to our FM Bug series. We have already produced a number of simple FM devices, (without the use of a crystal) and showed how the power and frequency depends on a number of factors including the voltage of the supply and the design of the stages. (electronic circuits 04/09) . . .  [email Colin Mitchell: talking AT tpg.com.au]

 

Electronic Eavesdropping Devices Detector -  Copyright of this circuit belongs to smart kit electronics. In this page we will use this circuit to discuss for improvements and we will introduce some changes based on original schematic. . . .  [by IQ Technologies Industry, unless otherwise noted online]

 

FM bug -  Schematic only, no circuit description. . .  [Designer's name not given]

 

FM bug 420-480 MHz -  How about getting that old Nokia phone out of your drawer and turning it into something freakishly cool? I will not lie to you, you will need a few tools and skills such as soldering/desoldering and making PCBs. Here you can download Sprint-Layout. . .  [designer's name not included]

 

FM Bug-transmitter -  The circuit consists of two separate stages. The first is an audio pre-amplifier and the second is a 90MHz oscillator. The first stage is very simple to explain. It is a self-biasing common-emitter amplifier capable of amplifying minute signals picked up by the electret microphone. . .  [kit is designed and manufactured by TALKING ELECTRONICS]

 

FM Telephone Bug -  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. . .  [Tony van Roon's circuit]

 

FM Telephone line Bug Transmitter -  . . .  [Circuit designed by Aaron Cake]

 

FM Transmitter Bug -  This small transmitter uses a hartley type oscillator. Normally the capacitor in the tank circuit would connect at the base of the transistor, but at VHF the base emitter capacitance of the transistor acts as a short circuit, so in effect, it still is. The coil. . .  [by David Sayles]

 

High Power FM Microphone FM 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. . . .  [from Harry Lythall's website]

 

Infinity 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 (circuit 02/07) . . .  [email Colin Mitchell: talking AT tpg.com.au]

 

Miniature FM Spy Mic -  This spy mic works from single 1. 5 volts AA type battery cell. It is highly sensitive and has a range of 300 meters. You can use any HF transistor with cut-off freq. >300 MHz for Q. Use electret mic. . . . 

 

One transistor FM transmitter / FM bugging device -  No circuit description, schematic only. . .  [CdS Electronic's website]

 

Simple Phone Tap -  Will record any conversation on any ph1-on same line, the circuit seems to be a bad design because it does not provide proper isolation and has too low DC impedance (can keep you line off-hook all the Time) . . .  [Circuit designed by Aaron Cake]

 

Surveillance Transmitter Detector -  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 a detector is to get its sensitivity just right, Too much sensitivity and it will respond to radio broadcasts, too little, and nothing will be heard. . . .  [Andy Collison]

 

Telephone Listening Bug -  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. . . . 

 

Three Transistor FM Radio Bug -  . . .  [from Harry Lythall's website]

 

Vibrating pocket bug detector -  . . . 

 

Voyager 2 FM Radio Bug -  VOYAGER is a super-sensitive FM Radio microphone developed by Talking  Electronics. The components are all common types of resistors, capacitors and transistors matched so well in this circuit that  amazing  sensitivity and  distance  are obtained. The name VOYAGER was given to it "because it  goes so far". We have re-designed the Board and further matched some components  to  suit  the  needs  of  the  classroom. The result is a superb bug which is compact but powerful, and quite easy to build. . .  [CdS Electronic's website]

 

VXO FM Bug -  After constructing my Solar Powered FM Bug circuit, I decided to try building an FM bug with a more frequency-stable oscillator. Numerous Variable Crystal Oscillator (VXO) circuits have been published for ham radio receivers and transmitters, these are normally used for fixed frequency CW applications. I decided to see if it would be possible to use a varactor diode (voltage variable capacitor) to modulate the frequency of a crystal oscillator with an audio signal. . .  [G. Forrest Cook]

 

Wireless Telephone Bug -  Here's a neat little project that will allow you to monitor your phone line as soon as your phone is off hook. You can use a regular FM broadcast band radio to monitor the conversation. Just remember, it . . . 

 

Wireless Telephone Eavesdropper Electronic Circuit -  The IR transmitter connects to a telephone circuit, and transmits both sides of all telephone conversations to any line-of-sight location, within 40 feet. No power is taken from the central office, as long as all phones remain on-hook. The current flows through the phone and back to the central office. . . 


Bugs (Electronic) & Detectors


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