All Electronic Parts - Digi-Key Electronics
Spy Circuits Listening Device Circuits FM Transmitter Circuits Radio Circuits Audio Circuits Electronic Surveillance Circuits
FM Transmitter Spy Recorder Circuit - RTR
Resistors: 1/4 Watt
R1 = 1K
R2 = 1 MEG
R3 = 100K
R4 = 10K
R5 = Use a 500K To 1 MEG Pot at this location
R6 = 22K
Capacitors: - Disc Or Electrolytic (
Electrolytic Shown with +/- ) All Low
C1 = .1
C2 = 220 MFD
C3 = 22 MFD
Standard LM386N-1 Audio Chip. Place A Jumper Wire Between Pins
2 and 4. The Pin Connections are indicated in the Schematic
Any, On / Off Switch Will Do - connecting the + side of the 9 volt
battery to the circuit
9 Volts D.C. The Positive Side Of The Battery Connects To The
Standard Mono Female Jack. Solder points shown at the rear of this
jack. Use a patch cord from this jack to the input of your recorder.
A standard 1/8" Male Audio Jack. This jack plugs into the external
speaker or earphone port of your receiver or scanner. Use a Twisted
pair - or small coax from the connection at R2/R3 to the male phone
J3: mono female jack to fit the size of your earphone cord.
A standard set of 8 Ohm earphones
Any 8 Ohm speaker
A DPST switch
Any 6 to 9 VDC L.E.D. - "Indicates Circuit Is Turned On.or Off."
What does the photo ( Below left ) have to do with the - RTR circuit displayed on this page?
This was one of many of the "Highly Confidential" units that was sold by a national/international company, to Law Enforcement and Governmental Agencies around the world.
It consisted of a tunable scanner in the 150 to 174 MHz band, a tape recorder, earphones and a speaker - and of course the usual bells and whistles, complete with operating instructions pasted on the inside upper lid of it's aluminum case.
It was designed as a portable unit to set up in the front seat of a car or in a van to monitor "A Wire" or in non-law enforcement terms, a transmitter being worn by someone on their body, such as the BBG or XMT unit ( electronic circuit also included in this website ) when an informants life may be in danger or intelligence is being gathered - and re-transmitted back to this unit, being recorded.It was also used for monitoring concealed transmitter bugs.
In 1994 ( 18 years ago - the price of this unit was over 5 grand. It would probably go for over $7,000 in today's market.
1994 Price: $5,175.00
Here is where the RTR Electronic Circuit shown below came into being. Back when I was making my sales calls, taking orders and selling custom surveillance gear, I was shown a lot of the confidential police equipment catalogs. The unit on the above left kept coming into play, and a lot of the low budget departments and agencies wanted one - but could not afford it from the confidential police catalogs.
I came up with the "Exact Same Unit" - only rather than a price tag of over $5,000.00, I produced the design for an actual electronic component cost of under $15.00. I packaged the unit in a Home depot $8.00 Aluminum case, added in a Radio Shack tape recorder, a couple of switches - jacks and a headset. The agency supplied the scanner. Some foam in the case made it complete.
Last year I saw a similar unit, the only new feature being - an addition that would turn the recorder on and off when the unit was unattended and hidden in the trunk or at a discrete location to monitor and record hidden or "Fixed" concealed transmitter bugs - and turn the recorder on and off electronically. It is currently selling for over $12,000.00. One only needs to look at the repeater/recorder electronic circuit # vox3 ( Included ) that I engineered many years ago and tap that circuit into the RTR, for a professional unit, not 12 Grand but under the cost of a carton of Ciggs. Enjoy, John S. Wilson Jr.