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Sensors / Detectors: RF (Radio Frequency) Detectors

RF Detectors:   #'s - H      I - R      S - Z

Sensors / Detectors -- Main Page


Last Updated: October 13, 2017 03:06 AM

Circuits Designed by Dave Johnson, P.E. :

2.45ghz RF Signal Detector -  This passive RF indicator is made from a few simple parts.  A 100uA moving coil meter is used to display the relative intensity of the RF signal.  This circuit can be used with some cell phones and many cordless telephones. . . Circuit by David A. Johnson P.E.-July, 2006

Display RF Signal Strength -  Many cordless telephones, computer networks and cell phones use a RF transmitter lefted on the 2.45GHz band.  Using a microwave diode detector and 100uA meter, this passive circuit will display the strength this signal.  The drawing shows how a bent piece of wire can be used as the antenna. . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2006

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-368-7747


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

1 W Experimental Output & 1 Meter Loop Antenna for 187 kHz (Lowfer) -  A pair of bipolar transistors makes a 1 watt output stage that drives a 1 square meter loop antenna.   __ Designed by Dick Cappels

1751 Meter Lowfer Band Amplitude Modulated RF -  The 74HC4060 oscillates at 6.000 MHz, and is divided by 32 to get 187.5 kHz.  Pin 5 of theCD4060 is a 732 Hz square wave which can be used to modulate the output stage rather than using a micro controller, but in this instance, the modulation __ Designed by Dick Cappels

1W RF Power Amplifier for iPOD Stereo FM transmitters -  This project explain how you can build and connect a powerful 1W amplifier to your FM transmitters.  A perfect solution for those wishing to listen to their favorite tunes in the car, house, garden, school, campus, party, you name it. Why not share your music with every one else in your city! __ 

2 Watt Switching Power Supply -  in this small switching power supply, a Schmitt trigger oscillator is used to drive a switching transistor that supplies current to a small inductor.  Energy is stored in the inductor while the transistor is on, and released into the load circuit when the transistor switches off.  The output voltage is dependent on the load resistance and is limited by a zener diode that stops the oscillator when the voltage reaches about 14 volts.  Higher or lower voltages can be obtained by adjusting the voltage divider that feeds the zener diode.  The efficiency is about 80% using a high Q inductor.   __ Designed by Bill Bowden

2.45ghz RF Signal Detector -  This passive RF indicator is made from a few simple parts.  A 100uA moving coil meter is used to display the relative intensity of the RF signal.  This circuit can be used with some cell phones and many cordless telephones. . . Circuit by David A. Johnson P.E.-July, 2006

300 MHz AM RF Remote Control System -  if you plan to build this project, simply replace the RE-99 receiver & TX-99 transmitter with the RWS-434 & TWS-434A RF receiver & transmitter modules found HERE.  These circuits will work with any RF transmitter and receiver modules.  Due to the huge interest in this project, I have just recently finished the NEW schematics.  The older schematics were scanned and pretty poor quality.  These new ones should make it considerably easier to recognize the parts used for the project.   __ Designed by © Reynolds Electronics

300MHz to 3GHz RF Power Detector in SC70 Package -  LTC5532__ Linear Technology/Analog Devices

300MHz to 7GHz RF Power Detector with Buffered Output in SC70 Package -  LTC5508__ Linear Technology/Analog Devices

4 channels RF wireless transmitter and receiver -  This is a very simple Wireless RF transmitter circuit that consists of the Holtek HT-12E encoder chip and AM 418MHZ-transmitter module (WZ-X01, other similar device can be used).  Using the hybrid RF xmit/receive modules make building the RF remote control a lot easy __ Contact info @ wzmicro.com

4 MHz Amplitude Modulated RF Source -  A while back I needed an amplitude modulated signal source at 4 MHz.  This circuit was literally thrown together with parts laying on the bench.  I built it dead bug style on a piece of copper clad board.  it should work with little or no modification, other thano get it to oscillate, and at higher frequencies, you might have to reduce the capacitor values a little.  Just be __ Designed by Dick Cappels

40 Meter Popcorn Superhet Receiver -  schematic for a no-frills, relatively low-cost CW superhet receiver with a 4.00 MHz intermediate frequency.  There is no AGC or RF gain control, however this receiver has good large signal handling capability.  This receiver uses just 6 bipolar transistors and an op amp for reasonable volume into headphones.  Much __ Designed by VE7BPO

50MHz to 3GHz RF Power Detector with 60dBDynamic Range -  LTC5535__ Linear Technology/Analog Devices

8 Hints for Making Better Measurements using Analog RF Signal Generators -  Application Note__ Aligent

8 Hints for Making Better RF Counter Measurements -  Application Note__ Aligent

9 Channel PWM Code AVR Controllers -  This article is about a software controlled, parallel port-interfacing 8-channel Pulse-Width-Modulated fan controller __ Designed by Dick Cappels

90 MHz voltage controlled oscillator for FM Band  -  Notice the abundance of 2N4401, 1 k resistors and 330 Ohm resistors? That's because I have a lot of each.2N4401's weren't intended to be used as varactors, but they work just fine.  Don't be afraid to xperiment with the parts you have on hand.  Build this on a ground plane board.  Layout is important.   __ Designed by Dick Cappels

A Dual Mode Superhet/Direct Conversion AM receiver for 181.818 kHz Lowfer ATtiny2313, AT90S2313 -  This is a description of an experimental AM receiver for VLF.  it is crystal controlled to receive 181.818 kHz (more or less) and operates as either a single conversion superhetrodyne or a direct conversion receiver.  The bandwidths are expected __ Designed by Dick Cappels

A Simple Circuit FM Stereo Transmitter -  (ATTiNY12, ATTiNY25, ATtiny2313, AT90S2313, AT90S232, or nearly any other CMOS microntroller-Yes probably even a PIC !) This project appeared in the December, 2007 issue of infoElektronika Magazine __ Designed by © Richard Cappels

AM Detector More sensitive than Simple Circuit diode -  EDN Design Ideas:  09/28/2016    A traditional diode RF detector has its limitations.  This DI describes a simple way to overcome them __ Circuit Design by Lyle Williams

ATtiny12 Fuse Restorer -  This restores the fuses in an ATtiny12 via High Voltage Serial Programming.  Plug an ATtiny12 into the 8 pin socket and hold down "GO! " button.  The LED will come on at the end of the programming process, which only takes a couple hundred millisecond.  The fuses are now restored to their factory default states.  This picture was taken before the voltage doubler, made with the 1N916 and 100 uf capacitor were added.   __ Designed by Dick Cappels

AttoBasic Home -  ATMEGA32u4, ATMEGA88 ATmega 168m, ATmega328, AT90S8515/ATMEGA8515, ATmega163, andATtiny2313 /AT90S2313 __ Designed by Dick Cappels

Attobasic with 32k of External SRAM -  This is a continuation of the work on AttoBaisc for the ATMega8515/AT90S8515 __ Designed by Dick Cappels

Building an RF Remote Control System -  With a handful of inexpensive components, a little creativity, and the power of PicBasic, you can build some pretty outstanding robotics creations as Rob Arnold proves with his Ruf-Bot project.   __ Designed by Rob Arnold

Cellular Phone Helper -  When your cellular phone receives a call, it begins transmitting even before you answer.  The circuit shown in fig.1 detects this signal and can operate a variety of devices referred to as "load" __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Commodore RF Modulator -  Schematic only, no circuit description__ 

Constant Reactance Voltage Controlled Oscillator -  For some time railroad companies have been wrestling with the problem of tracking rail cars.  This has traditionally required manual log entry of identification numbers displayed on the cars as they pass through the switching yard.   __ Designed by Raymond T. Page, Reprint courtesy of RF Design Magazine

Coupling Methods for RF Power Detectors replace Directional Couplers -  AN91 AN91 describes an RF feedback coupling method which eliminates the directional coupler.  instead, a 0.4pF ±0.05pF capacitor and 50Ω resistor are used to feed RF signal back to the LTC power controller.  This method reduces coupling loss variations, cost and lead time.  __ Linear Technology/Analog Devices

Crest Factor, Peak & RMS RF Power Measurement Optimized for High Speed, Low Power & Single 3.3 V Supply  -  Follow the instructions contained in the Readme file for installing and using the evaluation software.  , Functional Block Diagram See Figure 1 of this circuit note for the circuit block diagram, and the “EVAL-CN0187-SDPZ-SCH” pdf file for the circuit schematics.  Launch the evaluation software and connect the USB cable from the PC to the USB mini-connector on the SDP board.  The software will be able to communicate to the SDP board if the Analog Devices System Development Platform driver is listed in the Device Manager.  __ Analog Devices from the Lab

Designing RF Probe -  make your self simple and heighly useful RF probe.  An essential tool for every home brewer.  __ 

Diode Frequency Doublers -  Ordinary fast switching silicon diodes, special fast recovery junction diodes, schottky barrier diodes, varactors and even old-fashioned germanium diodes or vacuum tubes may be used to construct signal powered frequency doublers __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Display RF Signal Strength -  Many cordless telephones, computer networks and cell phones use a RF transmitter lefted on the 2.45GHz band.  Using a microwave diode detector and 100uA meter, this passive circuit will display the strength this signal.  The drawing shows how a bent piece of wire can be used as the antenna. . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2006

Divide-by-N using '161s  -  Here is a simple circuit for obtaining divide-by-N from '161s.  The technique will work for one, two, or more dividers to obtain the desired N value.  One counter handles N values up to 16, two counters divide by N values up to 256, etc __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

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.   __ Contact IQ Technologies

ESG Series RF Signal Generators Option 200 W-CDMA Personality for the Real-Time Baseband Generator -  Agilent Application Note__ 

F.E.D. Detects digital RF signals -  The F.E.D. (Frequency Emissions Detector) will, of course, detect anyone's cell phone, so the detector really responds to just about anybody with more than two pennies to rub together.  Most phones occasionally transmit short bursts to the nearest cell tower, even when the phone isn't in use, so a typical 21st century loiterer will eventually set off the detector.  On the other hand, a deer can stare at it for an hour with no effect.  Let's face it, even most burglars emit digital signals these days.  So, in a sense, the F.  E.  D.  is a human detector.  With that in mind, consider using the output to activate a digital camera or video recorder to capture a record of the prowlers.  A recorded barking dog or, one of my favorites, a recording of police radio traffic will scare off most crooks.  Add some hidden flashing red and blue lights to the police chatter and the culprits will actually run away.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Four channels RF wireless transmitter and receiver -  This is a very simple Wireless RF transmitter circuit that consists of the Holtek HT-12E encoder chip and AM 418MHZ-transmitter module (WZ-X01, other similar device can be used).  Using the hybrid RF xmit/receive modules make building the RF remote control a lot easy __ Contact info @ wzmicro.com

Frequency Dividers -  This paper is a collection of unusual frequency divider techniques which offer features not achieved with ordinary divider ICs  or prescalers __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Frequency Emissions Detector -  The F.E.D. (Frequency Emissions Detector) will, of course, detect anyone's cell phone, so the detector really responds to just about anybody with more than two pennies to rub together.  Most phones occasionally transmit short bursts to the nearest cell tower, even when the phone isn't in use, so a typical 21st century loiterer will eventually set off the detector.  On the other hand, a deer can stare at it for an hour with no effect.  Let's face it, even most burglars emit digital signals these days.  So, in a sense, the F.  E.  D.  is a human detector.  With that in mind, consider using the output to activate a digital camera or video recorder to capture a record of the prowlers.  A recorded barking dog or, one of my favorites, a recording of police radio traffic will scare off most crooks.  Add some hidden flashing red and blue lights to the police chatter and the culprits will actually run away.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Frequency Tripler using the CA3029 -  Here is a simple frequency tripler using a CA3028 differential amplifier.  The CA3028 has internal bias resistors for setting the differential amplifier's current at about 7 mA when connected as shown.  With this current, the output level is about 0 dBm at 30 MHz with a 1v p-p, 10 MHz input.   __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Fundamentals of RF & Microwave Power Measurements -  Application Note__ Aligent

Generating & Downloading Data to the Esg-D RF Signal Generator for Digital Modulation -  Application Note__ Aligent

HCMOS Gates Make Frequency Multipliers -  The rapid edges produced by HCMOS logic ICs  are rich in harmonics which can be selectively tuned to make simple frequency multipliers.  The desired harmonic may be selected in a number of ways but a few points should be observed.  First, the tuning network should not present an excessive capacitive
load to the output of the IC and it is recommended that a series current limiting resistor __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

High-Impedance FET probe extends RF-spectrum analyzer's usable range -  21-Jul-05 EDN Design Ideas:  Op amp and careful design/construction build high-impedance RF probe __ Circuit Design by Steve Hageman, Windsor, CA

How RF transformers work & how they are measured -  Application Note__ MiniCircuits.com

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RF Detectors:   #'s - H      I - R      S - Z

 


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