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Amplifier Circuits: 
RF (Radio Frequency)

RF Amplifiers:  #'s - C      D - K        L - R       S - Z

Amplifier -- Main Page

Last Updated: December 25, 2017 01:43 PM

Circuits Designed by Dave Johnson, P.E. :
RF 2.45Ghz 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 . . . Hobby Circuit designed by Dave Johnson P.E.-July 09, 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:

R2T2 Haywire Home Station -  Something about the R2 receiver module (and the T2 phasing SSB exciter) by Rick Campbell, KK7B, really fascinated me, and got me seriously into homebrewing.  Probably the sense of audio cleanness described in the article was the first appealing thing, then the unique character of the non-superhet approach.  Now, this approach is definitely "in" in the communications industry, with tons of chipsets for quadrature receiver/transmitter setups. __ Designed by John Seboldt, K0JD

Radio Control made from Junk -  Here we are going to make a simple radio controlled device using supplies from your local dumpster.  This project should cost less than a dollar to make.  If you spend more than a dollar on this project, you need to dig more. __ Designed by sixmhz @ yahoo.com

Radio Shack Special -  This radio is sensitive enough to tune 20 stations across the FM band, some with volume high enough to drive a small PM speaker.  The ability to tune 88.9 MHz and 89.1 MHz is testimony of its selectivity.  The signal-to noise ratio rivals that of the better walkman type radios __ Contact: IQ Technologies

Receiver based on NE602 -  Schematic only, no circuit description __ Designed by Web David White, WN5Y

Receiver building blocks -  This amplifier has about 20dB of gain, bandwidth of 100MHz and noise figure of about 7dB.  The output transformer is 8 turns bifilar wound on a ferrite core.  Use a medium power UHF transistor 2N5109, 2N3866, 2N4427 or similar.  The transistor will need a small clip on heatsink.  This amplifier is suitable for use in the front end of a HF receiver or as a post mixer amplifier following a diode mixer (see below.) __ Designed by EI9GQ homebrew radio

Regenerative receiver for the AM broadcast band using two transistors -  The receiver, dubbed 'The Moorabbin', is a two transistor regenerative receiver of conventional design. Most parts are mounted on a printed circuit board that you get to make yourself. __ Designed by Peter Parker VK3YE

Regenerative Short Wave Radio -  If you happen to have a ferrite bar antenna for short wave reception, try to build a regenerative short wave radio like one shown above.  Separated function for regeneration and detection enables this circuit to be fairly sensitive to weak signals without any external antenna. __ Designed by MINOWA, Makoto  7N3WVM

Remote Control Volume -  17-Aug-11 -Design News:   Andrew Morris decided the usual wireless volume controls donít offer enough functionality, so he created the ultimate volume control that connects between a computer or MP3 player and an amplified speaker system __ Designed by Andrew R. Morris, Gadget Freak-Case #192

Remote RF Xmiter -  This device was built into a small (1 1/4 by 2 inch) Radio Shack project box.  It features four push buttons which can produce 2 codes each.  (Pushing a button for less than one second sends the first code, holding it for over one second sends the second code.) __ Designed by Luhan Monat Mesa Arizona

Repeater Fan Controller -  an 18 kB PDF file __ Designed by Robert Shepard KA9FLX

Retuning a Stationmaster type antenna -  It is not hard to tune a Stationmaster down in freq. Take a number of strips of aluminum foil, starting about 2" wide and tapering down to about 1 to 1-1/2" and long enough to wrap around the antenna mast. Secure the antenna as far as possible from other objects, at least 4-6 feet. I have heard of people have success with two tall sawhorses or better yet tall step ladders to get it high enough off the ground. __ Designed by Jim Barbour WD8CHL

Return Loss Bridge for the Radio AM ateur -  Device to quickly check the integrity of a radio antenna system. __ Amateur Radio circuits from Green Bay Professional Packet Radio

RF & Microwave structure Design & simulation -  The Sonnet field solver software is used in a couple of cases.  While it easier and quicker to design and optimize Microstrip or Stripline structures with a program such as Agilent ADS, I always put the resulting design into a field solver just as a "second opinion" check to make sure that all is OK.  In some cases: such as the design of a coaxial to Microstrip transition, the only way to get a design going is to use a field solver __ Designed by Steve Hageman

RF & Waveform Generator -  Generates RF-Frequencys 0.8-2.5 GHz (resolution 100Hz) , 22MHz-512MHz (resolution 125kHz-1MHz depending on frequency) and Waveforms 0-100kHz (resolution 1Hz).  Waveforms are Sine, Square, Triangle, Pulse, Sawtooth (positive and negative).  All modes work independently and can be used at the same time.  Very convenient user interface with LCD Display and up/down/cursor functionality.  But please don't expect an easy to copy, 10 Minute instant design.  The waveform part is a nice project for everyone, but the RF part is only for very experience hobbyists. __ Designed by Herbert Dingfelder

RF 2.45Ghz 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 . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2006

RF Actuated Keying Monitor -  Sending Morse on a rig without a sidetone is not impossible, but is not particularly pleasant either.  This battery-powered monitor has been designed to provide an audible indication of keying for those whose rigs lack a CW sidetone. Its sensor wire is wrapped around the transceiver's coax ‚Äď no direct connection is required. Of course Morse isn't the only use for this nifty circuit ‚Äď it should also be useful any time you need a simple alarm that detects the presence of RF. __ Designed by Peter Parker VK3YE

RF Amplifier for Ferrite Bar Antennas -  The author described assembling this circuit on a 1"*1" perf board, I actually laid out a small PC board with excellent results.  In this era of surface mount components, I think a much smaller version can be laid out on a PC board, allowing this circuit to be put inside even the smallest radios, such as Walkmans.  If I do such a board, I will put the PC board artwork here. __ Designed by Bruce Carter

RF Dummy LoA - D -  make this simple RF Dummy Load for off-air testing of your radio transmitter

RF front-end for triple conversion GPS receiver -  A low-power, 1.57-GHz RF front-end for a global positioning system (GPS) receiver has been designed in a 1.0- m BiCMOS technology.  It consists of a low noise amplifier with 15 dB of gain, a single balanced mixer with 6.3 mS of conversion gm, a Colpitts LC local oscillator, and an emitter coupled logic (ECL) divide-by-eight prescaler.  This front-end has a singal sideband (SSB) noise figure of 8.1 dB and is part of a triple conversion superheterodyne receiver whose IF frequencies are 179, 4.7, and 1.05 MHz.  Low power consumption has been achieved, with 10.5 mA at 3-V supply voltage for the front-end, while the complete receiver is expected to draw about 12 mA __ Designed by Francesco Piazza & Qiuting Huang

RF Isolator Uses Differential Amplifiers -  An RF isolator is a seemingly magic device that allows signals to pass in only one direction.  Signals applied to the input port are sent to the test port and signals coming into the test port can only go to the output port.  This one-way property is usually accomplished with special non-linear ferrite/magnet structures operating at very high frequencies.  Fig.1 shows an active RF isolator __ Contact: Charles Wenzel of Wenzel Associates, Inc.

RF Microwave Plasma Generator -  This page details how a RF plasma source of approximately 1 kW can be constructed from house-hold materials.  Possible uses include plasma cleaner, plasma etch, remote activation species generation and no use at all (my personal favorite). __ Designed by Greg Miller

RF Module Design & integration -  In many cases it's just hard to beat the pricing on many of the pre-built 300 MHz RF modules (as pictured above).  These modules are useful in OOK (On Off Keying) applications and data rates to 2400 baud.  Specialized coding with checksums, forward error correction, remote control codes or Manchester coding is available for applications that need it.  When it comes __ Designed by Steve Hageman

RF noise bridge for HF -  This rf noise bridge will provide about 40dB of noise over the 160m to 6m amateur bands. The unit uses 3 x BC547 transistors for amplification of noise produced by a 6.8 volt zener diode. Drawing a current of around 17mA, makes the unit suitable for portable battery operation.

RF Power meter / dummy loA - D -  A 50 Ohm dummy load is an essential part for any radio amateur as is a power meter.  The prices of such relative simple equipment is expensive, but not for us handy Hams HI.  All you need is a metal box (or plastic box painted inside with graphite or other conducting/RF-shielding capable material), a few resistors and basic components (which can be salvaged from old radio's, switching power supplies etc.  .) and a analog meter.  I used a Radio-shack meter, but any (sensitive) meter can be used.  It's all a matter of calibrating your meter correctly, which is easy if you can lend a good commercial RF power meter. __ Designed by Guy Roels ON6MU

RF Power Meter 10MHz-3.5GHz -  (Available now for rebuilding.  Due to the many requests I received, I have developed a second, larger design that is easier to rebuild.  There is a lot of theoretical and background information on the different sensor as well.) __ Designed by Herbert Dingfelder

RF Power Meter for QRPers -  Here is a simple set up which will enable them to measure the out put power of their transmitter. All that they require is a good multimeter which has a sensitivity of 20k ohms/4 Watts which is adequate for low power transmitters.

RF receiver -  Schematic only, no circuit description __ Designed by Web David White, WN5Y

RF Remote Control Project -  Making a RF radio link to control things remotely using the the Basic Stamp II and Ming RF modules.  It can remotely control up to 16 different relays from up to 300 feet away.  The relays could control anything from a tv to a motor.  For my application i used this system to remotely start the engine of my truck.  I"m tried of getting up in the mourning and have to go to school in a frezzing cold truck. __ Designed by Shaun Wilson

RF Remote Control SystE - M -  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

RF Remote Control Volume -  17-Aug-11 -Design News:   Andrew Morris decided the usual wireless volume controls donít offer enough functionality, so he created the ultimate volume control that connects between a computer or MP3 player and an amplified speaker system __ Designed by Andrew R. Morris, Gadget Freak-Case #192

RF Remote Controller -  On these pages, I will introduce Remote Controller with Radio Frequency.  The electric wave sending-out is controlled with the code by PIC for transmission and the code is deciphered by PIC for receiving.  PIC16F84A __ Designed by Seiichi Inoue

RF Signal Detector -  This simple circuit can be used to trace the presence of RF signals and electromagnetic noise in your residential area, office or shop.  It can be a useful tool while testing__ Electronics Projects for You

RF Signal Generator -  amateur radio construction projects. __ Designed by Peter Parker

RF signal meter with LEDs -  The simple but effective circuit presented here converts an RF input signal into a visible LED indication.  Only discrete components are used.  The circuit can be used as field strength analyser or RF Wattmeter when a 50 ohms resistor is connected between ground and HF (J1).  Calibration required.  Of course you can add extra LED stages in case you want to extend the range.  The second picture shows how the circuit can be build on a very small piece of vero-board. __ Designed by Ron Zoetermeer, JO22gb, Netherlands

RF signal-and power generators -  several circuits on this page. __ Designed by Jan-Martin NÝding

RF sniffer finds 2.4-GHz sources -  11/23/06  EDN-Design Ideas Locate interference sources in the ISM band __ Circuit Design by Vladimir Dvorkin, Linear Technology Corp, Milpitas, CA

RF Synthesizer Uses Generic ICs -  06/24/10  EDN-Design Ideas You can design a hardware-based frequency synthesizer with one inexepensive IC and a few passive components.  Such synthesizer chips are not always available, however, because they are typically single-sourced and are not in stock w __ Circuit Design by James B Wood, Inovonics Inc, Felton, CA

RF Transmitter -  This is probably the simplest radio transmitter that you will find anywhere.  It has a total of five parts and can be constructed into a very samll space __ Designed by Andy Wilson

RF Transmitter Light Sensing -  This transmitter is very similar to the Simplest RF Transmitter.   The only difference being the photoresistor placed in series with R1.   This could also be a thermistor or other variable resistance sensor. __ Designed by Tony van Roon  VA3AVR

RF transmitter uses AM I encoding -  11/24/99 EDN-Design Ideas Although alternate-mark-inversion (AMI] encoding is well-suited for direct-conversion FM transmission, designers often overlook the technique.  AMI, a three-phase, synchronous-encoding technique, uses bipolar pulses to represent logic ones and no signal to __ Circuit Design by Paul Sofianos

RF Wireless PWM DC Motor Speed control -  The wireless PWM DC motor transmitter circuit consists of WZ-X01 RF module, Holtek HT-640 encoder and 8-bit A/D converter.  U1 ADC0804 converts the analog voltage to digital data; U2 encodes that data (D0~D6) along with D6, D7 and transmitting through the RF transmitter module.  The potentiometer VR1 varies the voltage to the A/D U1 pin6, __ Contact: info @ wzmicro.com

RF-Based Dual-Mode Robot -  Here is a dual-mode robot that can be operated manually using an RF-based remote control and can also move automatically avoiding all the obstacles.  The robot has some inbuilt intelligence to__ Electronics Projects for You

RF-Controlled Aircraft -  Presented here is a remote-controlled aircraft project based on Arduino and 433MHz RF modules controlling a brushless DC motor and three servo motors.  It comprises an Arduino-based remote control at the__ Electronics Projects for You

RFID Transponder-Low Power -  This is the Grand Prize winner in the design category of the 1993 RF Design Awards Contest.  This entry exhibited both innovative use of RF technology and an elegant implementation of that technology __ Designed by  Raymond Page

RS-232 to Wireless Instrument Data Channel -  This is an adapter that allows a terminal to communicate via a 100 MHz data channel with peripherals on the same desk top.  Keystrokes from the terminal are are received through the RS-232 connection and sent through the 100 MHz RF data channel.  See the page, Digital Wireless for the Desktop, on this site, for the basics of the transmitter, receiver, and data format.  The reason I made this was to make a simple method of switching between instruments on my desktop.  I was staring to accumulate a number of microcontroller-based devices that I want to be able to switch my computer among quickly and this provided the simplest desktop networking solution I could think of. __ Designed by Dick Cappels

RX3302 433MHz super regenerative receiver Module -  Schematic only __ Designed by Peter Jakab

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RF (Radio Frequency) Amplifiers:  #'s - C      D - K        L - R       S - Z

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