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Amplifier Circuits: 
RF (Radio Frequency)

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

Amplifier -- Main Page
 

Last Updated: November 30, 2017 10:27 AM

Circuits Designed by Dave Johnson, P.E. :
characteristics of CMOS Logic Inverter Amplifiers -  This chart shows some of the measured characteristics of three different unbuffered CMOS logic gates, used as voltage amplifiers . . . Hobby Circuit designed by David Johnson P.E.-February, 2002

CMOS Logic Inverter Amplifier characteristics -  This chart shows some of the measured characteristics of three different unbuffered CMOS logic gates, used as voltage amplifiers. . . Circuit by Dave Johnson P.E.-February, 2002

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

Basic 10GHz / 24GHz gunplexer / gunn diode control -  Schematic only, no circuit description __ Designed by Ron Jones K7RJ Dec 2005

Basic RF Oscillator #1 -  This circuit switches a relay at dark via a Light Dependent Resistor or LDR for short.  The applications are numerous.  In my application, it switches on a light with an older type movement sensor and is mounted on the top corner of my workshop with the LDR facing upwards.  The Dark Activated Relay prevents that the light is triggered during daylight hours.  But, it can also be used to switch led-beacon lights for your driveway, or whatever __ Designed by Tony van Roon  VA3AVR

Basic Stamp 1 & 2 Repeater Controller construction projects -  Cheap controllers __ Designed by Roger Cameron NØYOX.

Basic VOX -  A recent look at some of the budget priced HF transceivers revealed that they were missing a VOX.  Although most of these budget priced transceivers performed admirably, it would certainly be nice to have VOX capability.  Figure 1 is a basic VOX circuit which will perform very well once the VOX level is set correctly.  This circuit is low cost and all parts can be found at your local Radio Shack store __ Designed by Radio Amateur Society of Norwich

Battery operated FM reBroadcast transmitter  -  This implementation is adapted to rebroadcast the output of a CD player, television receiver, or radio receiver.  I use it so that I can move about the house and listen to my favorite programs without disturbing others.  Within and the house, I find that I can get 10 to 20 meters away __ Designed by Dick Cappels

Beat frequency oscillator for AM /SW radio receivers -  schematic only

Bidirectional 2.4 GHz One Watt Amplifier -  This will show you how to add a bi-directional, 2.4 GHz amplifier to your Proxim Symphony for under $100.  Bi-directional means you can mount the amplifier at the antenna to help overcome any cable loss, and the amplifier will automatically switch between receive and transmit modes.  The cost is reduced by using readily available materials and components. __ Green Bay Professional Packet Radio

Bidirectional 900MHz One Watt Amplifier -  This device is a stereo amplifier for a high sensitivity stereo parabolic microphone.  It can be used for listening to distant sounds.  Typical parabolic microphones are monophonic, this unit has a stereo audio path that helps produce more realistic sounding audio.  The Big-E can be used with headphones or as an audio source for a stereo tape recorder __ Green Bay Professional Packet Radio

Bipolar transistor mixer -  Ham RadioV-U)HF AMPLIFIERSchematic __ Designed by Guy Roels ON6MU

Bipolar Transistor Tester -  This tester is primarily meant to test bipolar transistors.  It can indicate the type of the transistor as well as identify its base, collector and emitter pins.  The circuit is very__ Electronics Projects for You

Bizarre: Crystal radio -  A crystal radio set is able to detect radio signals without a power supply. It works best if there is a transmitter within 25 miles (40 km) of the set. The antenna, a very long wire, picks up the waves and passes them through the set as electronic current, and then down to the ground. The set itself is a tuned circuit that can select a desired frequency from the many that are picked up by the antenna. Brian Carusella

Bootstrapping a Phase Locked Loop for Better Performance -  This paper describes a bootstrapping technique for phase locked loops to improve the oscillators’ performance 1 .  The compensation scheme may be useful for correcting aging, warm-up characteristics, temperature stability, short-term stability, and vibration induced phase noise. __ Designed by Charles Wenzel

Broadband UHF Amplifier -  This design uses an GALI-39+   (from Minicircuits) as it has the lowest noise figure   (of this series) NF = 2.4 dB.  The gain is 20 dB.  The bias current can be adjusted by choosing six resistors.  The bias of the monolithic amplifier is done with an TCBT-14+   (Minicircuits), as it is very challenging to do it better __ Designed by Alexander C. Frank, aka Ajarn Changpuak

Broadcast-Band RF Amplifier -  The complete schematic is shown in Fig.1.  The circuit has frequency response ranging from 100Hz to 3MHz; gain is about 30dB.  Field Effect Transistor Q1 is configured in the common-source self-biased mode; optional resistor R1 allows you to set the input impedance to any desired value.  Commonly, it will be 50 ohms __ Designed by Tony van Roon  VA3AVR

Bug Detector -  Figure 1 shows a schematic diagram of the Countersurveillance Monitor.  The circuit, built around a single integrated circuit   (U1.  an MC3403P quad op-amp), three transistors   (Q1-Q3), and a few support components, receives its input from the antenna   (ANT1).  That signal is fed through a high-pass filter, formed by C1, C2, and R1, which eliminates bothersome 60-Hz pickup from any nearby power lines or line cords located in and around buildings and home. __ Designed by Vincent Vollono and Tony van Roon

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. __ Designed by Collin Mitchell

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, . __ Designed by Tony van Roon  VA3AVR

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). __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Build a Band Pass-Band Reject Two Meter Duplexer -  From the W1GAN article in the July 1972 QST 

Build a good Audio Buffer Amplifier -  Audio power amplifier circuit diagrams / circuit schematics __ Designed by Kevin Custer  W3KKC

Build a good GaAs FET preamp for 2 meters, 222MHz or 440MHz -  This circuit will work on 2 meters, 220 or 440 Mc.   Some part values are different for the 3 bands, however general layout and construction are similar. __ Designed by © Kevin K. Custer  W3KKC

Build a Rugged Half-Wave Coaxial Antenna -  This is a coaxial sleeve dipole antenna and is the same basic design as the California Highway Patrol uses at some base stations   (others use full dipoles, ot even a pair of them). __ Designed by Courtesy of the Scanner Buff Network

Build a Two Channel Signal to Noise Voter -  As hand-held transceivers   (H-Ts) become smaller, and low power, battery conserving operation becomes more popular, the disparity between the transmitting range of a typical 100 watt repeater compared to the repeater accessing range of a typical 1 watt or less H-T becomes more and more apparent.  How often have you found it difficult   (or impossible) to access a repeater with a low power H-T even though you can hear the repeater at full quieting? This can happen even if the repeater is equipped with a high sensitivity, state-of-the-art receiver. __ Designed by Mark Kolber  WB2WHC

Build an Isolated Tee Sampler for a Bird 43 Wattmeter -  Build an IsoTee Sampler for the Bird from a blank slug! __ Designed by Kevin Custer  W3KKC

Build your own Iso-Tee -  Build an Iso-Tee from an ordinary T-adapter. __ Designed by Ted Bleiman K9MDM

Build Youself a Service Monitor? -  A simple deviation monitor circuit used with a scanner receiver. __ Designed by Tom Alldread VA7TA

Build Youself a Service Monitor? -  For creating a COS signal on radios that don't have one.  This is a VOX circuit that uses a FET as the input amplifier to avoid loading down the source. __ Designed by Tom Alldread VA7TA

Building a simple crystal radio -  A crystal radio is the distilled essence of a radio. It has very few parts, it needs no batteries or other power source, and it can be built in a short time out of things you can find around the house. __ Designed by Simon Quellen Field

Building blocks -  Radio building blocks __ Designed by EI9GQ homebrew radio

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


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