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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:

All Discrete Components 40 M transceiver with super-het receiver using no IC's -  When I was a little kid I asked my Dad,   (who was a TV repairman), "If a 6 transistor radio works good, wouldn't a radio with 100 transistors work better?" __ Designed by Steven Weber, KD1JV

ALT-Altoids L Tuner -  Altoids L Tuner   (ALT) "L" tuner for half wave end feed antennas. __ Designed by Steven "Melt Solder" Weber  KD1JV

AM BCB Radio Receiver -  An a.m.  receiver relies upon the original carrier signal   (station frequency) having been amplitude modulated.  This means the original amplitude   (strength) varies at an audio rate.  Looking at figure 1 we can see an unmodulated carrier signal as it might be seen on an oscilloscope. __ Designed by Ian C. Purdie VK2TIP

AM DSB Transmitter for Hams -  circuit diagram of simple double side band suppressed carrier   (DSBSC) transmitter for hams.  Circuit uses crystal oscillator, crystal can be switched for multi band operation

AM Farm Radio Power Supply -  Prior to the 1950s, many rural areas in the US had no electricity.  Many companies sold battery operated vacuum tube radios for use in these areas, the radios are commonly called Farm Radios.  Farm radios are often available at very reasonable prices and can make a good restoration project __ Designed by G. Forrest Cook

AM to FM converter -  The above circuit can be used to hear AM Stat;ion on your FM Radio.   It is a regenerative circuit that samples Amsingnals of all frequendy and retransmits them in the FM band   (88-108) and even in the TV Band. __ Designed by aswinkumar

AM-FM-SW Active Antenna -  This simple little circuit can be used for AM, FM, and Shortwave   (SW).  On the shortwave band this active antenna is comparable to a 20 to 30 foot wire antenna.    It is further more designed to be used on receivers that use untuned wire antennas, such as inexpensive units and car radios __ Designed by Tony van Roon  VA3AVR

An 80 meter rig for the MAS contest by KD1JV -  Designed to be competative in the DL 80M "Mininum Art Session" contest, this rig features a crystal controlled 2W transmitter and a sensitive regenerative receiver, using 51 discrete parts on a 3.5" x 2.5" circuit board. __ Designed by Steven Weber, KD1JV

An Audio Equalizer for Communications Use 234 kB PDF file -  This five-band audio equalizer was originally designed for use at a multireciever site   (a voting system hub).  Originally published in the May 1990 QST __ Designed by Robin Humbolt WA4TEM

An Audio Limiter for NBFM use -  This image is of a hard audio limiter used to limit the amount of deviation in an exciter.  After the "knee" the compression ratio is infinite to 1   (hard limiter.)  Smaller amounts of compression ratio can be achieved by inserting resistance between the output of the rectifier, and the DC input of the FET   (gate.)  This circuit can be used ahead of the processing in a standard exciter to add compression, or hard limiting. 
The "R" and "G" are red and green led's.  The op amp can be a 5532, LF-353, or TLO82. __ Designed by Kevin K. Custer  W3KKC

An Audio-Noise-Based Voting -  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

An end-fed antenna -  A piece of wire of almost any length can be used as an antenna on the HF bands.  However, just because an antenna can be made to work is no guarantee that it will perform efficiently.  This article will initially concentrate on the half wavelength of wire and its useamateur radio construction projects. __ Designed by Peter Parker VK3YE

An Inexpensive Tone Encoder -  Figure 1 illustrates an easy circuit that can be constructed with mostly Radio Shack parts on any general purpose circuit board.  The only rigid requirement is that capacitor C1 be stable over a wide temperature range.  Use only Mylar, Polyester or Metal film for capacitor C1.  The frequency is determined by the following formula: FREQUENCY = 1/R1C1The specified values should allow any tone between 100 to 300 Hz.  Increase R1 or add another resistor in series with R1 for lower tone frequencies __ Designed by Radio Amateur Society of Norwich

AN-60-008  Operating precautions for RF Amplifiers -  AN-60-008 App Note__ MiniCircuits.com

Antennas for Ham Transmitters -  Describes how to construct various type of antenna for Ham Radio Transmitters

Audible S-Meter -  hand-drawns schematic only __ Designed by byon Garrabrant N6BG

Audio Amplifier -  SSB Transceiver-Receiver Section:  The AF amp has about 60 to 70 dB of gain.  The transistor is a BC109C.  I might try replacing it with a lower gain device.  A typical 59+ signal, gives more than a volt pp at the collector.  The power amplifier IC is an LM380N   (14 pin version).  If you intend to use the rig on CW, the LM380N must be powered up on transmit as well as receive   (for the sidetone osc.). __ Designed by EI9GQ homebrew radio

Audio Buffer & De-Emphasis -  Use this circuit after a repeater receiver to de-emphasize the audio going to your controller. __ Designed by Lou Harris  N1UEC  offsite link

Audio Equalizer for Communications Use 234 kB PDF file -  This five-band audio equalizer was originally designed for use at a multireciever site   (a voting system hub).  Originally published in the May 1990 QST __ Designed by Robin Humbolt WA4TEM

Audio Limiter for NBFM -  This image is of a hard audio limiter used to limit the amount of deviation in an exciter.  After the "knee" the compression ratio is infinite to 1   (hard limiter.)  Smaller amounts of compression ratio can be achieved by inserting resistance between the output of the rectifier, and the DC input of the FET   (gate.)  This circuit can be used ahead of the processing in a standard exciter to add compression, or hard limiting. 
The "R" and "G" are red and green led's.  The op amp can be a 5532, LF-353, or TLO82. __ Designed by Kevin K. Custer  W3KKC

Automicro RX3304 receiver Module schematic -  Schematic Only __ Designed by Peter Jakab, Electrical Engineer, Engineer of Informatics

Aviation Band Receiver -  Figure 1 shows a schematic diagram of the Aviation Receiver--a super heterodyne AM   (Amplitude Modulated) unit built around four IC's: an NE602 double balanced mixer   (U1) , an MC1350 linear IF amplifier   (U2) , an LM324 quad op-amp   (U3) , and an LM386 audio amplifier   (U4).  In operation, an antenna that plugs into J1 picks up the AM signal.  That signal is then coupled through C1 to a three-section, tuned-filter network consisting of L1-L5 and C2-C6 __ Designed by Tony van Roon  VA3AVR

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


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