Vacuum Tubes Valves
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4 Band Resistor
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RF Receiver Circuits
RF Receiver Circuits
A Regenerative Receiver with AGC for 80 Meters or 3-10 MHz Shortwave
Here`s a Regenerative Receiver project that I designed for the 80 meter Amateur band, but which can also be used in a wider-tuning configuration that covers approximately 3 MHz to 10 MHz, for Shortwave (World Band) listeners. Built in the same style as my previous "40-Meter Tweeter" which can also be found at my Radio Projects menu at, this radi
A Regenerative Receiver with AGC for 80 and 40 Meters
Here`s a dual-band Regen that came from some encouraging emails from Jerry (K9UT) and another gentleman named Harvey, who built my original AGC-80, and its experimental "Regenerodyne" successor, the AGC-80/30. Jerry and I have corresponded on several occasions, and he tells me that he enjoys both receivers and that they work surprisingly well for
Tuned Radio Frequency (TRF) Receiver
Superheterodyne receivers have been mass-produced since around 1924, but for reasons of cost did not become successful until the 1930s. Before the second world war other, simpler receiver technologies such as the TRF receiver and the regenerative receiver were still widespread. The circuit described here is based on the old technology, but brought
Complete Stand-Alone GPS Receiver Solution with MAX2742
Complete GPS solution using MAXIM CMOS RF front-end receiver MAX2742 and SONY GPS baseband CXD2932 is presented..
Data Slicing Techniques for UHF ASK Receivers
This application note explains the operation of the data slicers found in the Maxim line of UHF receivers like the MAX1470, MAX1473, and MAX1471 and transceivers like the MAX7030 and MAX7032..
Regenerative AM Receivers
The regen is basically an oscillator circuit with a gain control that allows the user to adjust the feedback to a point just below oscillation or, quite often, just above the critical level such that a small oscillation is present. The typical regen uses a tapped coil or additional windings to connect into the tuning tank and the tuning capacitor
super simple shortwave receiver circuit
Integrated circuit Ul (an NE602 double-balanced mixer) is a combination oscillator and frequency mixer. Signals from the antenna input (at Jl) are fed through dc-blocking capacitor C1 to the RF-gain control, Rl, and fed to the input of Ul at pins 1 and 2. The local-oscillator frequency, which varies with the settings of R2 and L2, is mixed...
The Demodulating Receiver (A3017) contains a 902 ’930 MHz 30-dB amplifier, a downshifer, a 60-dB 50-MHz limiting IF amplifier, a frequency discriminator, and an amplitude demodulator. The A301701A circuit board also includes, just for good measure, more copies of the A3016SO SAW Oscillator and the A3008C Spectrometer. If you can`t understand our
Medium Wave radio reciever circuit
This radio reciever can work with any of the following transistors zn414, mk484 or ta7642.
5 Tube AC/DC Radio Receiver
Virtually all AM radio manufacturers used this exact circuit from about 1948 to 1963 or so. People are starting to collect these radios as antiques of sorts. I would be happy to credit the creator of this figure and caption, but I don`t recall from where I down-loaded this. If you made it or know who did, please give me an electronic holler.
Simple Pyro RF Receiver (27 MHz) Circuit
The schematic for this project flows naturally from left to right. Beginning at the antenna and the regenerative receiver front-end, then flowing through the amplification stages and then into the 555 timer. This is a very common regenerative receiver front-end that you can find in circuits all over the web. I tailored the parts used to what I ha
Simple Pyro RF Receiver (27 MHz) - Signal Mixing
After the wizardry that is our standard renegerative front-end receiver circuit, we will be able to see some initial output receiver from our transmitter. The point in the schematic we`ll look at first is right after the LC tuning circuit and DC blocking capacitor: On the Left side there is a picture of that point when nothing is being transmitte
K7LR Memorial Receiver
This web page is a memorial to Mike Caughran, KL7R, who died suddenly in January 2007. Mike was a passionate experimenter who was embraced by the homebrew radio electronics community. He was best known as the co-creator of and sidekick to Bill Meara, M0HBR on the podcast Solder Smoke. Mike was a hardcore science and technology buff. His knowledge
Simple Direct Conversion Receiver
Simple Direct Conversion Receiver
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 of the ideas/design of the various stages must be credited to
40 m Band Superhet Receiver
By the addition of one integrated circuit and some passive components, I was able to convert my earlier developed 40-meter direct conversion receiver design into a superhet model. Anyone who has listened to 40 meters during the evening hours on the crowded 40 m band will appreciate the advantages of the single signal reception, which this circuit
136 kHz QRSS receiver
For digital modes the ideal receiver must be very simple, front end selectivity, manually adjustable gain, IF filter. All the goodies you can find on the HF receivers can be done by software. In my junk box there were one surplus 1. 4 MHz, 3 kHz wide Xtal filter, too large for SSB equipments but ready to pass all the 136 kHz band, and some DBM mixe
Battery Powered Tube Regenerative Receiver
Basic Regen design is pretty common, so BEFORE the schematic comes the "concept stage", the "what`s available in the junkbox stage", back to the "concept stage", followed by the "mechanical/electrical layout stage", then sketch a rough schematic. and do it all over again. The BC-221 has always impressed me as having about the simplest, smoothest,
A 30 Mtr Direct Conversion Receiver for QRSS
The schematic for the crystal bandpass filter/amplifier board appears below (left) withimages of the assembled and boxed unit appearing below center andright. The signal frequency bandpass filter isconstructed over a ground plane and housed in its own enclosure measuring 75 x 75 x 50 mm. The separate enclosure ensures freedom from unwanted signal
Vacuum Fluorescent Device Regenerative Receiver
This little project arose from a desire to experiment with some of the more "traditional" methods of radioconstruction which enjoyed popularity some 70 years ago. I wanted to find out for myself what kind of performance could be achieved using simple circuits incorporating Valves/Vacuum Tubes and low budget design techniques popular in the 1930`s.
The EC10 communications receiver
One thing we should keep in mind is that the EC10 is now a vintage receiver, it has collector appeal. Any-thing we do should really be carried out in a manner that preserves the original state, most of the following adheres to this. Things like replacing all of the Germanium transistors with Silicon devices could be done but this would be...
AM IC Radio Receivers
AM Radio Receivers
Tube Regenerative Receiver
Wideband AM Radio Receivers
Improving the MICOR Receiver for 435-450 MHz
This is a detailed explanation of a procedure you can use to modify a UHF MICOR "M" range (450-470 MHz) receiver board so it operates adequately in the 435-450 MHz range. This is an enhancement to Kevin`s text-only article. These receivers are commonly found in a Spectra TAC chassis as well as base stations, mobiles, and satellite receivers. They
RF Cafe visitor David M. wrote to ask that I scan and post this article from the January 1963 edition of Popular Electronics. It is an article written by Philip Hatfield, of the Receiving Tube Department of General Electric that describe a very simple design that uses a " compactron " vacuum tube, which consist of two triodes and a pentode.
1.8MHz AM transmitter and receiver
Before starting on the receiver side of the` Chatterbox`, we ought to take a final look at the transmitter itself. The Chatterbox transmitter is built separately, because many constructors will want to use it in conjunction with an existing receiver on 1. 8MHz. It`s been assumed that an existing antenna tuner and low-pass filter unit will be used w
Super-regenerative receiver at 433MHz
GP2015 - based GPS receiver RF front-end circuit
MRFICl505R2 based GPS receiver RF front-end circuit
MRFICl505R2 is a 1. 575GHz GPS downconverter chip. It integrates mixer, VCO, PLL, crystal oscillator, A / D converter and loop filter and other circuits. MRFICl505R2 IF output frequency is 4. 1MHz; it has 105dB typical conversion gain, 2. 7V operating voltage, 28mA typical current consumption; it is available in LQFP-48 package.
FM Radio Circuits
RF Transmitter Circuits
RF Amplifier Circuits
AM Radio Circuits
FM Transmitter Circuits
Ultrasonic distance finder circuit
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is measured. There are three main categories of distance measurement methods in use: a) By...
Simple Metal detector circuit with CD4030
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to find something potentially valuable, hidden a few centimeters below the soil. So many...
Fully automatic watering circuit for flower pots
Many times for various reasons we forget or can not water the plants that we have in our homes. And many humidity sensors units just notify us with a beeping sound or with a flashing light, that the pot needs watering. But what if we are away from home? This circuit comes as a solution to this problem. Depending on humidity of the pot at...
Simple deep searching metal detector circuit
The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the circuit of this metal detector, it is possible to detect a metal coin in depth of 90 to...
Sub-Harmonic Bass Converter for Electric Guitars
The sub-harmonic bass generator is a sound producing unit for guitars. The sound it produces looks very much like that of the bass guitar. The octave generator is sometimes quite unusual since it does not produce any of the usual ways of coloring the sound, such as filtering or distortion. Instead, a frequency division system produces outputs...
Echo Depth Sounding Sonar for Boats
In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the calibration of the rope. This arrangement still exists in some yachts. The big...
100W HiFi Audio Amplifier Circuit
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power supply must be symmetrical so that no electrolytic capacitors are needed at the outlet....
Plant-Pot Water Level Indicator Circuit
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower. The circuit of the device is shown in Figure 2. The water detection is made from the bottom...
Analogue Sound Preasure dB-Meter Circuit
The best human ear can capture sounds from 20Hz to 20KHz. These limits are known to be the broadest that can exist. Normally the normal limits range from 100Hz to about 13KHz and depend on the age and health of the individual. We for our measurements and to have a good accuracy we will get the limits of 20Hz to 20KHz. A sound to be heard does...
Digital Signal Integrity
Interconnection and Timing of Digital Circuits
CMOS Circuits Tutorial