A radio receiver is an electronic circuit that receives its input from an antenna, uses electronic filters to separate a wanted radio signal from all other signals picked up by this antenna, amplifies it to a level suitable for further processing, and finally converts through demodulation and decoding the signal into a form usable for the consumer, such as sound, pictures, digital data, measurement values and navigational positions. Consumer audio and high fidelity audio receivers and AV receivers used by home stereo listeners and audio and home theatre system enthusiasts.
Communications receivers, used as a component of a radio communication link, characterized by high stability and reliability of performance. Simple crystal radio receivers (also known as a crystal set) which operate using the power received from radio waves. Satellite television receivers, used to receive television programming from communication satellites in geosynchronous orbit.
Specialized-use receivers such as telemetry receivers that allow the remote measurement and reporting of information. Measuring receivers (also: measurement receivers) are calibrated laboratory-grade devices that are used to measure the signal strength of broadcasting stations, the electromagnetic interference radiation emitted by electrical products, as well as to calibrate RF attenuators and signal generators.
Scanners are specialized receivers that can automatically scan two or more discrete frequencies, stopping when they find a signal on one of them and then continuing to scan other frequencies when the initial transmission ceases. They are mainly used for monitoring VHF and UHF radio systems.
Internet radio device.
DSP technology, short for digital signal processing, is the use of digital means to process signals and is coming into wide use in modern shortwave receivers. It is the basis of many areas of modern technology including cell phones, CD players, video recorders and computers. A digital signal is essentially a stream or sequence of numbers that relay a message through some sort of medium such as a wire.
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6-17 MHz SW reciever
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This circuit is a SW band reciever of range 6 to 17 MHz. Its very simple as It uses only 3 transistors 2n2222.The Coils can be altered to change the range of reception by lowering or highering the frequency...
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Crossed from: Inside Circuits | Clicks: 11513 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Crystal Radio II
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Nice Crystal Radio with 1N34A Germanium Diode. Use a 24 inches piece of wire for the antenna...
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Simple Coil-less AM receiver
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This AM receiver is working perfectly without the need of coils or even a variable capacitor. The LF356 is the basic component. P1 and P2 are the frequency selectors. Use a small telescopic antenna. The stations selectivity is not perfect but is acceptable. ..
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Crossed from: Bug | Clicks: 18986 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Wireless Bug detector
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This fairly simple circuit makes it possible to place such a wall as a conduit to locate. It is a conduit for power, no water or gas-seeker. The only requirement is that there is tension on the line. The antenna in the table can consist of a simple piece of copper wire. The correct adjustment is done through R7, in order to prevent the buzzer and LEDs still light up even though there is no leadership in the area.
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Crossed from: AM radio | Clicks: 13347 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
AM Radio Receiver schematic
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Pictured above is a little AM superhetrodyne receiver that covers the broadcast band from 550 Khz to 1650 Khz. The circuit employs the 8 pin Signetics balanced mixer IC (NE602) which converts the incoming RF signal to the standard 455 Khz IF signal and provides about 13dB gain. The IF signal is amplified by a single transistor stage and audio is recovered using a biased shotkey diode (5082) and JFET buffer transistor. The LM386 audio amp is used to drive a small 2.5 inch speaker at about 200 milliwatts. The circuit contains four LC tuned circuits, all of which need to be fine tuned to obtain good results. An oscilloscope and RF signal generator are
useful, but the circuit can also be setup using local radio stations and an additional portable AM radio...
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Crystal Radio III
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This is basically a crystal radio with an audio amplifier which is fairly sensitive and receives several strong stations in the Los Angeles area with a minimal 15 foot antenna. Longer antennas will provide a stronger signal but the selectivity will be worse and strong stations may be heard in the background of weaker ones. Using a long wire antenna, the selectivity can be improved by connecting it to one of the taps on the coil instead of the junction of the capacitor and coil. Some connection to ground is required but I found that standing outside on a concrete slab and just allowing the long headphone leads to lay on the concrete was sufficient to listen to the local news station (KNX 1070). ..
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Pocket Radio AM / FM circuit
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Earphones, batteries are sold separately. AM / FM seems to be a common mold. But stamping is different. AM / FM E193577 UL94V0 board with the AM / FM etching printed circuit board manufacturers are the same. Shape is considered to be shared. (Design, sharing the production process design?). Radio FM transistor S9014, IC LA1800 is used. 100 AM, FM Radio and 2W IC Amp substrate incorporated into the case. Variable capacitor is used for the junk FM · AM variable condenser 2. FM section, and turned the proximity variable capacitor, AM has a distance as a measure of the local oscillator wrap, leads unavoidably variable capacitor, Sorudatoru (desoldering wire), and with the shield. Radio low-frequency portion, FM ANT has converted part of the circuit. Radio is the height of perfection impressed.??..
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Crossed from: RF | Clicks: 14774 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
500kHz to 4 MHz Converter
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This converter allows reception of signals below 500 kHz on a 3.5 ? 4 MHz HF receiver. It should therefore be useful for those with receivers that do not receive the lower frequencies. Again the converter uses the popular NE602 mixer/oscillator chip. A cheap 4 MHz crystal provides the local oscillator tuning. Note that tuning is backwards ? 100 kHz corresponds with 3.9 MHz and 500 kHz with 3.5 MHz. If your receiver tunes above 4 MHz, the 4 ? 4.5 MHz range will provide forwards tuning, making it easier to ascertain the frequency of an unknown station. The mixer is preceded by a low pass filter to attenuate strong local broadcast stations above 500 kHz...
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Crossed from: AM radio | Clicks: 271 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Regenerative receiver for AM band
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The regenerative detector uses a field effect transistor (FET). Like with the better valve designs, feedback is controlled by a variable capacitor. A ferrite rod was used to allow reception of local stations without an external antenna. This FET stage forms a complete receiver on its own, but the audio output is quite low. The received audio is amplified by an NPN bipolar transistor. The gain of this transistor amplifier is sufficient to provide speaker reception of local stations in most areas. The 1k to 8 ohm transformer in the collector allows the set to be used with both low and high impedance headphones...
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Crossed from: AM radio | Clicks: 15669 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
AM Radio with ZN414
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The ZN414 IC contains an entire automatic gain controlled AM receiver in a small three pin package. With only a few external components, a simple radio with excellent selection and reception can be constructed. Since the chip also uses a low supply voltage of only 1.3V, 3V coin cell battery can make for a physically small circuit with many covert uses. The chip has a wide bandwidth of between 150KHz and 3MHz, so by playing with values in the tuning circuit you can pick up a wide variety of signals...
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One Valve SW Radio reciever
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A regenerative radio works by feeding back a small amount of amplified output of the detector back into the input. Thus it achieves sensitivity far beyond what only a detector could alone. This simple regen radio uses a single tube as it's detector and amplifier; the "Audion". It's a great first project for those wishing to bring back some nostalgia by building one of the first amplified radio sets. Built on a board using point to point wiring and a set of period headphones, it can be a great functional conversation piece...
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TDA7000 FM Radio
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This extremely simple FM radio receiver circuit is made possible by the special purpose TDA7000 IC. It integrates nearly all the functions necessary to build an FM receiver needing only a few external capacitors and a tuning circuit. Using a simple active RC filter made of only a single inductor, a few resistors and a varicap, this FM receiver will pick up broadcast radio between about 88 and 108 MHz. The mono output signal can then be used to drive a set of high impedance headphones, or feed a power amplifier...
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Aircraft Radio Band Receiver
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The communications between commercial aircraft and the ground can be interesting, amusing and sometimes even disturbing. However radios that receive the approximately 220MHz to 400MHz band commonly used for aircraft (both military and commercial) are not easily found. And scanners can be complicated, large and expensive. With an easy to build circuit such as this one, everyone can enjoy listening in on these conversations...
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40 meter band Receiver II
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Using the circuit of 40-metre band direct-conversion receiver descr- ibed here, one can listen to amateur radio QSO signals in CW as well as in SSB mode in the 40-metre band. The circuit makes use of three n-channel FETs (BFW10). The first FET (T1) performs the function of ant./RF amplifier-cum-product detector, while the second and third FETs (T2 and T3) together form a VFO (variable frequency oscillator) whose output is injected into the gate of first FET (T1) through 10pF capacitor C16. The VFO is tuned to a frequency which differs from the incoming CW signal frequency by about 1 kHz to produce a beat frequency in the audio range at the output of transformer X1, which is an audio driver transformer of the type used in transistor radios...
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0.1Hz to 10Hz RF reciever
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The frequency covered is from 0.1Hz to 10Hz and useful signals are received up to 16Hz. The first Op-Amp, properly shielded, must be installed close to the antenna (1-3m long) and connected to the rest of the circuit with a 5-core shielded cable. Adjust the 100k trimmer so that the DC setting at the output of the OPA124 does not change when turning the 220k sensitivity pot. A low pass filter followed by a notch filter take care of the mains induced noise. The values in brackets are good for a 60Hz mains. 1% components should be used for the 3 resistors and 3 capacitors of the notch filter. ..
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