This is important because the gain of a differential pair decreases with increasing input level. . That is when the set is most sensitive. See the links below for an article by him. 80m All-BJT's Direct Conversion Receiver. Post subject: Re: Interesting design for regenerative receiver. This second oscillation periodically interrupts or "quenches" the main RF oscillation. Regenerative receivers require fewer components than other types of receiver circuit. JFET Regenerative Radio Receiver. A regen receiver has 1,000 times more RF gain than a crystal set, but not necessarily better audio quality for stations that are nearby. Staff member. There are also 3 PDF files in the ZIP -- two on "hybrid feedback" regenerative receivers, and one on a regenerative antenna. The solution here is something called automatic gain control, abbreviated AGC. When a regenerative receiver is oscillating, it can cause radio interference in the reception of other receivers. The unit shown Figs. Receptor regenerativo de HF com transistores comuns. Tuning is accomplished by a 1SV149 hyperabrupt varactor powered by a separate 9-volt supply. Pixie 40m CW & DSB modulated 0,5W ceramic resonator operated VXO. I have in plan to build version with BF256 BJT HF transistors. A minimalist shortwave regenerative receiver circuit is presented that is powered by a 1.2-volt cell and uses exclusively 2N3904 transistors. The on-chip frequency is maintained at a fraction (1/16) of the off-chip data Top . Low-power BJT converter stage for superhet - The RadioBoard Forums.html; Multi-band regenerative loop antenna - The RadioBoard Forums.html; . Ultrasonic quench rates between 30 and 100 kHz are typical. from active component used in detector, there is BJT version and FET version An FET version of the 1-V-1 Regenerative Receiver, designed and built by C.F. Ultrasonic quench rates between 30 and 100 kHz are typical. In practice this is not a problem. Failure to properly spot the VFO/transmitter in the receiver is why many modern hams fail to make successful QSOs with vintage gear or regenerative receivers. Building a simple 27Mhz transmitter is simple but I'm struggling with the receiver. Pixie DSB. The Neutralization Cure Louis Alan Hazeltine in 1920 filed a patent [6] that will help us to fix our RF . A continuous reception range of around 160 kHz to 30 MHz could be covered over five switchable wavebands. The careful use of JFET devices in regenerative radio design can bring many benefits. A tuned radio frequency receiver (or TRF receiver) is a form of radio receiver which is made using a number of tuned radio frequency (RF) amplifier stages accompanied by a detector (demodulator) circuit to draw out the audio signal, along with an audio frequency amplifier for amplifying the extracted audio into a loudspeaker. I used a preset potentiometer since my receiver was only used for one band. Initially I thought a super regenerative receiver would work. A Three-Transistor Receiver The FET as a Regenerative Detector BY WALTER F. LANGE, * WIYDS VEX in this age Of crowded hands and sophis- ticated communications systems, there is room for the lowly regenerative receiver. The large value of the capacitor between the source of the FET and the emitter of the BJT resulted in order to be able to make the circuit oscillate even in the long-wave range. Having discovered regeneration, Howard Armstrong stumbled on superregen ten years later, while doing some checking for his court battle of the regen patent. . Failure to properly spot your transmitter frequency can place your transmitter frequency as many as 2kHz or more off from your receiver frequency! Here's a list of the threads and articles that I saved in that ZIP file: . A regenerative receiver can be constructed using a single transistor. Member: Joined: Feb Sat 08, 2014 6:43 pm Posts: 79 Location: Denver, CO Good info, OldWireBender. Now tune C2 to the desired frequency. Your circuit has the audio output at the collector of a regen receiver. Superhet Transceiver QRP 40m CW QSK 30m SSB Superheterodine Receiver. This time, built the NA5N pipsqueak Regen receiver. Multi-band regenerative loop antenna - The RadioBoard Forums.html. The PNP transistor audio amplifier is designed for connection to the emitter of a super-regen receiver. 40m CW-SSB Simple Superhet Receiver. A suitable location is a metal cold water pipe. Regenerative receivers have a long history in radio dating back to the first days of the vacuum tube. Transceptor QRPp CW / DSB 0,5W com ressonador ceramico. causes in BJT and MOSFET and we need different cures. 6. 1X . Regenerative receiver for SWL use, made with bjt transistors . Figure 8 A useful audio filter circuit. Low-power BJT converter stage for superhet - The RadioBoard Forums.html. 1) replace lm386 with a 100x feedback pre amplifier plus a 8x power amplifier 2) replace one 1N941 with a RED led, make the. The receiver tunes the entire 30m band (10100-10150) and performs quite well. Increase R1 until the headphones squeal, then back off. You can avoid this by adding a RF amplifier stage between the antenna and the regenerative detector. 11,248. 9 years ago. ULTRA SIMPLE MEDIUM WAVE REGEN RECEIVER USING ONLY AN LM386 AUDIO AMPLIFIER - The RadioBoard Forums.html; Unusual AM Superregenerative? I think the author meant Super-Regens.These are frequently used in simple commercial products, but rarely are Regens.Also it is a big pity that the article has such a USA bias. 3X 2N2222A TRANSISTORS OR ANY NPN BJT TO92 PIN COMPATIBLE like 2N3904. It's kind of a regenerative receiver with a crystal in it. Since there are really two valves in one glass envelope, the set is really a two-valve receiver.The triode section is used as a regenerative detector, and the pentode section (wired as a triode) is used as a stage of audio amplification. BJT regen rcvr.jpg [ 39.15 KiB | Viewed 3846 times ] Last edited by pentagrid on Mar Sun 08, 2015 5:21 am, edited 1 time in total. 40m MRX-40 Receiver - K8IDN. Most of this reputation is due to design short cuts that have been implemented over the years. Closing the Loop. Prea instrues (only in portuguese) 94kb. 5. The line "Regenerative receiver circuits are still used in low-cost electronic equipment such as garage door openers" is utter nonsense. It uses 4 Russian electronic tubes (6N3P) very similar to ECC81 / ECC85, but with a different pin code. So this time I would build a regenerative receiver that is much lower frequency, and I chose 10.000 MHz because I can receive the WWV time signal most of the time on this frequency. If it fails to oscillate, reverse the connections to the reaction winding. The normal way is to have a tap on the coil - probably about 1/5 to 1/10 of the way up from ground. Since I only need a maximum of 10m, a 27MHz rf signal would be ideal. A superregen receiver is just an extension of a regenerative receiver. Variable capacitor C1 and coil L1 from the usual parallel resonant circuit that determines the receiver frequency. The super-regenerative receiver uses a second lower frequency oscillation (within the same stage or by using a second oscillator stage) to provide single-device circuit gains of around one million. Low-power BJT converter stage for superhet - The RadioBoard Forums.html; Multi-band regenerative loop antenna - The RadioBoard Forums.html; During tuning of the antenna input, miller-effect of the RF stage adds more to the effect of unwanted coupling. It is easy to listen SSB, even on 18 MHz. Posted: Mar Fri 13, 2015 3:05 am . Receiver - The RadioBoard Forums.html . #10. The 10K potentiometer controls the reaction and greatly increases the receiver sensitivity. The QRPGuys K8TND Regenerative Receiver covers the 60, 49, 41, 31, 25 meter shortwave bands (approximately 4.5 to 12.7 MHz), with a receiver you build complete from the supplied chassis pieces, electrical components, and hardware. Increase the setting until oscillation ONLY JUST starts. However, its performance is similar or better than usual regenerative receiver. We can intuitively conclude that there really is no way to achieve this in an open-loop systemthe amplifier circuitry must have knowledge of the output amplitude in order to properly adjust the gain. Download File PDF High Performance Regenerative Receiver Design overcome by parallelizing the data. The problem with the regen is that the best sensitivity is when it's on the verge of oscillation. I should be able to use the phase difference between the received signal and a local oscillator to calculate the change in distance. diodes, step recovery diodes, BJT, HBT, MESFET, HFET, and various microwave circuits like switch, phase shifter, . The audio input should have a relatively low impedance to give correct filter performance. They are. I through is a simple receiver that Should be easy for most anyone to build, regardless Of his experience. You can copy CW and SSB signals quite easily. This SW regenerative receiver has only 12 V for B battery. Audioguru. The audio quality of a regen receiver is okay for broadcast AM band, but is unacceptable for music. Early vacuum tubes had low gain at radio frequencies (RF). Following the antenna buffer is a high . Note: Regenerative receivers embrace a wide spectrii of subjects, and span a wide area of time, thus thread topic can range widely, from circuit dynamics to old radio lore. Feb 6, 2008. A capacitor across the feedback resistor of the transistor reduces its gain to zero. They excel at receiving amplitude modulated signals from below the AM broadcast band up to the higher short-wave bands above which the superregenerative detector becomes the better choice. Note, however, that you still have an active oscillator connected to an antenna, so it will be radiating. A part of the oscillator signal is transmitted via the antenna that is coupled to the regenerative detector. A regenerative frequency divider (analog divide-by-two) with quadrature outputs [12] was selected for this design. but with some modify. There are also 3 PDF files in the ZIP -- two on "hybrid feedback" regenerative receivers, and one on a regenerative antenna. The regenerative radio receiver or, even super-regenerative radio receiver or, "regen" if you prefer, are basically oscillating detector receivers. This second oscillation periodically interrupts or "quenches" the main RF oscillation. The circuit's original attraction was that it got more amplification ( gain) out of the expensive vacuum tubes of early receivers, thus requiring fewer stages of amplification. The consequences of regeneration of the regenerative TRF receivers are the radiation and unwanted coupling of the antenna and the L-C circuit. instead of a JFET or RF transistor it used a regular BC548 BJT (bipolar junction . Feb 14, 2014 #60 betwixt Super Moderator. Dynamically damped regenerative receiver. 3 MHz - 5 MHz Cascade Regenerative Receiver - WD5HOH. I want use a BJT w/o having to resort to a transformer for coupling the output of the transistor to the headset. Top I've now got the all the worst features of regeneratives: Hand capacitance: the oscillator wavers and even halts when I touch the regenerative control. Further modifications include an inductor with the emitter of the transistor, and a capacitor across the emitter resistor of the transistor. The Q Multiplier relies on the BJT square law AM Detector to provide sufficient dynamic damping to give smooth control of regeneration. JFET's have much lower noise than BJT transistors and their high input impedance allows them to be directly connected to a resonant LC circuit without the impedance matching that BJT's require. Compared to an RC polyphase filter (for quadrature signal generation), the regenerative technique is less susceptible to process gradients and tolerances, requires less chip area, provides signal gain, and Practical Circuits A simple but effective regenerative radio circuit is shown in Figure 1. This causes QRM and the loss of QSOs. ; Jun 16, 2021 - This Pin was discovered by Prunaru Stefan. Being primarily a Tube/FET guy, I don't usually play around with BJTs. Internal freq and cathed freq overlaps and gets more power. Also the station is easily recognizable with its constant tones and beeps. Regenerative Receivers Regenerative receivers provide a surprising level of performance with only a handful of components. The extra transistors and ICs allow for speaker operation and for other improvements in performance. It follows, then, that AGC requires feedback. 80m-40m Direct Concersion Receiver - VK3AWC. MY question: I am looking to build a small headphone amp for 65ohm/channel JVC headset (or my cheap earbuds) for a small SS regenerative receiver that I am designing. To use the set, place C2 at about midway, set R1 fully counterclockwise and then turn on S1 and allow the tubes several seconds to warm up. ; MK484 AM Receiver by Chad Castagana 28. JFET's have much lower noise than BJT transistors and their high input impedance allows them to be directly connected to a resonant LC circuit without the. There are a couple of things that could be improved: The tuning coil needs matching to the input impedance of the transistor - as shown the transistor will heavily damp the resonance causing the selectivity to be low. You connect the receiver to a simple wire antenna, that can be a simple wire in the attic, or one thrown up in a tree.. The oscillator starts and stops unpredictably. Rockey, is directly mapping from value. The input is an antenna buffer that presents a high impedance to the antenna and results in a short wire acting like an active antenna. The 2 JFET devices are arranged as an AC-linked differential pair. 3 x Superregenerative Receivers - RSGB. This does two things: it keeps you from getting nice QSL cards from the FCC for spurious emissions (maybe), and it lets signals coming in the antenna affect the strength of oscillation. Output power is good for headphones. The special feature of a regenerative receiver is that an active component, or more precisely the gain of an active component, is used to implement a form of feedback that is adjusted to the point where the circuit is just on the edge of oscillation. This called for an increase in the feedback capacitor and also to use a transistor specifically designed for handling extreme high frequency ranges such as a BF494. A regenerative radio receiver is unsurpassed in comparable simplicity, weak signal reception, inherent noise-limiting and agc action and, freedom from overloading and spurious responses. Joined Jul 4, 2009 Messages 15,575 Helped 5,036 . Antenna catches fm waves, first transistor works as oscillator. No special coils or uhf transistors. The circuit is based on a design by EN Bradley for a pocket one-valve receiver, which used a 3A5 (DCC90) valve.The regenerative circuit remained a favorite . As a test I tried to change the two-transistor cross-coupled regen to a one-transistor common-base Hartley regen, but there was no improvement in dynamic range and the regenerative stage still overloaded easily on strong signals. . Thanks. Though they were once very popular among amateurs and professionals alike, they are now thought of as mere play toys instead of legitimate receivers. the 2 different frequencies would feedback with each other infinitely when connected to a regen circuit. Build very simple and easy to find parts. I think the regenerative stage, when running at this low voltage, simply has a low dynamic range. This is a regenerative Fm radio. . The superregenerative receiver uses a second lower-frequency oscillation (within the same stage or by using a second oscillator stage) to provide single-device circuit gains of around one million. JFET Regenerative Radio Circuits.The careful use of JFET devices in regenerative radio design can bring many benefits. R1, L1 and C1 determinates oscillation frequency. All HF Bands Direct Conversion Receiver . JABAQUARA. The Armstrong super-regeneration receiver from 1921 is a squegging oscillator [2], as the ARRL handbook explains: "There is a related effect called squegging, which can be loosely . If you adjust the regeneration control until the oscillator starts, you can back up and it will stay running until it suddenly clicks off. My particular regenerative amplifier has 3 factors that may contribute to its noisiness: its use of a low-Q varactor 1SV149 for tuning at HF, its use of a garden-variety BJT that is coupled strongly into the LC tank (which exposes the tank to varying parasitic capacitances of the BJT), and its low-voltage biasing technique where base and collect. A JFET based regenerative receiver using an AC-linked differential pair. Regenerative receiver projects Lemon Drops This is a homebrew regenerative receiver, mostly based on several designs by Charles Kitchin N1TEV. Here's a list of the threads and articles that I saved in that ZIP file: . Sorted by: 2. Joined Dec 20, 2007. Definitely it is not a super regenerative or Heterodyne Receiver, not that kind of difficult stuff for many people who doesn't care about IF frecuency, AGC, RF filters, RF Cans, Decoupling Capacitors, Multiple Trimmers into a large capacitor and thing like that haha.

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