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R2T2 Haywire Home Station - Something about the R2 receiver module (and the T2 phasing SSB exciter) by Rick Campbell, KK7B, really facsinated me, and got me seriously into homebrewing. Probably the sense of audio cleanness described in the article was the first appealing thing, then the unique character of the non-superhet approach. Now, this approach is definitely "in" in the communications industry, with tons of chipsets for quadrature receiver/transmitter setups. __ Designed by John Seboldt, K0JD Radio Remote Control using DTMF - Here is a circuit of a remote control unit which makes use of the radio frequency signals to control various electrical appliances. This remote control unit has 4 channels which can be easily extended to 12. This circuit differs from similar circuits in view of its simplicity and a totally different concept of generating the control signals __ Designed by Radioland.net
RC network quashes auxiliary winding in quasiresonant converter - 04/01/04 EDN Design Ideas: Quasi-square-wave-resonant converters, also known as QR (quasiresonant] converters, allow the design of flyback-type SMPSs (switch-mode power supplies] with a reduced EMi (electromagnetic-interference] signature and improved efficiency Design by Nicolas Cyr, On Semiconductor, Toulouse, France
RC Receiver Hosts Two Independent Switches - 06/06/96 EDN Design Ideas: Typical inexpensive radio-control (RC] systems have servo-motor outputs, but no on/off switch outputs. You can add two independent RC switches to a system without making any transmitter or receiver modifications Design by Tom Howell, US Army ARDEC, Picatinny Arsenal, Dover, NJ
RDS Coder Board using ATmega32 - This board is a RDS coder using an ATMEL AVR ATmega32. This board can be controled by a RS232 link, USB interface or SPi. TA data is displayed wiyth a LED and can be controled by :, Hardware input, RS232, USB, SPi (not yet implemented) __
Real Yagi AntennFor UHF CB - Are you good at scrounging? All it takes is some plastic conduit and a couple of wire coat hangers to build this really effective antenna__ SiliconChip
Receiver based on NE602 - Schematic only, no circuit description __ Designed by Web David White, WN5Y
Receiver Battery Low Voltage Alarm - Here is another equally cool low voltage alarm circuit for your glider receiver battery that I'veshamelessly stolen from George Steiner's book "A to Z--Radio Control Electronic Journal" (see below). I'vemodified it to use with small battery packs in R/C gliders. This design has a trigger voltage at about 4.3 volts, and it draws 1mA or less when quiet and about 4mA when buzzing. This can be constructed from parts fromt Radio Shack, though you may need to order a few through them. __ Contact Rob Crockett
Receiver Building Blocks - This amplifier has about 20dB of gain, bandwidth of 100MHz and noise figure of about 7dB. The output transformer is 8 turns bifilar wound on a ferrite core. Use a medium power UHF transistor 2N5109, 2N3866, 2N4427 or similar. The transistor will need a small clip on heatsink. This amplifier is suitable for use in the front end of a HF receiver or as a post mixer amplifier following a diode mixer (see below.) __ Designed by EI9GQ homebrew radio
Receiver without Coils (Mediumwave radio) - Recently I discovered a pile of old issues of Elektuur magazine in our local university library. in one of these (July/August 1973) I spotted a highly unusual circuit: a receiver without coils! 1. Elektuur is the name of the Dutch electronics magazine which in other countries is known as Elektor. The header of the article said: “Gevoelige spoelloze MW en LW synchrodyne ontvanger”, i. e. “Sensitive synchrodyne receiver for MW and LW without any coils”. When I saw the receiver, I knew I had to try it – I am fond of strange and simple circuits. __ Designed by Aren van Waarde
Receiver-Ultrasonic Switch - The circuit described generates (transmits) ultrasonic sound of frequency between 40 and 50 kHz. As with any other remote control system this cirucit comprises of a mini transmitter and a receiver circuit. Transmitter generates ultrasonic sound and the receiver senses ultrasonic sound from the transmitter and switches on a relay __ Designed by Andy Wilson
Receiving Converters 88-108 Mc to AM Broadcast band - i designed this circuit. it can be connected to an FM tuner to play FM stations on an AM radio. __
Regenerative receiver - Hi all, whilst looking through my lab book I came across this little receiver circuit. it looks like "kid's stuff" but it can be used for the lower HF bands and gives quite an impressive account of itself if used with a decent antenna. it can also be built into a cigarette box which makes it almost perfect for portable use. it will need a decent AF amplifier after it; A simple 741 OP-AMP will be adequate for the job as you only need a few millivolts to a headphone. I used a stereo with a "phono" input, but that was not very portable! ! __ Designed by Harry Lythall-SM0VPO
Regenerative Receiver #4 - This Winter, after a ~4 year hiatus from regenerative receivers, I built 4 while studying the plethora of published designs in print and on the web. How do you describe the sounds that regens deliver? Perhaps the adjective "screechy", or adjective-verb phrase "alive with vibe" might do --- and when tuning across a SWL band they emit those classic wee-woo sounds that signal we're close to receiving some yet unknown, far off, station. __ Contact Vasily Ivanenko
Regenerative Receivers - Regenerative receivers provide a surprising level of performance with only a handful of components. 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. Many designs for regenerative receivers are available and most will do a fine job. 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 provides the total tank capacitance. __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Regenerative Short Wave Radio - if you happen to have a ferrite bar antenna for short wave reception, try to build a regenerative short wave radio like one shown above. Separated function for regeneration and detection enables this circuit to be fairly sensitive to weak signals without any external antenna. __ Designed by MINOWA, Makoto 7N3WVM
Regenerative shortwave receiver - Circuit Only __ Designed by C. Kitchin
Remote control using VHF Modules - A few designs for remote control switches, using VG40T and VG40R remote control pair, are shown here. The miniature transmitter module shown in Fig.1, which just measures 34 mm x 29 mm x 10 mm, can be used to operate all remote control receiver-cum-switch combinations described in this project __ Designed by Radioland.net
Remote Extender Circuit - This circuit is designed to be placed directly in front of a standard TV or VCR remote. The exiting light pulses produced by the circuit match the pulses from the remote but are about 10 times more powerful. Using the device, the remote can operate a TV or VCR over three times the normal distance. . . Circuit by Dave Johnson P.E.-June, 2000
Repeater Fan Controller - an 18 kB PDF file __ Designed by Robert Shepard KA9FLX
Resonate CW Speaker - 600 Hz Resonant speaker. Folded channel box design. Makes an amazing difference! __ Designed by Steven "Melt Solder" Weber KD1JV
RF Activated Relay-W7ZOI - Schematic only __ Designed by va3iul
RF Actuated Keying Monitor - Sending Morse on a rig without a sidetone is not impossible, but is not particularly pleasant either. This battery-powered monitor has been designed to provide an audible indication of keying for those whose rigs lack a CW sidetone. its sensor wire is wrapped around the transceiver's coax – no direct connection is required. Of course Morse isn't the only use for this nifty circuit – it should also be useful any time you need a simple alarm that detects the presence of RF. __ Designed by Peter Parker VK3YE
RF Buffer Stage - This bufferstage is intended to be used after a BF900 or BF199 (even a BF245) oscillator. it delivers several milliwatts and is perfect to drive a 2N2219 or 2N4427. Be sure the coils are really round and can "see" each other: place metalplates between the coils. The supply voltage is around 12V (typ.13, 8V). __
RF Four Channels transmitter & Receiver - This is a very simple Wireless RF transmitter circuit that consists of the Holtek HT-12E encoder chip and AM 418MHZ-transmitter module (WZ-X01, other similar device can be used). Using the hybrid RF xmit/receive modules make building the RF remote control a lot easy __ Contact info @ wzmicro.com
RF front-end for triple conversion GPS receiver - A low-power, 1.57-GHz RF front-end for a global positioning system (GPS) receiver has been designed in a 1.0- m BIC MOS technology. it consists of a low noise amplifier with 15 dB of gain, a single balanced mixer with 6.3 mS of conversion gm, a Colpitts LC local oscillator, and an emitter coupled logic (ECL) divide-by-eight prescaler. This front-end has a singal sideband (SSB) noise figure of 8.1 dB and is part of a triple conversion superheterodyne receiver whose iF frequencies are 179, 4.7, and 1.05 MHz. Low power consumption has been achieved, with 10.5 mA at 3-V supply voltage for the front-end, while the complete receiver is expected to draw about 12 mA __ Designed by Francesco Piazza & Qiuting Huang
RF Isolator Uses Differential Amplifiers - An RF isolator is a seemingly magic device that allows signals to pass in only one direction. Signals applied to the input port are sent to the test port and signals coming into the test port can only go to the output port. This one-way property is usually accomplished with special non-linear ferrite/magnet structures operating at very high frequencies. Fig.1 shows an active RF isolator __ Contact: Charles Wenzel of Wenzel Associates, Inc.
RF noise bridge for HF - This rf noise bridge will provide about 40dB of noise over the 160m to 6m amateur bands. The unit uses 3 x BC547 transistors for amplification of noise produced by a 6.8 volt zener diode. Drawing a current of around 17mA, makes the unit suitable for portable battery operation.__
RF Power Meter - RF Power Meter for QRPers __ Designed by Peter Parker VK3YE
RF Power meter / dummy load - A 50 Ohm dummyload is an essential part for any radioamateur as is a powermeter. The prices of such relative simple equipment is expensive, but not for us handy Hams Hi. All you need is a metal box (or plastic box painted inside with graphite or other conducting/RF-shielding capable material) , a few resistors and basic components (which can be salvaged from old radio's, switching power supplies etc. .) and a analog meter. I used a Radio-shack meter, but any (sensitive) meter can be used. it's all a matter of calibrating your meter correctly, which is easy if you can lend a good commercial RF power meter. __ Designed by Guy Roels ON6MU
RF Preamplifier - input needs only several mWatts (e. g. BF900) -> 300 mWatts OUT. This schematic is a often used buffer. it's easy to build, clean and cheap. When you want even more power, you can replace the 2N2219a by a 2N4427 or 2N3553. You can lower the output by adding a little resistor (10.47 Ohm 1/2W) in the emitter line of the 2N2219a. __
RF receiver - Schematic only, no circuit description __ Designed by Web David White, WN5Y
RF signal meter with LEDs - The simple but effective circuit presented here converts an RF input signal into a visible LED indication. Only discrete components are used. The circuit can be used as field strength analyser or RF Wattmeter when a 50 ohms resistor is connected between ground and HF (J1). Calibration required. Of course you can add extra LED stages in case you want to extend the range. The second picture shows how the circuit can be build on a very small piece of vero-board. __ Designed by Ron Zoetermeer, JO22gb, Netherlands
Rush Converter for the Car - This converter allows an ordinary AM car radio to receive 15.42 MHz (WRNO). A famous talk show is transmitted by this station. The unit should be constructed in a metal box with antenna connectors compatible with the car radio. The converter includes a relay which automatically bypasses the converter when power is removed. A single power wire comes out of the converter box and goes to a power switch located in a convenient spot. (The unit is connected to ground through the coax. __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Ruthroff's Voltage balun using 4C6 core for HF inverted VEE antenna. - i like to use Atmel AVR Atmega PIC 16 PIC 16F876 PIC 16F84. Most electronics easy made for the novice and something is for the more experienced. __ Designed by Thomas Scherrer OZ2CPU
RX3302 433MHz superregenerative receiver Module - Schematic only __ Designed by Peter Jakab
RX3302 receiver Module schematic - Schematic only __ Designed by Peter Jakab
RX3302 superregenerative receiver Module schematic - Schematic only __ Designed by Peter Jakab |
