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Active antenna that will work from below a few kHz to over 100 MHz - The first 10 mH inductor used in the prototype has about 100 ohms of resistance and that resistance is important in the source of the first J309. if you inductors are significantly lower in resistance, add a series resistor to total around 100 ohms. The other two chokes in the power supply should be below about 100 ohms, but lower resistance is fine. Lower value chokes can be used, but at some point, the low frequency response will suffer. For 100kHz and above, 1 mH is good. Also make sure that the lower value choke exhibits 100 ohms of resistance in the source of the JFET by adding series resistance. __ Contact: Charles Wenzel of Wenzel Associates, Inc. Active Antenna, easy to build - When fate or nasty neighbors prevent you from stringing a long-wire receiving antenna, you'll find that this pocket-size antenna will give the same, or even better, reception. This "Active Antenna" is cheap to build" and has a range of 1 to 30Mhz at between 14 and 20dB gain __ Designed by Tony van Roon & Rodney A. Kreuter
Active Attenuator - This active attenuator works as a simple mixer. A signal from a 1 MHz oscillator is mixed with the received signal in a 1N914 diode. The 1000 ohm potentiometer adjusts the level of the local oscillator fed to the mixer diode. it is possible to get over 100 db attenuation using this device. This circuit is a variation of one first described in the November, 1992 issue of QST. That circuit was designed by PA0ZR. it used a L/C tuned 500 KHz oscillator. __ Contact Joe Leggio WB2HOL
Active FM Antenna Amplifier - 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
Active RF antennuator - This active attenuator works as a simple mixer. A signal from a 1 MHz oscillator is mixed with the received signal in a 1N914 diode. The 1000 ohm potentiometer adjusts the level of the local oscillator fed to the mixer diode. __ Designed by Joe Leggio WB2HOL
Add a signal-strength display to an FM receiver IC - 09/05/02 EDN Design Ideas: The Philips (www. semiconductors. philips. co) TDA7000 integrates a monaural FM-radio receiver from the antenna connection to the audio output. External components include one tunable LC circuit for the local oscillator, a few capacito Design by José Miguel-López, RF Center Ltd, Barcelona, Spain
Add on AM Modulator has High-Bandwidth - 09/11/98 EDN Design Ideas: (FILE
has many circuits, scoll to find this one) The simple circuit in Figure 1 is an add-on modulator that converts the output of a continuous-wave (CW] source to either an amplitude-modulation (AM] or a suppressed-carrier-modulation (SCM] format. Because the circuit has unity gain and 50 Ohm input and output impedances, the CW generator's Design by MJ Salvati, Flushing Communications, Flushing, NY
Adding a removable Antenna to your WRTSL54GS - Over the past few months I'vebeen contemplating a few projects for some WRTSL54GS routers with OpenWrt, however I really need these to have a high gain antenna on the WRTSL54GS. As you may recall, this model has a fixed antenna, with no __ Designed by Mike Perez
ADSB Receiver - With this design you can expect to get several 100 km range with a good antenna. I use a home made J-pole with a single 32 Eurocent BFP420 transistor giving excellent low noise gain for very little money. it can be bought like most of the needed components at Reichelt. Many good quality (Kathrein for example) Satellite L band line amplifiers use this transistor and if you can get at least 12 Volts to the preamp they offer excellent performance despite being laid out for 75 Ohms. i'll document the preamp later. This is what you can get in Luxembourg with a clear view to the South for several kilometers __ Designed by Edward John Cardew
Advanced VHF Power Meter - The DVM (Digital Volt Meter) also displays the correct polarity sign. There’s neither rocket science nor smoke and mirrors here folks: it’s all done simply with op amps and resistors! __ Designed by Prject Wes Hayward, W7ZOI and Bob Larkin, K7PUA that appears in QST, June 2001
AGC Amplifier features 60-dB dynamic range - 4-Aug-05 EDN Design Ideas: Using discrete components only, build an audio-band AGC Design by Julius Foit, Department of Microelectronics, CTU Prague, Czech Republic
AGC disciplines RF & fiber signals so they "ain't misbehavin'" - EDN-Design ideas -- 02/02/1998 AGC disciplines RF and fiber signals so they "ain't misbehavin'"BiLL SCHWEBER, TECHNIC AL EDiTORYou may need AGC to keep wayward RF, optical, and video signals--which swing over a wide dynamic range--within acceptable bounds. By considering key specifications and techniques, you can get optimum AGC results. Design by Bill Schweber, Technical Editor, EDN
AGC Uses an Analog Multiplier - 11/03/11 EDN Design Ideas: (Originally published in the September 4, 1986, EDN-Design ideas) in the AGC circuit of Fig 1, a 4-quadrant analog multiplier (IC 1) , an amplifier stage (IC 2) , an active, full-wave rectifier (D1, D2, R4-R7, and IC 3) , and an integrator (IC 4) accomplish automatic gain control of ViN’s amplitude variations in the audio-frequency range. Design by Steve Lubs, Department of Defense, Washington, DC
AIR Transparency Monitor, Xenon Flash Receiver - i designed this receiver circuit many years ago to monitor the quality of a mile long column of air for future optical communications experiments. The transmitter system (circuit 72 below) uses a powerful xenon flash in conjunction with a large 12 inch. . . Circuit by David A. Johnson P.E.-June, 2000
AIR Transparency Monitor-Pg2 - This is Page 2 of the receiver circuit AiR TRANSPARENCY MONiTOR, XENON FLASH RECEiVER. . . Circuit by Dave Johnson P.E.-June, 2000
Aircraft Radio Communications Receiver - 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. __ Designed by Aaron Cake
Aircraft Receiver - The Passive Aircraft Receiver is basically an amplified "crystal radio" designed to receive nearby AM aircraft transmissions. The "passive" design uses no oscillators or other RF circuitry capable of interfering with aircraft communications so it should be fine inside the cabin of the aircraft. Nevertheless, check the regulations before using this receiver on a commercial airliner __ Contact: Charles Wenzel of Wenzel Associates, Inc.
All Band Receiver - Schematic + info + pictures __ Designed by Lennie Zink
All-purpose 0-30 MHz DDS VFO & Signal Generator based on the article by WB2V in QEX July, 1997. - DDS VFO for use with vintage transmitters based on the module by ZL1CVD __ Designed by WD8DAS
ALT-Altoids L Tuner - Altoids L Tuner (ALT) "L" tuner for half wave end feed antennas. __ Designed by Steven "Melt Solder" Weber KD1JV
Alternative Power Regulator - Here's a cheap, simple shunt regulator that's ideal for use with alternative power generation systems, whether they be wind, solar, hydro you name it. it will prevent your batteries from being cooked by over-charging and can even assist with hot water or other heating.__ SiliconChip
Alternative Power Source for Magellan GPS Receivers - This GPS receiver is powered by 2 AA batteries. They are only strong enough for the GPS to stay on for about two hours, and this seems like quite a waste. I would like to be able to use a larger battery, and sometimes even an AC adapter. __ Designed by Ryan Janzen
Alternator Regulators - For Typical 12 Volt Charging and also HiGH Voltage Outputs Possibly up to 100 Volts OUTPUT. __ Designed by G.L. Chemelec
AM Band Antennas - Scroll down to find this Circuit design. A good AM Band antenna can be a simple long-wire strung between two trees or across the top of the roof. Even a modest length wire will give your receiver greatly improved reception with less static. __ Contact: Charles Wenzel of Wenzel Associates, Inc.
AM Broadcast Band Portable Loop Antenna - Lamenting the passing of local AM radio? Desert island or outback mining camp based? Unable to clamber up on the roof for a long wire aerial anymore? Here's a simple medium wave tunable loop that, even indoors, will bring signals out of thin air! __ SiliconChip
AM Broadcast Band Regenerative Receiver just two transistors! - amateur radio construction projects. circuit only, no description given. __ Designed by Peter Parker
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 Loop Antenna & Amplifier - PIC AXE VSM: The PIC AXE Circuit Simulator! __ SiliconChip
AM Modulator has high bandwidth - 09/11/98 EDN Design Ideas: (FILE
has many circuits, scoll to find this one) The simple circuit in Figure 1 is an add-on modulator that converts the output of a continuous-wave (CW] source to either an amplitude-modulation (AM] or a suppressed-carrier-modulation (SCM] format. Because the circuit has unity gain and 50 Ohm input and output impedances, the CW generator's Design by MJ Salvati, Flushing Communications, Flushing, NY
AM Receiver - This is a compact three transistor, regenerative receiver with fixed feedback. it is similar in principle to the ZN414 radio IC which is now replaced by the MK484. The design is simple and sensitivity and selectivity of the receiver are good. __ Designed by Andy Collison
AM Receiver for Aircraft Communications - This receiver is controlled by a Frequency Synthesizer Circuit. The receiver is VERY stable, low noise-level and easy to build and tune __
Contact: info @ rfcandy.biz
AM Receiver with Quadrature Mixer - This circuit is for a superheterodyne receiver where the image frequency is suppressed without the use of an input filter. instead, it uses two NE (SA) 612 type mixer ICs that each work 90. must register on this site __ Designed by Published in Elecktor July/Aug, 2010
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
AM2 - This is the schematic only __ Designed by quadworld @ reocities.com
Amazing All Band Receiver - The Amazing All-Band Receiver is basically a diode detector followed by a high-gain audio amplifier. This is not a multi-band receiver; it picks up everything at once! The detector uses a biased Schottky diode for excellent sensitivity and bandwidth; the detector will detect signals from below the AM broadcast band up to the microwave bands. The number of interesting signals is surprising; it is fun to drive around listening to the numerous strange sounds. __ Contact: Charles Wenzel of Wenzel Associates, Inc.
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
Am-Receiver for Aircraft Communication 118.250MHz - This receiver is controlled by a Frequency Synthesizer Circuit. The receiver is VERY stable, low noise-level and easy to build and tune __ Contact maxit91 @ hotmail.com |
