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Active Antenna Circuits
Active Antenna Circuits:  #'s - K     L - Z

 

Last Updated: November 30, 2017 07:37 AM



Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

1-Ground pole Antenna -  This Antenna is most widely used all over the world. For example, when you see a police car it has a transmitter with Ground Pole Antenna The body of car serves as ground). It accepts load from 50 ohm source and has larger power output than Half-Wave Dipole Antenna. (File has several designs, scroll for this one) … [alkhaki AT yahoo.com]

 

2-Half-Wave Dipole Antenna -  It accepts load from 75 ohm source and has much smaller power output than Ground Pole Antenna. Use this antenna only when you don't have GP Antenna. (File has several designs, scroll for this one) … [alkhaki AT yahoo.com]

 

5 Watt FM Transmitter with Antenna 88-108 MHz -  Two stages -- AUDIO AMPLIFIER AND OSCILLATOR and RF POWER AMPLIFIER…

 

6 x 6 Loop Antenna -  This new loop antenna is his best design yet and I am proud to be the first to present his work. It uses one, six foot square, six turn loop, and is aperiodic in nature, covering the frequency range 50KHz, 5000KHz… [Design by Graham Maynard]

16 turn Helix Antenna for 70cm band (400-450 MHz) -  Ask anyone with a helix.  It really is the best and simplest antenna for the job.  Selected by the University of Surrey   (SSTL) for the UoSat ground control station, and for their many international customers; used by hundreds of satisfied radio amateurs worldwide. __ Designed by James Miller G3RUH

6 x 6 Loop Antenna -  This new loop antenna is his best design yet and I am proud to be the first to present his work.  It uses one, six foot square, six turn loop, and is aperiodic in nature, covering the frequency range 50KHz, 5000KHz __ Designed by Graham Maynard

A magnetic loop antenna for 160 to 15m -  amateur radio construction projects. __ Designed by Peter Parker

A magnetic loop antenna for 40 to 17m local & DX contacts from tight spaces -  amateur radio construction projects. __ Designed by Peter Parker

A QRP DX antenna -  amateur radio construction projects. __ Designed by Peter Parker

Active 3-30 MHz Hula-Loop Antenna for Shortwave -  If you have a shortwave or high-frequency receiver or scanner that is struggling to capture signals with a short, whip antenna, and you'd like the kind of performance that a 60-foot 'longwire' antenna can provide but lack the space to put one up, consider __ Contact: Charles Wenzel of Wenzel Associates, Inc.

Active antenna 1 to 20dB, 1-30 MHz range -  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 Antenna for HF-VHF-UHF -  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 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

Adding a removable Antenna to your WRTSL54GS -  Over the past few months I've been 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

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-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

An automatically tuned HF Mobile antenna -  This elegant design covers the complete spectrum from 7 to 30 MHz at less than 1.3:1 SWR, is compact, very weatherproof, robust and has good performance.  This article was first published in the QEX / Communication Quarterly magazine.  The article comes in five pages, with lots of photos, mechanical drawings, schematic diagram, PCB layout and software listing.  Exact duplication is not for the faint of heart, but some of you may find individual parts and ideas useful for your own projects! __ Designed by Manfred Mornhinweg

An end-fed antenna -  A piece of wire of almost any length can be used as an antenna on the HF bands.  However, just because an antenna can be made to work is no guarantee that it will perform efficiently.  This article will initially concentrate on the half wavelength of wire and its useamateur radio construction projects. __ Designed by Peter Parker VK3YE

Antenna Projects -  Specifications and designs are subject to change without notice.
Use on your own risk. __ Designed by Mijo Kovacevic, S51KQ

Antenna Tuning Unit -  A simple passive   (no power required) circuit to match an antenna to a radio receiver.  This will be a useful addition to the short wave listener, but in addition a medium wave coil is almost used to tune the medium wave band. __ Designed by Andy Collison

Antennas for HAM Transmitters -  Describes how to construct various type of antenna for Ham Radio Transmitters

Antennas for Low Power Applications -  There seems to be little information on compact antenna design for the low power wireless field.  Good antenna design is required to realize good range performance.  A good antenna requires it to be the right
type for the application.  It also must be matched and tuned to the transmitter and receiver.  To get the best results, a designer should have an idea about how the antenna works, and what the important design
considerations are.  This paper should help to achieve effective antenna design. __ Designed by Kent Smith

Antennas for the space-restricted -  amateur radio construction projects. __ Designed by Peter Parker

Antennas-Includes longwire, loading coil, active ferrite antenna, active short antenna, vertical. -  Home-made antennas can greatly improve the performance of AM and FM radios, short-wave receivers, and scanners.  If you are a talk-radio fan then experiment with the AM band antennas and you will be able to hear shows from all over the country with surprising clarity.  Short-wave receivers are always coping with weak signals and they must have a good antenna to perform adequately.  Scanners can pick up local police and two-way radio with the little telescoping antenna provided but with good antennas a scanner becomes an amazing ear on the world nearby.  No pre-amp, filter or other receiver refinement offers anywhere near the level of performance improvement t that a well-designed antenna offers.  The results can be quite satisfying, leaving no doubt that the project was well worth the effort __ Contact: Charles Wenzel of Wenzel Associates, Inc.

ATL3 Loop Antenna -  All ATL-3 loop windings are centre tapped and balanced w.  r.  t.  their amplifier/receiver chassis ground, and therefore electric field interference pick up tends to self cancel.  Magnetic noise fields, e.  g.  televisions and the electric meter box, or __ Designed by Graham Maynard

General Purpose RF Amplifier -  The first article had a 3PDT switch that not only acted as a power switch, but also allowed the user to bypass the amplifier.  This would be very useful for areas with strong stations, to avoid overloading the receiver.  The second article utilized a ferrite bar antenna, which severely compromised sensitivity.  It did, however, include PCB artwork: __ Designed by Bruce Carter

Improved Active Antenna -  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 Circuits:  #'sK     L - Z


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