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Active Antenna AA-7 HF/VHF/UHF, 3-3000MHz - 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 building the AA-7 HF/VHF/UHF Active Antenna described in this article. __ Contact: kangyono99 @ yahoo.com
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
Aerial 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
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 Loop Antenna - A loop antenna can greatly improve medium wave reception. Loop antennas
are directional and receive signals along the plane of the windings. The directional quality improves signal to noise ratio of the desired signal while rejecting signals perpendular to the plane of the windings. Larger loops are better than smaller ones but good results can be obtained from moderate sizes of one or two feet on a side __ Designed by Bill Bowden
AM Loop Antenna & Amplifier - PICAXE VSM: The PICAXE Circuit Simulator! __ SiliconChip
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 active Receiving Antenna for 0.5-30 MHz - A close-up picture of the BF254 source follower. __ Designed by Herbert Dingfelder
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 & RF preamp for weather satellites - All the details for a simple turnstile/reflector antenna plus an RF preamp that mounts up on the mast to really drag on those satellite images. __ SiliconChip
Antenna 1/4 wave for 940 to 980MHz easy homemade - My Radio amateur callsign is OZ2CPU. I like to use Atmel AVR Atmega PIC16 PIC16F876 PIC16F84. Most electronics easy made for the novice and something is for the more experienced. __ Designed by Thomas Scherrer OZ2CPU
Antenna height measurement made easy - My Radio amateur callsign is OZ2CPU. I like to use Atmel AVR Atmega PIC16 PIC16F876 PIC16F84. Most electronics easy made for the novice and something is for the more experienced. __ Designed by Thomas Scherrer OZ2CPU
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
Boost your ZigBEE range - Simple "roll your own" antennas for the XBee __ SiliconChip
Build a hanging dipole for two metres - Ideal for the portable operator. amateur radio construction projects. __ Designed by Peter Parker
Build a Simple Circuit crystal set - amateur radio construction projects. __ Designed by Peter Parker
Compact L-match ATU for portable use - amateur radio construction projects. __ Designed by Peter Parker
Dipole Antenna - A simple dipole antenna can be used for improved FM broadcast signals. A dipole is basically a length of conductor (wire) split into two portions and signal is taken off at the split. It has a nominal 3 dB gain over an isotropic source and is directional, tending __ Designed by Radio Brandy
E-fields - If you place the amplifier at the antenna, you avoid all that cable capacitance but your amplifier must have a correspondingly higher input impedance to maintain flat gain at the lower frequencies. For a typical 10 pF antenna (about a meter long) you would want a 100 megohm input impedance to have flat gain down to 150 Hz! One simple solution is to add some shunt capacitance across the antenna, eating __ Contact: Charles Wenzel of Wenzel Associates, Inc.
Full wave omnidirectional vertical groundplane antenna for 2-meters - Ham RadioAntennas-Schematic __ Designed by Guy Roels ON6MU |
