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A general article on CMC, common mode choke include a description and tipical usage.

Antennas for Broadcasters, PSI manufactures a complete range of slot antennas for UHF television broadcasting

The AB2RA bowtie 80 meter antenna includes also a 40 meter dipole

Electrically shortened dipole antennas, article by Mark Connelly, WA1ION

Small antenna, what causes loss and how to increase radiation resistance in small antennas., A description of loss and radiation resistance.

The vertical Double-Zepp 2x7 m is a very simple, effective 8-Band-antenna. The end of the Dipol must be 5-10 m above the ground

Based on a simple project based on a 2 elements Yagi for 20m band, and then becomed a triband yagi with a open-sleeve feed system

Hi-Z Antennas offers specialized high-impedance receiving systems, primarily focusing on phased vertical arrays for HF reception. Their product line includes preamplifiers designed for shortened vertical antennas, featuring optimized 15dB gain and array-matched characteristics. These components are engineered to enhance weak signal reception and improve signal-to-noise ratio across the HF spectrum. The company provides controllers for managing multiple vertical elements in a phased array configuration, enabling directional reception patterns. These systems are particularly effective for mitigating local noise and interference, a common challenge in urban and suburban operating environments. Specific offerings include solutions for 160-meter and 80-meter bands, addressing the unique requirements of low-band DXing. Technical details often reference components like the 2N3866 transistor in preamp designs and discuss concepts such as out-of-band attenuation. The focus remains on optimizing receiving antenna performance through impedance matching and active amplification, rather than transmit capabilities.

The 160 meter ground plane is constructed from #10 stranded insulated wire available in most hardware stores. The feedpoints / tiepoints use PVC pipe T-sections Article by W1TR

Since they were first described by the French mathematician Benoit Mandelbrot in the mid-1970s, repeating geometric figures known as fractals have fascinated computer scientists, mathematicians and graphic artists.

Ten essential tips and truisms for understanding HF antenna: Non-resonant wire dipole antennas fed with open-wire line and an antenna tuner can function effectively as multiband antennas, as detailed in "The Classic Multiband Dipole Antenna" by WB8IMY in March 2004 QST. Coaxial cable, unlike balanced parallel-wire feed lines, can cause RF to travel on the outer shield braid, leading to RF feedback to the station; a 1:1 balun at the dipole center can mitigate this by isolating the unbalanced coaxial feed line. Antenna gain is achieved by shaping and directing RF energy, with beam antennas concentrating power in a specific direction, and wire antennas also exhibiting shaped radiation patterns. An antenna tuner's primary role is to match the transceiver's 50-ohm output to the antenna system's impedance, allowing modern transceivers to deliver full power. Wire antennas do not always require center feeding; end-fed long wires or off-center-fed dipoles (like the Windom) can be used, though they often necessitate an antenna tuner and a counterpoise or radial network. Dipole antennas do not need to be perfectly horizontal; their legs can be bent or inclined, which affects feed point impedance and may require SWR experimentation with coaxial feed. Vertical antennas shorter than a half wavelength require an efficient ground system, typically comprising elevated or buried radial wires, with more radials generally leading to better efficiency. A 1:1 SWR indicates an impedance match but does not guarantee antenna efficiency; an inefficient vertical antenna with a poor ground system can show a low SWR while wasting most RF as heat. Investing in high-quality, low-loss feed line, especially coaxial cable, is crucial for maximizing RF signal transfer and overall antenna system performance.

Experiences with Loop antennas at G3YMC include some loop antenna tests and theory by G3LHZ

The HyGain LJ-153BA a monoband 3 element Yagi, designed for the 15 m band 21.00 - 21.45 MHz

ITELITE manufactures omnidirectional, sector and directional antennas 900 MHz 2.4 GHz 3.5 GHz 5 GHz 5.8 GHz antennas.

In this article the author provides some guidelines on how to solve a common problem when stacking different types of yagi antennas on the same mast, limiting the effects on gain and radiation pattern of both antennas

An unconventional antenna family, the VHF/UHF Zigzag Dipole Antennas. Design, theory and practical construction, transformation and balancing with a half wave balun.

Experimentig magnetic loop antennas for VHF and HF by M0UKD

A Batwing Antenna Design Challenge

This antenna can gets you on the air on 14MHz, and it has a useable frequency range. The VSWR is almost perfect at the centre-frequency abd the design uses no expensive components.

22 Different Wire Antennas for the 160 Meter Band, Random Length Radiator Wire, delta loop, loop antennas, off-centered antennas, sloper, dipoles, Z antenna, Zepp and Clothesline Antennas

MyAntennas.com offers standard and custom made multiband antennas, Baluns, Common Mode chokes and accessories. All products are designed and made by Danny Horvat, E73M an antenna design engineer formerly employed by Cushcraft Corporation.

The article presents a detailed examination of 40-meter wire antenna performance, specifically focusing on the impact of antenna height on gain and radiation patterns. It quantifies how a 40-meter dipole at 1/8 wavelength above ground exhibits a high-angle radiation pattern, while raising it to 1/2 wavelength significantly lowers the take-off angle, improving DX capabilities. The author, VE3VN, leverages _EZNEC_ simulations to illustrate these changes, providing visual representations of the antenna's lobe structure at different elevations. Comparing a single dipole to a two-element wire array, the analysis shows that a 2-element array at 1/4 wavelength height can achieve **3.7 dBd** gain, outperforming a single dipole at the same height. This gain is further enhanced to **5.7 dBd** when the 2-element array is elevated to 1/2 wavelength, demonstrating the practical benefits of optimizing both element count and height for improved signal strength and directivity on the 40-meter band. The findings offer practical insights for hams seeking to optimize their wire antenna installations.

The advantage of 5/8 wave antenna is that it has the lowest angle of radiation and has about 1dB more gain when compared to 1/4 and 1/2 verticals. So the 5/8 should be the favourite choice for DX.

An excel spreadsheet that in a really simple way checks how much to trim your antenna elements. Download the xls file and watch the presentation video include in this page

About basics of the horn antenna used for many rf microwave antenna applications.

This antenna was designed for the CQ WW CW 2009 at EA8URL. All elements are made out of fishing rods with an insulated copper cable fixed on the rods by cable ties. Both fishing rods and cable are UV resistant.

The 60-page PDF document, "Antenna Systems and Theory For The Non-Technical Ham" by Jim Abercrombie, N4JA, provides a foundational understanding of antenna systems. It explains basic antenna theory, including how antennas work, electromagnetic wave polarization, and the role of frequency. The resource details various antenna types such as flat top dipoles, inverted-V dipoles, shortened loaded dipoles, G5RV dipoles, Carolina Windoms, and end-fed configurations. Vertical antennas, including ground-mounted trapped verticals and inverted-L verticals, are also covered. Directional beam antennas like monoband Yagis, cubical quads, and log-periodic arrays are discussed. Propagation modes, including ground-wave, direct wave, and skywave propagation, are explained in detail, with specific attention to the D, E, and F layers of the ionosphere and their effects on HF communication. Technical concepts such as standing wave ratio, decibels, resistance, and reactance are defined, along with calculations for half-wave resonant dipole lengths. The document addresses feed-line radiation, balun applications, and critical antenna and tower safety considerations. It aims to dispel common antenna myths and educate hams on making informed antenna choices.

Getting the most out of LowFER transmitting antennas, designing an efficient antenna for the 1750-meter band by K0LR

Carolina Cyclone series of mobile antennas

Homebrewing a Gamma Match to tune yagi antennas

Wheel antenna informations by The Olde Antenna Lab

Experimenting vertical wire antennas for 40 and 20 meters supported by balloons resulting in excellent gain in RX and good overall performance against horizontal dipole

Dipoles at the correct height are not only stealthy antennas, they work great

This is about Small Antenna types and their properties which can help choosing proper antenna for high-frequency wireless communications as: two-way radio, microwave short links, repeaters, radio beacons or wireless telemetry

Theory and origins of W4RNL Asymmetrical Hatted Vertical Dipole AHVD for portable operations.

cq-contest reflector comments about the performance of the EWE receive antennna collected by KA9FOX

Manufacturing selling and supporting the classic W7FG True Ladder Line Wire and Antenna

The collinear antenna, or Marconi-Franklin antenna, is an omnidirectional, high-gain antenna composed of in-phase half-wave dipoles aligned vertically. By using quarter-wave transmission line segments, it maximizes gain at a low horizon angle, outperforming a half-wave dipole. Adding segments increases gain but narrows bandwidth. A popular DIY version, the CoCo antenna, uses half-wave coaxial cable segments connected by non-radiating transmission lines. Built with stable velocity factor cables, a matching quarter-wave sleeve balun, and ferrite rings for attenuation, the antenna achieves performance comparable to commercial models.

US amateur radio antenna manufacturer, design and build monoband, dual band and multiband Yagi Antennas for HF bands as well as receive antenna systems

Manufacturer of WiFi (2.4 & 5 GHz), Marine WiFi, Military and other antennas of various frequencies and styles.

Amateur radio antennas manufacturer, produce multiband and monoband high performance yagi antennas and vertical antennas based in Poland

Introduction to Shortwave Antennas. Understanding Shortwave Radio Listening and Antenna Design and Construction

Ham Radio Vertical HF multiband antennas manufacturers based in Spain

Mounting antenna close each other. Distance calculations and tips on setting up antennas by KB9VBR

A page descibing the principles of OCF antennas also known as windom antennas by DJ0IP

This method of construction can be used on most UHF through \"low\" microwave Yagis, and is especially useful for the 33, 23 and 13 cm bands

A collection of drawings of most popular wire antennas for hf ham radio bands

Constructing a 2-meter Moxon antenna for MURS channels, this resource details the antenna's geometry and expected radiation pattern. The design, optimized for low SWR, high gain, and front-to-back ratio on the first three MURS channels, uses 1/8-inch bronze brazing rod for elements. Author John E. Davis provides specific geometric parameters (A, B, C, D dimensions) rounded to the nearest 16th of an inch, along with a link to the final _.nec_ file for further analysis. Performance results show the attic-mounted Moxon performs well on the 2-meter band, despite its MURS optimization, with measured SWR plots provided. NEC-2 modeling predicts over 6 dBi gain and 40 dBi front-to-back ratio in free space. The author compares its directional performance to a _J-pole_ antenna, demonstrating substantially better signal strength for a nearby repeater when the Moxon is pointed in its general direction, confirming its superior gain and directivity.

Optimizing weak signal reception on the HF bands, particularly in the presence of strong local QRM, often necessitates specialized receiving antenna systems. This resource details the _HI-Z Antennas_ product line, focusing on phased vertical arrays designed for superior noise rejection and directivity. It covers components such as the 4-Square and 8-Element array controllers, which allow for rapid switching of receive patterns, and dedicated low-noise preamplifiers to improve system sensitivity. The site also presents various bandpass filters, crucial for mitigating out-of-band interference and enhancing the dynamic range of the receiver. The HI-Z systems are engineered to provide significant front-to-back and side rejection, often yielding **20-30 dB** of attenuation to unwanted signals, which is critical for DXing and contesting. Users can achieve a notable reduction in local noise, allowing for the discernment of signals that would otherwise be buried. The array controllers facilitate quick pattern changes, enabling operators to null out interference or peak weak signals from distant stations, effectively extending the reach of their receive capabilities by improving the signal-to-noise ratio.

Amateur, scanner, wi-fi and land mobile antennas and accessories online store