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Quad antenna

A quad antenna, also known as a cubical quad antenna, is a type of directional wire radio antenna commonly used on the high frequency (HF) and very high frequency (VHF) bands, consisting of multiple full-wavelength loop elements shaped as squares or other polygons, arranged in a planar array similar to a Yagi-Uda design but with loops replacing straight dipole elements.^[1] Each loop element is typically one electrical wavelength in circumference, with the driven element fed at one corner and parasitic elements (such as reflectors and directors) positioned along a boom to achieve gain and directivity.^[2] This configuration provides a unidirectional radiation pattern, focusing transmitted or received signals in a specific direction while suppressing others, making it popular for amateur radio, shortwave broadcasting, and other point-to-point communications. The quad antenna was invented in 1942 by Clarence C. Moore, an engineer and amateur radio operator (call sign W9LZX/HC1JB), while working at the HCJB shortwave missionary radio station in Quito, Ecuador, at high altitude where corona discharge from traditional antennas posed significant issues due to low air pressure.^[3] Moore's design addressed this by distributing voltage uniformly across closed loops, eliminating high-voltage endpoints and reducing corona loss without needing expensive insulators or resistors.^[2] He patented the invention in 1951 as a multi-turn loop system adaptable to square shapes, initially deploying a two-element version for 15-meter broadcasting that proved highly efficient.^[2] The concept gained widespread popularity in the amateur radio community after Bill Orr's 1959 book All About Cubical Quad Antennas, which detailed construction and performance, establishing the two-element driver-reflector as the standard configuration.^[4] Compared to the traditional Yagi-Uda antenna, the quad offers several notable advantages, including broader bandwidth for impedance matching (often achieving a 1.5:1 SWR across an entire HF band like 20 meters), easier polarization switching by adjusting the feed point, and simpler multiband operation through scaled loops without traps.^[4] It also exhibits lower wind loading due to its wire construction and provides comparable forward gain (around 7 dBi for a two-element model) with a narrow beamwidth for enhanced directivity. However, quads can be more complex to construct and tune precisely, particularly for larger arrays, and may suffer from narrower front-to-back ratio bandwidth in some designs.^[4] Today, quad antennas remain a favored choice for radio enthusiasts seeking efficient, compact directional performance in challenging environments.

Fundamentals

Definition and Basic Principles

A quad antenna is a directional antenna system composed of full-wavelength loop elements arranged in a configuration analogous to the Yagi-Uda antenna, with square loops commonly employed for their structural simplicity and ease of construction.^[5]^[6] At its core, the quad antenna operates through the electromagnetic interaction among its loop elements, where each closed loop has a perimeter of one wavelength (\lambda) at the operating frequency, resulting in a side length of approximately \lambda/4 for square configurations.^[5] This full-wavelength perimeter allows the loop to exhibit radiation characteristics equivalent to those of a half-wavelength dipole, as the current distribution around the loop produces a similar far-field pattern, with maximum radiation occurring broadside to the plane of the loops.^[5] The driven element, which is actively fed with RF power, is typically connected at one corner to establish the desired current phase, while parasitic elements—a reflector positioned behind the driven element and one or more directors ahead—are inductively or capacitively coupled and tuned by varying their dimensions (slightly longer for the reflector, shorter for directors) and inter-element spacing to direct and focus the radiated energy.^[5] The feedpoint impedance of the driven loop generally measures between 100 and 120 ohms, necessitating matching networks for standard 50-ohm transmission lines.^[5] In high-frequency (HF) applications, quad antennas are oriented to produce horizontal polarization, aligning the electric field parallel to the ground for optimal propagation over long distances.^[5] This design draws on foundational concepts of directional antennas, which concentrate radiated power into a preferred direction to improve signal strength and efficiency, and parasitic elements, which reradiate energy from the driven element without direct electrical connection, thereby modifying the overall radiation pattern through mutual coupling.^[6]

Comparison to Yagi-Uda Antenna

The quad antenna differs structurally from the Yagi-Uda antenna in its use of closed full-wave loops for each element, rather than straight half-wave dipoles. Each quad element forms a square or diamond-shaped loop with a perimeter of approximately one wavelength, typically oriented in a vertical plane and stacked along a horizontal boom. In contrast, Yagi-Uda antennas feature linear elements—consisting of a driven dipole and parasitic reflectors and directors—aligned horizontally along the boom. This loop-based design in quads features a current distribution that varies sinusoidally around the perimeter but with a phase relationship between the upper and lower halves that differs from the sinusoidal variation along the linear elements of a Yagi.^[7]^[8] Theoretically, a quad loop element can be modeled as two vertical half-wave dipoles separated by a quarter wavelength (λ/4) and connected at their ends, creating a stacked array configuration. This equivalence yields gain comparable to a basic two-element Yagi but with an altered current distribution that enhances phase relationships between the upper and lower halves of the loop. The result is potentially improved impedance matching, as the loop's geometry provides a nominal radiation resistance of around 100–120 ohms, facilitating easier integration with common feedlines compared to the 50–73 ohm impedance of Yagi dipoles.^[7] A key advantage of the quad's loop geometry is the ability to position elements closer together along the boom without significant mutual interaction, leading to reduced overall boom length for equivalent gain levels relative to a Yagi-Uda design. For example, multi-element quads can achieve similar forward gain with booms that are roughly 70% the length of those in comparable Yagis, as the closed loops minimize end effects and allow optimized spacing of about 0.15–0.2λ between elements.^[9]^[10] In terms of bandwidth, quad antennas typically offer slightly wider SWR bandwidth than Yagis of similar complexity, attributed to the inherent distributed capacitance in the loop elements, which flattens the impedance curve and maintains lower VSWR over a broader frequency range—often 5–10% wider for 2:1 VSWR limits. However, the bandwidth for maximum forward gain in quads tends to be narrower than in Yagis, requiring precise tuning for peak performance at the operating frequency.^[10]^[8] Quad antennas also feature a smaller turning radius than Yagis for comparable gain, as the loop elements extend only about λ/4 from the boom centerline, compared to the λ/2 span of Yagi elements. This compact profile—often half the width of a Yagi's element tips—simplifies mechanical rotation, particularly in space-constrained installations.^[8]^[11]

History

Invention and Early Development

The quad antenna, also known as the cubical quad, was developed in the early 1940s by Clarence C. Moore (W9LZX), an American engineer and amateur radio operator working at the HCJB missionary shortwave radio station in Quito, Ecuador. Located at an elevation of approximately 9,200 feet in the Andean mountains, HCJB faced significant challenges in broadcasting reliable signals over rugged terrain to global audiences, particularly after upgrading to a 10 kW transmitter in 1940 that exacerbated issues like corona discharge and arcing in traditional wire antennas due to the thin, ionized air at high altitude.^[3]^[12] Moore conceived the design out of necessity for a more compact and robust high-gain antenna that could handle the power without the voltage concentration at element ends seen in dipoles and Yagi-Uda beams, which had proven unreliable during an emergency broadcast interruption caused by equipment failure. Drawing on basic loop antenna principles for simplicity and to avoid sharp endpoints prone to arcing, he created the first prototype using full-wavelength square loops arranged in a planar configuration, with the initial version incorporating a reflector for directionality. This approach allowed for easier construction with available materials while promising better performance in the station's demanding environment.^[5]^[3] Early on-site testing at HCJB revealed the prototype's two-element configuration significantly enhanced signal strength and stability for shortwave transmissions without the corona problems of prior setups. The refined design was deployed at the station in 1942, enabling consistent operation of the 10 kW transmitter and marking the quad's debut in practical broadcasting use. Moore documented his work in technical articles during the 1940s and later secured a U.S. patent (No. 2,537,191) in 1951, formalizing the loop-based array as a novel solution for high-power applications.^[2]^[12]

Adoption and Evolution in Amateur Radio

Following World War II, the cubical quad antenna gained significant traction among amateur radio operators in the 1950s, particularly for HF bands like 10 and 20 meters, due to its efficiency, simplicity in construction, and resistance to corona discharge in challenging environments.^[5] This adoption was facilitated by the availability of affordable materials and the antenna's lightweight design, which made it accessible for homebuilders seeking directional performance without the complexity of larger beam antennas. Early documentation, such as William I. Orr's "All About Cubical Quad Antennas" (first published in 1959 and revised in 1970 with Stuart D. Cowan), provided detailed construction guidance and helped popularize multi-element configurations, emphasizing the quad's gain advantages over dipoles.^[13]^[5] Key milestones in the 1960s included the introduction of commercial kits by Cushcraft, founded in 1954, which standardized quad designs for easier assembly and broader accessibility among hams.^[14] By the 1970s, evolution toward multi-band quads—covering multiple HF frequencies with shared booms—became prominent for contesting, where their compact size and forward gain (often 6-7 dB over a dipole) supported high-power, directional operations in limited spaces.^[5] ARRL publications, including the Antenna Book series starting from the 1950s editions, and presentations at ham radio conventions further promoted quads for their superior signal strength in DX work, solidifying their role in the amateur community.^[15] In the 1980s, quads became commonplace in DXpeditions, valued for their portability and performance in remote locations, enabling reliable long-distance contacts with minimal infrastructure.^[16] The 1990s brought refinements through digital modeling tools like EZNEC, released in 1991, which allowed precise optimization of element spacing and tuning for enhanced bandwidth and pattern control.^[17] More recently, ongoing adaptations focus on stealth installations to comply with antenna restrictions in urban or regulated areas, such as low-profile wire-based half-quad variants that blend into residential settings while maintaining effective HF coverage.^[18]

Design and Construction

Element Configuration and Dimensions

The standard configuration of a quad antenna features a planar array of 2 to 5 square loop elements, each forming a full-wavelength loop, arranged along a boom in an end-fire pattern similar to a Yagi-Uda array. The driven element is a single loop fed at one corner to excite the structure, while parasitic elements include one reflector positioned behind the driven element and one or more directors placed in front. This setup typically yields a 2-element beam (driven plus reflector) for basic directivity or extends to 3-5 elements for enhanced gain through progressive phase shifts induced in the parasitics.^[19] Each element in the array is shaped as a square with side lengths approximately equal to one-quarter wavelength (λ/4) at the design's center frequency, resulting in a perimeter of one full wavelength for optimal resonance. The reflector's sides are tuned to be 2-5% longer than the driven element's to lower its resonant frequency and induce a reflective phase, while each director's sides are 2-5% shorter to raise its frequency and provide forward directing action. For instance, on the 20-meter band (14 MHz), a driven element side might measure about 17 feet, with the reflector at 17 feet 6 inches and a director at 16 feet 8 inches, though exact values require adjustment based on wire insulation and environmental factors. Parasitic tuning relies on these length variations to align current phases across elements, maximizing forward radiation without additional reactive components.^[19]^[7] Element spacing is critical for beam formation and is typically set to 0.15-0.25λ between the reflector and driven element to balance gain and front-to-back ratio, with closer spacings around 0.12-0.15λ often preferred for compact designs. Director spacings are narrower, ranging from 0.1-0.2λ to maintain progressive wave velocity along the array. For a 3-element quad, the total boom length thus approximates 0.5-1λ, such as 8-16 feet on 20 meters, ensuring the array's effective aperture without excessive interaction losses. These intervals derive from the need to position parasitics at distances that induce 180° phase shifts for reflection and 0° for direction, akin to dipole arrays but adapted for loop geometry.^[19]^[20] The array geometry positions all elements in a common vertical plane, with the square loops oriented such that adjacent elements share the same horizontal or vertical alignment, though a 90° rotation option creates a "diamond" configuration for alternative polarization or mounting. This planar layout, with elements stacked at λ/4 internal height equivalents due to the loop's folded structure, emulates two horizontal half-wave dipoles per element separated vertically by λ/4, enhancing the array's vertical directivity.^[7]

Materials, Assembly, and Tuning

Common materials for constructing quad antennas include 12- to 14-gauge copper or aluminum wire for the elements, selected for its strength and low resistance to support wind loads without excessive sag.^[20] Fiberglass or PVC tubing serves as spreaders and booms, providing non-conductive support that resists weathering; for example, 1-inch to 1.5-inch diameter fiberglass poles or Schedule 40 PVC pipes are frequently used to form the square loops.^[21] Insulators at the corners, such as PVC fittings or ceramic standoffs, prevent electrical contact between wires and spreaders, while a balun—typically a 1:1 current balun or quarter-wavelength 75-ohm coax section—matches the antenna's impedance to the 50-ohm feedline.^[22] Assembly begins with laying out each full-wave loop on a flat surface to ensure planarity, using the spreaders to form precise squares or slight trapezoids as per design dimensions. Wires are threaded through pre-drilled holes in the spreaders or insulators and secured with UV-resistant cable ties, hose clamps, or epoxy to allow minor adjustments without compromising structural integrity; for instance, stainless steel hose clamps attach spreaders to a central aluminum or PVC boom, typically 8 to 10 feet long for two-element designs.^[20] The elements are then mounted onto a rotating boom mechanism, often using U-bolts or brackets on a mast, with the driven element positioned for feedpoint access; vertical stacking of multiple quads can be achieved by spacing booms 0.5 to 1 wavelength apart on a longer mast for increased gain, secured with guy wires for stability.^[23] To mitigate wind loading, lightweight designs incorporate rope tensioning systems, such as Dacron cord stays, to keep elements taut without over-stressing the structure.^[22] Tuning involves using an SWR meter or vector network analyzer connected at the feedpoint to measure standing wave ratio across the desired band, aiming for a minimum SWR of 1.5:1 or better at the center frequency. Element lengths are adjusted incrementally—typically shortening the reflector by 1-2% and directors similarly—to shift resonance and optimize impedance, with changes made by trimming wire ends or sliding clamps while rechecking SWR after each iteration.^[21] For impedance matching, a gamma match (capacitor and rod assembly) or hairpin (parallel stub) can be fine-tuned on the driven element to transform the approximate 100-120 ohm feedpoint to 50 ohms, ensuring efficient power transfer.^[20] Safety measures include grounding the boom and mast to protect against lightning, using non-conductive guy lines for rotation, and verifying all connections for mechanical integrity before elevating the antenna.^[23]

Variations

E-Z-O Quad

The E-Z-O Quad represents a modern variation of the quad antenna, optimized for amateur radio applications with an emphasis on portability and ease of use. Developed by Daniel Mills, N8PPQ, in 2008, it emerged as a response to the limitations of traditional cubical quads, particularly their high material costs and structural rigidity. By incorporating flexible dielectric tubes to support wire elements, the design achieves significant cost savings while delivering comparable or superior performance.^[24] Key design features include three circular loop elements—a reflector, driven element, and director—mounted on a lightweight boom, where each loop is formed by wire tensioned across non-conductive flexible supports such as fiberglass tubes. This circular configuration electrically mimics a standard quad but reduces surface loading, overall weight, and peak mechanical stresses on the boom compared to square-loop designs.^[25]^[24] The E-Z-O Quad offers distinct advantages for portable operations, including a reduced parts count that facilitates quick assembly and disassembly, making it ideal for field deployments or temporary setups by amateur operators. Its flexible construction lowers wind and ice loading, enhancing durability in varied environments, while the lightweight nature allows for easy transport and erection without heavy equipment. Performance metrics indicate slightly higher forward gain than conventional quads, with effective directivity suitable for HF and VHF bands.^[24]^[25] Construction emphasizes simplicity and accessibility, utilizing readily available materials like fiberglass poles for element spreaders, copper or aluminum wire for the loops, and a short aluminum boom for spacing the elements. Tuning involves adjusting wire lengths for resonance, typically achieving SWR below 1.5:1 across the band without complex tools. For a 20-meter band example, the element diameter is approximately λ/π (around 0.32λ), keeping the overall height below 20 feet when mounted vertically or horizontally.^[24]

Other Configurations

The Birdcage Quad, developed by G4ZU in England during the mid-20th century, employs multiple parallel wires per side of the loop elements, connected via aluminum tubing supports, to achieve electrical equivalence to a full-size two-element quad in a more compact form suitable for space-constrained installations.^[19] This design maintains performance comparable to standard quads but in a more compact form suitable for space-constrained installations.^[26] The Spider Quad is a boomless configuration featuring radial spreaders extending from a central hub, typically made of aluminum or iron pipe, to support the loop elements with bamboo or fiberglass arms.^[19] This skeletal structure minimizes weight and wind loading, with boom lengths as short as 2 feet for two-element versions operating on bands like 20, 15, or 10 meters.^[27] It facilitates multi-band operation through trap loading at the hub or elements, allowing resonance across HF frequencies without a traditional boom. Non-square variants such as Delta and Diamond loops adapt the quad principle for VHF and UHF applications by altering the element geometry to triangular or rhombus shapes, respectively, with perimeters approximating one wavelength.^[19] The Delta loop, often mounted apex-up or apex-down above the boom, provides about 1.4 dB gain over a dipole with an impedance of around 120 ohms for a single element or 80 ohms in a two-element array.^[28] Diamond configurations, derived from folded dipoles expanded into rhombus forms fed at the bottom vertex, yield similar gain (1.4 dB over dipole) and ~144 ohms impedance, commonly used in early quad designs.^[29] In VHF/UHF contexts, side length ratios in these shapes can be adjusted—typically deviating from equilateral or square proportions—to optimize for circular polarization, enhancing performance in satellite or repeater communications.^[30] A key approach in these alternative quads for multi-band capability involves traps or loading coils inserted along the elements, which isolate segments for different frequencies and enable resonance across bands like 20-15-10 meters.^[19] These devices also shorten the overall structure by 20-30% compared to full-size designs, as seen in mini-quads using stub loading to reduce side lengths (e.g., from 67 feet to about 46 feet on 80 meters), though at the cost of narrower bandwidth. Skeletal designs further reduce complexity by using fewer spreaders—typically four to six radials per element from a central hub—lowering material needs and wind resistance while preserving directivity, as exemplified in lightweight fiberglass or aluminum frameworks for portable or tri-band setups.^[27]

Performance

Advantages

Quad antennas provide directional gain typically ranging from 8 to 12 dBi for three- to four-element configurations, offering performance comparable to or slightly superior to equivalent Yagi-Uda antennas due to the inherent efficiency of full-wave loop elements.^[5]^[31] This gain arises from the larger effective aperture of the loops, which capture more energy than half-wave dipoles used in Yagis, while the radiation pattern features lower sidelobes and a cleaner forward lobe with front-to-back ratios often exceeding 20 dB, reducing interference from off-axis sources.^[7]^[5] In terms of bandwidth, quad antennas achieve up to 10-15% SWR bandwidth (2:1) when tuned for broader coverage rather than maximum forward gain, allowing operation across significant portions of HF or VHF bands without retuning; this low-Q design also contributes to better noise rejection by minimizing response to high-angle skywave interference.^[31]^[5] Mechanically, quad antennas require shorter booms—often about 0.5λ for a three-element design compared to 1λ or more for a Yagi with similar gain—resulting in a smaller turning radius and reduced wind loading from their planar, wire-based construction, which enhances durability in exposed installations.^[31]^[5] Efficiency is improved by the higher radiation resistance of full-wave loops, approximately 100 ohms, which minimizes ohmic losses relative to lower-impedance elements and supports better power transfer in practical setups.^[7]^[5] Real-world tests at HF heights demonstrate a 1-2 dB gain advantage over half-wave dipoles, particularly in low-angle radiation for DX communications.^[7]^[5]

Disadvantages and Limitations

Quad antennas, while offering directional performance, present several challenges in construction due to their multi-element loop design, which typically requires more components such as spreaders and wires compared to Yagi-Uda antennas with simpler straight elements.^[32] Achieving precise alignment of the loops is essential, as even minor deviations can distort the radiation pattern and reduce gain, necessitating careful mechanical support and tuning during assembly.^[6] The physical size of quad antennas is a significant limitation, with full-wave loop elements demanding substantial vertical space—often on the order of λ/4 per side for square configurations, but scaling to larger dimensions for lower frequencies, such as over 140 feet for 80-meter designs.^[32] This large footprint contributes to increased weight, particularly when using materials like bamboo spreaders (approximately 2 pounds per 12-foot section), making the structure more susceptible to loading from ice, snow, or high winds, which can compromise stability without additional reinforcements.^[32] Bandwidth is another constraint, particularly when optimized for maximum gain, where the 2:1 VSWR bandwidth may be limited to 2-5% of the operating frequency, resulting in a shallow SWR curve that requires exact tuning for peak performance.^[6] For multi-band operations, incorporating traps to enable coverage across frequencies introduces additional insertion losses, typically around 0.7 dB per trap on lower bands, though cumulative effects can reach 1-2 dB overall, reducing efficiency.^[33] Cost and durability further limit quad antenna practicality, as the higher material requirements for wires, non-conductive booms, and spreaders—essential to prevent detuning from conductive supports—elevate expenses compared to simpler designs.^[34] Durability issues arise from environmental exposure, with spreader materials like bamboo lasting only 3-4 years in harsh conditions, while more robust fiberglass options increase costs but offer better resistance to weather-related degradation.^[32] At low mounting heights, quad antennas exhibit poorer low-angle radiation compared to vertical antennas, as their horizontal orientation produces higher takeoff angles, limiting effectiveness for long-distance DX communications without elevation.^[35]

Applications

Use in HF and VHF Bands

Quad antennas are widely employed in the high-frequency (HF) band, spanning 3 to 30 MHz, particularly for long-distance (DX) communications and contesting activities on the 10-meter to 40-meter bands. A typical three-element quad, mounted at approximately one wavelength above ground, provides an optimal low takeoff angle of around 20-25 degrees, facilitating efficient skywave propagation for transcontinental contacts. This configuration delivers about 9.3 dB of gain over an isotropic radiator, surpassing equivalent Yagi designs by roughly 1.2 dB, which enhances signal strength in competitive environments where marginal propagation conditions are common.^[5] In the very-high-frequency (VHF) band (30 to 300 MHz), quad antennas are favored for their compact size relative to wavelength, making them suitable for the 6-meter and 2-meter bands. These designs, often with two to four elements, achieve higher gain—up to 10-12 dBi—compared to dipoles, supporting specialized modes like meteor scatter and amateur satellite operations where directional performance is critical for weak-signal detection. Vertically polarized loops are common in VHF quads to minimize noise from urban sources, enabling reliable bursts of communication via ionized meteor trails or low-Earth-orbit passes.^[5]^[36] For shortwave broadcasting, quad antennas saw legacy use at stations like HCJB in Ecuador, where a cubical quad design was implemented in the 1940s to handle high-power transmissions without arcing issues at high altitudes, enabling global coverage in multiple languages for over six decades. However, such applications are now rare, as modern solid-state transmitters favor simpler, more efficient curtain or log-periodic arrays that support broader frequency coverage without the mechanical complexity of rotatable quads.^[3] A key advantage in both HF and VHF deployments is the quad's inherent polarization flexibility; feeding the driven element at the bottom yields horizontal polarization, ideal for matching skywave paths in long HF links to reduce fading from ionospheric twists. Stacking multiple quads vertically, typically at 0.5 to 0.75 wavelength spacing, adds approximately 6 dB of gain through constructive interference, further boosting effective radiated power for DX or weak-signal work. Overall, quads excel in space-constrained urban settings, requiring shorter booms (e.g., 6-10 feet for multiband HF) than comparable Yagis while maintaining superior front-to-back ratios and lower noise floors.^[16]^[7]^[5]

Modern and Specialized Implementations

In contemporary amateur radio practice, quad antennas have found niche applications in satellite communications, particularly for Oscar (Orbiting Satellite Carrying Amateur Radio) missions, where circular polarization is crucial to counteract signal fading due to Faraday rotation. The WiMo X-Quad series, designed specifically for VHF/UHF satellite work, incorporates switchable polarization options—horizontal, vertical, right-hand circular, or left-hand circular—enabling seamless adaptation to varying satellite passes and minimizing losses from polarization mismatch.^[37] Similarly, the Quagi, a hybrid design merging quad loop elements with Yagi directors, delivers high gain (up to 12 dBi) and inherent circular polarization capabilities for reliable uplink and downlink with low-Earth-orbit satellites like AO-91 (operational in sunlight passes as of 2025).^[38] Portable and emergency deployments benefit from lightweight quad variants like the E-Z-O configuration, which bends traditional square loops into an octagonal shape to reduce boom stress, overall weight (typically under 20 kg for a 10/15/20-meter model), and wind loading while maintaining or exceeding the gain of conventional quads (around 7-9 dBi).^[24] This design's simplicity facilitates rapid assembly in field day events or disaster response scenarios, such as ARRL Field Day operations, where operators prioritize quick setup over permanent installations.^[39] Recent advancements in the 2020s include hybrid quad beams like the MQ-26, which integrate trapped elements for six-band HF coverage (6/10/12/15/17/20 meters) in a compact 4.5-foot boom, offering beam steering via manual rotation and improved bandwidth without active electronics.^[40]^[41] For urban environments with height restrictions, stealth adaptations using telescoping fiberglass fishing poles as supports enable discreet deployment of mini-quads on balconies or rooftops, providing VHF directional performance for local repeaters.^[42]

References

[1]
Ham Radio Glossary - ARRL
Cubical quad antenna -- An antenna built with its elements in the shape of four-sided loops. Current -- A flow of electrons in an electrical circuit. CW ...
[2]
Antenna - US2537191A - Google Patents
A loop antenna system for a wave signal device operating at a predetermined frequency compr sing, an even number of conductor'turns each having an electrical ...
[3]
1940 - 10 KW Transmitter and the Cubical Quad Antenna
Clarence Moore found that solution by inventing a new antenna design, which in effect had no ends, called a cubical loop, or Cubical Quad Antenna.
[4]
The "Quad vs. Yagi" Question
The history of the cubical quad antenna is equally fascinating. Bill Orr's 1959 book on the subject devotes a chapter to Clarence Moore's invention to overcome ...<|control11|><|separator|>
[5]
[PDF] All About Cubical Quad Antennas - the Kauai Amateur Radio Club
Each side of the square is approximately one-quarter wavelength long, and the high impedance points of the loop fall at the mid-point of the vertical sides.Missing: ARRL | Show results with:ARRL
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[PDF] The ARRL Antenna Compendium Volume 1
The cubical-quad antenna has a relatively broad operating bandwidth. This is ... wavelength spaced, 50.125-MHz quad antennas. My choice of element ...
[7]
Cubical Quad Antenna - W8JI
1/4 wavelength is the internal "stacking distance" of a square quad element. Two dipoles 1/4 wave apart produce enough pattern compression to provide 3.22 dBi ...Missing: principles | Show results with:principles<|control11|><|separator|>
[8]
Yagi vs. Quad, October 1966 QST - RF Cafe
Feb 13, 2013 · It seems to be pretty well established that at the lower heights a quad has a definite edge over the Yagi. However, I was curious to know how ...
[9]
[PDF] Light and Sturdy Quad for 10 and 15 Meters - ARRL
This two-element quad uses 14" aluminum tubing, 4'8" spacing, and 14-foot fiberglass fishing poles, with a boom-and-cross-arm design. It performs well at low ...
[10]
Some Model Quads: 2. Variations and Comparisons - Antentop
Because the quad and the 2-element Yagi are both driver-reflector designs, their gain curves parallel. A driver-director 2-element Yagi gain curve would ...
[11]
Quad Vs Yagi | Lightningantennas
Quad antennas have more gain, are lighter, have better front-to-back ratio, better side rejection, and operate efficiently at lower elevations than Yagi ...
[12]
[Towertalk] The Quad antenna was developed by HCJB
Nov 16, 2002 · ... Patent Office to be of sufficient importance to permit the issuance of a patent to Clarence C. Moore covering the so-called Cubical Quad antenna ...Missing: inventor | Show results with:inventor
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All about Cubical Quad Antennas - Amazon.com
All about Cubical Quad Antennas [Orr, William I., b/w Illustrations & Photos] ... Publication date. January 1, 1971. ISBN-10. 0933616031. ISBN-13. 978 ...
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The ARRL Antenna Book covers antenna theory, design, construction, and practical projects, including new and time-tested designs for radio communications.
[16]
Cubical Quad Antenna
A two loop antenna that he called a Cubical Quad. He developed this antenna to resolve issues caused by large coronal discharges while using a yagi beam ...
[17]
EZNEC Antenna Software by W7EL
View Antenna display, showing the "wires" making up the model of the five-element beam, with currents and 2D slice superimposed to show orientation.EZNEC Pro+ Printable Manual · EZNEC Pro+ v. 7.0 Updates · NEC-5 · AutoEZMissing: quad | Show results with:quad
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Half Quad Stealth Antenna - Ham RadioVideo - YouTube
Jan 25, 2023 · The Half Quad is yet another example of a compact HF antenna that can be squeezed into a small garden. Peter G3OJV, goes back to 1976 where ...
[19]
[PDF] All About Cubical Quad Antennas - SP5PPK
In his spare time, Moore built a second Quad antenna, this one to be used in the 20 meter band at his ham station, HClJB, in Quito. * * * * \". At a later date, ...Missing: inventor | Show results with:inventor
[20]
None
### Quad Antenna Element Configuration and Dimensions
[21]
Build a Stronger 2 Element Quad Antenna - Ham Universe
This is where you will adjust your SWR by lengthening or shortening your antenna wire. Since the wires are slack in the middle this design makes adjusting easy.
[22]
[PDF] 4 Element, 2 Meter Quad Antenna - QSL.net
It featured a wooden construction, and was tuned for 147 MHZ. I re-tuned it for 146 MHZ and refined the mechanical design for durability and portability.
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https://www.kb5tx.org/oldsite/DIY%20(Do%20it%20Youself)/Build%20a%20Hi-Performance%20Quad.pdf
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Cost savings were significant, but I found other advantages. Surface loading, weight, and peak stresses to the boom are all lower than with a conventional quad, ...Missing: features construction
[25]
How does an E-Z-O Antenna work and why does it appear in ...
Feb 27, 2019 · It's described on the Wikipedia page because the creator of the antenna put it there in Feb 2009. The E-Z-O section has subsequently been ...Missing: history | Show results with:history
[26]
The Birdcage Antenna
The Birdcage is a double folded X-beam. For reference, Figure 1 provides a free space pattern of an X-beam tuned for maximum front-to-back ratio.Missing: 1950s | Show results with:1950s
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3-Band, 2-Element Spider-Supported Quad Beam
The tri-band spider quad based on wide-band monoband quad designs achieves its goals of providing close to monoband performance across all three included bands.
[28]
Delta loop - W8JI
The delta loop is nothing more and nothing less than a reshaped quad element. The delta is pulled to a point at one side, generally the apex.Missing: Diamond circular ratios<|control11|><|separator|>
[29]
Modeling the Double-Diamond for UHF
Using the more conservative and more accurate NEC-4 value, a (vertically polarized) quad loop has only about 1.6 dB more gain than the vertical dipole. We must ...<|control11|><|separator|>
[30]
Cubical Quads & Delta Loops - Antenna - VU2NSB.com
Oct 9, 2019 · A Cubical Quad loop can produce either vertically polarized or horizontally polarized radiation depending on the way it is set up and on the ...
[31]
Cubical Quad Antenna - Electronics Notes
The basic cubical quad driven element on its own has a gain of about 2dB over a dipole because it is essentially a pair of stacked dipoles. It is generally ...
[32]
[PDF] Chapter 12 - Quad Arrays - QRZ.RU
... Yagi antenna. The quad antenna was designed by Clarence Moore, W9LZX, in the late 1940s. ... The full-wave loop was discussed in Chapter 5. Two such loops ...
[33]
[PDF] The Compact Quad Multiband HF Antenna
An easy to build loop with a simple matching section offers four band HF coverage. Andrew Roos, ZS6AAA for a multiband antenna, since it can be easily ... I have.
[34]
SHRUNKEN QUADS - Antentop
The decrease from 2" to 1" yields a larger increase in resonant frequency than the decrease from 3" to 2" of load width. Fig. 7 Single load-line width vs.Missing: multi- | Show results with:multi-
[35]
Horizontal vs. Vertical Antennas on the Low HF Bands - Antentop
At the lowest angles, the verticals have higher gain, plus a very dramatic reduction of high-angle radiation.
[36]
https://www.wimo.com/en/blog/post/meteor-scatter
[37]
https://www.dxengineering.com/parts/wmo-18010
[38]
Circularly polarized Quagi antennas for space communications
Presto - an instant, high-gain VHF or UHF antenna! The quagi is a linearly polarized antenna, and OSCAR 13 uses circular polarization. This is not a problem if ...
[39]
*PRODUCT WATCH* E-Z-O antenna by OMICRON - Delta-Alfa
Jun 20, 2015 · According to Roger, the E-Z-O antenna is said to be cheaper in price, lighter in weight and easier to install than the cubical quad. It's also ...Missing: portable emergency
[40]
T.G.M. Communications Six Band MQ-26 2 element "Hybrid Quad" bea
Review Summary For : T.G.M. Communications Six Band MQ-26 2 element "Hybrid Quad" bea. Reviews: 30, MSRP: 369.95 US. Description: 6 Band Mini Beam hybrid ...Missing: VHF 2m satellite<|separator|>
[41]
I have a small backyard. What kind of HF antenna could I put back ...
Sep 11, 2020 · Inverted-V dipoles, or even folded/shortened dipoles in inverted V form should work well. Loops, deltas, quads and Small beams are an option too ...