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The Cubical Quad antenna is a popular choice among amateur radio operators due to its robust design and excellent performance characteristics. This resource provides essential scaling formulas that help determine the lengths of the antenna elements and the necessary gamma match values for various frequencies. The design is adaptable, allowing operators to optimize for gain or front-to-back ratio by adjusting the spacing between elements. The accompanying Excel files facilitate precise calculations, making it easier for both beginners and experienced hams to construct their own Cubical Quad antennas. In addition to the design formulas, the resource includes practical insights from the author, who has successfully built and utilized these antennas in various field events. The document outlines the tuning process for achieving minimum VSWR, ensuring optimal performance. With detailed illustrations and performance data, this guide serves as a comprehensive reference for anyone looking to delve into Cubical Quad antenna construction and optimization, enhancing their amateur radio experience.

G5RV Formula, a simple multiband antenna, by Rick, KC8AON

Dimension and formula for a 4 element QUAD antenna for the 10 meters band

Easy for calculate formula which could be a wake-up call for you. The SWR value at the input of antenna cable is not a actual SWR of your favorite antenna.

End-Fed Half-Wave Antennas (EFHWAs) are analyzed for their utility in portable QRP operations, emphasizing their simplicity, efficiency, and predictable radiation patterns compared to other portable antenna types. The discussion contrasts EFHWAs with vertical antennas, random length wires, and center-fed dipoles, highlighting the common pitfalls of each, such as ground system dependency for verticals and feedline issues for dipoles. The article details the electrical half-wavelength calculation using the formula L (Ft) = 468/F(MHz) and explains how EFHWAs can be resonant on harmonic frequencies, enabling multiband operation. Various deployment configurations are presented, including the inverted L, inverted Vee, sloping wire, and vertical setups, each with specific advantages for radiation angle and polarization. For instance, a vertical EFHWA offers a low angle of radiation suitable for DX contacts without requiring an extensive ground system. The resource also addresses the counterpoise requirements, suggesting a quarter-wavelength wire or connection to a metallic structure for decoupling. A schematic diagram for a simple parallel-tuned circuit tuner, based on the _Rainbow Bridge/Tuner_ design, is provided, detailing component values for 30 and 40 meters, including a 6 microhenry toroidal inductor and a 20-100 picofarad mica compression capacitor. The tuner's adjustment process for SWR matching is also outlined.

This PDF document, authored by KT4QW in October 2004, details the construction and modeling of a dual-band, horizontally polarized hanging rectangular loop antenna for **10 and 17 meters**. The design, adapted from *The ARRL Handbook*, utilizes _NEC4WIN95_ software for scaling and optimization, targeting a 50 ohm feedpoint impedance. The resource includes a bill of materials, step-by-step construction instructions, and a discussion of the antenna's radiation characteristics. It presents NEC-generated elevation and azimuth patterns, comparing the loop's performance to a half-wave horizontal dipole at the same height and frequency. The 17-meter element is centered at 18.140 MHz for low SWR across the phone band, while the 10-meter element is centered at 28.500 MHz. Construction involves 14-gauge stranded copper wire and Schedule 40 PVC spreaders, with the total wire length calculated by the formula: Length in feet = 1005/MHz. The feedpoint impedance can be adjusted by modifying the rectangular aspect ratio. The document specifies hoisting the antenna to at least a half-wave above ground for testing. It notes that a balun was tested and found to have no measurable effect on SWR or radiation characteristics. A 2-meter scale model is presented to illustrate the physical design, and a "rotator" string is incorporated for directional adjustment up to 90 degrees.

This resource presents over 100 Q-signals, each with its corresponding question and answer format, as standardized by the International Telecommunication Union. The content delineates how these abbreviations can be expanded with additional groups, call signs, place names, or numerical data to provide specific context. It clarifies that a question mark following an abbreviation or its complementary information transforms it into a query. The document highlights that these operating signals, or Op Sigs, are prescribed for international use across all communication types, including military and non-military applications. It references their inclusion in Appendix 9 to the Radio Regulations Annex of the International Telecommunications Convention (Atlantic City) 1947 for QRA to QUZ blocks, and ICAO publications Dec 6100-COM/504/1 for QAA to QNZ blocks. The page specifically marks Q-signals of particular interest to amateur radio operators in red. The utility of Q-signals for concise communication in radiotelegraphy is evident, providing a structured method for conveying complex information efficiently. The resource serves as a practical reference for operators needing to quickly interpret or formulate messages using standardized codes, particularly beneficial for CW operation and international contacts.

Based on DL6UW Yagi antenna's design-formula The forward gain is 13.6 dBi (about 11.5 dBd) and it's pretty small, about 1,5 m in length

Demonstrates the essential steps for winding **toroidal cores**, a fundamental skill for amateur radio operators engaged in homebrewing and kit building. It addresses the critical aspects of selecting the correct core material and wire gauge, emphasizing the importance of precise turn counting and consistent winding tension to ensure optimal circuit performance. The resource details methods for preparing the wire, including techniques for safely removing enamel insulation from leads using flame, sandpaper, or a solder pot, and provides guidance on tinning the exposed wire. Explains the process of mounting the wound toroid onto a printed circuit board, highlighting the need for careful lead placement and secure soldering to prevent shorts and ensure mechanical stability. It also offers a practical formula for calculating the required wire length based on the desired number of turns and the specific **toroid** size, referencing common core types like T-50 and FT-240. The guide stresses the importance of verifying the inductance of the wound component, often using an inductance meter, to confirm it matches design specifications. Provides practical tips for handling multi-filar windings and managing short lead lengths, which can be particularly challenging. It underscores the necessity of meticulous attention to detail throughout the winding and installation process to achieve reliable and efficient RF circuits.

Calculate Cable Loss from SWR and reverse. Text file with only two simply formulas

Demonstrates the design and construction of a compact, portable multi-band mini-delta loop antenna, specifically optimized for /P (portable) operations from remote locations like Scottish islands. The resource covers the theoretical underpinnings of half-wave loops, contrasting closed and open configurations, and then details the application of a folded dipole principle to achieve a 50-ohm match for direct coax feed. It presents empirical formulas for calculating element lengths, considering the velocity factor of common wire types, and provides a detailed example for a 20m (14.175 MHz) version. The article includes a comprehensive table of dimensions and allowances for a five-band (20m, 17m, 15m, 12m, 10m) mini-delta beam, along with construction hints for the central support and balun. It specifies a 1:1 trifilar balun wound on a ferrite rod and describes the antenna adjustment process using an _MFJ-259B Antenna Analyser_. Initial test results indicate an SWR of 1:1 at resonance and a bandwidth of approximately 240 kHz on 20m, even at a low height of five feet above ground. The distinctive utility lies in its focus on a practical, easily deployable beam antenna for portable DXing, offering a viable alternative to more complex or larger arrays.

Processing a single RTTY signal from a transceiver's 3-kHz audio, GRITTY employs _Bayesian statistics_ for superior decoding accuracy compared to traditional trial-and-error methods. This approach not only decodes 5-bit Baudot codes but also calculates the probability of error for each bit, enabling features like color-highlighting unreliable characters and smart squelching based on error probability rather than signal amplitude. This allows decoding of very weak signals while suppressing strong, undecodable interference, resulting in minimal garbage text. The program intelligently analyzes decoded text, comparing similar callsigns bit by bit and merging probabilities using the Bayes formula. This often allows GRITTY to determine the correct callsign and place it on the call stack even when all received copies are corrupt. The same methodology is applied to correct errors in exchange numbers and CQ/DE keywords, and to fix incorrect shift states. GRITTY offers an open API interface, documented in its Help file, for integration with other programs, allowing them to receive decoded data and mouse click events.

Over 1,000 stations in approximately 60 countries were worked using this modified twin-lead folded dipole, demonstrating its effectiveness with just 4 watts on 20 meters. This design, adapted from an ARRL Handbook concept, eliminates the shorting strap found in traditional folded dipoles, simplifying construction while maintaining performance. It utilizes readily available 300-ohm TV antenna feeder ribbon, making it a cost-effective solution for radio amateurs. The antenna's robust construction allows it to handle up to 100 watts without issues, even without a **balun**. The inclusion of a variable trimmer capacitor at the stub provides flexibility for tuning across different frequencies within a band, a practical feature for operators using transceivers like the Icom 735. Formulas are provided to calculate the precise dimensions for any desired operating frequency, enabling customization for various **HF bands**.

The G5RV multiband HF antenna, designed by Louis Varney (G5RV) in 1946, is a popular compromise antenna offering good overall performance on most HF bands when paired with an external antenna tuner. The basic full-size G5RV measures 102 feet across the top for 80 through 10 meter operation and is fed at the center via a 34-foot low-loss feed-stub. This interaction between the radiating section and the feed-stub facilitates matching across 80-10 meters with a standard tuner, often eliminating the need for ladder line directly to the shack. The antenna's design center frequency is 14.150 MHz, configured as a 3/2-wave dipole on 20 meters, with its 102-foot length derived from long-wire antenna formulas. Construction details emphasize the matching section, which can be open wire, ladder line (window-type), or TV twin lead. Each type has a specific velocity factor (VF) affecting its physical length for an electrical half-wave on 14 MHz; for instance, open wire requires 33.7 feet (VF 0.97), ladder line 31.3 feet (VF 0.90), and TV twin lead 28.5 feet (VF 0.82). The article provides formulas for calculating these lengths and discusses the antenna's behavior on individual bands, from 3.5 MHz where it acts as a shortened dipole, to 28 MHz where it functions as two three-half-wave long-wire antennas fed in-phase. Practical construction notes include recommendations for vertical descent of the matching section, sealing the coax junction, providing strain relief, and winding a coaxial choke coil to mitigate common mode current. The resource also presents dimensions for double-size (204 ft) and half-size (51 ft) G5RV versions, along with their corresponding matching section lengths for various line types, making it a versatile reference for hams considering this classic wire antenna.

A page in french dedicated to the double bazooka antenna, with a short history of this antenna model and main characteristics including a comparison versus the dipole antenna and formulas to determine elements size.

This article includes an online calculator for a 3 element Yagi Antenna. The formula and basics theory of Yagi Antenna are also explained with examples.

Building a Windom HF Antenna. A PDF file presentation about homebrewing a windom antenna for the HF bands with formulas for 40 and 80 meters bands and step by step guide on making a 4:1 balun to feed the antenna.

Operating magnetic loop antennas requires careful consideration of RF safety, particularly regarding near-field magnetic field intensity. This resource presents calculations for magnetic field strength (H-field) at various distances from a magnetic loop, emphasizing that the H-field is significantly higher than the E-field in the near-field region due to the inductive nature of the radiating element. It provides specific formulas and examples for determining safe operating distances based on power levels and loop dimensions, crucial for compliance with RF exposure limits. The analysis compares calculated H-field values against FCC and ICNIRP maximum permissible exposure (MPE) limits for controlled and uncontrolled environments. It demonstrates that even at QRP power levels (e.g., 5W), the H-field can exceed MPE limits within a few feet of the antenna, necessitating greater separation distances than often assumed for electric field considerations. The practical application of these calculations helps amateur radio operators configure their stations to ensure personnel safety and regulatory compliance when deploying compact, high-Q magnetic loop antennas.

How to calculate range for a VHF antenna with a simple formula and how to increase VHF coverage.

The article, "Using 75 Ohm CATV Coaxial Cable," details methods for employing readily available 75-ohm CATV hardline in standard 50-ohm amateur radio setups. It addresses the inherent impedance mismatch and practical considerations, such as connector compatibility, for hams seeking cost-effective, low-loss feedline solutions. The resource specifically contrasts common 50-ohm cables like RG-8, RG213, and _LMR-400_ with 75-ohm hardline, highlighting the latter's lower loss characteristics, particularly at VHF and UHF frequencies. It explores two primary approaches to manage the impedance difference: direct connection with an acceptable SWR compromise and precise impedance transformation. The direct connection method acknowledges that a perfect 1:1 SWR is not always critical, especially when using low-loss coax. For impedance transformation, the article explains the use of half-wavelength sections of coax to reflect the antenna's 50-ohm impedance back to the transmitter, noting its single-frequency effectiveness. It also briefly mentions transformer designs using toroid cores and a technique involving two 1/12 wavelength sections of feedline for broader bandwidth. The content further clarifies the concept of _velocity factor_ for calculating electrical versus physical cable lengths, providing a generic formula for precise length determination. It notes that while half-wave matching is practical for 10 meters and above, it can result in excessively long runs for lower bands like 160 meters, potentially adding **250 feet** of cable. The article also mentions achieving a usable bandwidth of 28.000 MHz up to at least **28.8 MHz** on 10 meters with specific transformation techniques.

Demonstrates the product line of CAIG Laboratories, focusing on specialized contact cleaners and lubricants essential for maintaining electronic components. Key products include **DeoxIT**, designed for deoxidizing and protecting electrical connections, and **DeoxIT Gold (ProGold)**, formulated to enhance conductivity and provide long-lasting protection on plated surfaces. Details the application of these solutions across various electronic devices, from audio equipment to critical ham radio gear, ensuring optimal signal integrity and component longevity. The product range also features **DeoxIT Faderlube (CaiLube MCL)**, specifically engineered for conductive plastic and carbon-based controls, mitigating wear and improving tactile feel. Explains how proper contact maintenance with these products can prevent intermittent connections, reduce noise, and extend the operational life of switches, potentiometers, and connectors in both commercial and amateur radio applications.

If you want to design vertical antennas you can find all theory and formulas used to model a vertical aerial calculating capacitance, reactance, building the inductor and calculating resistances. Includes an excel spreadsheet to calculate efficiency.

What is VSWR and why you should care, formal definition of VSWR and SeaSonde Measurements, formulas

A 0-30 MHz step attenuator, constructed from switchable Pi attenuation pads, provides a practical tool for evaluating receiver sensitivity and calibrating S-meters. The design utilizes readily available 5% tolerance resistors, with values derived from paralleled components to achieve specific attenuation steps. A schematic (Fig 1) illustrates the circuit, including PCB pad shielding, while a table details required and actual resistor values, along with percentage differences. Measurements of voltage input versus output at various frequencies are used to calculate dB attenuation, presented in a graph (Fig 4). The resource includes formulas for determining output voltage from a known input and a comprehensive 0-40 dB voltage multiplier table, which is crucial for precise signal level management. The project also references external attenuator calculators and equations for further study. Photos (1-3) provide visual guidance for the assembled unit, showing bottom, top, and front views. The project emphasizes the use of **Pi attenuation pads** and **receiver sensitivity** evaluation, offering a hands-on approach to RF signal management.

Calculate inductance online, with the cylindrical Coil Inductor Design Equations Formulas Calculator

Over 25 years of experience in custom brass casting informs the production of personalized amateur radio call sign belt buckles. These solid brass buckles are crafted using traditional sand casting methods, ensuring a unique, durable product for radio operators. Each piece is hand-poured and polished in Washington State, reflecting a commitment to quality craftsmanship. The manufacturing process begins with a customer's idea, which is then translated into a graphic proposal. Upon approval, patterns are created for the custom edition. An antique foundry press compresses specially formulated sand around these patterns, followed by hand-pouring molten brass into the molds. After cooling, the castings are sandblasted, inspected, and meticulously polished by skilled craftsmen. Northwest Brass Works provides a lifetime guarantee on the buckle hardware, offering repair or replacement for any breakage. They also offer guidance on maintaining the polished luster of the brass using products like _Nevr-Dull_, ensuring the buckle's longevity and appearance for many years of wear.

A quarter wave vertical omni-directional antenna for 7 MHz. Formulas for dimensions in feet and meters are provided. Ideal radial angle is between 35° and 45°. Velocity factor (Vf) varies based on coax type.

Calculate distance, bearing and more between Latitude/Longitude points. This page presents a variety of calculations for lati­tude/longi­tude points, with the formulas and code fragments for implementing them.

Determining the characteristic impedance (Z) of an unknown coaxial cable, a common challenge for many radio amateurs, can be resolved with a straightforward method. The impedance of a coaxial cable is derived from its inductance and capacitance, and importantly, these values are independent of the cable's length or the operating frequency. This means that measuring a random length of cable, such as 20 meters, provides sufficient data for calculation. The core of this technique involves an LC-meter to obtain the inductance (L) in microHenries (uH) and capacitance (C) in microFarads (uF). The impedance is then calculated using the formula Z = L/C. For instance, a measurement yielding L=1.2uH and C=450pF (0.00045 uF) results in an impedance of 51.6 Ohms, closely matching **RG-58** specifications. Similarly, a TV coaxial cable with L=1.8uH and C=320pF (0.00032 uF) calculates to 75 Ohms. While the accuracy of this method, depending on the LC-meter's tolerance, is approximately 10%, it proves sufficiently precise for practical determination of unknown coaxial cable impedance, as noted by Makis, SV1BSX, who credits Cliff, K7RR, for the formula's dissemination.

This type of antenna is a popular antenna design as the performance is very good across the HF bands and requires little or no tuning. It’s a dipole fed off center with a 4:1 balun at the offset feed point. The antenna shown covers 80, 40, 20 and 10 meters. The formula can also be used to adjust the overall length to cover more or fewer bands and the resulting overall length. 160-10m, 80-10m or 40-10 meters depending on your available space. Other bands will require a tuner.

Passive Bandpass Filter online calculator and filter formulas. Active Inverting Op Amp Bandpass Filters, Active Noninverting Op Amp Bandpass Filter, just enter the Low ir High Cutoff Frequency

Here is a formula and calculator for creating a loaded (shortened) quarter wave vertical or balanced dipole. The calculation refers to either a loaded 1/4 wave or a loaded dipole

The antenna I built was inspired by a portable delta loop designed by Doug DeMaw, W1FB. Given that I constrained myself to a 50-foot roll of speak wire, I scaled my antenna for the 20M band. Using the formula, 1005 divided by the frequency in megahertz, I calculated a total length of 71 feet (21.6 meters) for the center of the 20M band.

The high-frequency inductance of single-turn loops of various shapes made of round wire can be estimated accurately with a simplified formula

This DIY guide details constructing a 5-element Yagi antenna for VHF frequencies. Yagi antennas offer directional signal transmission/reception compared to omnidirectional ones. The guide covers material selection (aluminum, screws, etc.), design using software or formulas, and step-by-step assembly including cutting elements, drilling holes, and attaching the coaxial cable. While calculations are provided for a 146 MHz design, adjustments are necessary for different frequencies. Safety precautions and potential result variations are emphasized.

The Dipole Bazooka Antenna for 40 meters is a popular choice among amateur radio operators. Its design allows for easy construction using materials like RG58 coaxial cable and PVC. Measurements are calculated using specific formulas; for instance, at a frequency of 7,100 MHz, the total length is approximately 19.74 meters. This antenna offers a performance range of 97% to 99%, with an impedance of 49 to 52 ohms. Additionally, it can handle up to 1 kW of power and requires no modifications for connection.

AutoEZ, Automated use of EZNEC, is an Excel workbook that works alongside EZNEC antenna modeling software version 5.0 or later. With AutoEZ, you can control different aspects of your model using variables and run multiple EZNEC test cases automatically. Formulas in Excel allow you to modify any part of the model. AutoEZ's interface resembles EZNEC's. Enabling macros in Excel might be necessary before using AutoEZ. The program opens various model file formats including EZNEC (.ez), NEC (.nec or .inp), AO and NEC/Wires (.ant), and MMANA-GAL (.maa). You can set the frequency and/or variable values for the test cases to be run through EZNEC. AutoEZ allows you to create animations showcasing how the pattern changes as the model configuration is modified. You can download a fully working, but limited demo copy from this site.

This article explores the powerful features of AutoEZ as an Excel application working with EZNEC antenna modeling software. The article demonstrates how variables, equations, and formulas enable versatile antenna design and automatic optimization. Through practical examples including dipoles, inverted vees, delta loops, and monopoles, the author shows techniques for achieving resonance, implementing transmission line resonators for broadbanding, and optimizing antennas across frequency ranges. The step-by-step demonstrations cover unit conversion, coordinate calculations, segmentation considerations, and SWR optimization. This practical guide illustrates how AutoEZ extends EZNEC's capabilities, making complex antenna modeling more efficient and accessible.

This page provides a detailed example of the modeling and analysis of an 80m delta dipole antenna with a 600-ohm bifilar feedline. The model is based on antennas used by the RAF from 1940 to 1970. It covers the original model specifications, conductor mass calculations, resonance frequency observation, geometry adjustment steps, and final antenna dimensions. The content includes theoretical formulas, resonance frequency calculations, and practical steps for adjusting the antenna for optimal performance. Overall, it serves as a practical guide for hams looking to understand and optimize the performance of a delta dipole antenna for the 80m band.

Fast Track offers simplified study materials designed to get you licensed quickly. Their approach focuses on understanding concepts rather than memorization. The site provides condensed study guides, mnemonic devices, and tips for remembering formulas and technical information. Their practice exams include explanations that connect to real-world applications, helping you understand why answers are correct. The resources are particularly helpful for visual learners, with diagrams illustrating complex concepts.

W4EEY offers specialized preparation materials focused on the mathematics and electronics theory portions of ham exams. Their approach breaks down complex formulas into step-by-step processes, making them accessible even to those without strong math backgrounds. The site includes calculators for common ham radio formulas, interactive circuit diagrams, and in-depth explanations of electronic principles. Their materials are particularly valuable for the Amateur Extra exam, where technical content becomes more challenging.