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HamCalc is a free collection of calculators for radio amateurs include Antenna ERP calculations, Attenuators, Audio Filter design, Coil Winding, Decibels, Great Circles map and calculator, HF Filters, HF Traps, Metric conversions OP Amps QRA Locator to Latitude/Longitude, Radio Horizon calculator, Resonance Satellite orbit calculator Timer calculations (555 timer)Zener Diode calculations Download zip By G4VWL

About grid locators and grid squares, includes links to locator and grid square calculators

How to make a simple but effective Slim Jim antenna. It includes a calculator to work out all the mesurements for the frequency you require.

Choose Iron Powder or Ferrite and calculate required turns

A free online calculator for making all of the calculations required to design and build small transmitting loop antennas, also known as magnetic loops by 66pacific.com

This is my simple implementation of the ARRL Antenna Book design equations for the axial-mode helical antenna.

Calculate the inductance of a single-layer, air-core coil.

Java script antenna calculators for ground planes, half wave verticals, quad antenna, 5/8th wave vertical antenna, dipole and inverted vee antennas

It consists of a group of JavaScript driven web pages that are intended for use as a quick reference for Ham Radio operators or just anyone interested in electronics. Offer calculators for Resistors, capacitors, inductors, power supplies, filters, attenuators and antennas

Various radio related software, including some antenna analysis, and impedance calculators.

LCF online Calculator, calculate relation between Frequency Capacitance Inductance and Reactance

Helical antennas invented by John Kraus give a circular polarized wave. They are one of the easiest to design. Find a tube with a circumference equal to one wavelength, and wrap wire in a helix spaced a quarter wavelengt

Online calculators for toroid coil, air-core coil inductance, XL, XC, and more.

An inverted Vee antenna calculator that consider also minimun vertical height and horizontal spread by M0UKD

Build an effective dipole antenna that needs much less space by adding two loading coils. This online calculator tells you how.

Use this online calculator to determine the length of a quarter-wave antenna from the frequency. Both metric and English units of measurement are supported.

Use this online calculator to determine the length of a full-wave loop antenna from the frequency. Both metric and English units of measurement are supported. Quarter-wave matching section lengths are also calculated.

Use this online calculator to determine the length of a dipole antenna from the frequency. Both metric and English units of measurement are supported.

Free basic and advanced system design tutorials for every component and aspect of solar power. Plus system sizing calculators, battery bank calculators and wire size calculators

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.

a website by vu2fd with theory lessons, details on rules and regulations and planty of homebrew projects for radio amateurs, java calculators.

A collection of calculators, contest schedules, references, databases and more for Palm OS by KB7AVT

This is an on-line rf attenuator calculator provided free in order to promote the FLEXI-BOX. Calculates the resistor values, attenuation, minimum attenuation, impedance, reflection coefficient, VSWR and return loss of a matching Pi attenuator

Electrical and electronics online calculators by Calculatoredge.com

Select the toroid by material type and dimension of the toroid, the desired inductance and you will get the numbers of turns

Basic priciples of Yagi antennas and its variations like Quagi antennas, Quad antennas includes pictures, drawings and online calculators by KN9B

Mic online calculator , Microphone Dynamic Range Calculator, Microphone Sensitivity Calculator

You can shorten a vertical antenna by using a loading coil. This online calculator tells you how the amout of inductance your loading coil will need to have.

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.

RF Feedline (Coax and Ladder-Line) Loss and ERP Calculators made with Javascript. This complex feddline loss calculator has already several line types paramenters for most common coaxial cables from Belden, Time LMR, Wireman and other common products. Result will give Matches loss, SWR loss, dB and Watts power loss.

An online calculator for designing and evaluating capacitors based on the capacitor's area, separation, number, and dielectric constant

Microwaves101 provides an extensive repository of information covering fundamental principles of microwave design, targeting engineers and radio amateurs interested in the higher frequency spectrum. The site features a detailed _encyclopedia_ of microwave terms and concepts, alongside practical design considerations for various components and systems. It serves as a foundational reference for understanding RF propagation, transmission lines, and active/passive microwave circuits. The resource includes numerous calculators for impedance matching, filter design, and other critical RF parameters, facilitating hands-on project development. Discussions on **10 GHz** equipment and **24 GHz** projects highlight practical amateur radio applications, extending to operations up to 134 GHz. Content spans from basic theory to advanced topics like MMIC design and antenna characteristics, supporting both educational and practical endeavors in microwave technology.

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 NOAA/GML Solar Calculator provides critical data for **solar position** and timing, including sunrise, sunset, and solar noon, for any geographic location on Earth. Users can input specific dates and times, or select from predefined locations such as World Cities, U.S. Cities, GML Observatories, and GML Data Sites. The interface allows for precise geographical input by dragging a red pin on an interactive map, complemented by extensive time zone selections and UTC offset adjustments. Key outputs include the Equation of Time, Solar Declination, and the sun's azimuth in degrees at local time. The tool also generates comprehensive sunrise/sunset tables for an entire year, opening these data sets in a new browser tab for easy access and analysis. While the calculator remains operational, NOAA explicitly states it is no longer actively supported or maintained, advising users that accuracy and functionality cannot be guaranteed, and no further updates or technical support will be provided. Despite the lack of ongoing support, the resource details the underlying calculations and offers spreadsheets for users interested in performing their own solar data computations. It also includes links to older versions of the solar calculator and a glossary of relevant terms, serving as a reference for understanding solar mechanics and their impact on radio propagation.

Coil64 (Coil32) is a versatile tool for calculating single-layer inductance coils used in various electronics, such as matching circuits and amplifiers. The online calculator enables users to estimate the number of turns, winding dimensions, and select the appropriate wire type for home-brewed RF inductors. It employs Bob Weaver's equation, factoring in wire corrections, and allows for the calculation of Q-factor and self-capacitance. Coil64 is compatible across multiple platforms, including Windows, Linux, Mac-OS, and Android.

This online calculator will return the inductance of a coil. It will ask you the total number of turns, the total diameter of the coil and its lenght, from the first winding to the last. Obtaining the correct inductance in winding a coil can be easy if you already know how many turns are needed. Available in inched and centimeters,

A 5/8 λ antenna, often thought to be ideal for all frequencies, has unique characteristics that don't universally apply. First introduced for medium-wave radio, it works optimally at 225° antenna length over ideal ground, yielding high efficiency. However, at VHF and higher frequencies, it offers no advantage over other antennas due to real ground conditions and complex matching requirements. DIY calculators provide only rough estimates, useful as a starting point for simulations, not for precise builds.

An online inductive reactance calculator, accepts as input Frequency and Inductance

Online impedance calculators grouped by types like Wire inductances, Toroid incuctances, Plane, PAD, Strap inductances, but even Core and Coax Inductances. Air core inductances and mutual inductance groups are also availbale. All these calculators let you input specific paramenters based on the inductor selected and will calculate specific incutance and related dimensions.

A Dutch website, with a translation option, about scanner radios, maritime, and aviation communication. With maps,a blog, free tools and calculators, and a large collection of Dutch frequencies.

Online Coil Inductance Calculator. To calculate the inductance of a single-layer, air-core coil, just select the measurement units, enter the number of turns, the coil diameter and the coil length.

The N5KWD website, maintained by David C. Taylor, presents a personal station page for an Extra Class amateur radio operator. It serves as a digital logbook and resource hub, offering insights into his on-air activities and technical pursuits. Visitors can find a **ham radio journal** detailing operating experiences, along with current news relevant to the amateur community. Beyond personal updates, the site incorporates practical tools such as online calculators for various radio applications and calendars for upcoming events like contests or hamfests. This blend of personal narrative and utility reflects a common approach among hams sharing their passion and knowledge. Furthermore, the platform showcases several **amateur radio projects**, providing details on construction, modifications, or experiments undertaken by N5KWD. This content appeals to those interested in homebrewing and technical aspects of the hobby, offering inspiration and practical examples.

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.