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Microprocessor based interface designed receives a signal from a Morse key, processes it, and re-transmits it to the radio. A microprocessor in the circuit is pre-programmed with a proprietary algorithm which makes a number of measurements and adjustments to the less percise human generated code.

Using a simple calculation, measure the distance between Earth and the Moon with the help of a local amateur radio station

A capacitance meter kit assembled. The meter measures from 1 picofarad to 500 microfarads with an accuracy of up to 1% and less than 2%

RF Wattmeters - RF Power Measurement - Bird Wattmeters Telewave - Coaxial Dynamics Wattmeters - Daiwa Wattmeters

Build a digital AC voltmeter to measure the output range from 0 to 150VAC with reasonable accuracy

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

Measuring noise fiugre on the W2IMU horn and the dual-dipole-feed

Frequency Counter w/Selective Power Measurement, Microwave Sythesized Signal Generator

Have you measured the SWR at the antenna?

The Tektronix digital multimeter is a feature-rich tool with the accuracy and precision you need for your most demanding measurements.

A fand dipole antenna home made for the 7,14,50 MHz. This article descbribes how to homebrew the antenna, hot to setup and some SWR measurements.

The PL259/SO239 (aka UHF) connectors have harsh critics and religious defenders. Questionable measurement techniques complicate matters.

New, used, & reconditioned electronic test & measurement equipment sales, rentals, & service. Agilent/HP Spectrum Analyzers, Tektronix Oscilloscopes, Fluke Calibrators, & much more.

Distributor of test and measurement and calibration instruments and provider of NIST traceable ISO/IEC 17025 accredited calibration services. Texso sells insulated tools, multimeters, insulation testers, and much more.

Antuino is an accurate instrument that can be used in the field to measure SWR, field strength, modulation, etc. In the lab, it can be used to sweep filters, measure gain, distortion, frequency response, etc. It works upto 150 Mhz. On the third harmonic, it is usable on 435 Mhz band as well (with reduced sensitivity).

N4L design and manufacture versatile, high-accuracy, easy to use instruments for power electronic test & measurement

An article on how to measure electrical current with a digital multimeter or analogue multimeter.

A page with several testing and measurement resources usefull for those ham radio operators who needs to align or repair their own radio equipment.

This project details the construction and testing of a M0PLK Delta Loop antenna for the 20-10m ham radio bands. Inspired by positive reviews highlighting its reduced local QRM compared to Cobweb antennas, the author built the antenna using aluminum tubes, DX-Wire FS2 wire, and a 1:4 balun. A mix of custom 3D-printed parts and careful assembly ensured stability and performance. Initial VSWR measurements met expectations, and test QSOs demonstrated success across multiple bands. Future enhancements include adding a lightweight, remote-controlled rotator for directional capabilities.

The structure of this dual band VHF UHF antenna is very simple. It consists of two identical square loops, whose sides measure a quarter wave, connected together at the ends. A project by I5NZR

A multimeter with standard resistance sorting function

Have you been looking for an easy way to measure power or SWR at 1296 MHz? One thing is certain, it is not easy - simply because the normal range of SWR meters that most of us have is not up to 1300 MHz.

This paper presents the method of calculating the maximum usable frequency (MUF) and field strength of radio waves reflecting 2 times at the F2 ionosphere layer under inhomogeneous conditions of the ionosphere. The comparison between predicted and measured MUF has shown that the proposed method significantly increases the accuracy of calculation MUF.

If you want to build your own common mode choke, this article explains how to measure the efficiecy of your choke before using it. In the examples has been used Amidon FT240-31 toroids.

An explanation of the different procedures and definitions that are commonly used for blocking dynamic range (BDR) measurements. Dynamic range in general is the ratio between the weakest signal a system can handle and the strongest signal the same system can handle simultaneously without an operator switching attenuators or turning volume potentiometers

The Icom IC-7300 is a popular SDR transceiver known for its excellent performance in ham bands. However, users have reported issues with reception reliability outside these bands due to ADC aliasing. This phenomenon occurs when the sampling rate of the radio interacts with frequencies outside the intended range, leading to unwanted signals being received. For instance, when tuned between 30 to 36 MHz, users may inadvertently pick up WFM broadcast signals or PMR communications due to aliasing effects. This guide outlines modifications to improve the IC-7300's performance by addressing the low-pass filter design, which is crucial for reducing interference from these unwanted signals. The proposed modifications involve adjusting the low-pass filter on the PA unit to better attenuate frequencies that cause aliasing. Measurements indicate that the original filter design allows significant signal leakage, leading to false receptions. By implementing the suggested changes, users can achieve a notable reduction in unwanted signals, enhancing the overall functionality of the IC-7300. While the modification requires careful soldering, the benefits in performance make it a worthwhile endeavor for serious operators looking to optimize their SDR experience.

Unlock the secrets of RF signal optimization in a presentation covering Balun essentials, diverse types, SWR Analyzer checks, revealing results, Ferrite impedance measurements, and practical applications on feeders and house conductors.

This device was designed as an SWR and power meter for Radio Amateurs. In addition to SWR, it measures forward and backwards power, therefore can also be used as a wattmeter. With a large measuring range from 1 to 1000 watts, it is suitable for use from QRP to QRO

Specialist for vertically adjustable supporting frameworks including telescopic masts and telescopic towers for ham radio systems, lighting systems, measurement techniques, observation systems. Located in Gnaschwitz Germany

Acknowledged worldwide for the quality, accuracy and the capability of its component measurement products.

NanoVNA based on edy555, use the odd harmonic extension of si5351 to support the measurement frequency up to 900MHz. GitHub repository.

Finding the the best ferrite material for a common-mode choke. How to create efficient ferrite cores and how to measure them

Since 1992, MATsolutions has delivered the assurance our clients need when acquiring, maintaining, and managing high-quality test and measurement equipment. Used Electronic Test & Measurement Equipment Sales, Calibration, Repair & Services

Extended Double Zepp measurements for all ham bands, and online calculator. The antenna is constructed much like an ordinary Dipole antenna but with 5/8 Wavelength Elements matched with an added Impedance Matching Section of balanced feed line

Common-mode chokes are useful solutions for RFI reduction. Winding a few turns of coaxial cable on the FT 240-31 toroid can reduced the noise below the received noise floor. In this article author measure different chokes

The author has build the Hermes-Lite SDR v1 and v2 versions describing with a very accurated text and picture the process. Additionally has documented measurements for each component

This page presents an online calculator tool for determining the dimensions of various HF wire antennas operating between 1.8-30 MHz. Users input their desired resonant frequency to obtain precise measurements for four popular antenna types: standard flat-top dipole, inverted Vee, quad loop, and equilateral delta loop. The calculator provides comprehensive measurements including leg lengths, minimum heights, horizontal spreads, and feedpoint distances. Accompanying the calculator are detailed technical explanations, construction notes, and installation guidelines for each antenna type, making it a practical resource for amateur radio operators building their own antennas.

There are quite a few recipes for building a suitable transformer for an end fed half wave antenna (EFHW), but I was never sure I really understood the main principles. So, I wound a bunch of transformers, made measurements on them using my NanoVNA, learned how to get what I really wanted out of the VNA measurements, and in the process discovered how to build better transformers and be able to predict what they will do

RF Power measurement using a DVM, RF Power measurement using an RF detector, RF Power measurement using an Oscilloscope and using a Spectrum Analyzer

The Bazooka antenna, a coaxial dipole, functions as an omnidirectional antenna with vertical or horizontal polarization. Patented in 1939 and refined in 2006, it features a quarter-wavelength coaxial cable with separated conductors. The outer conductor connects to a sleeve, while the inner conductor extends vertically. Initially complex, it has been simplified for versatile use, including military applications. Adding elements can modify its behavior for NVIS or Yagi-Uda configurations. Experiments in 2007 at the Campus de Pesquisas Geofísicas in Paula Freitas-PR demonstrated consistent VHF and UHF performance, showing reliable return loss measurements despite variable weather.

This article is an attempt to shed some light on this misunderstood component, covering topics like why you need a common mode coke, what it does, what properties it should have, ho to build one and how to measure its performance.

Constructed in May 2008, this innovative 4m tall electrically full-size halfwave vertical dipole, tunable to multiple bands, offers HF coverage despite its space-saving design. Inspired by cost-effective DIY alternatives, the antenna design departs from conventional center-fed approaches, utilizing asymmetrical dimensions. Despite resonance challenges, the antenna's performance remains viable, boasting broad bandwidth and adaptability, as demonstrated through SWR measurements and EZNEC predictions.

Otto enhances WSJT-X, the popular weak-signal digital modes program for amateur radio. It automates tasks like managing QSOs, prioritizing DX stations, replying to specific calls, and optimizing band usage. Otto works with a modified WSJT-X version (v2.7.0) to add advanced features such as directed CQs, automatic logging, and multi-stream replies. Its intuitive modes streamline operations, while safety measures ensure controlled transmissions. Ideal for DX enthusiasts, Otto improves efficiency and focus, making weak-signal operations more engaging and productive.

This blog post details the construction and usage of a 4:1 current balun, using two FT240-31 ferrite cores and 12 bifilar turns. It clarifies common misconceptions about using 4:1 baluns with G5RV antennas and ladder-line to coaxial cable connections. M0PZT emphasizes the importance of proper measurements and the limitations of internal baluns in manual antenna tuners. Detailed instructions and considerations for winding and deploying the balun are provided, along with advice on choosing suitable cores and wire for various power levels and frequency ranges.

The mini Radio Solutions miniVNA PRO is the only affordable vector network analyser (VNA) I know of that offers remote wireless operation. This is very interesting because it allows to measure the input impedance of HF antennas installed at height without having to deal with coax cable lengths, baluns nor common mode suppression chokes. However, to render the miniVNA PRO truly field proof, it requires a number of significant modifications.

This page offers an online antenna designer tool for Hams to calculate the dimensions needed to construct a coaxial collinear antenna for a specific frequency. It provides guidance on the required frequency input, coax velocity factor, and element measurements for optimal performance. The tool is recommended for experienced antenna builders due to its complexity and technical requirements. Users can input the frequency in MHz and the tool will generate the necessary dimensions based on the chosen parameters. The page emphasizes the importance of accurate measurements and connections for successful antenna construction.

Constructing a 5-element quad antenna, the author aimed for low cost and simplicity, resulting in an effective design with 11 dBi gain and SWR of 2:1 or better across the 2-meter band. Using wood and dowels, the antenna costs under $8 and takes less than two hours to build with basic tools. The model predicts excellent performance, confirmed by ARRL Lab measurements. Practical field results demonstrate improved communication, even in simplex mode.

Homebrew a 9:1 transformer and measurement for testing purposes with a miniVNA

SNASharp is a free software application designed to work with scalar network analyzers compatible with NWT software from DL4JAL. It is used to measure and analyze the scattering parameters (S-parameters) of microwave devices. Provide several measurements and analysis tools including Smith chart, Polar plot, S-parameter tables, Transmission line calculator

It is very worthwhile to understand how Beverages of all types work. Without that understanding it can be quite difficult to interpret what you hear and what you measure.