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How fix Astron 70 model number VS-70M amp meter not working

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

Sort of similar to the one of the 6m omni. Instead of using twin-lead, this design makes use of a more or less regular double bazooka antenna (coaxial dipole). Your attention shall be drawn to the available standart literature, such as Rothammel. In order to "compute" the dimension, Karl Rothammel mentioned that the total length of the dipole shall be 95% of the free-space wavelength. The short-circuit bridges (closing the folded dipole) are to be placed at a distance-fraction being equal to the velocity factor of the coax cable used, which will be 66% using RG-58 or RG174.

A 70 MHz Transverter project with a block diagram and schematics

Developing operational amateur radio equipment for the 134 GHz band presents significant technical challenges, particularly in frequency generation and stability. This resource details the construction of a 134 GHz system, outlining its architecture with separate transmit (Tx) and receive (Rx) modules, each employing a local oscillator (LO) and RF head units. The system utilizes a dual Flann 50 GHz lens-type horn antenna configuration for optimal signal coupling. The transmit path incorporates an LMX2541 synthesizer chip operating at approximately 2.8 GHz, referenced by a 10 MHz double-oven Morion OCXO for exceptional stability. This signal is multiplied through a series of stages (X4, then X2) to generate a 22.4 GHz signal, which subsequently drives a dual series diode multiplier to produce the final X6 signal for 134 GHz operation. The receive side features an anti-parallel diode mixer coupled to a 144 MHz transceiver via a preamplifier, ensuring effective downconversion. Operational mode is CW, achieved by keying a multiplier stage. The project includes images of the Tx and Rx head units and describes a successful 3.5 km test with G8ACE, demonstrating stable signal tones due to PLLs locked to OCXOs at both ends, confirming the system's robust performance.

Online variometer calculator by IN3OTD

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

Transmitting operations in the 50-54 MHz range offer some unique problems that over the past 50 years have stymied station owners, forcing them to tolerate quiet hours and hostility from family and neighbors attempting to enjoy other electronic services.

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.

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.

Quads beams consist of 2 1 wavelength (approximately) loops, ordinarily arranged so that one is the driven element and the other is the reflector. In this project author explains how to build a two element Quad Antenna for the 28 MHz.

The page provides information on a simple 50MHz J-Pole Antenna project based on the DK7ZB design. It explains the principle of the Wireman-J-Pole, the feeding process, practical mounting, and simulation results using MMANA GAL. The content aims to guide amateur radio operators in building their own J-Pole antennas for the 6-meter band.

A top band shortened vertical antenna project. This project includes drawing and MMANA-GAL output screens.

A page with an embedded video about a two elements yagi antenna for 28 MHz based on the original antenna design by VE7CA

This module is an analogue and digital SWR and power meter/monitor, designed to replace analogue SWR and power metering in an AM Transmitter project.

Over 150 pages of content are dedicated to maximizing activity on the 6-meter band, often referred to as the _Magic Band_. The resource details various propagation modes, including sporadic E, F2, and tropospheric ducting, providing insights into their characteristics and how to leverage them for DX contacts. It also covers essential equipment considerations, from transceivers and transverters to specific antenna designs optimized for 50 MHz operation, such as Yagis and Moxon antennas. The eBook presents strategies for participating in 6-meter contests and pursuing awards like _VUCC_, offering practical advice on logging software and operating techniques. It includes discussions on software tools useful for predicting propagation and managing contacts, alongside guidance on finding and utilizing DX maps to identify openings. The author, K5ND, shares his extensive experience to help operators achieve successful 6-meter DXing. Specific sections address the code of practice for 50 MHz operations and provide assistance in locating rare DX opportunities. The content is structured to guide both new and experienced operators through the nuances of the band, from initial setup to advanced operating strategies.

A 144 MHz transverter made by ur3lmz and connected to and Elecraft KX2 transceiver

KC901S Handheld vector antenna analyzer RF ANALYZER 3GHz S11 S21 Fieldmeter RF Source Spectrum

How to build a limited space 10 and 20 meter band Square Halo DX antenna. A horizontally polarized antenna for 10 and 20 meter band, which is suitable for a limited space.

A portable operation experience with a SpiderBeam pole during a contest, testing wire antennas, like dipole and delta loops configurations on 20 40 and 80 meters band.

This page describes a comparison study on seven different beam antennas for 40 meters band. Yagi antennas, moxon antennas, mini horse all antennas are described with schema diagram , azimuth plot and SWR F/B Gain diagram

An home made multimeter using a SparkFun multimeter kit, includes a time lapse movies of multimeter kit assembling

Make them simple then Make them work. The LAZY H antenna is a general type of antenna that is in the curtain array family. By placing two 1 wavelength dipoles in a plane that is at right angles to the direction of maximum radiation and keeping the proper in-phase current condition to each element, you can achieve a high gain bi-directional antenna.

A homemade j-pole antenna for six meters band, designed to work on local repeaters, and working on the 52-53 MHz. Includes a list of needed materials and detailed description on assembling the copper tubes used to build this antenna.

Active on 28.321,47 MHz in CW and Qrss3

An Hentenna project for the six meters band. The standard size of standard hentenna is width 1/6 wavelength x height 1/2. The antenna build in this project is a full wavelenght antenna for the 50 MHz providing a 6.8 dbi gain.

About the four meter band on wikipedia

A multimeter with standard resistance sorting function

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

Project by N9SSA

Top Loaded Vertical Antenna 3,5 MHz 80m and a 14 MHz Trap for the 20m band. The weight of this portable vertical antenna is less than 1 kg, including the ground network. The weight of the telescopic fiberglass fishing rod is another 1kg. The rod expands from 1.5 meters to 8 meters.

Schematic drawing and instructions for the construction of a simple portable dipole for use in low power and portable operations

Four or Five turn one meter loop antenna for 80 and 160 meter band. This home made receive only antena can be assembled in a small place.

Fix VHF TVI problems usign a quarter wave stub filter

Constructing a dual-band antenna for 40 and 20 meters often involves compromises in size or complexity. This resource presents a compact _open sleeve dipole_ design that addresses these challenges by using 450-ohm ladder line and folded elements to achieve a total length of approximately **17.17 meters**, significantly shorter than a full-size 40-meter dipole. The design leverages electromagnetic coupling, where a primary radiator handles the 40-meter band, and a second conductor resonates on 20 meters without direct electrical connection. This configuration eliminates the need for traditional traps, loading coils, or switching components, simplifying construction and reducing potential loss points. The antenna is fed with RG-58C/U coaxial cable, and a common-mode choke is recommended at the feed point to suppress sheath currents, ensuring a cleaner radiation pattern and minimizing RF in the shack. The design is well-suited for portable operations, field deployments, temporary installations, and restricted urban environments where space is a premium, offering solid performance on both HF bands.

A review of the 30 meter MonoGap Antenna. This review covers from the unboxing go the Gap product, the assembly of the elements, the test and tuning phase and a performance report during the years

Entities First Worked from Hong Kong on 50MHz

SMCC Amateur Radio Club - K9ONA

How test transistors and diodes with a simple digital multimeter.

Replacement high voltage metering resistors procedure

This article include a circuit that allows a cheap 0-1mA meter to be used as a micro-ammeter or a milli-voltmeter

This article is about a homebrew 6 meter lightweight Moxon antenna. Article includes a full part list, instruction to assemble the parts and pictures.

This PDF guide provides detailed instructions and diagrams for constructing a fan dipole antenna, a popular choice among hams for multiband operations. The guide covers the design, materials needed, and installation process, offering step-by-step guidance to help hams set up an effective antenna system for their radio operations.

This page describes an entirely simple, One-Knob matchbox that will match this antenna efficiently on 40, 30 and 20m, using a simple circuit that can be switched between series-resonant and parallel-resonant with just one banana jumper

Building A Full-Wave Quad Loop Antenna for 6 Meters. This is an easy antenna to build and the materials cost about $15-20. It exhibits 1.8dB gain over a 1/2-wave dipole. Using an open-wire parallel feedline (commonly called ladder line) with an antenna tuner, it tunes up on the 10m band as a 5/8-wave loop as well

This article provides details on building a 6 Meter J-Pole antenna using PVC pipe for an enclosure. This antenna uses flat 450 ohm Window Line for the tuning stub.

AC7GZ/B is a converted Sharp CB-2460 Citizens Band transceiver operatin on 28.2118 MHz.

Amateur radio repeaters, often designated by an "R" number like _R6_ or _R5_, serve as crucial infrastructure for extending VHF/UHF communications range. This resource from Essex Ham explains the fundamental concept of a repeater, detailing how it receives on one frequency and simultaneously retransmits on another, typically with a 600 kHz offset for 2-meter repeaters. Understanding the input and output frequencies, along with the required CTCSS tone, is essential for successful access, ensuring your signal is processed and relayed across a wider service area. The article clarifies the importance of using the correct _CTCSS_ (Continuous Tone-Coded Squelch System) tone, often referred to as a sub-audible tone, to activate a specific repeater. It also touches upon the concept of _simplex_ operation versus repeater use, highlighting the benefits of repeaters for mobile and handheld transceivers. Proper operating procedures, such as listening before transmitting and keeping transmissions concise, are emphasized to maintain good amateur practice on shared repeater assets.

This page describes an update to a project for a Power and SWR Meter for ham radio operators. The update includes a more powerful microcontroller, increased sampling rate, and improved display options. It explains how to use the new components and provides detailed instructions for building the updated meter. The page also offers alternative display options and includes the full source code for the firmware. Overall, this update enhances the functionality and performance of the Power and SWR Meter project, making it more versatile and user-friendly for hams looking to measure RF power and SWR in their radio setups.

A light portable 2 element Delta beam antenna for 14 MHz. It is basically a two element delta loop wire antenna made for portable usage providing good directivity and a 4.2 dBd gain