Duoband Yagi 2m/70cm with 4 Elements on 2 m and 5 Elements on 70 cm and one Feed point. The 4-El. Ultralight-Yagi for 2m can be used on 70cm with an SWR of 1,5 without any changes.
A simple 2-tone-generator for testing the linearity of SSB transmitters. This device is as simple as useful. With 2 transistors and an oscilloscope, it is fairly easy to test the linearity of your SSB transmitter. The 2-tone-method is a standardized test method that can be used to determine the maximum output and the amplification characteristics of a sideband transmitter.
A Home made antenna tuner for QRP transceivers. This small tuner is the ideal for portable operations with random length wires or whenever you have not a resonant antenna.
This documentation effort is intended to outline some of the primary steps to take in activating a SOTA Peak. It includes some of the planning steps, the activation, and post-activation steps. This outline is designed to serve as a general guideline for SOTA Activators
This page is a discussion about impedance matching by Off Center Fed dipoles in the Wide L-form. When a vertical or horizontal dipole is bent into a 90 degree L-form, the impedance drops about half.
The programming cable is intended to be used with a computer RS-232 port for programming radios and other devices. The main goal of this cable schematics is inverting signal levels.
Measuring the Frequency Accuracy and Stability of WWV and WWVH by Michael A. Lombardi. An examination of just how accurate these frequency standard stations are.
A dual band X-frame wire antenna made using 4 turns for response down to 3 MHz or so, and 2 turns (switched) for response up to around 18 MHz. The loop configurations are tuned using common eBay 365 pF tuning caps.
QO-100 Communications with the LimeSDR Family. LimeSDR can transmit in the expected uplink frequency for QO-100 – which is 2.4GHz – and has a nice reference onboard that makes it relatively stable in frequency aspects
Icom IC-R75 tabletop HF communications receiver came onto the market back in 1999 and was taken out of production in late 2015. Frequency coverage is from 30 hz right to 60 MHz. This allows one to catch the 6 Meter amateur band as well.
The Award promotes portable activity from South Australia’s National & Conservation Parks. This award follows in the tradition of other successful parks awards in Australia
The PMR-171 is an ultra-portable, all-band, all-mode SDR radio designed and manufactured by Chinese Guohetec. It covers a frequency range of 100 kHz to 2 GHz and supports a variety of digital modes, including FT8, USB, LSB, CW, AM, FM, RTTY, DMR (optional), and WFM (receive only).
The PMR-171 has dual VFO modes, which means that you can listen to two frequencies simultaneously. It also supports split-frequency operation, which allows you to transmit on one frequency while listening to another.
The PMR-171 has a number of other features that make it a versatile radio for a variety of applications. These features include:
Intermediate frequency offset adjustment
Fine tuning
Noise suppression
AGC speed selections
RF gain and squelch controls
Integral pre-attenuator processing
Integrated AM/FM broadcast receivers
Automatic sleep and transmit-time-out timers
CAT and configuration cloning capabilities
The PMR-171 is powered by an externally attached modular 5AH battery-carrier. This battery-carrier can be augmented with dual battery backup to significantly extend battery-powered operation times. The PMR-171 also has a standardized external 9VDC-18VDC power input, making it compatible with a wide range of power sources.
The PMR-171 has a high-resolution LCD display with adjustable backlight brightness. This, combined with the user-selectable brightness level of the keypad, allows for clear and easy readability, even under bright sunlight.
The PMR-171 can be controlled wirelessly via Bluetooth using the QRadioBLE mobile app. This eliminates the need for wired connections and helps to prevent common-mode interference. The PMR-171 can also be connected to a computer using a USB cable, allowing it to be used with a wide range of standard amateur radio software.
PMR-171PMR 171 Read and batteryPMR-171 full
The PMR-171 is a powerful and versatile SDR radio that is suitable for a variety of applications. It is a good choice for amateur radio operators, field radio enthusiasts, and anyone who wants a high-performance radio with a wide range of features.
Here are some of the optional add-on modules that are available for the PMR-171:
Compass module: This module provides the radio with a built-in compass, which can be used for navigation.
DMR module: This module allows the radio to communicate with other DMR radios.
GPS module: This module provides the radio with a built-in GPS receiver, which can be used to track the radio’s location.
The PMR-171 is a great radio for a variety of applications. It is a good choice for amateur radio operators, field radio enthusiasts, and anyone who wants a high-performance radio with a wide range of features.
PMR-171 Features
Real-time spectrum.
Waterfall chart.
Doppler frequency tracking.
Using software-defined radio technology (SDR), full-band support FT8, USB, LSB, CW, RTTY, AM, FM, DMR (optional), WFM (Receive Only).
Dual frequency conversion circuit structure.
The IF width and IF displacement hardware and software can be modified to provide powerful IF interference suppression.
DSP digital noise reduction.
Built-in (4~160) m high-speed automatic antenna tuner.
Built-in electronic key controller, all parameters can be set flexibly.
Built-in sound card with IQ and audio output.
Microsoft Word – PMR-171-⁄(7K„V1.0.docx
External battery compartment design.
USB TYPEC3.1 to connect to the computer
High-precision TXCO ± 0.5ppm (-10°C~60°C). 14. Ultra-wide working voltage range: 9~18VDC, some voltage transmission is limited
This small dual band UHF VHF directional antenna is good choice for portable operations. This antenna is composed by a moxon antenna for the two meters band and it includes two parastatic elements for 70 cm band.
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.
An information paper by the International Amateur Radio Union. The amateur service seeks the return to an exclusive, worldwide allocation of no less than 300 kHz in the vicinity of 7 MHz.
Beam Controller Interface Project. The control system will be via the internet and consist of a Rig-Expert WTI-1 interface which provides access to CAT commands, PTT, and Rx and Tx audio.
A new, simple way to build the Eggbeater Antenna. This document introduces a new, simpler way to build the Eggbeater antenna. It also introduces a technically proper way to construct the Eggbeater antenna in order to achieve the best result.
This antenna was conceived mainly for high-speed digital transmission via satellite. The antenna is made of two full waves loops , mounted at right angles to each other. Then coupled together, 90 degrees out of phase over a horizontal circular reflector. With this configuration the antenna is omni directional and circularly polarized.
This is a remote antenna switch I use in my attic to connect transceivers in the basement to multiple antennas in the attic. The goal of this project is to be able to remotely connect one of the antennas in the attic to the only antenna cable available.
For this project, I decided to try my hand at building a Z-Match tuner from scratch. This type of tuner has been around for a while. While the Z-match can take on several variations, what distinguishes it from other circuits is that it is a resonant circuit that uses a fixed inductor.
This active antenna for the shortwave band provides surprising performance, even indoors. As the name implies, the main loop is made from a Hula-Hoop with the metallic paint stripped off and a single turn of 14AWG copper wire inserted inside the hoop.
This is a power amplifier project for a RF 600W 1.8 MHz to 70 MHz linear amplifier including a Low Pass Filter. Projects includes schematics, pictures, PCD design, fans details, note on PA ferrite chokes and assembling instructions
The influence of temperature changes in Common Mode Chokes. To get an indication of the impedance behavior when the core temperature changes, the author tested a CMC by heating it with a hairdryer, and measuring its temperature with an infrared thermometer. When the CMC temperature rises from 30C to 90C, the frequency of maximal impedance shifts down from ca.10 MHz to ca.7.2 MHz, or by a factor 1.4.
This page offers radio amateurs (experienced and beginners) a useful overview and tutorials on HF propagation conditions. Here you will find basic and advanced explanations, as well as practical methods, charts, maps, models, real-time measurements, assessments, comparisons, references, and an index.
This is a small collection of K9YC info and my experiences. Problems by feed lines of 1/2 lambda length. CMCs in transmitting and receiving systems. Antenna unbalance, Maximal allowed power, Choke winding tips.
This page is a project for a small loop antenna for reception of short wave broadcasting. It is in Portuguese and contains pictures and schematics to build your own antenna
This article describes the construction of a 9,50 m long dipole for the 30 m band (10.1 MHz to 10.15 MHz). It was designed to be mounted ca. 6 m above ground inside an attic. The calculations were performed by OE1MEW
If your FT-817 has stopped powering up from the internal battery but works from external power, then maybe the internal battery fuse has blown. There is a small PCB mounted fuse to protect the battery and radio. This fuse can blow, if it does your radio will not work from battery power. This page will describe how to test the fuse and describe how to make a repair.
The estimated international sunspot number (EISN) is a daily value obtained by a simple average over available sunspot counts from prompt stations in the SILSO network.
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.
This article describes the phases for the construction of a Yagi antenna. The calculations of the parameters are made using 4NEC2 software. This type of antenna is used for transmissions and receptions of electromagnetic waves. The project shown here refers to the frequency of 433.92 MHz.
This script queries the QRZ.com callsign database and returns the result to the command line. A XML subscription plan with QRZ.com is required for full functionality. QRZ.com callsign data query script written in Bash
This article is from the book Ham Radio For Dummies and features some tips for portable amateur radio operations, on Field Day or generic outdoor operation, like selecting the proper antenna and portable power.
SimpleHRR is a free ham radio remote control web application (or web app) hosted by Raspberry Pi in the ham station to remote control a ham radio HF transceiver through a supported web browser from a Desktop PC, Laptop or Android phone. Supports recent ICOM IC-7x series transceivers
This tutorial introduces and explains Smith Charts, and then gives an introduction to impedance matching. Smith Chart is a tool to visualize the impedance of a transmission line and antenna system as a function of frequency.
This Website is here to enhance the Amateur Radio experience and for those who are interested in multiple areas of our great hobby. We have information about Amateur Radio Emergency Communications. There are many areas in our great hobby that serve different capacities, ARES, RACES, NTS, FEMA, Linux, and much more.
A free educational website offering hands-on battery information. The tutorials evaluate the advantages and limitations of diverse battery chemistries, advise on best choices, and suggest ways to extend life.
Testing of real antennas is fundamental to antenna theory. The most common and desired measurements are the antenna radiation pattern including antenna gain and efficiency, the impedance or VSWR, the bandwidth, and the polarization. The procedures and equipment used in antenna measurements are described in this page.
Generators are broken down into three basic types: conventional gas, inverter, and diesel. What is the difference between these? Which is best? Do you even need a generator if you already have solar or other off grid energy available? Let’s sort it out.
Four part series of assembly videos of the Elecraft KX3. Even if these videos are not a step by step format of the build but rather viewing completed steps with learned information, the author pass along to help your build go smoother
