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DX Pedition TX3X Chesterfield Isl. OC-176, 2015 October 1-12

NARC affiliated to RSGB

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.

DMR personal web site. Includes download links for Codeplug for Hytera AR685 PD685G, PD785G, PD785 & X1P with DMR Plus and Brandmeister support with VFO like channels. Repeater maps. In German.

Dealer in HF, RF and microwave components based in Italy, offering a wide product catalog for amateur radio projects and more.

If You are using a separate receive antennas then you need a good protection circuit to eliminate the possibility of blowing out the receiver front-end while using these auxiliary receive antennas specially on low bands.

DX Pedition from Palau T88RF Apr.30 - May 4, 2012

The use of an isolation interface between the radio and the pc is higly recommended,in order to avoid the problems that could be caused from ground loops. This project includes schematic and assembly instructions

Surprisingly, although PCB soldering is the core process of electronics assembly, few people do know how to solder reliably

The Necessary Bandwidth for CW Signals By George Grammer W1DF

Recent researches seem to support the hypothesis that Sporadic E propagation could be connected to presence of thunderstorms.

This antenna just requires about 24m of free space instead of 41m that a normal half wave 80m antenna needs to hang up. The so called loaded dipole uses a coil in every dipole arm to electrically lengthen the mechanical too short dipole arms. Every coil has an inductivity of 120 microHenry.

I have RFI, now what– Locating it. This article is the first of a three parts article, that covers the problem of locating the RFI source. Author make use of an SDR receiver to locate RFI emissions. Ai interesting RFI location process diagrams helps on following the various phases, permitting the discovery of almost 75% of the RFI issues.

Discover the key facts about what radio propagation is, the different types available and how they affect different frequencies.

Experimental Long Boom Antennas - CP, LPDA, multiband with several NEC Files for 50MHz 144MHz 222 MHz 432MHz but also 902MHz and 1296 MHz Antenna projects. Includes also for each antenna model, in a general comparison table each antenna characteristics including Directive Gain, G/T, E-F/R, H-F/R abd Boom Length. This is a great value comparison table of several commercial and home made VHF UHF antenna projects.

CW_Shark is a 32-bit Windows program designed for analyzing, decoding, and encoding Morse code. The program offers four modes: Decode Only, Keyboard QSO, Straight or Paddle Key QSO, and Straight or Paddle Key Practice.

The sudden explosion of new digital modes has taken the Amateur Radio world by storm. New modes such as PSK31 FT8 JT65 FSK441, ISCAT as well as established modes such as RTTY, SSTV, Hellschreiber and others have rocketed in popularity. In order to use these modes all that is required is a simple computer-to-radio interface which couples the computer soundcard to the radio

List of global weather fax (HF fax) stations, including their locations, call signs, and frequencies. Click on any station's call sign to view its weatherfax broadcast schedule. This site provides various radiofax receiver manuals in PDF format, on the Receivers page.

Home brewing a high performance, high power common mode choke for HF bands

Super Simple APRS Position Reporter. This project idea has been in response to the more hardware heavy Raspberry Pi projects that involve extra TNC hardware, additional sound cards, and custom cabling. This APRS position reporter is done using a Raspberry Pi B+, USB GPS receiver, Baofeng UV-5R, and a mono 3.5mm audio cable between the Pi and HT.

Article about the essentials of radio signal path loss, its causes and prediction, and its use in radio coverage and wireless survey tools

Utilizing snap-on ferrite cores and practical insights, the author enhances their shack's cleanliness against electromagnetic interference. With meticulous experimentation and installation, they improve noise levels across HF bands, reflecting on the effectiveness of their filter in minimizing common-mode disturbances. Updates underscore ongoing refinement and cautionary advice for optimal filtering and radio reception amid changing RF environments.

open source hardware for software-defined radio. HackRF One is an open source hardware platform that can be used as a USB peripheral or programmed for stand-alone operation. 1 MHz to 6 GHz operating frequency

Very Tiny Palmtop Vector Network Analyzer by edy555. This is the original GitHub firmware repository implementing the standard 50KHz to 300MHz model

Simple soundcard interface that can satisfy several requirements like totally isolated AF interface, Totally isolated PTT and CW Key interface, Extend Accessory connector to interface to allow easy connection of TNC and provide a solid PTT or SEND connection

Modification to an old cellular phone base station modules, with a fairly reduced output power (10 watts or so), the stock power amplifier modules will cover the 2.3 GHz and 2.4 GHz amateur radio bands.

This article provides a step-by-step guide for assembling a Raspberry Pi-based Satellite Tracker Interface, designed to work with Green Heron Engineering's RT-21 controllers and MacDoppler software. The guide covers hardware assembly, SD card image installation, and system configuration for satellite tracking.

A SSTV interfsace (soundcard) to minimize RF feed back and a soundcard limiter to prevent over driving the soundcard

The _G3TSO_ Mobile Antenna Page details construction and tuning methods for mobile antennas operating across **10 to 160 metres**. The content describes a Hustler-based design, optimized for RF performance and vehicle speeds, featuring centre loading. For optimal operation on various bands, the loading coil placement requires clearance from the vehicle body. Antenna resonance is critical for efficient mobile operation. A mobile antenna's base impedance may be as low as 27 ohms, requiring specific matching to achieve maximum radiation, as a minimum SWR at the transmitter does not always indicate resonance or maximum output. Tuning involves physical adjustment of antenna length to achieve resonance at the operating frequency. The _G3TSO_ page outlines a tuning procedure utilizing a low-power signal source and a field strength meter to identify maximum radiation before impedance matching. Loading coil placement, either at the base, center, or top of the antenna, influences radiation efficiency and mechanical stability for mobile installations. Centre-loaded whips, such as the Hustler design, offer a compromise between efficiency and stability, often for single-band operation. Helically wound antennas, including those for **28 MHz**, may present base impedances around 17 ohms, resulting in a 3:1 SWR at resonance. Low resistance grounding at the antenna base is also specified for optimizing performance and minimizing RFI during mobile operation. DXZone Focus: Mobile | Any | Antenna Tuning | HF

This project uses an inexpensive Teensy microcontroller as the core of a flexible interface that provides a high-fidelity sound card and VOX functions for controlling the radio.The interface firmware supports variable VOX delay, CW and RTTY keying via audio (such as is available from Fldigi), and RTS and DTR control of any keying function, all via a single USB connection to the PC.

Remote Orbitron enables either direct connection between a computer and the shack unit using a serial port OR remote operation from the internet using a WIZ110SR serial to ethernet board.

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

This is a simple interface that will let you use your pc-multimedia headset on your ham rig. It’s a small plastic box with two sockets for the headset jacks.

In this article, Steve G0UIH presents a straightforward guide for constructing a lightweight 15m 3 Element Yagi antenna with impressive performance metrics. With a focus on ease of construction and efficiency, the design boasts a nearly 8.2dbi forward gain and 30db front to back ratio. Utilizing readily available materials and a hairpin match for impedance matching, this Yagi offers broad bandwidth and simple tuning for optimal operation across the 15m band.

This article details the design and construction of a homebrew two-element loop antenna array for HF reception. The DIY receiving antenna system consists of two 30-inch diamond-shaped loops spaced 20 feet apart, offering superior directivity compared to traditional vertical arrays. The design features broadband operation from 160m to 20m bands, requiring only phase-delay adjustments via feedline lengths. This home-built antenna system achieves 9dB RDF (Receiving Directivity Factor) performance comparable to a 300-foot Beverage antenna, while requiring minimal space and no ground radials, making it ideal for suburban installations and low-band reception.

This PDF document reviews the POTA PERformer Antenna by KJ6ER, providing insights and details about its performance and features. The content is aimed at hams looking for information on this specific antenna model to help them make an informed purchasing decision. It contains technical specifications, user experiences, and possibly recommendations for optimal use. The review is valuable for hams interested in portable operation and seeking a reliable antenna solution for Parks on the Air (POTA) activations.

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

Nuand bladeRF 2.0 Software Defined Radio (SDR) 47MHz to 6GHz, 2x2MIMO, 61.44MHz sampling

This air-core solenoid style RF inductor calculator calculates the inductance, wire size, number of turns, and other parameters for an air-core solenoid inductor used in radio frequency (RF) circuits, based on user input of frequency, desired inductance value, and physical dimensions.

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.

Track aircraft by reprogramming an inexpensive digital TV USB stick to receive Automatic Dependent Surveillance-Broadcast signals.

Official PDF guide to WSJT-X FT8 SuperFox operating mode published on June 2024 by Joe Taylor, K1JT

This article on basic antenna theory explains why is a 5/8 wavelength vertical antenna better than a 1/4 wavelength antenna

A step by step guide to install the NS Roofing filter into the Yaesu FT-2000

This RF Toroid Calculator provides graphical calculator used to determine the inductance and other parameters of ferrite and powdered-iron toroids. It simplifies the process of selecting the appropriate toroid for use in radio frequency (RF) circuits

The 80-meter Skyloop antenna, a top-performing HF antenna, excels in weak signal work, low-noise operation, and omnidirectional coverage. Ideal for fixed stations, it delivers strong performance at low power, outperforming many alternatives, including 80m half-wave end-fed antennas. Requiring significant space for deployment, it’s well-suited for NVIS and groundwave use. Though not portable, it’s cost-effective and durable, with minor maintenance needs. Tuning may require adjustments for optimal resonance. It’s a standout for base stations, though a lighter portable version could enhance its versatility.

If RF noise threatens to take your hobby away, this could be probably a good solution to reduce or even eliminate RF Noise.

This interface includes both the CAT and the PTT circuits,and it can be controlled from a single COM port for the Yaesu FT-817 transceiver

With some fantasy the circuit can be easily assembled on a small scrap of pre-perf board,and then fitted in the DB9 serial connector shell. The interface requires two NPN transistors and few more passive components.

Homemade custom CAT interface cable for the Yaesu FT-817 this article include schematics diagram for the interface and some pictures