Search results

Presentation of the QO-100 the first geostationary OSCAR from Qatar by AMSAT-DL

Mini-Operating Guide includes useful hints on Using the HM-133 Microphone, Basic Operation, Operating through a Repeater, Programming a Memory Channel and Assigning a Memory Channel to a Memory Bank

This magnetic loop DIY site is ment to be an introduction into making DX high quality magnetic loop antennas that will beat any dipole

CERT Communications Team Procedures Alinco DJ-191 quick reference in a four pages PDF file

Free Windows program intended to be used as a training aid for sending CW using an iambic Winkeyer from K1EL Systems. Iambic Master operates as a game. The objective of the game is to send the text in the Target box as accurately as possible.

Complete microphone wiring handbook for most popular radio transceivers provided by Astatic Microphones.

A collection of 450 MHz Cheap Yagis that have proven great portable operations, back-packing and transmitter hunts, and are something inexpensive you can throw up in the attic for that weak repeater

Although most Preselectors are designed with an internal T/R relay, theoretically enabling direct insertion between the transceiver and the antenna, there is a problem when running CW, especially when running full QSK. The switching time of the internal relay is too slow to follow full QSK. The best way to avoid this problem altogether is to insert the Preselector directly into the transceiver’s RX antenna line, thus avoiding entirely the need to switch the Preselector in and out.

All available frequencies & offsets configurations for repeaters can be downloaded as database for Kenwood MCP-2A memory channel programming software for TM-D710 & TM-V71. Zip file is no more available from the author, but the full table of frequencies is still online

This free app encode pictures in Slow Scan TV SSTV signals. Support the most popular modes Martin 1, Martin 2, Scottie Modes, Robot and Wraase modes. Image editing is even possible with som text overlaying features

An inductance and capacitance meter, measuring range is from 0 to >0.1uF for capacitance and 0 to >10mH for inductance. A project by Phil Rice, VK3BHR

A homemade morse code decoder project, providing a detailed schematic and pictures

Have you ever thought of setting up a portable HF station for an activity like the Field Day ?

Operating on Airplane scattering. Scattering of radio signals by airplanes. An introduction to operating ariplane scattering, using aircraft to redirect RF that would otherwise be lost in space. Antenna Pointing, Doppler Shift/Digital Modes, using digital modes to operate airscatter.

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.

This presentation applies to HF / VHF / UHF antennas and is about 14 different type of antennas suitable for indoor od apartament installations

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

This is a very small vertical 160m antenna that fits in the loft of even my small house. It was built as a way of getting a signal out on 160m for local AM contacts, but the local noise level was far too high to allow it to be used at night for this purpose. However, on WSPR it did a pretty good job with WSPR spots from a very long way across Europe being received when running 2.5W out.

This morse key and buzzer design only requires parts that one may already have or are easy to find on the web. There is nothing critical except that the contacts must meet when the key is depressed.

A document that will guide you on Coaxial-Cable trap optimization process to gain on global antenna performance and on increasing effective bandwidth.

Experimenting with capacitive antennas for 40 and 80 meters band. A very space-saving antenna with good receivings caracteristics

MorseKOB is a program for doing landline telegraphy and American Morse with the help of a computer. Can run on Mac OS and Linux, in addition to Windows.

A QST Article published in November 1922 is about the origin of Beverage antennas, an unidirectional antenna type that was discovered and experimented for the first time in that period. This article is the introduction to beverage antenna theory, by the homonimous autho H. H. Beverage.

Operaring portable during field day by VK4ADC

Collection of several topics on antenna tuners and their performance. Why use an antenna tuner? How does an antenna tuner…tune Does an antenna tuner fool the radio? Will an antenna tuner waste power? Can an antenna tuner help get more power to the antenna?

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 article describes a multi-band antenna design for amateur radio enthusiasts by G3FEW. The antenna is designed to cover at least five HF bands with low SWR and without the need for an ATU. It is also designed to be easy to construct and adaptable for different locations. The antenna is a full-wave dipole with traps at the quarter-wave points. The traps are used to tune the antenna to different bands. The antenna can be fed with a 4:1 balun. The article includes instructions for building the antenna, as well as information on the theory behind its operation. The author also discusses the results of his tests with the antenna. This multi-band antenna is a well-designed and versatile antenna that can be used by amateur radio enthusiasts on a variety of bands. It is relatively easy to construct and can be adapted for different locations.

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

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

Getting a licence with Dyslexia/ADHD can be frustating expecially after several and repeated fails. This article help understanding and helping candidates with cognitive disorders.

Modifying the Collins KWM-2 for Serious CW Operation, Make this old SSB workhorse perform like it should on CW.

This HOWTO explains in detail how you can use the Kenwood TS-590S USB, COM and ACC2 ports for digital operation, set up the radio for digital data and digital voice operation

From buying an amateur radio transceiver, choosing the correct power supply, selecting the antenna and its feed line, to choosing the best microphone and accessories. A nice presentation for beginners.

Start by getting your audio levels sorted out, Having your levels correct is critical to maximum effectiveness in both TX quality and also for being able to decode signals properly. Guide to Filters and other Rig Settings to optimize your output signal

Yaesu FT-710 AESS MF/HF and 6-Meter Transceiver review on QST

Two easy to build microcontroller projects for machine recognition of hand-sent morse code

A small active voltage probe antenna to aid reception on the LF bands

An analysis and performance improvement of the HyGain TH3JR on the 20 meters band.

Explore two magnetic loop antenna constructions, utilizing a 6-foot and a 12-foot square loop. Accompanied by a detailed description, the 6-foot loop features a built-in stepper motor control circuit, while the 12-foot loop incorporates a separate loop controller. Efficiency, tuning ranges, and the innovative autotuning solution using a microcontroller are discussed, offering insights into overcoming the antenna's narrowband limitations.

Article on portable HF antenna where author diverge about antenna efficiency versus size based on his personal experience on using HF antennas during portable operations

A multi section article on learning the morse code for beginners. The article include a list of tips the author consider to be uesful when someone want to begin the trip to learn the morse code.

An article on amplitude modulation (AM) operation on VHF bands.

If your multiple transceiver station is suffering of intrastation interference, this handy and inexpensive band pass filters and help you. QST article Sept 1988

aLog365 is a ham radio (amateur radio) logbook for Android and for apple iOS. Includes features for SOTA, POTA, WWFF operations, export to all popular log file formats ADIF, EDI, Cabrillo. Upload data to HRDLOg.net Ham465 and includes dx cluster spots. iOS version is compatible with iPhone, iPad, and iPod touch and provides also an up to date DX Pedition plan.

GB3WX - GB3WSX - GB3YS

Make your own dipole for 40 and 80 meters band, assembling standard product parts like 40 meter traps, the 1:1 balun and insulators

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.

The document discusses the classifications of sunspots and their potential for solar flare activity, categorizing them into Alpha, Beta, and Delta groups based on their magnetic field characteristics. It explains how these classifications relate to the likelihood of solar flares, ranging from minor to extreme events. The report also outlines the geomagnetic indices and conditions that affect high-frequency (HF) radio propagation, emphasizing the effects of solar flares on radio communication and geomagnetic storms. The information is geared towards amateur radio operators, providing insights into how solar activity influences HF radio operations.

A home made CW keywer based on the W5UHX board.

List of Worldwide HF Beacons published by RSGB. The beacon service is a vital part of amateur radio propagation knowledge. Updates to the HF list, which is is a heavily edit form of the G3USF list, are continued by the current committee. It now only contains beacons that are known to be active and have been heard recently.