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This document details the construction, programming, and operation of a modular WSPR transmitter. The transmitter utilizes an ESP8266 NodeMCU, an SI5351 synthesizer with a TCXO for stability, and selectable low pass filters. Construction involves soldering headers, components, and assembling filter module. The ESP8266 is programmed via the Arduino IDE, requiring library installations and code modifications, including network credentials, callsign, and frequency . The transmitter is powered by USB or Vin terminals and its frequency is selected by jumpers and software settings. The document also covers FCC restrictions and how to use the WSPR network

Review of Yaesu VX-3R 2 m/70 cm FM transceiver. Receives 0.5-999Mhz AM/FMN/FMW, Transmits 144-148 and 430-450Mhz VHF/UHF FM.

Vanuatu YJ0X, DX pedition 3-14 October 2014

A polarity checker is a very useful item to have around the shack and in a go-kit. This project, inspired by a QST article on powerpole connector protection illustrate how to build a polarity checker.

The weather station described here uses a TTGO v3 1.6.2 module and various sensors. It displays the data on an OLED screen and transmits them among a choice of protocols to the APRS, APRS-IS, Wunderground servers or via an MQTT broker. APRS data is transmitted on 433.775 MHz (can be changed) using the LoRa protocol. APRS beacons picked up by iGate gateways are then transmitted to APRS servers.

Web site and blog that reviews equipment, goes over safety, and display projects being built. Includes Yaesu FT-891 and Ameritron RCS-10 Review, a 555 Morse Code Practice Oscillator, and and arduino based Morse Code Practice Oscillator

A simple and cheap solution to monitor temperature of your repeater implementing a Raspberry Pi device with a set of popular tools made in python a database and RRD tool

The Steampunk-styled air cannon sending tennis balls flying at 500 mph!

Operating within the low-frequency spectrum, transformers serve critical roles in antenna systems, particularly for 160m applications. The resource details the construction and performance of 1:1 transformers built on BN-73-202 cores, emphasizing their use as hybrid combiners or phase inverters for RX antenna arrays. Measurements reveal that these transformers exhibit minimal losses, around 0.12 dB at 1.8 MHz, with variations based on wire type and number of turns. The analysis includes comparative data on transformer performance, highlighting the impact of different winding techniques on frequency response. Notably, the use of coaxial cable for winding improves bandwidth while maintaining low-frequency efficiency. The resource also discusses braid breaker transformers, which minimize inter-winding capacitance, achieving low losses around 0.21 dB at 1.8 MHz. These insights are crucial for optimizing low-band antenna systems, allowing operators to make informed decisions regarding transformer design and implementation.

Creating a 2m Fm Repeater with a Raspberry Pi (B) and a RTL dongle.

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

This blog chronicles the development of an 80-meter vertical antenna for amateur radio operation. The author constructs a top-loaded vertical using fiberglass poles, achieving significant performance improvements over their previous end-fed wire antenna. Comparative testing using the Reverse Beacon Network and on-air contacts demonstrates 8-10 dB gain on the east coast. The project evolved to include 40-meter capability through a modified design featuring a four-wire vertical cage, loading coil, and strategic guying system. Despite challenges with signal wobble during windy conditions, the vertical consistently outperforms the end-fed wire, particularly for reaching distant stations during nighttime propagation.

H44MS is call of DL2GAC during DX vacations in Solomon Islands 1.Febr. to 30.April 2015

The Eagle Radio Group Mablethorpe England United Kingdom

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

Build A Shortened 40 Meter Vertical antenna For POTA / SOTA Activations. A project for a portable wire antenna for 40 meters band suitable for POTA or SOTA operations.

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.

VP8PJ by The Perseverance DX Group will activate the South Orkney Islands IOTA AN-008 from approximately Feb. 21, 2020 through March 5, 2020

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.

A homemade MFSK16 APRS HF tracker, worked pretty well for 1.5W on a Lipo supply with only 2 of the 3 BS170 FETs in the final

DMR Handheld TDMA Tier I and Tier II VHF or UHF product review with information on accessories

Antique and Vintage Speaker Restorations for over 35 years. Grunow,Atwater Kent,Fairbanks Morse,McMurdo, Stewart Warner,to name a few.

Construct the Peaberry, a SoftRock-compatible SDR transceiver. This project is aimed to build an amateur radio transceiver that operates on the medium or short wave bands

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

Probemaster manufacturers probes of all kinds, including oscilloscope probes, differential probes, test leads and much more, all proudly made in the USA

Quansheng Dock v0.32.22q is a specialized software application designed for remote operation of Quansheng UV-K5 (and equivalent) handheld radios using a programming cable. The software enables various advanced functionalities and features for these radios, enhancing their usability and flexibility. Quansheng Dock is a Windows application designed for remote control of Quansheng UV-K5 handheld radios using a programming cable. It offers enhanced features such as advanced preset and channel scanning, customizable LCD displays, spectrum analysis, and audio passthrough. The software requires firmware version 0.32.21q and the .NET 6 runtime. An AIOC cable is recommended for full audio functionality. Installation is straightforward and portable.

The UniBalun is a PCB for building a lightweight antenna transformer (Balun) or impedance converter (UnUn) for low power radios. By soldering jumpers and a toroid core, you can create a 1:1, 1:4 Balun or 1:49, 1:9 UnUn. The latest revision (1.2) includes improved pads and supports both BNC and SMA connectors. Build instructions are available for German speakers.

WSJT DX Aggregator is a program that allows the stations using the WSJT-X or JTDX or MSHV programs to automatically upload DX reports to DXMAPS.com

Programming software for the Icom IC-R2 handheld receiver and scanner.

DX Cluster spots represented in a google map, for 10m 6m 2m bands taken from the VE7CC DX Cluster. Some filtering options are available.

This project taps into the NMEA stream and provides both a visual display with an LCD and also LED indicators and a sounder. The LCD outputs include 3D Lock, 2D Lock and NO Lock while the UTC time is also displayed to screen.

Schemaric diagram for a 80m, 40m, 30m, 20m EFHW Antenna Antenna Tuner. The tuner has been designed for an antenna length of 41m and the counterpoise 7.5m.

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.

How to solve the problems with the ICOM IC R7100 receiver that every time the squelch opens or closes, it produces a clicking noise.

Kantronics Pinouts with information on Icom, Kenwood Motorola, Yaesu and Vertex radio connections.

Logisim is an educational tool for designing and simulating digital logic circuits. With its simple toolbar interface and simulation of circuits as you build them, it is simple enough to facilitate learning the most basic concepts related to logic circuits.

Main Trading Company, MTC Radio has been helping Hams All over the country since 2009. Amateur radio dealer of popular hma radio brands based in Texas

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.

Undertanding the velocity factor in coax cable feed lines. Meaning of the veolcity factor index related to the RF speed of a signal inside the coax cable.

This page details the restoration of an early production Collins 75A-4 Amateur Band Receiver that had previously been vandalized.

Dipole for 40m band. It is a simple linear loaded dipole feeded with 450-Ohm openwire feedline. Designed it for resonance at 7.050 MHz, can be tuned on 30m and 80m bands with an external antenna tuner. Build with simple electrical copper wire (2.5 mmq/13 awg) and two fishing poles with size of about 7 m/23 ft.

Originally designed by John Kraus, W8JK in about 1940, this antenna has some interesting properties. The W8JK antenna is 2 (Two) centre-fed double-dipole fed by a pair of anti-phase signals. Small size, simple antenna, offer nice performance but need a tuner. Tested in this project from 30m to 6m bands

The 1 watt 20 meter QRP transmitter with VXO. This is a nice QRP transmitter that can be used in combination of one of the simple receivers.

Fans of NIST signals cite benefits including understanding the near-Earth environment

A Different way to construct a tried and true antenna out of PVC, especially for the 10 meter and higher frequencies.

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

A page dedicated tho the IC-756PROIII transceiver. This radio, discontinued, incorporates many of the features that made its predecessors so successful. However, the integration of the latest technology employed in the IC-7800 such as receiver technology, +30dBm class IP3, miniscope makes this new rig the very pinnacle of the IC-756PRO series.

A review of the most popular and traditional methods to learn morse conde and a different method that foreseen to learn 100 most common words in CW

This antenna works on 17, 20, and 30 meters, with the best bandwidth on 20 meters. The bandwidth on 17 and 30 is quite small but usable. There is a 20 KHz bandwidth on 20 meters.

This document details the construction of a multi-band end-fed antenna, suitable for situations with limited space for larger antennas. The design utilizes a 1:49 to 1:60 impedance transformer to match a half-wave wire antenna fed at one end. Compared to a traditional dipole, this antenna resembles a highly unbalanced Windom antenna with one very long leg and a virtual short leg. The design eliminates the need for radials but relies on the coax cable shield for grounding. The document recommends using at least 10 meters of coax and installing a common mode filter at the entry point to the shack for improved performance.