nanoBeacon: a simple personal CW beacon

There are times when you wonder if your receiver and antenna are really working as they should. The band is dead, or empty, it’s the middle of the day, the D-Layer is sponging up every radio frequency excitation. Perhaps you can hear a few signals, but they are fleeting — and you need a steady and predictable signal source for a proper test. An RF signal generator will give you a steady carrier, but there are times when you’d prefer to have a true CW beacon to tune onto. This simple, general purpose multiband CW beacon can be run up on the frequency (or frequencies) of your choice, is powered on a 9V transistor radio battery, and can moved to attenuate to the desired signal level, for radio receiver system testing purposes.

Scratch-built 8-band HF SSB/CW transceiver (EI9GQ) – Part 2 – Receiver completion

There’s a reason why most homebrew transceiver kits and scratch-built projects are monoband and single mode — theres a chance you’ll finish it, or at least, get it working for a while. Building a multiband HF transceiver is a big job, as any homebrewer who has attempted it will tell you. It may take years.

20 meters, 200mW & 12,000 miles: WSPR magic!

Weak Signal Propagation Reporter is a global radio propagation monitoring and reporting network comprised of thousands of low power beacons operating on the amateur radio bands. WSPR beacons can be detected from the lowest of Medium Wave frequencies (137kHz) all the way through the HF spectrum (all the bands from 160m to 10m are popular) to the VHF bands, 50 and 144MHz. WSPR receivers decode the tiny beacon packets and upload them to a central database, at WSPRNet.org, where anyone can literally ‘see’ the propagation paths that are currently open.

Universal VFO Controller (ATMega328 & si5351)

This board is a universal radio project controller, with an ATMega328P(U) microcontroller and lots of options. The intention was for it to become a basic building block in transceivers, receivers, transmitters, signal generators, anywhere you need either a digital controller, one to three clocks, or both. The board has headers for the common si5351 breakout board, available from Adafruit or as a .CN clone, and a 16×2 HD7044 Liquid Crystal Display using the standard 14+2 parallel data header (+2 for backlight). It brings out all of the available digital IOs (D2..D13), analogue inputs (ADC) A0..A5), as well as headers for a 12V supply, and access to the regulated 7805 5v output, access to the LCD backlight in case you wish to take control of this in software, and an FTDI-compatible USB-to-serial programming board.

Digi-chirp! Digital synthesis of ‘nostalgic’ CW

The bottom ends of 80, 40 and 20m are not what they used to be. For starters, the busiest part is the digital segment where computers talk to computers – listening to this segment is like eavesdropping on a bunch of dialup bulletin boards having a party in 1983. Then there’s the CW segment. When there are CW signals to listen to, all are frequency stable, chirp and click-free, generated by more computers from deep inside rigs that are more computer than radio. These shining examples of digital CW perfection have traded efficiency and quality… for personality.

AGC for a Termination Insensitive Amplifier

For AGC controlled IF stages in receivers I have often chosen a 2 or 3 stage dual gate MOSFET strip, or a cascode arrangement with a bipolar and JFET pair.  These work well, have more than enough overall gain, and provide good AGC-controlled gain range.    I’ve also built a BiTX style transceiver (Andy G6LBQ’s design) with two Termination Insensitive Amplifier blocks. TIAs exhibit stable input and output impedance regardless of load, and work symmetrically (for receive and transmit) but are fixed gain. My BiTx receiver worked acceptably on 40m but was underpowered on 20m. Increasing the gain to make it more lively on 20m would have made it over-powered on 40m. You don’t have this problem when you have an AGC controlled IF.

2B2C: A video series on the design and construction of a Dual-Band 2 Channel QRP CW rig

My radio projects have involved a build and test effort, often spanning 3, 4 or even 6 months, culminating in one long, detailed blog post which was assembled over many months and a video that serves the dual purposes of showing and explaining the rig followed by an outing to one or more SOTA summits.

40m AM Transmitter (120 watts, PWM/Class D)

This AM solid state Class D single band transmitter was assembled over a three year period. Started in 2018, it’s first configuration used a 100 watt push pull RF module published by Drew Diamond VK3XU in Amateur Radio magazine, modulated by a 200 watt linear power amplifier driving a reversed mains transformer, available as a kit from local supplier Jaycar. I built up the RF board, 50 volt power supply (using a stock 300VA toroids mains transformer, no regulator) and proceeded to destroy half a dozen power FETs (STW20NM50) in the RF power stage. Realising I didn’t really know what I was doing, I wisely put it aside.

SP-X, a pocket rig for the CW activator in a hurry!

I’ve long been interested in compact and fairly minimal SSB and CW rigs with good performance. I’m not into bells, whistles or menus. Menus are for restaurants! When hiking, walking or bouncing around summits I want to minimise things that are not absolutely necessary, things that can go wrong. Less is more when it comes to a transceiver for portable work.

SP-9: A Compact Five band SSB/CW QRP Transceiver

‘Summit Prowler 9’ is a homebrew five band SSB/CW 5 watt transceiver designed for and tested on the summits near Melbourne Australia. This project further developed my interest and ideas on the right mix of features and design choices in a moderately compact case that any keen radio builder could reproduce in the home workshop with modest equipment. The transceiver project was completed over an 18 month period to April 2021.