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.

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.

QRP By The Bay, Chelsea Beach, Melbourne, Saturday 8th February 2020

QRP By The Bay is a regular meet-up of amateur radio operators, makers and experimenters , Chelsea Beach, Melbourne. On Saturday 8th February the weather was summery, a warm 28 degrees C, but windy, 35km/h blow from the south-east. A strong turn out resulted in lots of conversation, show-and-tell, and general story telling. The video shows some of the faces and activity. If you want to know more about any of the people or projects drop a comment below.

I was expecting Peter VK3YE to take his wade-tenna into the shallows for some pedestrian mobile contacts, but the wind made that option risky. No matter, there was plenty to see and discuss at the tables.

Thanks to Peter VK3YE for continuing this series of ‘eyeball’ QSOs, a now regular and much appreciated date on the amateur radio calendar in Melbourne.

A compact Arduino, si5351 VFO with Keyer and OLED display

The remarkable compact transceivers of Peter DK7IH inspired me to dream up a compact transceiver of my own. This project would be an experiment on a shirt-pocket scale — not as dense as some of Peter’s rigs, but small on my scale. Starting with the PLL VFO/controller along the familiar lines of Raduino (Arduino Nano and si5351), I sketched out a physical design, and it became clear that the display choice would dictate the size of this module. Where small displays are concerned, there’s only one option … OLED.

Scratch-built 8-band HF/6m transceiver (EI9GQ) – Part 1 Receiver

Eamon EI9GQ’s book (‘Building a Transceiver’, RSGB 2018) started me down the path of another modular transceiver project. For this build I wanted to continue working with surface mount but without the compulsion to pack it all in tight. More space and the freedom to replace a module later. It would be a Shack Sloth rig (a base station), not a Summit Prowler, so the space, weight and power budget shackles fell off from the start.

Desklamp conversion to 12v DC 20w power supply

Picked up a halogen desk lamp from a street hard rubbish pile the other day. This particular desk lamp model has been a popular product for many years and appears to be still available. As I stood on what Melburnians strangely refer to as a ‘nature strip’, starting at someone else’s pile of junk, I faced a familiar dilemma– take it and do something with it, or walk away.

Hard-to-find faults and other homebrew ‘Gumption traps’

I recently cut this small piece Veroboard to hold two vertically aligned miniature potentiometers on a receiver front panel. The three soldered tracks to the right allow connection of the audio signal to the volume control using shielded twin conductor cable. Very standard stuff, I’ve been wiring up audio amplifiers to volume controls like this for about four decades. But this one wouldn’t work. It has a fault — it’s there, in the picture above, right in front of your eyes… can you see it?

Veroboard at radio frequencies

Charlie ZL2CTM has been pushing out a series of excellent videos on his YouTube channel that take you through the circuit design, making and testing of superhet SSB transceiver modules.  Yesterday my eyebrow involuntarily raised ever so slightly at his use of Veroboard as the substrate for his latest 8MHz crystal filter.  Veroboard? At radio frequencies?  Veroboard et les fréquences radio ne sont pas compatibles!