Category Archives: QRP

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.

Continue reading
Tagged , ,

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.

Continue reading
Tagged , , , , ,

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.

Continue reading
Tagged , , , , ,

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.

Continue reading
Tagged , ,

SP-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.

Continue reading
Tagged , ,

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.

Continue reading
Tagged , , , ,

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.

Continue reading
Tagged , , ,

SP-8: a homebrew 28MHz SSB transceiver for a UR3LMZ 144MHz transverter

Ten meters or the 28MHz band is showing glimmers of life from sunspot cycle 25. Even so, its not an obvious choice if you want to build a portable SSB monobander and have lots of contacts. But 28MHz is the IF of choice for VHF and UHF transverters. After noticing the 6, 2 and 70cm transverters available on eBay from the workshop of UR3LMZ and the good reports from buyers, I cooked up the idea to build a 28MHz ‘transverter IF’ transceiver, to be paired with one or more VHF or UHF transverters.

Continue reading
Tagged , ,

Mt Ritchie VK3/VC-003 and Mt Toolebewong VK3/VC-033

Paul VK3HN and David VK3KR.

David VK3KR and I made plans for a visit to Mt Ritchie VK3/VC-003, 1255m (8 pts) and Mt Toolebewong VK3/VC-033, 735m (4 pts). This would be our first use of the approach from the north, rather than using the usual 8km round trip via Road 15 (from Acheron Way) then Road 10. While the southern route is a great hike in the Yarra Ranges, it takes up most of a day. But more so, some more skilled cartographers than I have determined that an alternate route in, from the north, has greater clearance from the water catchment area boundary. Two good reasons to choose the new route, from the north.

Continue reading
Tagged ,

Ten Tec Model 1056 DC Receiver – is it any good, and what to do with it?

One of life’s simple pleasures is to rediscover something that bought you engagement and enjoyment in the past. And in COVID lockdown, stuck at home, it’s the perfect time to rummage through boxes in dark corners to sort, throw out, and rediscover old treasures. So it was that I came across this Ten Tec direct conversion receiver board, built around 20 years ago.

Continue reading
Tagged , ,
Shack of VK2KMI

Ham Radio Blog of VK2KMI

Ham Historian

A passionate amateur looks at Melbourne history

R.IT

My journey of repairing and recycling anything I put my hands on that I believe is still useful. Not just hardware, but including software with relevant content and issues in the field of Cyber Security, Vulnerability Scanning and Penetration Testing.

G4YDM Ham-Radio and SWL news

Radio craft, homebrew, QRP/SOTA, AM

VK1DA.blog

Amateur radio experiences with VK1DA

Tj Lab

信号処理とラジオ

The Microscopic New Yankee Make Shop

Bits of technology and illogic by WA2MZE

Paul Gacek

W6PNG/M0SNA

NewURL: https://dk7ih.de

This blog is no longer in use!