About

Welcome to VK3HN’s amateur radio blog. My interests are radio craftsmanship, homebrew, QRP (low power communication), SOTA, repair, repurposing and ‘ad hoc-ism’ (making things from what’s available in piecemeal, bricolage fashion). I also like to write. For ‘about me’ search up my QRZ.com page. If you like what you find here please leave a comment, no matter how brief.

Mt Kosciusko in late Spring (Australia’s highest mountain), 4th November 2018.

Homebrewing

‘Homebrew’ is an American term for user-designed and hand-made radios and electronics equipment. I have always built radios, mostly from scratch with whatever parts are on hand or could be scrounged, re-purposed or bought cheaply. I consider amateur radio homebrew (radio making) to be a kind of vernacular design language and its practice a craft, comparable with traditional hands-on crafts like tool making, ‘Bush carpentry’ and black-smithing.

Using homebrew radios and minimizing spend does not compromise my enjoyment of amateur radio — it is the basis of it. I choose designs and construction techniques not because they are State-of-the-Art but because they bring me engagement, enjoyment, or fulfill a whim. I have only one commercial transceiver (Icom 746Pro) which is mostly used for oscillator and signal monitoring. It’s not that I don’t like it, I just prefer to use my own project creations.

My projects are a curious mix of hand drawn/etched and manufactured circuit boards, surface mount and leaded components, analogue oscillators and Arduino micro-controllers and their software. I particularly like re-purposing a salvaged or liberated component, chassis, ‘found object’ or long-held piece from my (or someone else’s) youth. Because I make most of my own boards, I frequently cut them to snugly fit a corner, or layer them to achieve a pleasing or compact configuration. No two projects or even PCBs are ever the same. That’s why I call it radio ‘craft’.

Project preferences

I mostly build QRP SSB and CW transceivers from the late twentieth century, with digital oscillators and controllers but analog signal paths. Returning to radio making in 2015, I have found that it is now possible to build a transceiver with coverage and performance for less than $100 that I could only have dreamed about when I started in the late 1970s.

In late 2018 I started my first Class E 100 watt AM transmitter for 160 meters. Top band, Class E and Pulse Width Modulation are new challenges to me that I hope to pursue with more QRO AM transmitter projects.

Blogging and Vlogging

This blog is an open project and SOTA diary. I use it like a classic logbook, recording stories and narratives, design decisions, layouts, sketches, measurements, and reference material. All my SOTA posts include enough navigation information to help me or anyone else get back there in the future. I find I look things up here more than any other reference. Since it started in 2015, there have been 53,000 visitors.

I use YouTube to supplement this blog. Video conveys so much information so efficiently it’s hard not to use it.

https://www.youtube.com/channel/UCJS-RCJIkCgLLj3xAkEicWQ/videos

SOTA

image
Sugarloaf Peak, Victoria, 2016.

I do SOTA activations around VK3, using CW and SSB, mostly 40m, but also 160 to 20m. I use homebrew QRP rigs that I call ‘Summit Prowlers‘. SOTA is, for me, a form of leisure and recuperation that involves three healthy and enjoyable things — bush-walking, exercise, and portable low power radio operating. SOTA gives my homebrew projects a purpose. Here are some favourite quotes on the experience of climbing mountains:

It’s always further than it looks. It’s always taller than it looks. And it’s always harder than it looks. — The 3 rules of mountaineering.

To those who have struggled with them, the mountains reveal beauties that they will not disclose to those who make no effort. The mountains reserve their choice gifts for those who stand upon their summits. — Sir Francis Younghusband.

On respect for the mountains and the environment:

Take only pictures; leave only footprints. — Anon.
There is no such thing as bad weather, only inappropriate clothing. — Sir Rannulph Fiennes

The choices we make lead up to actual experiences. It is one thing to decide to climb a mountain. It is quite another to be on top of it. — Herbert A. Simon.

On why we climb:

Its not the Mountain we conquer, but ourselves. — Anon.

Chasing angels or fleeing demons, go to the mountains. — Jeffrey Rasley.

On mountain climbing as a metaphor for life:

Nobody trips over mountains. It is the small pebble that causes you to stumble. Pass all the pebbles in your path and you will find you have crossed the mountain. — Anonymous.

To live only for some future goal is shallow. It’s the sides of the mountain which sustain life, not the top — Robert Pirsig, Zen and the Art of Motorcycle Maintenance.

QSO Today interview

In April 2020 I was interviewed by Eric 4Z1UG for the 298th episode of QSO Today. https://www.qsotoday.com/podcasts/vk3hn

History of VK3HN

In 2003-4 I re-licensed as VK3HN, a callsign distinguished by at least one of its former holders — J . McCandlish is engraved onto the Remembrance Day Trophy (with only 25 others) as an Australian amateur who lost his life in World War II (see the trophy and the list of amateurs here). He is listed in the text of the 1936 callbook at Sea Lake, north west Victoria.

The next holder (HJ NEWLAND, PO BOX 1134, BENDIGO) is a mystery to me and I would appreciate hearing from anyone who knew or worked him.

In response to my QRZ.COM page I received an email from David GW0OGI:

I was checking through old VK contacts and saw on qrz.com you asked if anyone had worked late VK3HN. My log shows contacts on 17m 16/02/93..21/03/93 and 08/10/93 all 59 signals both ways. Henry was a lovely character,full of wit and good humor,loved a rag chew.

So it seems Henry, the second holder of the call, was active up until at least 1993. More reports of Henry are most welcome!

If you’ve gotten this far, thanks for reading, and please leave a comment or a ‘like’ !

14 thoughts on “About

  1. Raj says:

    I have been looking to buy a couple of Motorola Varactors (MVAM109) and thus came to your site. There is some mention of the specs by you on this site. Perhaps you may have bought them and used it at sometime in the past. Do you by any chance know where I can find a couple of these MVAM109 locally in Oz? 73’s Raj VK2IPD

    Like

    • Paul Taylor says:

      Hi Raj, apologies for the delay. I think MVAM109s are now fairly old. Mine were bought on eBay some years ago. There are some on eBay and also from US specialty suppliers. I suggest you try to find an equivalent current varactor, if possible, they will be much cheaper and you will have learned something in the process. You can also ask on the internet groups, eg. G-QRP, vkzlqrp, etc. Good luck.

      Like

  2. g4ydmone says:

    Great website with lots of thought-provoking ideas, I have followed you on my blog, would you consider a reciprocal link, please. 73 de John G4YDM https://johnallsopp.blogspot.com/p/home-page.html

    Like

    • Paul Taylor says:

      Hi John, thanks for your nice comments. My goodness, you are a talented artist! What an amazing combination, art and amateur radio! You are a rare and highly skilled individual! Happy to follow your Blogger blog, just done that, you’re at the top of my blogroll. Regards Paul VK3HN.

      Liked by 1 person

  3. ROLAND DE BEUKELAER says:

    Hello Paul,
    I was looking on your fine website and I like to build your ‘8 band Super AM Receiver”.
    Unfortunately the drawing picture (in jpeg) is not visual clear (even magnifying makes it worse). Do you have this drawing in another format (PDF orBMP?)
    Thanks
    73 de ON4RDB
    Roland

    Like

  4. Christiaan says:

    Hi Paul.
    Help….
    I’m in the (very beginning of the) process of building the 200Watt AM CLass D Transmitter as described on your (most interesting) site. I’m sort of stuck trying to generate the Arduino-code based on your Github-repository.
    More specific, my Arduino IDE complains about the absence of “rotary.h” and “pcf8574.h”.
    Can you please check whether you yourself are still able to build the code? And maybe even provide links to the exact sources of the forementioned two?
    Any help appreciated!
    73’s Christiaan PA3FUN

    Like

    • Paul Taylor says:

      Hi Christiaan, thanks for commenting and trying my script. Have you installed these libraries in your Arduino IDE? Please reads all the instructions including the Wiki. Also use one of the AM transmitter #defines to include only the code your project requires. Try #define SS_AM_TX_TEST_VFO and comment out the other project label, see line 38.

      Like

  5. Neville says:

    Hi Paul. Is there a way to keyword “search” this site/blog?

    Like

    • Paul Taylor says:

      Thats a good question Neville. I’m not sure. I suggest you use Google , just search for “vk3hn topic”. The tags link posts in categories like a YouTube playlist but that may not help. Anything in particular you are looking for?

      Like

      • Neville says:

        Yeah, that’s sorta why I ask. I’ve googled various topics in the past and often there’s a link to you which makes you one of my “gold mines”. Many times I’ve wondered what other gems you may have that I’m yet to discover! Random thought … do you have a list of post topics? That might help with my googling 🙂 Nothing particular at the moment but I’ll keep your offer in mind. I have pinched your suggestion for SA630’s. Mine have just arrived and I’m planning to use them to switch between two homebrew crystal filters (ssb/cw) and also switch the filters between rx & tx. Your site also put me on to the most excellent book “Building A Transceiver” which I’m now delighted to own – many thanks to you!

        Like

      • Paul Taylor says:

        Thanks for your positive comment Neville, it’s nice to know other people find some of the content useful. There is no list of post topics, it might be possible to better organise the site using WordPress, I might have a look at the options during a quiet moment, WordPress is pretty good at that kind of thing.

        The SA630s are an excellent switch for small signal paths in homebrew projects. They will work fine to switch IF filters, RF preamps, and BPFs. Note that the open circuit connection sees 50 ohms, not infinite resistance as is the case for a mechanical switch. This is not normally a problem but worth remembering. The datasheet is simple to follow. They require a few parts around them but as a switch they exceed relays and will never wear out. If you leave the control pin un-terminated they may oscillate open/closed which will sound like noise. Ground it or take it to +5v. You still need relays where their is any power involved, so in the transmitter, LPFs, and of course the T/R relay. The other advantage is they can be driven directly by an Arduino digital output (0-5v), eliminating the need for a relay driver (2N7000) or the like.

        The EI9GQ book is a superb resource, in the class of EMRFD, but more current. I particularly like they way Eamon experiments with each stage, trying different options, and always measuring and reporting on the performance.

        I don’t know that you’ve missed to many other ‘gems’, if you have read the last years or so of posts you have probably caught most of the things I’ve been working through. I started collecting homebrew tips on a page on the menu, there are a few good ideas there, but that page could be used for tips on the components I’ve n=fond most useful.

        The other thing to do is to look thru the Reference page, a grab bag and online workshop notebook of stuff I like to not forget, like calculators, components, tables, etc.

        Good luck with your projects! 73 Paul VK3HN.

        Like

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