Microphone Compressor from 1978 lives again (ETI490)

Whilst sorting electronics junk recently I unearthed this board. My build of the Electronics Today International microphone compressor, ETI490, published in the magazine in December 1978. I remember preserving my copy of this magazine for many years, long after the pages faded and cover tattered, as it contained the construction article for this useful amateur radio station component.

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!

1977 digital clock kit retrospective

I recently came across a small electronic treasure from my youth. It is a digital clock kit, circa 1977. This was the first electronics kit I ever bought and built. It might have been bought from Dick Smith Electronics although there is no DSE branding — that may have come later.  I think it cost in the order of $25. I remember it being pricey enough that I had to put a few dollars aside for a while until I had enough.

On repair

My mower broke last time I used it. Payback for all the times I have mistreated it, yanked its handle, tilted it on 2 wheels over a gutter, or banged it roughly into a tree stump. The chassis rusted out where the handle attaches, so much so that the handle on the left side pulled off, taking with it a nicely rectangular chunk of rusted mower.  So I did what any self respecting man would do. I left it in the shed and ignored it.

Hack Green online SDR service

As if listening to 75 meter AM from the US West Coast on the train going to work in Melbourne, Australia wasn’t entertaining enough, I googled to discover other WebSDR receivers, thinking an ear in central Europe or the UK might make for an interesting contrast. Websdr.org lists some of the world’s active online Software Defined Receivers.  One that looked promising was a station on the wonderfully named Hack Green in Cheshire UK.  Hack Green turns out to be a regional Cold War nuclear bunker, established in the 1950s and declassified in 1993.  Now the site hosts a popular online SDR.

Listening to West Coast AM on 75 meters

Standing on  a crowded commuter train, going home at the end of the work day in Melbourne Australia, listening to a late night west coast AM QSO on 75 meters, 3870khz, using my Samsung smart phone, via W7RNA’s web SDR.  This is just one of the miracles of SDR and the Internet — the ability to use someone else’s station anywhere in the world, from almost anywhere in the world. My old elmer from my school days in the 1970s, Moss VK5TU, would turn his tuning knob in his grave if he could see this. KB6 and WB6es chewing the rag, on big AM transmitters.  You can almost smell the burning dust on the ultraviolet glass envelopes.  Pressing the tiny audio buds into my ear to shield some of the ambient train noise I hear the tone of the transmitter, rounded low-mids and bass.  It could be 1972. It’s a nostalgic and beautiful sound.

EMDRC Hamfest 2016

Sunday was the annual EMDRC Hamfest. I had a table with David VK3KR.  It’s the second time David and I have shared a table at this event and on both occasions we were individually clearing out saleable shack stuff that had been previously liked, appreciated and admired, even loved, kept for a rainy day, cached to be dug up acorn-like in our antipodean equivalent of a snow storm… in our hour of homebrew need.  Of all our accumulated goods this was stuff which had passed the interest threshold. None of it was without some kind of appeal and most items had a potential use.  But all of the items had fallen down the priory list relative to other stuff.  In a ham’s middle years there is a dawning that ones’ days as an active key (as opposed to a silent one) will not go on forever, and that there are more potential shack projects than one mortal life will allow one to complete.  On that basis, some items just have to go.

David VK3KR at our table.

QRP by the Bay, Saturday 14th November 2015

QRP by the Bay is a twice-yearly afternoon of QRP portable operating and eyeball QSOing at Victory Park on Chelsea Beach, Melbourne.  The location has been made famous in QRP circles as the beach locale for many of Peter VK3YE’s Aussie beach-themed videos.  The banner image on Peter’s YouTube channel  is of the Chelsea pier a few hundred meters further down the beach.  Peter has become a visible ambassador for minimal QRP, pedestrian mobile operating, wade-tennas and the gentleman’s art of making sophisticated amateur radios work with ridiculously few parts.  He founded and hosts Melbourne QRP by the Bay and it was with some expectation that I attended my first meet-up last Saturday.

Dan VK3FAJO and Peter VK3YE listening intently to an EA8 station on 20 meters on a portable Sangean.

The SOTA experience

If the incidence of global spots on sotawatch.org is anything to go by, Summits On The Air appears to be a big success.   The world-wide program and community galvanises people interested in low power (QRP) gear, portable operation, and outdoor operating, each with its own long traditions in amateur radio. What is it about this relatively new competition that has caught the enthusiasm of radio enthusiasts world-wide?

SOTA is a new concept that reprises familiar themes.  Mountain-top amateur radio operating, most visibly in the USA, is certainly not new.  In the States, where large amateur populations, great roads and prominent peaks often overlap, the mountaineering radio ham movement could be seen as a consistent meme in the dog eared pages of ARRL handbooks in the 1970s and 1980s.  A flea-power culture emerged, featuring the apocryphal QRP classics such as the Rockmite, the Norcal kits, and a hundred different keyed oscillators crammed into Altoid tins.  Homebrew QRP, with all of its quirks, fueled the mountain-top and hiking brigade, adding a kind of  idiosyncratic craftsmanship to the mountain top stories.

VK3/VC-002 Mt Donna Buang, my first SOTA activation on Easter Monday (6th April) 2015.