QCX CW decoding

One of the aspects I’ve been surprised and impressed with is the quality of the CW decoding while sending. While playing with the onboard microswitch as a morse key I felt I needed to emphasise the length of the dashes for the encoder to resolve my sending. So I was pleasantly surprised at how well the decoding worked with a straight key and a sideswiper. These keys didn’t seem to impose the same timing expectations as the microswitch – which is odd because I believe they are wired across each other.

In any case, the decoder was able to present a pretty reliable rendition of what I had sent with both keys. Other systems I’m familiar with are only successful with keyer generated CW sent on a paddle. I’ve only seen sideswiper CW decoded by the Begali CW Machine which is a bit more expensive than the QCX but essentially built around a tiny AVR Butterfly.

Decoding in receiving on the QCX sometimes seems to be jeopardised by noise and static, although some quite clear and strong signals occasionally would not be decoded. I need to experiment more to do it justice and check what impact the speed adjustment has because ultimately it all must be using the same microcontroller code to decode the morse, sending or receiving.

QCX enclosure

One topic on the QRPLabs discussion group is the ideal enclosure for the little radio. The designer Hans G0UPL planned for all controls to be mounted on the small 10 x 8 cm PCB and provided for those who prefer to mount it in a protective enclosure.

As mounted on the PCB the shafts of the AF gain control and the rotary encoder are slightly different lengths and the tiny momentary switches are a long way from any front panel.

Part of the appeal of such a small radio is being able to show it off to friends so in one sense especially for this prospective audience an enclosure denies this pleasure – unless of course its transparent.

For the moment at least I think I may stumbled on to a neat solution. On the kitchen bench.

A suitably sized plastic container

The price is right and it’s tasty too!

Almost made to measure!

This way I can keep tweaking the radio and store it with a degree of protection. I started out with this 40m version with the pot and encoder connected by headers with a view to finding an enclosure later, but this solution feels a little neater and safer. And there may even be space for a battery.

QCX CW transceiver

I plan to use this category of my blog as a kind of sub-site to track the building of this delightful new transceiver kit from Hans Summers G0UPL and his QRP Labs. Since its launch in late August when all stock sold out in a day, sales of the QCX CW Transceiver continue at a pace that still surprises the developer as he prepares his fourth batch of 500 kits.

This is my QCX in action receiving and decoding signals during the Oceania DX CW contest this past weekend

It is a feature packed design focused on delivering an up to 5-watt single band CW transceiver. It includes built-in test equipment to be used during alignment and the QCX can be used as a WSPR beacon.

It’s such a compact design – the PCB is 102 x 81mm with a hard working blue 16 x 2 backlit LCD display – and with its tiny onboard microswitch that can be used a key, it should probably be renamed the QTX!

It boasts a long list of design features that seem amazing for the modest price of US$49. They include a Class E power amplifier, 7 element Low Pass Filter, CW envelope shaping free of key clicks, at least 50dB of unwanted sideband cancellation, a sharp 200Hz CW filter, Si5351A Synthesized VFO with rotary encoder tuning down to 1Hz, Iambic keyer or straight key option, CW decoder, displayed real-time on-screen, S-meter, Full or semi QSK operation, Frequency presets, VFO A/B Split operation, RIT, configurable CW Offset, Configurable sidetone frequency and volume and can be connected to a GPS interface for reference frequency calibration and time-keeping (for WSPR beacon)!

Also super impressive is the quality of the 138-page long assembly instructions that make Heathkit style instructions seem abrupt! Nothing else comes close to the thoroughness of this document. As well as getting a radio that works, Hans clearly wants builders to understand how it works and why he chose the components he did. Prospective builders can download it freely from his site.

Firmware for the ATmega328P microcontroller is up to version 1.00B and available from the QRP Labs groups.io group. It is not open source.

Sputnik 60 years ago today

One of the clearest memories of my childhood is being taken up our steep driveway to the roadside out the front of our house from where there was a commanding view of the western and the southern sky. Sixty years ago today the Russians launched Sputnik and it would have been a few days after this that my father took me as a seven year old boy to watch as the satellite passed over Sydney. He must have chosen a clear night because I do remember seeing it as a fast moving bright light. What was even more impressive was that then my father took me back inside and turned on our radiogram and switched over to the shortwave bands and seemed to know exactly where to tune the radio to pick up the beeping sound of the satellite’s radio signal. The Sydney Morning Herald has just republished its coverage which captures the local mood at the time.

A Russian 400 kopeks stamp showing the Sputnik’s orbit around the Earth

There are youtube videos online claiming to reproduce the actual sound of the sputnik.
Wikipedia links to this sound, but the authenticity of this too is challenged. From the wikipedia entry on Sputnik 1 I learned that there is a direct link between the satellite and the internet. The launch was brought forward to sync up with and maybe upstage the IGY – International Geophysical Year – which began in July 1957. The Soviet success and the US failure with Vanguard led to a major reassessment of the US approach to science & technology. One of the first responses from the US to this challenge to their technological and scientific prestige was to set up ARPA Advanced Research Projects Agency, later DARPA in February 1958. Australia followed the US lead. My generation saw a boost to science education. One of the scientists quoted in the Sydney Morning Herald report, Harry Messel, went on to edit the amazing ‘Science for High School Students’ textbook for high school which I devoured and almost memorised by heart.

The science textbook Harry Messel convened in the wake of the Sputnik crisis for Australian students.

I stumbled across a 55 minute long documentary on Sputnik ‘The Story of the Sputnik Moment’. It’s full of contemporary footage that really evokes the time from the US perspective. From this doco I learned that ‘Leave It To Beaver’ premiered on the same day! This was a popular program in our home – my parents thought I was a double for Beaver, but so did many others as I do remember there was a Beaver lookalike competition even here in Sydney! Anyway this video includes sound of the sputnik. It also echoes in reverse the current impasse with North Korea. There is almost identical footage of marching Soviet troops, admittedly with slightly less energetic steps. But the threat is the same. And the issues impingeing on the technological struggle such as the US civil rights fight remind us the civil war didn’t ever really end.

This is a flight-ready backup of Sputnik 1, on display at the Kansas Cosmosphere in Hutchinson, Kansas

If anything my father seemed more impressed by the achievement than fearful for what it might mean about global nuclear war, but really what would I have known as a seven year old!?! I do remember he had a friend at his work, Tullochs a railway rolling stock and steel building material manufacturer, who was a radio amateur. It was most likely this ham who gave Dad the info he needed to tune into the signals, although I believe it was probably included in newspaper stories. This was probably the same man he took me along to meet after I had started building radios as a 12 year old. I think his name was Bob and he lived in Ermington or thereabouts. I don’t remember his call but I do remember that he had built all his gear and operated exclusively CW on 20 metres into a dipole in his modest backyard, to keep in touch with friends back in the UK where he’d emigrated from.

What I know now as well is that 1957 coincided with the best radio propagation conditions ever. It was the high point of the best solar cycle, so the few feet of copper wire hanging in the air as an antenna would have had no trouble pulling in the 1 watt signal from Sputnik. And of course background interference would have been minimal compared to today. So maybe I’m mostly nostalgic for the quieter and yet more lively radio conditions of times past.

What’s great about this memory is that it’s clear my father had a strong sense of the significance of the event and my potential interest. Even though he wasn’t a technical person he was quick to sense my interests and encourage them. Maybe it would have been hard to miss noticing the young me in the backyard hammering away at a piece of metal downpipe trying to fashion a rocket nose cone! From this day on I remember being given How and Why Wonder Books about rockets and science, and avidly collecting cards from Nestles chocolates for their ‘Adventure in the Sky’ album.

Cover of ‘Adventure in the Sky album published by Nestle to encourage kids like me to buy more chocolate bars to collect images of planes and rockets!

From reading about the launch it’s apparent that what we probably actually saw was the larger remnant of the R-7 rocket that followed the satellite into orbit. It was first magnitude compared to the Sputnik’s sixth magnitude size and brightness in the night sky. That knowledge however doesn’t dim the excitement I remember.