20dB – what a massive loss

A couple of subscribers requested an update on the minimalist urban station development. I guess primarily due to their interest in SunSDR2DX – a 100W HF/6/2m SDR transceiver and it’s performance in RF polluted urban environment.

After two weeks of spending a couple of hours a day on air, I am pleased to report that the radio is performing flawlessly. There is one particular aspect that has impressed me more than any other: it’s stability and reliability. SDR has come long way: from flaky issues with audio conversion, audio drivers, hardware compatibility, notorious windows drivers problems, constant need to fumigate and debug core code, endless variations, desire to introduce countless new features to outright unexplainable crashes which drove crazy even the most loyal users and proponents of SDR technology.

With SunSDR2DX hardware running the beta 3 version of EE software, all the above is simply history. In two weeks I only had one instance where I had to restart the radio! This is truly amazing.

Fifteen, or even ten years ago, SDR was called the future of ham radio communications. Plenty of enthusiasm, with unquenchable expectation that in a year or two, SDR will become a mainstream and that all radios with knobs will end up in a pile of rubbish. That didn’t happen. It turned out that SDR development requires not just an enormous amount of money, but also a relatively large number of software and hardware experts dedicated to the cause. And an army of supporters- buyers not just willing to invest but to stick around, together, until the movement becomes mainstream.

Reality failed to cooperate. Today the vast majority of radios sold are SDR embedded, knobbed radios by Japanese mega brands. With the exceptions of Flex – the only ‘original’ SDR project which has managed to establish itself as a reputable ham radio brand name. ANAN, SunSDR, Hermes — they are still with us but no matter what, and no matter when – the average amateur is simply no longer interested in SDR. “I’ve tried it, it doesn’t work for me’.

And I think, going forward, convincing fellow amateurs to ‘give SDR another go’ is going to be the biggest challenge of all.

The good news: if you’ve been out of SDR for a decade or so, things have changed for the better. Significantly.

Of course I do have a reason to speak highly about SunSDR, Flex and other manufacturers. I am in the business of selling radios of all kinds, but above all, I am a (hyper) active user so everything I share here comes from my personal, first-hand experience.

Back to the actual on-air action: I have smoked out yet another domestic appliance, a polluter with a very specific RF footprint. Again, this was only possible thanks to the wide band spectrum of  my SDR transceiver. More about that next time!

The true surprise comes  from the realization that 50 Watts into a humble vertical with two radials was sufficient to work 89 DXCC countries on 20m band in two weeks time. And not just on FT8 mode! Making CW contacts is equally easy, especially during the peak opening to Europe and Asia, both on short and long path. Thanks to our own VK0DS, all seven continents were worked too. Of course, the transmitting side is easy; it is the receiving side that will always remain limited and challenging for an urban chaser.

For the first time, I now have an opportunity to directly compare, in real time two receiving locations: a quiet ‘island in the middle of pacific’ and Sydney. My original assumption was that we will be looking at about a 10dB difference. Unfortunately, the difference is an astonishing 15-20dB. In some cases, and in certain directions – even more. This is simply heart breaking. 20dB is a massive difference. In practical terms, that means decoding only half of the signals in the FT8 mode. Or less. Luckily, and thanks to the ionosphere, propagations between two points do change over time which means that a weak and undecodable signal could in an hours time come up loud and clear, even for a brief movement. We live for those moments. If you do live in the country, on acreage, with a neighbour kilometres away, then you are one very lucky amateur.

Over the weekend, a considerable amount of time was spent ‘connecting’ various pieces of software, and ensuring they ‘talk’ to each other as they should. Currently, the setup looks like this: SundSDR connected via TCI to FT8 software (JTDX). Grid tracker serves a role of a ‘server connector’ receiving  and forwarding UDP and ADIF data to Log4OM logger as well as to JTAlert application (by our own VK3AMA). The JTAlert’s role is to track ‘what to chase’, in my case wanted DXCC countries, WAS states and WAZ zones. N1MM for CW yet to be integrated; I feel that EE3 beta CW module is yet to be re-written.  Again, there are no physical cables, nor even virtual audio cables or virtual ports- except for N1MM which does need a pair of virtual ports for sending the CW macros and PTT command. I am not going to pretend that is was all straight forward: it took a few hours to get it all running, but it was definitely worth it. With just one click, a new contact is made, log populated, QSO uploaded to LoTW,  details forwarded online to various clusters.

Next on the to do list: hardware integration.

I am not sure if I’ve mentioned this before or not: DXing is an exclusive Australian dealer for SunSDR transceivers. Plenty of radios in stock, immediate delivery.