Radio and rails...

Here is a quick and dirty comparison between the Behringer UMC204HD + PA0RDT mini whip and the Airspy HF+ Discovery and YouLoop looking at a similar amount of spectrum from 0 up to 96kHz or so. First the UMC204HD: And the Airspy: This was not done in any scientific fashion, it's just to show that the soundcard method works ok but is not as good as the Airspy. No surprises there and this is no criticism of either method. I can see the utility of the soundcard method when coupled with the vlfrx-tools package as all manner of analyses become possible. I have only just started reading about that.

Another new toy arrived today. A Behringer UMC204HD "2x4, 24-Bit/192 kHz USB audio/MIDI interface". I had been reading about the use of soudcards for VLF reception and the raves about the UMC202HD - the 204 model has the addition of a MIDI interface as well which may be useful and one came up at the right price (ok, I missed several of the 202 models on eBay so grabbed this 204 one buy-it-now!) I did experiment previously with the built-in soundcard on the Linux PC but got very poor results, quite possibly due to a lack of perseverence (fiddling) on my part. Anyway, I took the advice of the many raves. And it works!I installed the excellent vlfrx-tools package plus an additional package vtlivesgram. Running vtcard and vtcat piped into vtlivesgram results in a very useful display: The trace above shows peaks where I see them using the Airspy HF+ Discovery / YouLoop combination which provided my first ever reception of SAQ. The results are limited when compared to the Airspy but that is to be expected. Here, the Behringer input is simply the output from a PA0RDT mini whip in the loft, plugged directly in via a 1/4" jack.

For logging purposes I just use QRZ.com as it does most of the things I need. I have nothing against the various logging packages, it's just that they are all way over the top for my meagure needs. I don't do high pressure stuff or contesting (yet!) so my needs are simple. However, I do maintain a local database primed from the data in QRZ. It is there that I store eQSL information and WAB square information. QRZ does have fields for eQSL but I decided to store it locally. Having all this data to hand made me think of ways to use it. Having reapplied my programming hat I now have a few useful modules. My next aim is to make them into a dashboard sort of display rather than console output as now. One module displays data from pskreporter via the extremely useful pskreporter MQTT feed (see mqtt.pskreporter.info) and stores this in a database along with distance (direction is planned). A web page displays it so I can see where I am being heard (provided that data gets into pskreporter of course). Another module takes UDP data from wsjt-x and tells me which of the stations calling CQ…

Just recently I have been comparing results on 2m FT8 between the Big Wheel and the QFH. I found there is very little diference between them, and although measuring via reported strength via pskreporter is hardly scientific the varying reports between the two - sometimes in favour of the Big Wheel and sometimes the QFH - brought me to rationalise the metalwork currently in the loft. Suffice to say the Big Wheel is no more and I am using the QFH from now on. This not to say that I don't want a nice Yagi and rotator on the chimey but that is a project for another day. Now the next interesting experiment is to see if I can reach FM satellites on the QFH. It should be better suited to those.

Very clear reception of the SAQ 100 year anniversary broadcast today, 1st December 2024. This is the first time I received SAQ despite previous attempts. I had two setups running in the hope to at least see something. SDRconnect was running on the Linux box connected via a Heros upconverter and a mini whip in the loft, and SDR# was running on the Windows 10 PC connected to the Airspy HF+ Discovery and a YouLoop antenna in the loft. The YouLoop was oriented towards SAQ at about 62 degrees from here. The mini whip saw nothing but as I mentioned previously it looks to have a serious drop off below about 20kHz. But the Airspy + YouLoop combination worked flawlessly. I saw the carrier appear at aroudn 09:45 UTC as they were switching everything on, followed by a loop of VVV SAQ. Then, at 10:00 UTC came the anniversary broadcast itself begining with CQ de SAQ. It was quite neat to see the gentleman on the key at SAQ and see the morse via the SDR. You can see the morse trail from SAQ on the image above, not a great deal above the noise floor but sufficient to read…