Radio and rails...

M0RVB

SAQ success!

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…

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M0RVB

VLF ready, hopefully!

I now have two new toys, an Airspy HF+ Discovery SDR, and an Airspy YouLoop antenna. Plus I already have a SDRplay RSPdx which was purchased some time ago. The initial aim of these is to hopefully receive signals from SAQ’s 100 year anniversary broadcast. The YouLoop is in the loft and connected to some RG213 coax back to the shack. That coax was feeding the random wire for HF but as I now use the external wire the coax was pulled back and shortened. It is entirely passive so does not require any voltage supply and has a range of 10kHz to 30MHz plus VHF up to 300MHz. There is also an IP35 mini whip which was acquired some years ago and as an active device needs a supply which is achieved by a bias-tee fed from the 12V shack PSU. That antenna has a range of 10kHz to 30MHz and is fed via some RG58. The YouLoop is pointing, quite by chance at the MSF 60kHz time signal transmitter. The IP35 is largely omnidirectional. The Airspy covers 0.5kHz to 31MHz and 64MHz to 260MHz whereas the RSPdx covers 1kHz to 2GHz with no gaps (200MHz on the BNC…

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M0RVB

Finally connected the 'temporary' external wire

Things happen slowly here. Very slowly... I finally got some coax fed out through and air brick and connected the external random wire up that slopes down to the workshop so I cna use it without needing to open the shack window and feed a cable out. Experimenting, the tuner was happy on 6, 10 and 12 but less so on 15 with the rig seeing a SWR close to 3. It would tune 30m too but knocked the GPS signal to the clock off, clearly RF in the shack. I did not try lower because I then realised that, like a twit I forgot to fit the 1:1 unun! With the 1:1 unun installed outside the tuner was happy-ish with 15 but now not 12. Oh well. And it refuses to get below a SWR of 3.0 on 30m and is quite bad on 40m which is annoying, but on the plus side tuning does not knock the GPS clock off! I suspect I have managed to get an awkward length of wire so I will shorten it later on and expreiment further. Surprisingly, it is happy on 80m and it will tune 160m but that did knock the…

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M0RVB

Getting ready for the December SAQ broadcast

I am making a better effort at picking up the SAQ broadcast due on the 1st of December. I now have a VLF mini whip (no idea where it came from now!) up in the loft fed via a bias-tee and connected to a Heros VLF converter which takes 0 to 500kHz and converts it to 4,000 to 4,500kHz. Although the loft is a poor location for this it is a lot better than in the shack. the Heros is connected to an RSPdx on it's BNC port and this is connected to the Linux PC which runs SDRconnect as a server. Reception is via SDRconnect on the Mac. So far, so good, I can see the MSF and DCF77 time signals on 60kHz and 70.5kHz respectively plus a ferw other peaks, at least some of which correspond with known transmitters. Getting the settings right is a fiddle. The above photo has the base set low and the red line is where SAQ should be. But there is quite a rolloff there so hopefully the signal will be sufficiently strong to receive. The antenna is supposed to work down to 5kHz and the Heros is specified as <5 to 500kHz.

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M0RVB

RF invasion

Something leaks here, not always, just sometimes when the autotuner has an issue. RF gets into the Bluetooth stuff in the Mac and it goes mad. The net result is the cursor moves very sporadically making it very hard to maneuver the cursor. In the past I have resorted to rebooting the Mac - switching Bluetooth off and on is a no-go because I only have a Bluetooth keyboard and mouse so I'd not be able to turn it back on. Helpfully, the current MacOS knows this and won't let me turn it off anyway. So I reboot. However, yesterday I had the other systems turned on with MMSSTV and wsjt-x running on them so rebooting the Mac would have been rather awkward given I use Barrier to control the other systems via the Mac. So a bit of searching turned up a simple console (terminal) command 'sudo pkill bluetoothd' which did the trick. Apple has info at https://discussions.apple.com/docs/DOC-250003311 One to remember but YMMV of course... also, serves me right for letting RF in the shack in the first place.

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