Radio and rails...

I've been meaning to set up something to generate a testcard via composite video for a while and, as is typical of me the ideal solution was sitting there in a BATC magazine on my bookshelf. CQ-TV No 270 has the details of one such setup using a Raspberry Pi Zero. I don't have one of those and Pi systems are hard to come by these days but surprisingly I had a 3B not doing anything. Software downloaded, 4-way jack to RCA plugged in and connected to a TV and, nothing. Well, a buzz. Checked the cable, all ok. Checked what the Pi wants... ...why does the Pi have to have the connections different from what appears to be a standard hi-fi 4-way to RCA lead? Or, rather, why does the hi-fi 4-way lead I have have to have different connections? Grumble. Ok. I wanted to test this seeing I had it all sitting in one of the bedrooms attached to a TV. Stripping down a 4-way jack lead that I never needed and which was far too short to be of use I made a lead. It would last probably half a second in normal use but worked sufficiently…

You know the thing... installing stuff on Windows where it counts down, and sometimes up again, then gets to 100% and seems to wait for ages. Our washing machine seems to run on Microsoft time too. Well, so too it seems does our old MacBook. This is a 2015 or so 13" MacBook Pro and is no longer used so sits on a shelf. I had it set up as me for testing but wanted to clean it all out so it can be sold. That's where things went a tad wrong. For some reason it took ages to even log in - very unusual as these generally boot in seconds. Then, after the reset it would not boot at all. Long story cut... I set it going doing a restore over the Internet. It began saying it would take 2 hours. Ok. This changed to 12 hours and seemed to come down ok, 11, then 10 each taking about an hour. Then it got down to 9 hours and dropped to 12 minutes! After an hour at 12 minutes left it went to 21 minutes and showed the Apple logo. After another hour it apparently had less than a…

I grabbed one of these a few days ago, in part because there are a couple of dashboards for the telemetry of a couple of cubesats, but also because of the RF range vs the cheap SDR dongles I already had (SDRPlay RSP2pro excepted, not cheap and very useful, but also, not a dongle!). I failed to get anything off of AO-73 on a good pass via waving the Arrow II at the window - almost got it, just insufficient waving / pointing vs the window blinds, wall, shelves...! But the dongle sometimes dies. I read that this can be because of the USB post so I need to work on that - I have a powered USB hub to try. Anyway, another toy. Maybe it's time to invest in a reasonable laptop (the MacBook is getting old now and being a 15" model is a tad unwieldy) and go outdoors. Update: a powered hub seems to have cured the lock-up as I had the AO-73 telemetry dashboard running from mid-day on 30th to mid-morning on the 31st. It also stands the dongle up rather than it drooping in the socket when horizontal. No luck with AO-73 telemetry though...

I acquired a DTX1 DATV transmitter. Although this is rather dated now it is still a useful tx capable of transmitting between 350 and 1350MHz. As a test setup over my usual 6" or so transmission path here it is on 437MHz transmitting a test card (yes the test card is all wrong but at least has the callsign and it is unlikely to propagate beyond the garden). The test card is coming from a little device that reads an SD card (and other formats) and sends a selected image. I did try an old digital camera I have which has video output but which refused to do anything, not even when plugged into a TV. Anyway it proves the DTX1 works.

I seem to have a lot of stalled projects currently. And then I got a kit of parts to build another Minitiouner... so I did that, and still have the same number of stalled projects! Oh well... The build went as well as the first one I constructed, very easy to put together and test. When connected to the Windows PC the test software all runs fine. This will go into the box I had for the previous Minitiouner the board of which is now inside the (stalled!) Portsdown.