Radio and rails...

Tonight none of the outdoor automated lights came on. On further testing the internal lights also refused to work. Odd, everything was just fine yesterday. I use Zigbee devices around the house with four devices controlling various outdoor lighting, two controlling dimmable internal lights and several devices reporting on room and heating temperatures. Two outdoor lights are all-in-one Zigbee bulbs, the others are diminutive units in various electrical boxes. All use 2.4Ghz Zigbee and all the lighting controllers are also Zigbee repeaters and so form a mesh. The whole lot is controlled by a Raspberry Pi with a Zigbee dongle, zigbee2mqtt, mosquitto and homebridge. This also integrates it into the apple stuff so everything can be controlled from the Apple Home app and/or Siri. Of coure the downside is there are few physical switches now so this was a problem I had to fix. I had no clue what was wrong. Rebooting made no difference. But a bit of searching suggested that USB3 devices can cause issues at 2.4Ghz. Remember from my previous post that I had attached a SSD to the server? Well, that alone made no difference but was a precursor to the issue. Today I had inadvertently…

After a life in IT you'd think I would be better at this stuff. Two things caught me out this week, both around the web server that runs this blog among other things. The first knocked it offline and I was unaware. The server is a dimimutive Lenovo ThinkCentre M92p and has 4 USB ports but none work which was annoying as I wanted to upgrade Lubuntu but really wanted a decent backup to an external device first. I had another of these systems with working USB ports so I swapped the hard disk between the two - the specs are essentially the same. All went well, apparently. I attached a USB SDD to use as a backup for the pending operating system upgrade. Then I noticed no incoming email plus I tried to access the blog from an external IP and it failed. Odd. No issues with accessing from the house LAN. Then I remembered having an issue with the PlusNet router but could not remember what so I logged into that to see if my memory would return. And it did. The PlusNet router helpfully follows MAC addresses rather than IP addresses so when I swapped the HDD…

Finally I have a rubidium 10MHz oscillator to play with. It is a Symmetricom X72 that needs between 10 and 32V input, so the shack supply will be fine. It came built into a case which also has a power and unlock LED on the front plus a fan. Why you ask? Well, I do not really know but I wanted one! Once it arrived I checked it over and powered it up. It took aroud 4 minutes for the unlock LED to go out and it has been giving a constant 10MHz sinewave frequency output since then. The unit has a 1pps input and output plus a serial interface which I have yet to investigate. It is also apparently controllable with the Lady Heather control program, something else I have yet to play with.

I finally got myself one of the BG7TBL 10MHz distribution amplifiers. I (will) have a few devices that need a 10MHz input for frequency stability so this is handy. It actually came from China via Aliexpress a lot cheaper than similar (and rare) offerings on eBay, and it only took 5 days. Anyway, here it is: The 10MHz source is coming from the DX Patrol GPSDO and as a test one output is to a 'scope and one to a counter. Rather unexpectedly (to me) it takes a square wave feed from the DX Patrol but gives out 8 separate sinewaves. Of note, the voltage input is specified as 11.7 to 12.9V, not the usual 13.8V. But as I need 12V for the Winterhill and the 13cm transverter I already have 12V around the place. Although this one says it has an OXCO this one does not - it is an option but I decided against it. I have a decent 10MHz OXCO if I ever need it.

Yes, ok, this is still not about the transmission path! But I wanted to experiment a little more with the wideband part of the transponder and DATV signals. To that aim I press ganged the small HD screen from our NVR (which in turn will be wired to the large TV downstairs) and attached it the the Winterhill box. With 12V from the lab supply to the Winterhill and the 25MHz LO being fed from the diminutive Leo Bodnar mini GPS reference clock it all appears to be working as expected. This was covered in Part 2 already but today I managed to get a screenshot with four DATV feeds, although one had just dropped leaving the last image that was received. Now I need to decide whether to keep this small screen for Winterhill or swap screens with the one I use for Hamclock with the latter then on the smaller screen. I will probably do the latter as this small screen will run from USB C from the PC meaning one less socket.