Radio and rails...

I have an allocation within 44net (aka AMPRnet) and so I set up a gateway based on a Raspberry Pi 4B – well, I had one unused one! My allocation is a /29, so 6 IP addresses. The Pi setup is the Pi 4, a PoE HAT, an Ethernet USB dongle for the second Ethernet interface, and a neat 3D printed case that I have used before and which has the height for the HAT. Software-wise it’s just Raspberry Pi OS, plus a daemon called ampr-ripd which listens for gateway announcements and sorts out routing tables. My link is to the IPIP mesh so I am not doing BGP or anything fancy. My initial experiment used the wifi interface and I could connect to 44net via the phone / wifi AP software running on the Pi. That worked ok but really I wanted to be able to connect a couple of systems and not bother with wifi. As I had an Ethernet dongle left over from the dismantled QO100 transceiver that did the job nicely. The plan is to connect this to a small network switch offering a couple of Ethernet ports to be used on 44net. So far, the…

Tidying up the whole shack make life easier to reach stuff but did not completely cure one issue, that of RF flying about the place and getting into things where it was not wanted. I tried 10m this morning and two things happened. First, it set off the house alarm. Second, wsjt-x would not hold a tx cycle or tuning. The autotune was happy but that acts quickly. Using wsjt-x's tuning for a few seconds, or transmitting a CQ and the FT450D would tx, then off, then try again etc. This has happened before. First off, yes there is RF in the shack and it's due to the rather naff antenna wire in the loft. I need to live with that until I get some wire in the air outside. And yes, I've been saying that for ages! But before it was really down to the mass of cables all entwined and those have been completely tidied up now. So I was rather annoyed that the same issue has returned. And then I discovered that my attempts to dust round the desk had moved the serial cable between the FT450D and the Signalink and it was now laid across the…

Recently the outside lights here decided to switch off at random intervals for no apparent reason. There are 5 different controllers, two being Zigbee bulbs and the others Zigbee switches. All use 2.4GHz. All had been running reliably for maybe a year. On/off cycles are controlled by scripts on the server as well as manually via an app. In each case whichever set of lights had gone out did report as being off and would turn back on via the app. Some days there was no issue, on others at least one would go off at some point. The Zigbee bulbs never failed, just the switches. There was no evidence of any commands being sent to turn the lights off, but there was the occasional error being reported. Rebooting the server made no difference. A power cycle of the server seems to have cured the issue so I am considering it likely to be the Zigbee transceiver itself. This is now nagging at me to figure out what happened and presumably it will reoccur some time in the future. Too many other things to sort out though!

It's surprising just how many things one gathers that need Ethernet. Having just made an NTP server out of a Raspberry Pi that took the last port in my 8+2 port PoE switch I needed more ports. The switch is a Netgear GS110TP, 8 Ethernet ports and up to two SFP modules for interlinking. So I have added a second GS110TP linked to the original one via a short fibre lead and two SFP transceivers. The house now has 4 Ethernet switches, all Netgear, making 48 Ethernet ports in total but not all in use, plus 3 wifi access points, Netgear again and all PoE powered. Actually I could have settled for a non-PoE switch as the additional one but this one came cheap, and new in box. All the switches and access points do SNMP too, centrally monitored using MRTG. Why? Because they can!

I decided to make my own Stratum 1 NTP server for the home. No, I don’t need the accuracy, but localising stuff like that is always interesting. So, I recently purchased an Uputronics GPS HAT from Pi Hut which is marked Raspberry Pi GPS+RTC Rev 6.4. It arrived next day along with some other bits. I also got another PoE HAT and already had a Pi 4. Raspbian installed on an SD card – this time I remembered to first set it up to work via ssh – and the Pi booted ok with the GPS board flashing it’s ‘time pulse’ LED once per second. I followed instructions on the web, in particular from the two websites shown at the bottom of this post. Initial setting up of the Pi involves the use of raspi-config to stop the serial port login shell but leaving the port enabled, and disabling serial getty and bluetooth. At this point, doing cat /dev/ttyAMA0 should return data from the GPS receiver but all I got was garbled characters. More on that later. The next step was to enable PPS support which involves modifications to /boot/config.txt and a module adding to /etc/modules, plus downloading pps-tools. Running…