Radio and rails...

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…

I now have an RSPdx which arrived today and connected it in the loft to a discone which was already there. I changed the o/s on my Pi 4 that runs an ADS-B receiver to the 64-bit flavour, reinstalled FR24feeder and installed SDRconnect. Running it as a server it communicates very nicely with SDRconnect on the Mac Mini. It will be interesting to watch this software as it develops. One this was clear… the discone is useless! While I realise it is little use at HF it is pretty deaf thereafter. So I have moved the RSPdx down to the shack so it can be plugged into ‘proper’ antennas. It is currently pulling in 20m. Of course, my HF antenna is on a tuner so I need to tune it via one of the HF rigs and then swap leads to plug the SDR in, but that is not much of an issue because it is all done via the BNC patch panel. I also had it looking at 2m via the white stick in the loft. My old RSP2 is destined to go into the garage with a couple of VLF antennas as it is far too electrically noisy…

I have, more or less finished the shack reorganisation which took 4 days! There are still some audio leads to sort out and I plan to do some woodwork to mount the two HF transceivers together. But here it is... It does surprise me how I created space out of the previous mess of wires. Now the radios and PCs are all in reach of each other, test gear is all in one place, and the Creed 75 teleprinter has joined the shack (pity it is not yet working...) Of the 4 screens, the top two are on a Linux PC, the bottom left is Windows 10 and the bottom right is on a Mac mini. A bit of very useful software called 'barrier' allows theMac keyboard, mouse and trackpad to control all three systems. All audio is connected through a mixer (or will be once I add a couple more leads) which also provides inputs to the computers. Now to mess it all up again... how long do you think?

Still sorting the shack out today, hopefully two more days and it’s done. Today’s task was to fit PoE HATs to the two Raspberry Pi systems that run things like Pi-Star, the ADSB grabber and HamClock. These were both Pi 3B’s which do not have the pins for PoE - the 3B+ or the 4 does. So, first off, strip the cards out of the box. Not too bad. The first Pi 4 and its HAT was easy but the Pi Star one has the RF board. Installing the PoE HAT does not leave any of the Pi 4’s pins protruding. Fortunately I had a small stock of extenders, in fact, just enough. Not the neatest of constructions but it works. One thing caught me out though. The Pi Star Pi gets a static IP address via DHCP. When it booted up it would not let me connect or get to the web interface. A scan of the network found it and only then did I remember that, of course changing the card means a new MAC address! Anyway, both cards now have their MAC addresses in pi-hole (even though the IP is static doing it that way makes pi-hole…