Pi PoE

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 record their activity against the names) and the Pi Star one has been reconfigured with a static IP rather than DHCP.


Late to the party as always I recently looked in more detail at POCSAG and that led me to DAPNET. I spotted this a while ago but somehow it didn’t register as interesting back then. Signing up to DAPNET was seamless. You first sign up for an account and the only thing that threw me there was the need to specify a RIC. A document suggested just using one’s DMR ID which I did. You need to send a copy of your licence and I keep a PDF handy for just this. I received account information early the next day. You then need a transmitter ID, same form, different option. That came back almost immediately. Details of that go into pi-star and it all worked in that the DAPNET website could see my pi-star, and pi-star started to display incoming DAPNET connections.

Given my desire for new toys for old technology I purchased an Alphapoc 602R pager from an eBay trader. This arrived in a couple of days but despite me programming it all up it never received any pages despite pi-star displaying some test ones directed at my RIC. Firmware perhaps? After soldering the wire pi-star could not update the image no matter what I tried (which after all was simply to try again!). Reading various posts indicated some older DVMEGA boards would not update this way. The DVMEGA website mentioned that one can update by removing the chip from the board and inserting it into an Arduino Uno, having removed the chip from that. That worked fine, although I have to admit it failed the first time as I forgot to chose the correct board in the DVMEGA website’s x-loader that comes with the firmware.

So, the DVMEGA is now on HR3.26 but still no DAPNET. Now here it seems my ability to permutate search terms (‘dvmega’, ‘dv-mega’, ‘dv mega’) clearly failed me as I eventually found a few posts suggesting that the DVMEGA firmware doesn’t support it anyway. By now this was all a bit of a straw clutching exercise as I had already ordered an MMDVM Pi hat which the DAPNET website itself suggests.

Amazon to the rescue. I ordered a AURSINC ‘MMDVM Duplex Hotspot Module Dual Hat’ on next-day delivery and it arrived at lunchtime today (30th April). This came with pi-star specific instructions which was very handy. Out with the DVMEGA and in with the MMDVM_Duplex hat, booted the Pi, chose the modem [STM32-DVM / MMDVM_HS – Raspberry Pi Hat (GPIO)] and it worked straight away radio-wise. After shutting down the radio modes so DAPNET could get a word in another test sent to my RIC and the pager worked. Success.

As this new board is duplex I have set up pi-star to use split 70cm frequencies for the radio side of things and it seems to work well now I have reprogrammed the FT2D. I did have pi-star connected for DMR, D-Star and YSF but I have now only enabled YSF to calm things down a bit. I hardly ever used DMR or D-Star.

Yes, pagers are old tech. I used to carry two for work, one that my team could use and which seemed to work anywhere in the UK, and another that would send me pager messages in response to emails to a specific address and which had rather less coverage – the Yorkshire Dales was lost to it. Those are long gone now, but why not? After all, this is yet another facet of the whole amateur radio experience.

(edited 16:15)



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