Phil M0OFX

Software preservation | electronics | software dev | ham radio | a maker of things!

Pronouns: https://pronoun.is/he/him

<philpem> the ionosphere doesn't care what your callsign is

Current projects:
#Datatrak radio navigation
DIY #AnalogCable TV headend
Software preservation (#DigiPres)
Silicon chip photos (#ICRE)

🏳️‍⚧️ Trans rights are human rights
💬 Opinions are my own

ham callsign: M0OFX
github: https://github.com/philpem
website: https://www.philpem.me.uk
backup account: https://oldbytes.space/@philpem

Public Key

npub1pu6x6lz9s8n200v758szpztnkq94nrnl55c5ujmhx3ul4arcvqjqmwp73t

NIP-05 Address

philpem_at_digipres.club@momostr.pink

Profile Code

nprofile1qqsq7drd03zcre48hk02rcpq39emqz6e3el62v2wfdmng70673uxqfqpz3mhxue69uhhyetvv9ujuerpd46hxtnfduqs6amnwvaz7tmwdaejumr0ds6savvz

Publishing to

relay.damus.io

nos.lol

Author Public Key

npub1pu6x6lz9s8n200v758szpztnkq94nrnl55c5ujmhx3ul4arcvqjqmwp73t

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Last Notes

2026-05-01 22:38:16 UTC

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emacs user sighted

2026-04-27 16:27:02 UTC

Well what else was I going to do with a VT420?
https://digipres-club.s3.bhs.io.cloud.ovh.net/media_attachments/files/116/477/605/175/687/206/original/337413b75182ef02.jpg

2026-04-24 12:17:16 UTC

I love "ugh the robot was trained on my art" posts. I've found so many skilled human artists that way.

2026-04-01 23:06:01 UTC

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they have a launch trebuchet at Cape Canaveral now?

2026-03-31 09:53:06 UTC

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I would take low-tripping as more acceptable than what the rotary-turn ones do -- locking on.
Re fusing down, I'd take a look at the IET Regs section on load diversity and see if that affects your numbers.
How much current does the inverter need? Is it practical to take its fuse and the charger fuse right off the busbar then take a cable to an MCB box via a service fuse?

2026-03-31 08:47:23 UTC

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For the HC runs to the subs, I'd probably fuse to cable rating less a 20% safety factor. Then the breakers can be whatever they need to be.
I'm cautious about DC breakers, the rotary Chinese ones are terrible. I'd want something name-brand. Metal enclosures too. Couldn't find a source when I did it. Still running my Jeanmuller 160A switchfuse.
If it's engineered right, the fuses are your Hail Mary and you shouldn't lose a HC bus fuse at the same time as a circuit fuse. But keep spares.

2026-03-31 08:43:43 UTC

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I don't think I ever blew a fuse on my solar DC system. My way of dealing with the blowing problem was to keep a couple of spares on hand.
I'd probably have a master high-current fuse panel near the batteries - solar, inverter, and a couple of lower-fused circuits for sub-panels.
I'd probably go with one SP for appliances (powerpole oulets, fridge, CPAP socket).
Put the infrastructure on another one (fridge, HVAC, water, LAN).

2026-03-23 18:54:29 UTC

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Grrr that's not Badr, it's Astra 2G. That constellation is loud enough that it's nearly impossible to align the dish without a spectrum analyser.

2026-03-23 18:21:35 UTC

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Badr is colocated (ish) with Es'hail 2, so I'll take that for a test run.
https://digipres.club/system/media_attachments/files/116/279/875/155/945/000/original/ad07de86ffaefc13.jpg

2026-03-23 14:39:52 UTC

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Hi there Astra!
https://digipres.club/system/media_attachments/files/116/279/003/523/781/243/original/a56f4ae22bc705ed.jpg

2026-03-23 12:30:01 UTC

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I'm pretty sure that's not checked the Network ID.
https://digipres.club/system/media_attachments/files/116/278/492/493/311/190/original/ab772aee1d41d1b8.jpg
https://digipres.club/system/media_attachments/files/116/278/492/799/253/423/original/3d7f44676f6861ab.jpg

2026-03-23 12:26:56 UTC

Well that'll be why I can't find the Es'hail 2 beacon That's Hellas Sat 3. I turned the dish the wrong way.... Es'hail 2 is south of Astra 2. Buuuhhh
https://digipres.club/system/media_attachments/files/116/278/475/700/286/559/original/4aeed812a6c96734.jpg

2026-03-22 19:59:25 UTC

You ever had a curry which was so good you don't mind the 45 minute wait for the train home?

2026-03-20 02:17:38 UTC

Wow. I'm literally on my way to bed, and @npub13hr…833j Britsniped me.
(Britsniping: when you say "Postman Pat" and the theme tune pops into the heads of all the Brits listening)

2026-03-15 22:00:55 UTC

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I guess maybe the problem isn't so much bsky as people who are so used to being treated like crap that someone saying "u a good egg, attaboy" and meaning it may look like manipulation or at least insincere

2026-03-15 21:59:49 UTC

Only on Bsky can you post "I wish the event all the best, I'm glad the mistakes have been acknowledged and learned from -- and also shout out to X, Y, and Z who are real hoopy froods" and get attacked for it...

2026-03-02 19:25:28 UTC

This sounds as legitimate as "Legitimate Technical Services" or "Flowers by Irene".
https://digipres.club/system/media_attachments/files/116/161/215/946/214/060/original/860f11cde4578ad0.png

2026-03-01 03:21:01 UTC

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"Shame he didn't realise the silence was disbelief not respect."

2026-03-01 03:17:27 UTC

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"Shame he enforced the rules and not the spirit. Lots of authority and chuff all discretion."

2026-03-01 03:16:47 UTC

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"He's great at handling problems with confidence, but not so much judgment."

2026-03-01 03:11:15 UTC

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OH: "[That project] was a bold new horizon, shame the Post Office and Fujitsu built it." (savage, I love it)

2026-03-01 03:09:50 UTC

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"Very agile, but the release train hit the buffers."

2026-03-01 03:07:07 UTC

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"He fixes his car like he writes his code. By the way if he offers you a lift, say no."

2026-03-01 03:05:32 UTC

"If confidence was torque, he'd have no drivetrain left."

2026-01-01 15:01:25 UTC

I've uploaded some of my TS-7300 notes to Github. If you enjoy porting newer Linux kernels to weird ARM single-board computers, you'll love this...
https://github.com/philpem/ts7300
(my next task is getting the kernel driver for SD Cards updated and getting the FPGA Manager to load the Cyclone II gateware)

2025-11-25 17:18:24 UTC

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New blades are here. They don't cut much better but they do last longer.
Problem is the main root holding the stump in, seems to be under the tree. And now it's too dark to do anything about it. Sunrise is nearly 8am which isn't...great when I'm working.
Oh well, curry night for now.

2025-11-25 13:48:13 UTC

Lunchtime half-time score:
Leylandii stump 1, reciprocating saw blade 0.

2025-10-28 18:53:38 UTC

"I think it's fair to say that anybody that lands on an aircraft carrier is mentally unstable"
- David "Bunny" Gunson, sampled in "loony2"
https://modarchive.org/index.php?request=view_by_moduleid&query=170709

2025-10-23 17:44:50 UTC

This isn't a repair one should consider doing lightly. But sometimes there's no alternative. #retrocomputing #electronics #acornarchimedes #AcornComputers
https://digipres.club/system/media_attachments/files/115/424/712/463/210/474/original/1587a3c1fa917eaf.jpg

2025-09-29 18:38:26 UTC

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You can do worse, of course.
Normally you'd encrypt it as obfuscation (this is optional) then sign the firmware -- and verify the signature. This is fairly secure, and you only distribute the public key.
One implementation I saw distributed both keys and encrypted the firmware package with GPG.
If you haven't spotted the issue: the usual workflow with GPG is you give out your public key so people can send you encrypted e-mails.
You can calculate the public key from the private key.

2025-09-20 16:49:23 UTC

Nice to know the Hilton experience is still consistent.
45 minutes, "hello, we ordered food 45m ago?"
"It'll be two minutes"
Ten minutes later... Nothing.
"It'll be two minutes"
I thought this was unique to the Birmingham Metropole.

2025-09-05 16:06:13 UTC

One for #embedded #linux folks. Has anyone seen a system running U-boot where the kernel was contained in the flattened device tree / device tree blob?
It's present as images/kernel@1/data, with LZ4 compression.

2025-08-18 07:36:22 UTC

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I expect the gen alpha response will be something like: "skibidi, we have VPNs and everything is on tor now."

2025-08-07 15:30:51 UTC

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(4) probably isn't going to matter too much, but everything else is making me scream internally and externally.

2025-07-28 20:25:08 UTC

The batteries for the Seplos 16kWh lithium battery arrived earlier, so I spent this evening assembling it...
https://digipres.club/system/media_attachments/files/114/932/728/790/230/852/original/29cab64f86da735f.png

2025-07-18 15:54:15 UTC

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Worse than CrossCountry in the UK? That's an impressive(ly bad) achievement.

2025-07-13 17:37:31 UTC

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I don't like it either. It's the same logic, just running on a different piece of silicon. Often with an outboard CPU exactly the same as the one in the original machine. Many of them are built from reverse-engineered ASICs or original schematics. They're better than software emulators.
And with the price of original hardware and software, they make the space accessible to newcomers. Which might be why people are upset...

2025-07-05 15:10:45 UTC

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If someone wants to calculate how much this monster weighs, let me know what you come up with. I'll post the answer later.

2025-07-05 15:07:54 UTC

I don't know whether it's being an engineer or being a sad old fart, but I've got a lot of respect for people who work in civil engineering with stuff this size.
https://digipres.club/system/media_attachments/files/114/801/239/271/525/832/original/ea7a89e54311f0e2.jpg
https://digipres.club/system/media_attachments/files/114/801/242/311/913/584/original/6471d8b82e2c8a10.jpg
https://digipres.club/system/media_attachments/files/114/801/242/764/854/323/original/c5e1978afe54b1f8.jpg

2025-06-30 00:03:03 UTC

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Now strictly speaking I could "just" buy a filter but £150 seems expensive for something I can make from a spare high-static-pressure fan and an ESP32.
Many also seem to be Enshittified with DRM, filers aren't available, or there's no easy way to pull the data into Home Assisant (I want NUMBERS for how good it is, dammit)

2025-06-29 23:04:04 UTC

I'm having Ideas again. And this time it's "building a scaled-down Corsi-Rosenthal box". I have hayfever and the antihistamines usually wear off before bed...
(also reducing dust would be handy because I'm sick of cleaning PC fans)

2025-06-27 07:09:15 UTC

Me earlier: "One of those Lambda 1U power supplies would work great for powering the radios in the DAPNET/Packet/Mobitex rack"
Me after seeing the price of them used: "... maybe I'll just get a couple of Meanwells..."

2025-06-26 01:15:44 UTC

It takes an impressive amount of ignorance to wire a BS1363 plug this badly.
https://digipres.club/system/media_attachments/files/114/747/016/590/742/727/original/624ae923cfa6e0fe.jpg

2025-06-25 20:08:47 UTC

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Garage phone 1 is plumbed in... and of course I'm going to make use of the @npub1sv0…rq9x trunk test... https://youtube.com/shorts/XMTaMxsWIxo
One cable to go, then it's Fun With LACP.

2025-06-25 18:44:17 UTC

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I've done some small tidying jobs too - all the cat6 cables are booted and labelled for convenience. My head might be a scrambled mess, but at least my newest network cabinet is tidy.
https://digipres.club/system/media_attachments/files/114/745/464/037/161/970/original/e73974df25336158.jpg

2025-06-25 18:40:00 UTC

Time for a little more work on the garage. I did most of the Cat5 wiring last night - I'm looking at getting some cable tray to tidy it up. I've also put the first of two phones up.
I'm trying to decide where to put the second one - on the (metal) side of the comms cabinet, or on the wall next to it?
https://digipres.club/system/media_attachments/files/114/745/449/171/761/613/original/d4d2a883cdf00ba5.jpg
https://digipres.club/system/media_attachments/files/114/745/451/704/606/907/original/d2bb7da61d43fbc0.jpg
https://digipres.club/system/media_attachments/files/114/745/461/033/004/209/original/371558f8df8613ec.jpg

2025-05-28 15:38:49 UTC

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Nice boot screen.
https://digipres.club/system/media_attachments/files/114/586/204/637/924/355/original/e314271c001336e3.jpg

2025-05-28 15:35:32 UTC

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This is the 12-pin serial port connector. It measures up as an M16 DIN plug - which probably means the Amphenol plug I just ordered from Rapid is the right one. Rock on.
https://digipres.club/system/media_attachments/files/114/586/185/901/846/886/original/085b7f5cd012c34f.jpg

2025-05-28 15:33:32 UTC

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Yeah I'm pretty sure this is a Fischer 102. 5mm diameter on the plastic insulator, and a 0.7mm gauge pin slips right into the socket holes.
https://digipres.club/system/media_attachments/files/114/586/179/142/030/690/original/8fbac108aabd9386.jpg

2025-05-26 09:31:31 UTC

Finally identified the power plug on the Husky FS3. I'm pretty sure it's a Fischer 102, in 5-pin. Vacuum-tight, apparently, and looks a lot like a Lemo plug. Which is what I thought it was before I found a photo of the plug.....

2025-05-16 08:29:01 UTC

I stumbled onto Australian DIY Youtube this morning and I don't think I'll ever be able to forget the sound of the words "angle grinder" spoken with a strong Aussie accent.

2025-05-15 14:03:33 UTC

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For anyone curious, this is a Makita GA9020KD 230mm disc cutter/angle grinder with a Diamak blade. It's meant for cutting concrete, with or without rebar. I am not made of concrete. Needless to say this tool will be treated with absolute respect.

2025-05-15 14:01:00 UTC

Warning: this chonky boi will f*ck up anything it touches. Including you.
https://digipres.club/system/media_attachments/files/114/512/206/679/125/930/original/7d5225639efd7553.jpg

2025-05-10 09:54:27 UTC

That phase of "Spring cleaning" where you think about putting the whole lot in the skip.
https://digipres.club/system/media_attachments/files/114/482/927/239/887/833/original/5a24aaed6f6c06ef.jpg

2025-04-01 17:11:15 UTC

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I've not done a dial-in server on a Cisco, my usual is a Raspberry Pi or Docker container with mgetty
Edit: The Serial Port (on YouTube) have been setting stuff like this up - I remember seeing a Portmaster and a USR Total Control in their videos. Clabretro has done stuff with Ciscos

2025-03-08 21:47:51 UTC

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Congratulations!

2025-03-06 16:23:38 UTC

Imagine having a 316MHz PC-AT with a 487MHz 80287 FPU... #dos #retrocomputing
https://digipres.club/system/media_attachments/files/114/116/365/374/597/529/original/1059096e81c7e62e.png

2025-03-04 22:52:08 UTC

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brave?

2025-03-04 09:44:27 UTC

Can't believe I was nerdy enough to chuck this line in a group chat -
"I'll have the SCP (disk) images ready soon, but not the Werewolves or Whenwolves, they're a different kind of SCP".
I'm 95% sure nobody got it.

2024-10-03 17:36:29 UTC

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Technically correct, the best kind of correct :D

2024-09-20 09:02:31 UTC

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I'm not a morning fox... I've got a similar number of alarms. Three on the DAB radio, another four on the phone... It probably doesn't help that my bed has a heated undersheet. On a cold morning being a burrito is much more appealing. And then I'm late.

2024-09-12 19:45:05 UTC

Is it just me or does the Steam Linux updater look like it's been borrowed from a piece of weird Chinese software?
It's the font, I'm sure of it.
https://digipres.club/system/media_attachments/files/113/126/294/957/345/670/original/4970c8159b97b756.png

2024-09-02 10:02:58 UTC

I need to find a Dutch friend to send me a care package of cheap stroopwafels, £1.50 for six is taking the mick a little.

2024-08-28 16:03:02 UTC

Hi. I'm the kid who liked to take things apart and figure out how they worked. Thing is, now I'm 30 odd years older, and I haven't grown out of taking things apart.

2024-08-21 13:08:57 UTC

@npub1sv0…rq9x Just wondering if there have been any logged issues with BT fibre? I can't see anything on AAStatus but have had a couple of LOS indications from the ONT and a bunch of PPPoE drops that took a while to recover, all between midnight and 4am, in the last 7 days.

2024-08-16 16:23:32 UTC

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If anyone's wondering "how did cable Internet happen then?" .... a lot of CATV headend gear works on the basis of an RF forward path (downlink) and an optional return-path. DOCSIS and DAVIC are no different.
Add a CMTS at the headend and wire it up to the RFoF TX and RX, and now the customers on that node can access the Internet using a cable modem. It's "just" a fancy TV channel!

2024-07-09 09:35:08 UTC

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To be fair, they were basically fancy high-power industrial smoke particle counters... they were even mentioned in the UL standard for smoke detectors

2024-07-04 11:56:42 UTC

Polling day, polling day - thankfully I voted by post last week so I don't have to decide between "do my civic duty and infect the whole polling station" and "don't, and probably be one less of the GTTO gang".
My only regret is that we won't get to see Rishi Sunak defenestrated out of one of the windows of Number Ten.

2024-06-10 22:08:17 UTC

I have a box full of WEEE in the garage I'd like to get rid of ... checked the local council website.
"Access to recycling centres is prohibited on foot: you must bring a vehicle."
"Any commercial vehicle is prohibited, defined as: any vehicle with Taxi or Hackney plates. Any vehicle with a trailer. Vans, pick-up trucks. Any car with more than 5 seats. Any vehicle whose registered keeper lives outside of the area."
It's like they want people to fly-tip.