Interesting findings on the internet

[tggzzz]

A privately-owned computer museum I hadn't come across before, in the Yorkshire Wolds.

From https://www.hulldailymail.co.uk/whats-o ... ed-9450159 "I went to England’s least-visited tourist attraction and had a major surprise in store" there is a link to https://www.computermuseum.org.uk/ "Jim Austin Computer Collection". Looks like some interesting kit there, with mentions of "RadioShed" containing radios and valves.

Has page of links to similar museums elsewhere https://www.computermuseum.org.uk/othersites.html

[EC8010]

Was it only me, or was it impossible to get into the forum over the last couple of days?

[tggzzz]

Was it only me, or was it impossible to get into the forum over the last couple of days?

I had problems too.

There has been "strange traffic" observed elsewhere e.g. "For some reason this thread has become super active again in the last 24 hours :-// We are supposed to be blocking AI bots now." https://www.eevblog.com/forum/chat/baid ... msg6314350

Then again, there can be a myriad reasons since the internet has recently become a battleground for commercial and military reasons.

[Cubdriver]

Was it only me, or was it impossible to get into the forum over the last couple of days?

No. Definitely not just you - I was getting bad gateway errors and refreshes were taking forever. I almost DM'd you on DIY Audio to see if you were seeing it too, but then decided to wait it out. It seems better for now at least. Fingers crossed it remains so.

-Pat

[Zenith]

I've noticed the site was hard to access because of gateway errors and a general lack of responsiveness. I haven't noticed it with other sites. There weren't ridiculous numbers of guests. I've no guess what caused it, possibly something misconfigured.

[AVGresponding]

I think Peter has added a captcha to help prevent this. It'll probably work; it nearly stopped me logging on

[MED6753]

I thought I was the only one having problems accessing this site as well as others. And it refreshed with a bunch of unread posts.

[synx508]

This is worth a look if you like mechanical and electrical bits, https://www.youtube.com/watch?v=JBRENGAtSRU inside a R&S ZDU instrument, at 26m40s there's a rotary variable delay line which uses some wonderful engineering to maintain the transmission line properties all the way to the rotary contact.

[Zenith]

The standards of mechanical construction in top end valve gear and some of the solid state equipment were very impressive. Aluminium castings and precision machining as well as ingenious mechanical engineering. I've always been impressed by the Racal RA17 receiver. That R&S unit takes it to another level and is awesome.

[tggzzz]

Here's a simpler example made by Decca Radar, the first company I worked for. It is the brass rotor from a microwave waveguide switch used in places like GPO Madley Comms Centre ground station. This one is small; I remember some being maybe 30cm tall.

I ought to polish it sometime, but you can make out:

• three rectangular waveguide cross-section holes
  the central hole is straight-through; you can just about see the background on the other side
  two other holes; each curves through 120 degrees
  various slots; these trap out leakage around the gaps between rotor and stator

This was all machined without CNC; everything required knowledge and imagination to manually set up milling machines to cut all the curves.

Customers used to moan that the prices indicated we made them from gold, but they kept coming back.

IMG_0799.JPG

[EC8010]

That R&S unit takes it to another level and is awesome.

I believe you have to be under thirty to use the word "awesome". But I will readily concede that the R&S shown is a beautiful piece of mechanical engineering. It's not a piece of test gear; it's a clock. And did you notice the anti-backlash gears? Some of those gears were actually two gears side by side with a spring to set rotational tension between them to eliminate backlash. Lovely. It must have been fearsomely expensive when new. I hope that chap is going to restore it to full operation. Undoubtedly, you could buy something new and soulless that would be way better, but it's a work of art/science.

That Decca part wouldn't be too hard to make, except for those rectangular holes. Naturally, they're the critical bit. I imagine they were broached, or perhaps it wasn't a single part, but an assembly of parts. If so, I could (given significant time) make one myself; it's a dividing head job. A skilled machinist could do it much faster and better than me.

Not to the standard of that R&S, but here's a voltage reference.

[tggzzz]

W.r.t. the waveguide switch...

You can just about see a horizontal line halfway up the waveguide holes. That's where the top half and bottom half meet. That makes milling out the waveguide conceptually trivial, but still requires considerable skill (especially, IIRC, with the tolerances).

They were being made while I was there, 78-82. They were an old 60s(?) design using that era's machine tools. Nobody still working there understood the theory well enough to modify the design. Effectively we regarded them as RF black magic

[Zenith]

And did you notice the anti-backlash gears? Some of those gears were actually two gears side by side with a spring to set rotational tension between them to eliminate backlash. Lovely. It must have been fearsomely expensive when new. I hope that chap is going to restore it to full operation. Undoubtedly, you could buy something new and soulless that would be way better, but it's a work of art/science.

Anti-backlash gears like that quite common in comms receivers. I'm sure TE like the big old Marconi sig gens also used them.

[tggzzz]

Amusing list of AI ailments, e.g. UpSkill Sisyphus, AI Attachment Disorder, Cognitive Laxity, Vigilance Decrement...
https://informationisbeautiful.net/visu ... ion-mania/

[BU508A]

The biggest 2D map of the universe:

https://www.legacysurvey.org/viewer#IC%204065

[EC8010]

I asked, "Why do data centres need water?" The response from various sources was that they use water for cooling. Not one of the responses used the phrases "specific heat capacity" or "latent heat of evaporation". It seems surface factoids beat genuine understanding. Engage Victor Meldrew mode.

[Zenith]

Some AI data centres are rated at 1GW. Almost all of it will end up as heat. That's some serious cooling required. I haven't done the sums but I'll wager 1GW applied to the river Severn between Worcester and Gloucester, would raise the temperature to an alarming extent.

A mini-computer system in the 80s could easily consume 8kW continously and they were kept in air-conditioned rooms. They were probably the sort of heat exchangers used for large buildings.

What surprises me is that people don't know the difference between kW and kWh, and really have no idea what things cost to run based on their wattage. e.g a 5W LED light bulb isn't going to break the bank if left on overnight.

[EC8010]

Twenty years ago, I borrowed a Hall effect current probe, a differential voltage probe, and a 13A plug to 4mm socket adapter. I plugged them into oscilloscope and let it calculate a maths waveform of V x I and produce an automated average of the maths waveform, which was power. I went round the house seeing how much power things actually used (as opposed to what they claimed). There were a lot of wall warts permanently plugged in for things like scanners, and various other bits of electronic junk. I calculated energy consumption 24/7 over a week and a lot of things were subsequently unplugged. But you're right, people don't understand kWh and kW. Electricity ought to be sold by the megajoule, anyway. But the chances of the post-factual generation understanding that are near-zero.

I once calculated the efficiency of Television Centre. Assumed power consumption was 5MW and it produced two television signals of 1V_pk-pk into 75 ohms. Clamped to the sync tips and assuming a reasonably bright picture, there would be about 0.5V over one line, call it 3mW, and there were two of them, so 6mW total. From 5MW input.

[tggzzz]

I asked, "Why do data centres need water?" The response from various sources was that they use water for cooling. Not one of the responses used the phrases "specific heat capacity" or "latent heat of evaporation". It seems surface factoids beat genuine understanding. Engage Victor Meldrew mode.

Yeah

Strangely, last week I used both those term with my daughter, explicitly noting the relative magnitude.

[tggzzz]

Some AI data centres are rated at 1GW. Almost all of it will end up as heat. That's some serious cooling required. I haven't done the sums but I'll wager 1GW applied to the river Severn between Worcester and Gloucester, would raise the temperature to an alarming extent.

Didcot power station, at best 30% efficient, managed. The cooling towers were a landmark. Maybe they'll add towers next to data centres, e,g Brick Lane in east London (yes, really!). Or use them for district heating systems.

There's a reason nukes are on the coast.

What surprises me is that people don't know the difference between kW and kWh, and really have no idea what things cost to run based on their wattage. e.g a 5W LED light bulb isn't going to break the bank if left on overnight.

Greenpeace and journalists are particularly bad. I like to ask them how many miles per hour away London is; they look at me as if I'm an idiot. It takes a long time to explain.

How many people can do multiplication? Or know which numbers to multiply?

[Zenith]

Didcot power station, at best 30% efficient, managed. The cooling towers were a landmark. Maybe they'll add towers next to data centres, e,g Brick Lane in east London (yes, really!). Or use them for district heating systems.

That seems like a good comparison. A 1.4GW plate capacity with 30% efficiency would give just about 1GW of waste heat do dispose of.

Had they been less quick on the trigger Didcot would have been a prime site for an AI data centre, with six hyperboloid cooling towers ready built.

Battersea power station, plate capacity 400 to 500MW, fed its waste heat into a district heating scheme.

I don't believe many of these AI data centres will be built.

[tggzzz]

Of curiosity interest only - strange things are happening at the Other Plaice.

It appears it started with some odd, but to mind innocuous, moderator interaction with "benta" (7k posts).

Benta eventually took umbrage and decided to announce he was logging out. Oh well, it happens.

That announcement was turned into a long thread, mostly wildly hypothesisng, then drifting into the traditional pro/anti moderation positions. Boring.

Then user "fzabkar" (3k posts) announces he is logging out because benta's announcement thread has been completely deleted. Weird.
https://www.eevblog.com/forum/chat/fzab ... gging-out/

My only comment? I dislike historical revisionism, since "students of Soviet history know how difficult it is to foretell Soviet history".

[Zenith]

I haven't followed it or even looked into it.

I find a lot of the people round there quite highly strung and combative. They see every discussion as a debate to the death. They get very annoyed if they have pronounced and an alternate view is put.

[MED6753]

It's August. Must be that time of year when the mods come out of hibernation and start their slash and burn. Which is why I'm here and not over there.

[EC8010]

I was a moderator for three years at diyAudio; it required a good deal of delicacy and we found that a gentle warning was most effective. So I doubt if there's really a "slash and burn". But I haven't looked closely; I don't waste my time watching playground arguments. I do notice that there are very definite cliques at the other place.

I'm up early to go to RATS (Rugby Amateur Transmitting Society) radio rally. Do they have a separate membership for receiving? The strongest argument I expect to be involved in there is whether I'm prepared to meet the vendor's asking price. In general, the prices asked at radio rallies are very reasonable.