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Cojawfee posted:It's literal magic. If I learned anything from flunking out of circuit analysis twice, it's this. Also differential equations.
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Aug 7, 2022 17:19
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Re: propagation over 90 miles of water It's a bit hard to say for me. If it's always 90 miles, some bending (ground wave effects) has to happen. If it's only occasionally, and depending on the time of year, it's a form of ducting between air layers. I don't know if there are situations in which there can reliably be a duct for prolonged periods of time. It could very well be that above a large lake, there's a temperature inversion for long periods of time working as a big mirror. I have no experience whatsoever in working with SHF radios except for my phone. With phones it's kinda difficult to gauge propagation modes, because you can't hear the specific ways in which signals degrade with different types of propagation, nor the almost instantanious variations in signal when some atmospheric condition changes. The tower's filter box is proper SHF voodoo. The blackest of black arts in RF engineering. Most RF engineers look at it, and then say a little prayer. May it never break, because whoever designed it, must certainly have a deal with some kind of demonic creature that gave them the knowledge.   These are very common little things - LNBs from a satelite dish antenna for television. Every little squiggle is an engineered component of a circuit. The little fan shapes are chokes (inductors). The 'stacks' of lines are bandpass filters, so they act both as capacitors and as coils. The other stuff i don't really know.
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Aug 7, 2022 19:29
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namlosh posted:CuriousMarc I love when they talk about lost engineering in the nasa computers and devices that worked but then later they found a better, easier way or some different materials, and the tech was abandoned. What this means is they're looking at alien technology cause no one knows very well how it works but it does and it's very complex, and the the era when people figured it out in wasn't the digital age and it required extreme brainpower to produce, but no one around today knows anything about it.
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Aug 7, 2022 19:39
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My college roommates were engineers (computer and electrical, I think). They were looking over group work together for a class once and had the funniest exchange to me, an Eng Lang major. "Hey, uh, you know So-and-So's part of this?" 'Is it bad? It's bad, right?' "Well... Uh. Maybe I just don't get it, look at this -- he put 4 inverter symbols here. What does that make?" 'a... Wire? A line?'
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Aug 7, 2022 19:43
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FilthyImp posted:My college roommates were engineers (computer and electrical, I think). They were looking over group work together for a class once and had the funniest exchange to me, an Eng Lang major. Stacked NOT gates are an easy way to delay the signal! This is useful for doing things like edge detection, so you can trigger a circuit exactly once when someone presses a button. 
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Aug 7, 2022 19:58
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Huh, I'm not an electrical engineer (like, at all), but I'd have assumed you'd do something funky with a capacitor for that. I guess stacking NOT gates is easier if they're a standard component you can just plonk in there?
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Aug 7, 2022 20:06
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Cojawfee posted:It's literal magic. A strip of metal that's one length is a capacitor, increase the length a little bit, now it's an inductor. It's pretty wild to think about electricity in general and how we've harnessed it to do poo poo that would have been seen as witchcraft all in a little under two centuries.
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Aug 7, 2022 20:20
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Computer viking posted:Huh, I'm not an electrical engineer (like, at all), but I'd have assumed you'd do something funky with a capacitor for that. I guess stacking NOT gates is easier if they're a standard component you can just plonk in there? they're a lot more predictable, and you generally don't want to mix analog and digital signals technically there are also buffer chips which delay a signal and do nothing else, but why keep those in stock when you can just have a pile of not gates
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Aug 7, 2022 20:20
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Computer viking posted:Huh, I'm not an electrical engineer (like, at all), but I'd have assumed you'd do something funky with a capacitor for that. I guess stacking NOT gates is easier if they're a standard component you can just plonk in there? Using logic IC will produce reliable and repeteable results, while discrete components output can float depending on stock quality. It was one of the first things i got teached at electronics school when dealing with real signal projects outside of electronics workbench/multisim  Edit: beaten
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Aug 7, 2022 20:21
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Tunicate posted:Stacked NOT gates are an easy way to delay the signal! This is useful for doing things like edge detection, so you can trigger a circuit exactly once when someone presses a button. This is a thing that's going to be taught in any intro to digital design class that both of those people should have taken.
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Aug 7, 2022 20:31
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Yes, several inverters make a plausibly useful digital delay. At least I think so, it is not my field. You wouldn't use a capacitor for delays because it can only contain one value at a time. What you would use for analog stuff is some actual delay line where the signal takes unusually long time. Like a speaker and microphone with some glass between those. Used to be common in TVs and also used in some Sovjet computers. The closest thing to using a cap for delay are the cross coupling in the big filter from last page, which look like inductors. But there the short path is electrically longer because the effective wave speed throught the main path will be infinite. And that is why you should stay away from that stuff, I am already getting flashbacks typing this.
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Aug 7, 2022 20:31
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so maybe this isn't a "tech" relic in the vein of a 486 but it sure as hell fascinated me - I was at a Cars & Coffee today - someone bought a 1926 Bugatti (possibly a replica, didn't ask).   I spent ages trying to make sense of the controls (e.g. hand-operated oil pump, gear shifter *outside* the car, protruding from the fender) and eventually had a chat with the owner. He races the thing in classic events - basically described keeping the engine operating as job #2 while driving.  What made me think of sharing the car here is that most anything involving the high heat of an engine bay was too hostile an environment for the rubbers of the time - so any place you'd put rubber in a modern car would have had to use something else. My favorite: the steering column connects to the rack through a bushing made of double-thick stitched leather. 
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Aug 7, 2022 20:55
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drat my essence be too low.
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Aug 7, 2022 21:46
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Have you heard of cyclekarting? Basically it's a standard of homemade go-karts that use spoked Honda motorcycle wheels and a standard 200cc motorcycle engine, and you're not supposed to spend more than $1750 total on the entire car. That Bugatti is exactly the type of car people use as visual inspiration. It looks like a hoot and I'm dying to build one.
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Aug 7, 2022 21:52
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sarcastx posted:My favorite: the steering column connects to the rack through a bushing made of double-thick stitched leather. owns... thanks for sharing this. I was getting my '76 Fiat 124 fixed at a shop in Las Vegas. Since I had nowhere to go I talked to the guy working on my car. He had worked on a super old car that I can't remember. I want to say an Austin-Healey or something, idk. Either way, he said that the front crank seal was made of rope. Just a length of rope, soaked in oil, meticulously coiled tightly around the end of the crank and wedged fairly tight by the main crank pulley when you put that on. He said it leaked, but not as much as you'd think and replacements were easy to find lol. Essence, another reason to love the French language. Back to RF black arts: I tend to like the similarities to modern day they find. Like the traveling wave tube used to amplify the signal for transmission. Marc was like: "I was astonished to find that these tubes, made by Collins are still in use today. I guess no better solid state version has been created yet." Space antennae are a pretty niche space I guess. If it works just fine, let it be.
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Aug 7, 2022 22:52
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Also if it’s dead-on reliable, for sure let it be
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Aug 8, 2022 13:22
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Aug 8, 2022 20:00
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i can hear the incredible machine music and space quest 5
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Aug 8, 2022 21:02
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Harman? Look at this high roller who can afford not to use Labtecs
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Aug 8, 2022 22:13
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Hold on I'm about to get a phone call
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Aug 8, 2022 23:16
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https://www.youtube.com/watch?v=f9nOqTN10Lk Iconic really
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Aug 9, 2022 00:33
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and I'm hearing this https://www.youtube.com/watch?v=FVX6t-ivMfE
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Aug 9, 2022 02:52
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I spent years and years with these as my main speakers - they were actually pretty good.
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Aug 9, 2022 04:12
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https://www.youtube.com/watch?v=xphxPPQXJKw
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Aug 9, 2022 04:12
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https://www.youtube.com/watch?v=MCyazKy4CRs
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Aug 9, 2022 11:09
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CaptainSarcastic posted:I spent years and years with these as my main speakers - they were actually pretty good. Hell yeah! Those were excellent.
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Aug 9, 2022 11:22
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Armacham posted:Hold on I'm about to get a phone call Oh god yes.
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Aug 9, 2022 12:46
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I love AdLib music. I owned an MT-32 for a few years recently, but I realized I had zero nostalgia for it and didn't really enjoy it. It was just a childhood odream to own one. I eventually sold it and prefer to play with my SB16.
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Aug 9, 2022 12:49
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Had to laugh at the classic pot breaking sound effect at 1:23.
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Aug 10, 2022 12:21
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e: wrong thread
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Aug 11, 2022 17:23
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Aug 11, 2022 17:57
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https://www.youtube.com/watch?v=UsW2EDGbDqg
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Aug 13, 2022 10:04
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Some pics from a vintage meet I was at today:         
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Aug 14, 2022 06:40
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You Am I posted:Some pics from a vintage meet I was at today: Nice, where was that? I keep finding out about local events after I've already missed out.
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Aug 14, 2022 09:28
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You Am I posted:Some pics from a vintage meet I was at today: The PET is just so perfect in its retro futuristic wackiness. They always make me want to login using a hacking minigame, read some journal entries, disable turrets and open a security door. 
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Aug 14, 2022 09:35
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The centre for computing history uploaded some nice talks. But, more importantly one of the videos ended in this: https://www.youtube.com/watch?v=bLuC4yZk7us
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Aug 14, 2022 11:34
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VictualSquid posted:The centre for computing history uploaded some nice talks. Amazing how nothing seems to be in the same tempo. Even back then a sensible person would have used a sequencer with quantization features for this kind of music and not badly play everything out of sync.
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Aug 14, 2022 11:42
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This was the same company that brought you Microsoft Songsmith though https://www.youtube.com/watch?v=mg0l7f25bhU [edit] have a whole playlist: https://www.youtube.com/watch?v=wHduATM-o7M&list=PLITELU_YVynm3-Wy_O8b6wgbPwS6IMBZk r u ready to WALK has a new favorite as of 11:51 on Aug 14, 2022 |
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Aug 14, 2022 11:47
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Bargearse posted:Nice, where was that? I keep finding out about local events after I've already missed out. They have just restarted recently, looks like it is a monthly thing on the second Sunday of every second month at the Keysborough swap meet. I'll PM you when the next one happens
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Aug 14, 2022 12:03
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You Am I posted:They have just restarted recently, looks like it is a monthly thing on the second Sunday of every second month at the Keysborough swap meet. I'll PM you when the next one happens Thanks, much appreciated. I might have to bring some of my collection.
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Aug 14, 2022 12:44
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