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Neito posted:Until the last couple of years, scanners in the US had to omit the 900mhz range to avoid accidentally intercepting cell phone calls, as they were protected by law, but not by any technological reason. I used to have a set of wireless RF Sennheisers in college. I would occasionally pick up wireless handset phone calls from other people in the dorm with them.
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Aug 3, 2022 16:34
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Thank you for giving me the search term "rf headphone" because I've missed non-Bluetooth wireless headphones so much.
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Aug 3, 2022 19:01
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Sennheiser RS120's are what I had. They'd pick up that lovely 00's cellphone interference when a call was coming in, too!
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Aug 3, 2022 19:52
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brugroffil posted:Sennheiser RS120's are what I had. Sometimes I miss that little rhythm playing on my speakers! Like a little heads-up your phone was about to ring
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Aug 3, 2022 19:55
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Scored a very clean Compaq 386/20e, that let out magic smoke the second I turned it on but just looks like a blown Tantalatum cap so I've got some of those on the way. After that hopefully make a nice fun system for someone.  Might retrobright, might not.  4mb memory upgrade, score.  Old Compaq engineers were awesome.
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Aug 3, 2022 22:00
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Grumio posted:Sometimes I miss that little rhythm playing on my speakers! Like a little heads-up your phone was about to ring I don't remember if this was a thing or just something I made up, but I feel like right around the time the iPhone came out, something about how it connected to the network or got messages or something could affect some mics, so a lot of podcasters had these weird clicking sounds in their recordings for a while.
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Aug 3, 2022 23:48
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Neito posted:I don't remember if this was a thing or just something I made up, but I feel like right around the time the iPhone came out, something about how it connected to the network or got messages or something could affect some mics, so a lot of podcasters had these weird clicking sounds in their recordings for a while.
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Aug 4, 2022 00:06
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Mr-Spain that computer brings back memories as I recognize that case badge as being on the very first PC my family ever had, the first computer I ever knew. Don’t know if it was that exact badge, but definitely some kind of Compaq 386. Thanks!
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Aug 4, 2022 00:09
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boar guy posted:humphreys you should look in to fixing beater pinball machines, seems like it'd scratch that itch you've got nicely. good mix of electromechanical and board work there I used to, also arcade boards. Hmm reminds me I'm still owed a Neo Geo cabinet. In all honensty, I am not allowed to get into pinnys anymore due to money, space and a missus. Were I am at the moment is a collection of consoles and computer stuff that all look the same to her and she doesn't notice another Xbox on the pile. I got in a lot of trouble the other day when a mate came over unannounced with a shopping bag with 3 xboxes for me.
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Aug 4, 2022 03:06
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Mr-Spain posted:Scored a very clean Compaq 386/20e, that let out magic smoke the second I turned it on but just looks like a blown Tantalatum cap so I've got some of those on the way. After that hopefully make a nice fun system for someone. I miss big, hefty power switches. My first PC had this big red power toggle that felt like turning on a factory machine.
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Aug 4, 2022 09:47
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lobsterminator posted:I miss big, hefty power switches. My first PC had this big red power toggle that felt like turning on a factory machine. Was it an IBM? The big power switches on those beasts made this massive KA-THUNK that really got you in the mood for some computing 
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Aug 4, 2022 12:38
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barbecue at the folks posted:Was it an IBM? The big power switches on those beasts made this massive KA-THUNK that really got you in the mood for some computing No it was no name computer from a local store. This video has a similar power switch, even though the case is totally different otherwise. 2:10 mark shows the power toggle. https://www.youtube.com/watch?v=f_nmpVs5eHs
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Aug 4, 2022 13:00
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lobsterminator posted:No it was no name computer from a local store. This video has a similar power switch, even though the case is totally different otherwise. 2:10 mark shows the power toggle. IBMs had a very similar big red switch.
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Aug 4, 2022 13:14
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What was the power draw on those old machines? I get the impression newer chips use less power but I don’t know if it’s significant.
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Aug 4, 2022 13:21
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I always want to turn to the side and whisper to nobody in particular, "You have to pump the handle to build up a charge. It's large, flat, and gray"
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Aug 4, 2022 13:29
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My speakers not picking up interference was how I called out the military recruiter visiting our house on only pretending to receive a phone call. They were on a weird as gently caress script even for military recruiters.
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Aug 4, 2022 13:32
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Dip Viscous posted:My speakers not picking up interference was how I called out the military recruiter visiting our house on only pretending to receive a phone call. *answers fake call* "Oh! Hello, Mr President! What? You're saying you need one more recruit immediately?? Or the terrorists win??? Well... I am just visiting the perfect man for the job."
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Aug 4, 2022 13:39
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Flash Gordon Ramsay posted:What was the power draw on those old machines? I get the impression newer chips use less power but I don’t know if it’s significant. An entire Dell slimline desktop 386 had an 85w PSU.
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Aug 4, 2022 14:02
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Flash Gordon Ramsay posted:What was the power draw on those old machines? I get the impression newer chips use less power but I don’t know if it’s significant. Not a whole lot, my big IBM ps/2 tower has a 160watt power supply. You gotta remember that in many machines, neither the GPU or the CPU even used a heat sink.
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Aug 4, 2022 14:08
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Back then GPUs were called video cards and only handled 2D, so they didn't use much power, and I assume there's some mathematical relationship between number of transistors, voltage and wattage so older CPUs used less due to the lower complexity
ymgve has a new favorite as of 14:45 on Aug 4, 2022 |
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Aug 4, 2022 14:41
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Humphreys posted:I am not allowed to get into pinnys anymore due to money, space and a missus. pin techs willing to make house calls here make $80 an hour with a 2 hour minimum. 
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Aug 4, 2022 16:28
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Wasn't there a guy who holidayed around the US by offering his in-house pinball repair talents in return for a place to stay and meals while doing it?
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Aug 5, 2022 00:05
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Gromit posted:Wasn't there a guy who holidayed around the US by offering his in-house pinball repair talents in return for a place to stay and meals while doing it? yeah that was super rad https://pinside.com/pinball/forum/topic/nics-american-pinball-tour-aka-im-coming-to-fix-your-games
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Aug 5, 2022 01:16
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JnnyThndrs posted:Not a whole lot, my big IBM ps/2 tower has a 160watt power supply. You gotta remember that in many machines, neither the GPU or the CPU even used a heat sink. compared to a modern performance/gaming machine, that's not a whole lot. but obviously we have really efficient processors too, like a NUC for example can be spec'd as low as 36W. the real reason for that big ol chonky power switch on old machines was because you were actually switching the AC mains line going into the system. on modern (ATX and newer) systems the power supply is controlled by the mainboard, so the front panel button just tells the board to begin booting. that's also why you used to have to wait for windows to tell you it was safe to turn off your PC, because you were cutting power to the whole machine by flipping that switch.
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Aug 5, 2022 06:56
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Raluek posted:compared to a modern performance/gaming machine, that's not a whole lot. but obviously we have really efficient processors too, like a NUC for example can be spec'd as low as 36W. Yeah, I had to fix one of my old machines that lost its AT supply by using an ATX supply with an adaptor that added a pushbutton which was in the same form factor as an AT switch. The only thing is that now, instead of the big CHUNK, you just push the lightly switch once and it springs back. Kinda took the magic out of it
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Aug 5, 2022 11:56
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ymgve posted:Back then GPUs were called video cards and only handled 2D, so they didn't use much power, and I assume there's some mathematical relationship between number of transistors, voltage and wattage so older CPUs used less due to the lower complexity Yup, power consumption is directly proportional to the transistor operating voltage and number. The threshold voltage has dropped over time as transistors got smaller, new tech was introduced, etc., but the transistor count... well, 
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Aug 5, 2022 17:14
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Is clock speed in that equation?
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Aug 5, 2022 17:16
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Yeah. It's proportional to the square of supply voltage (so 1V is 4x better than 2V), clock frequency, capacitance per transistor, number of transistors, and probability any given transistor will switch during any given clock cycle. That last one can be tricky, since you may double transistors but spend most of the new ones on cache memory, which doesn't switch much. E: A cool thing is that achievable clock rate is also affected by supply voltage, so running 400MHz might be more than twice as efficient as running at 800MHz because you can also run at a lower supply voltage at 400MHz than 800MHz. A lot of ink has been spilled over how to best take advantage of this. Stack Machine has a new favorite as of 18:00 on Aug 5, 2022 |
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Aug 5, 2022 17:54
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Looking back, it's a little surprising how often I had to use the trick for powering up an ATX power supply without a computer: use a paperclip to short the green wire to one of the black (ground) wires. It's only 5 volts, so it's not dangerous to a human. However, a friend of mine was once doing this on a crowded desk right next to his laptop, and the paperclip came in contact with the metal underside of a PCMCIA card, and... well, it turns out 5 volts applied to the wrong place is sufficient to release magic blue smoke and kill a laptop stone dead.
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Aug 5, 2022 17:57
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Meanwhile, in texas
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Aug 5, 2022 18:46
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Powered Descent posted:Looking back, it's a little surprising how often I had to use the trick for powering up an ATX power supply without a computer: use a paperclip to short the green wire to one of the black (ground) wires. This is an excellent way to ensure you take advantage of an extended warranty, BTW.
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Aug 5, 2022 18:46
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an actual frog posted:Meanwhile, in texas unts unts unts unts unts
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Aug 6, 2022 15:23
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Jim Silly-Balls posted:Extra fun cell weirdness: if your signal Is low enough on the Wisconsin side of Lake Michigan, you can often unintentionally pick up service from the Michigan side, despite it being like 90 miles away over water, which also has the fun bonus of shifting your clock forward an hour. I was at NY state park/beach on the south coast of Lake Ontario a few weeks ago, and my cell reception was spotty. About an hour after we got there I got a text saying "welcome to Canada! From [service provider]. Additional fees may apply while you are outside of country. Is it like shortwave radio where the signal can bounce back and forth between water surface and clouds to reach far away?
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Aug 7, 2022 07:59
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No, it doesn't usually bounce. Those super high frequencies usually just pass through the ionosphere straight ahead, or they get absorbed. But over water, there is very little damping of the signal by stuff that's inbetween, and the water surface itself is also good for signal propagation. Trees, buildings and such absorb some of the signals. They can also cause reflections which confuse the phone when there are too many of them. There are very specific situations in which there is a sort of tunnel between two layers of air in the troposphere where SHF phone frequencies can travel through beyond the horizon (tropospheric ducting) or where the signal is reflected by water vapor (tropospheric scattering). That can turn a 10km range into a 100km range, but that is not something highly predictable or reliable. It's one of the things amateur radio operators use for fun. It's pretty interesting to experience how physics can play very weird games. Once i (near amsterdam) had a connection with some germans 500km away, on VHF (just above the FM broadcast band, 144MHz). They sounded as if they were in my own town. Usually my signal doesn't reach more than 50ish km.
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Aug 7, 2022 11:03
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What I've never understood about cell technology but haven't bothered to Google is how the tiny low-powered antenna in my phone, at ground level, broadcasts back to the tower apparently as well as the megawatt tower that needs to be elevated above everything in the area broadcasts to individual phones.
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Aug 7, 2022 13:26
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LimaBiker posted:No, it doesn't usually bounce. Those super high frequencies usually just pass through the ionosphere straight ahead, or they get absorbed. That was the part that blew my mind about it because Lake Michigan is 90 miles wide so the curvature of the earth should be enough that you can’t get line of sight to a cell tower on the other side. You certainly can’t see across it at all
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Aug 7, 2022 14:24
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The main secret is that there's a ton of cell tower antennas almost everywhere in cities these days so the phone rarely transmits at full power. But also since the tower antenna is much bigger and more complex than the one in your phone they can pick up weaker signals. Just look at it, no wonder it can pick up a gnats fart from a mile away. I have no idea how the hell they engineered these things.  
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Aug 7, 2022 14:32
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I googled it and you have to be about 3500 feet in the air to get line of sight across most of Lake Michigan, so it’s clearly some sort of refraction happening that’s bending or reflecting the signal around the lake, because at ground level, line of sight is straight through the ground/lake itself.
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Aug 7, 2022 14:46
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r u ready to WALK posted:The main secret is that there's a ton of cell tower antennas almost everywhere in cities these days so the phone rarely transmits at full power. Holy crap! Anyone have any good tear down videos or something of these? Microwave/high frequency RF circuit design is so crazy and I want to see more of it. Especially modern stuff now that CuriousMarc has done a bunch of videos on the old NASA Apollo GHz transceivers
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Aug 7, 2022 16:35
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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.
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Aug 7, 2022 16:57
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