[HN Gopher] Chasing RFI Waves - Part Seven
___________________________________________________________________
Chasing RFI Waves - Part Seven
Author : walrus01
Score : 279 points
Date : 2025-03-10 00:16 UTC (22 hours ago)
(HTM) web link (raoulpop.com)
(TXT) w3m dump (raoulpop.com)
| zx8080 wrote:
| I wonder if any of the currently produced cars will have seats
| still comfortable after so many years. Probably, no.
| MarcelOlsz wrote:
| My 1986 early model E30 leather sport seats are still nearly
| perfect.
| don-code wrote:
| 1987 E30 owner - even after getting the mold out during a
| restore, and in spite of a crack in the bolstering, the E30
| sport seats are the _second_ most comfortable I've had the
| pleasure of owning. The seats in these old cars definitely
| have something up on modern leather seats, even its 27-years-
| older brother (4-series) that I drive daily.
|
| The champion in that department, though, was the 1986 Volvo
| 740 that I briefly owned. Those seats were perfect in nearly
| every way.
| frompdx wrote:
| The seats weren't really all that comfortable to begin with.
| However, you can rebuild the seats. LMC Truck has rebuild kits
| with new foam and covers. You can even add heated seats.
| mobilene wrote:
| This was one of the most wicked cool things I've read in a long
| time.
|
| I grew up in a TV market that was UHF only (South Bend, IN) in
| the 1970s. TVs from before about 1963(?) didn't have to have UHF
| dials. So a company named Blonder-Tongue (Blonder was pronounced
| like blunder) produced UHF receivers you could attach to your TV
| through the little screw tab things on the back, the predecessor
| to the coax input. I had never seen Blonder-Tongue referenced
| anywhere except in nostalgia articles about my hometown.
| walrus01 wrote:
| Blonder tongue was a well known vendor for regional cable tv
| network (analog) operator equipment, supplies, electronics. I
| think it still exists in some form for video mixing/live studio
| broadcast equipment.
|
| https://www.blondertongue.com/
| wolrah wrote:
| I work in a lot of nursing homes and their in-house "cable"
| systems are almost universally a rack full of DirecTV
| receivers connected to a rack full of Blonder Tongue NTSC
| modulators. I would have to assume similar systems were
| common in all sorts hospitality environments in the past, and
| only survive in nursing homes because most of the residents
| don't care about HD and might not even want it.
| Scoundreller wrote:
| Also white labelled so e DishNetwork receivers with a few
| mods: https://www.youtube.com/watch?v=jBf3dZUAImk
| qingcharles wrote:
| The is probably how all jails and prisons are running their
| systems, too. Lots of these places still running CRT 4:3
| TVs too. The 4:3/16:9 issues are rampant. And obviously the
| picture quality is just like you remember from the 1980s.
| walrus01 wrote:
| On a only slightly related note, there's a thriving
| collectors market on ebay and other places for "clear
| plastic" see through enclosure prison CRT TVs since
| they're both a novelty, and nobody makes CRTs anymore.
| People buy them to hook up to like Sega Genesis, Super
| Nintendo bare metal hardware for retro gaming.
| qingcharles wrote:
| It's getting harder and harder to bring them home. The
| prisons are trying to keep the items inside the system,
| even though the prisoners actually bought the items
| outright.
| lazide wrote:
| Like industrial equipment - you know it's going to be good
| when it has an absurd name (company or model). Assuming it's
| been around awhile.
| Kon-Peki wrote:
| Ah yes, South Bend is too close to Chicago, too close to
| Indianapolis, too close to Detroit... No VHF frequency left to
| allocate! The biggest problem is Chicago. South Bend is on a
| subcontinental ridge, with an average elevation nearly 300 feet
| higher than Chicago, and with all the transmitters in Chicago
| up 1500-1800 feet above ground and close to the lake,
| overcoming the curvature of the earth limitations on VHF
| propagation is fairly simple. Anyone in South Bend with a large
| antenna on their roof would easily receive all the stations.
|
| On the upside, that meant having two versions of CBS and NBC (I
| don't remember an ABC affiliate in South Bend) plus the couple
| of other stations. My cousin got his start as a weatherman on
| NBC in South Bend simply by them needing someone to fill in
| from time to time and him being essentially the only person
| they could find that grew up in South Bend but had gone off to
| study meteorology at a university that was very very good for
| meteorology.
| veunes wrote:
| It's funny how certain brands or bits of tech can feel almost
| legendary in one place but totally unknown everywhere else
| JJMcJ wrote:
| Just for completeness, the screw tabs were for an antenna, the
| notorious rabbit ears if you were close to the stations, or one
| on the roof if you were farther away.
| dhosek wrote:
| I imagine that there will come a time when they'll need to revert
| to horse and wagon transport at the site. Or perhaps lay down
| railroad tracks and use cable cars.
| frompdx wrote:
| You can buy what is basically the same engine new.
| https://quadstartuning.com/products/amg-gep-optimizer-6500-l...
| netsharc wrote:
| They could get one of these
| https://www.offgridweb.com/transportation/toyota-gibraltar-t...
| nubinetwork wrote:
| > Land Cruiser
|
| Not a great idea, those engines like to blow holes in their
| pistons...
| fy20 wrote:
| Up until the 2000s diesel engines in cars used mechanically
| controlled injection. With those, once started, the engine will
| run without any electronics.
|
| Engines produced for industrial applications (such as tractors)
| in developing countries still use this, as it's a lot simpler
| and more reliable. Military trucks are the same. Just don't
| tell the EPA.
| genewitch wrote:
| I have a 10kW diesel motor that doesn't have any wires at all,
| no battery. It's my SHTF generator for my well.
|
| I might have to wind a generator motor if the reason stuff went
| bad is because of emp, but otherwise, yeah, you can buy 100%
| mechanical diesel engines still.
| msandford wrote:
| I feel like they could probably buy some 80s Mercedes 300d and
| get newer cars with lots of parts available as there's junked
| ones everywhere.
| Braxton1980 wrote:
| But the ECM?
| msandford wrote:
| What ECM? They're mechanically injected diesels. The main
| purpose of the electrical system is to run the starter to
| crank the engine. And maybe headlights and stuff.
|
| They're very simple cars.
| blankx32 wrote:
| Yep to parent poster look at the fascinating mechanical
| fuel pumps in some detail they are incredible machines in
| their own right
| johnklos wrote:
| My Diesel has an analog glow plug controller. That's
| literally the most complicated electronics in the whole car.
| frompdx wrote:
| I would argue the 6.2L/6.5L Detroit Diesel is a superior choice
| in North America, which is the engine used in the article.
| topspin wrote:
| The 5.9L 12-valve Cummins is also a fine choice. Another
| fully mechanical engine. In theory, with a manual
| transmission, you can operate a vehicle without even a
| battery after it's started.
| cellularmitosis wrote:
| Well, almost. The 5.9L fails safe: there is a fuel shutoff
| solenoid which operates in reverse: you give it power to
| keep the fuel flowing. You'd need to modify it to force the
| solenoid open (or remove it).
|
| The OM617 (as used in many 1980's Mercedes sedans) fuel
| shutoff operated on vacuum, and once started, the engine
| would run with no electrical system at all.
| laurencerowe wrote:
| > Before retiring from NRAO (years after my interviews with him),
| Mr. Sizemore outfitted a new Dodge Ram extended cab truck as an
| RFI vehicle, a feat which was written up in USA Today.
|
| Dead link but luckily archive.org has it.
|
| https://web.archive.org/web/20140725075606/http://usatoday30...
| defrost wrote:
| Today, in the Murchison Radio Quiet Zone: The
| Power and Signal Distribution (PaSD) SMART boxes (Small Modular
| Aggregation RFoF Trunk) are an essential component of the Square
| Kilometre Array Low frequency (SKA-Low) telescope, currently
| under construction at Inyarrimanha Ilgari Bundara, the CSIRO
| Murchison Radio-astronomy Observatory, in Western Australia.
| The SMART boxes provide electrical power to the SKA-Low
| telescope's 131,072 antennas and collect signals received from
| the sky to go off-site for processing. [ .. ] "The
| 'radio quiet' results that the ICRAR-designed SMART boxes
| achieved were to the highest standards in radio astronomy. A
| mobile phone on the surface of the moon would cause more
| interference to the antennas than the SMART boxes that sit among
| them,"
|
| ~ https://www.australiandefence.com.au/defence/cyber-space/icr...
|
| I still haven't found any vehicle guidelines for the Inner Zone (
| 70 km radius ), but for anyone with an interest:
|
| * General introduction: https://www.industry.gov.au/science-
| technology-and-innovatio...
|
| * Restricted airspace:
| https://www.avsef.gov.au/consultations/restricted-airspace-o...
|
| * Limits of intereference by frequency and distance table:
| https://www.ursi.org/proceedings/procGA11/ursi/JP2-17.pdf
| walrus01 wrote:
| RF over fiber is a fairly well established thing, it's used in
| two way data satellite earth stations to convert a L or S band
| signal into something that can go a longer distance from the
| antenna to a conditioned equipment room at the same place.
|
| https://www.vialite.com/market-sectors/satcom/
|
| https://dev-systemtechnik.com/rf-over-fiber/
| toomuchtodo wrote:
| Very cool. Is there a reason the RF has to be converted back
| to RF after the fiber link vs processing the RF spectrum data
| optically?
| walrus01 wrote:
| your typical satellite modem will have an RF interface
| either somewhere between 70 to 140 MHz (where it's intended
| to be upconverted/downconverted by the LNB and BUC/SSPA at
| the antenna), or somewhere between 1100 to 1900 MHz, both
| intended for attachment to low loss coaxial cables. This
| works fine if you're putting the modem fairly close to the
| LNB and BUC/SSPA. If it needs to be a hundred meters away
| or something, it's a lot of RF loss, and path loss/link
| budgets in geostationary satellite are already hard enough
| without introducing any more loss at the ground side.
|
| https://www.comtechefdata.com/products/satellite-modems
| MadnessASAP wrote:
| I would imagine it's because electrical amplifiers,
| filters, and other such items are cheap and well
| understood. Whereas optical amplifiers, filters, and other
| such things, particularly ones that operate at low-GHz
| frequencies are expensive and kinda wild
| walrus01 wrote:
| well, an optical amplifier wouldn't do anything at all
| attached to a waveguide into a feed horn, in something
| like a 6.3 meter ku or c band cassegrain antenna design
| antenna aimed at a geostationary satellite... that's the
| job for a BUC/SSPA. You need. it needs to be RF.
|
| rf over fiber in a satellite teleport application is more
| about being able to separate the modem from the antenna-
| mounted LNB and BUC/SSPA which might be some distance
| away.
| frompdx wrote:
| My time to shine! I still own an early square body truck with the
| 6.2L Detroit Diesel. The thing that stands out to me in this
| article is that the Suburbans shown are an earlier generation
| produced from 67-72. Those did not have a Diesel engine, however
| the 6.2L Detroit Diesel was designed to drop into anything with a
| Small Block Chevy, so I can see how these may have been
| retrofitted. In fact, these engines are still produced today in
| 6.5L form (see the AM General Optimizer) and are used in the
| HMMWV.
|
| These really are very simplistic engines and simplistic vehicles
| in general. Mine has power nothing, at least electronically. The
| shifter really is comically large and very inconvenient to
| whoever sits in the middle. The highest gear is third gear.
|
| Powerful? No, not really. But surprisingly efficient for the
| size. Reliable as well.
| seabrookmx wrote:
| The original castings were pretty poor in the 6.2 and 6.5 and
| lots of them crack at the crank webbings. This is supposedly
| fixed in the AM General blocks. They were common work trucks in
| the PNW (forestry, mining) but while you see the old Cummins or
| Ford IDI's around still the "Detroit"'s (no relation to the 2
| stroke Detroit or Series 60) are quite rare. My family still
| has an early mechanically injected 6.5 that's held up OK though
| (~300,000km on it).
| frompdx wrote:
| I'd say that 6.5 as plenty of life left. My 6.2 is pushing
| 400,000km.
| bluGill wrote:
| the 6.2 and 6.5 are good engines - but dodge has the
| cummins and the ford powerstroke (other than the 6.0) are a
| much better engine and so they get a bad reputation.
| blankx32 wrote:
| Came to say 6bt aka the 12 valve must be a contender
| bluGill wrote:
| The 6.2/6.5 were gm engines not detroit diesel. very different
| engenes.
| userbinator wrote:
| Detroit Diesel was a division of GM at the time:
| https://en.wikipedia.org/wiki/Detroit_Diesel#Origins
| cellularmitosis wrote:
| I once swapped an OM617 (the 5-cylinder turbodiesel used in
| many 80's Mercedes sedans) into a 67 Chevy pickup.
|
| Once started, the engine would run with no electrical system at
| all! Even the fuel shutoff operated on vacuum.
|
| https://youtu.be/5teg3Zlj0bo
|
| https://youtu.be/q8LEWIZi21Q
|
| https://youtu.be/kuDcSuwdzaw
|
| https://youtu.be/MqWwUC3h3VU
|
| By far my favorite hack :)
| veunes wrote:
| You must get a lot of questions (or confused looks) when people
| see that thing still running! The simplicity of those engines
| is kind of a lost art these days. Everything now is so
| computerized that you can't even diagnose half the issues
| without special software.
| MisterTea wrote:
| Whats very coincidental is those suburbans in the article are
| on the Wikipedia page for that generation:
| https://en.wikipedia.org/wiki/Chevrolet_Suburban#Sixth_gener...
|
| > The highest gear is third gear.
|
| Was it the strait 3 speed or the 4 speed with a "granny gear"
| aka the stump pulling L - Low range? 4 speed should be the
| Muncie SM465 which I had in a GMC 6000.
| 1970-01-01 wrote:
| Those are what you need after an EMP blast.
| gooseyard wrote:
| I grew up in this area of West Virginia, it's such a crazy thing
| that a community of really amazing scientists are nestled in the
| middle of this incredibly rural area. It's really neat to see the
| old blue trucks if you take the tour, and the Cass Scenic
| Railroad is just nearby and gives a really beautiful view of the
| telescope array. The National Youth Science Academy Camp is also
| surprisingly located nearby, it was wild as a kid knowing that
| this batch of future scientists were flying in from all over the
| country and once I learned of it I wished I'd studied a bit
| harder. Such a beautiful, strange place.
| garaetjjte wrote:
| I suppose they removed the alternators, and that's why they keep
| them plugged in?
| bloomingeek wrote:
| No, they were plugged in to supply power to the block heaters.
| These kept the oil warm so they were easier to start.
| genewitch wrote:
| Diesels use glow plugs to heat the cylinders prior to starting,
| to explain why sibling mentioned needing to keep them warm.
| Luckily resistive heat doesn't make RF noise, at least not that
| I've noticed. But they could also garage them with potbelly oil
| burners, too.
| iancmceachern wrote:
| One of my favorite parts about the old perkins diesel engine in
| our boat is that you need to press a button to stop it from
| running once started. You turn off the ignition and it just runs
| on physics until you do something to interrupt the fuel or air
| supply.
| doubled112 wrote:
| Diesels diesel (the verb). It keeps them exciting.
|
| I've been in a friend's car while it ran away on motor oil
| passed by a failed turbo. Turning it off didn't stop the
| engine.
| robocat wrote:
| The scariest story I've heard was a parked diesel pickup
| truck going runaway acceleration because of the hydrocarbon
| vapours in the air due to an industrial accident.
|
| They abandoned the pickup and it subsequently got blamed "A
| diesel pickup truck that was idling nearby ignited the vapor,
| initiating a series of explosions and fires that swept
| through the unit and the surrounding area".
|
| I read about it in one of the disaster reports about the
| Texas City BP refinery explosion. Ugly mistakes were made.
| Lammy wrote:
| > I read about it in one of the disaster reports about the
| Texas City BP refinery explosion.
|
| Relevant part of USCSB accident reconstruction animation:
| https://youtu.be/goSEyGNfiPM?t=550 (but worth watching the
| whole thing!)
| namibj wrote:
| Can't quite call it parked if it's idling...
| spacecadet wrote:
| Grew up around some farm trucks that were electronic free
| diesels. My grandfather called them "luddite diesels". Later in
| life I realized the humor, considering that a diesel engine is a
| technology, and that luddites likely prefer horses...
| db48x wrote:
| No, the technologies that the Luddites disliked were very
| specific and regional. They only cared about machines that
| threatened their own personal jobs, not anyone else's job.
| genewitch wrote:
| Okay, loomer.
| spacecadet wrote:
| :D
| spacecadet wrote:
| If you were a Luddite horse farmer or yoke maker you might
| hate diesel engines lol.
| db48x wrote:
| No, because those specialists never quite existed. That is,
| every farmer who owned horses would let them breed and then
| sell most of the foals every year. Similarly, any farmer
| could carve a yoke whenever they needed one; it wasn't
| skilled labor that required years of training the way
| lacemaking or weaving was.
| spacecadet wrote:
| ...it's just some fun conversation.
| genewitch wrote:
| I think the Amish are closer to what people envision when
| they hear the word "Luddite", but luddite these days
| means anyone who is wary of or eschews technology. It was
| specific to the textile workers, originally, destroying
| machines.
| CobaltFire wrote:
| This is an awesome article. I'm a HAM in an urban area trying to
| figure out how to operate in the mess that is my EM spectrum with
| low power gear. It's a fun challenge, but having some quiet would
| be nice!
|
| I haven't had the pleasure of seeing this site, but I did have
| the opportunity to visit Sugar Grove Station (not too far away)
| while it was in operation. I had a friend stationed there while I
| was nearby, and took a detour to spend the weekend at his house
| on the base.
|
| Seeing the massive old radio telescopes and the tracks they used
| for positioning them was something else. The scale is hard to
| communicate; it's kind of like the first time you get up close
| with a Navy Aircraft Carrier. It's hard to fathom just how BIG
| they are until you are next to them.
| driggs wrote:
| Were you allowed on base? What was your experience like and
| your perception of what was going on?
|
| I had the opportunity to perform a bat survey at Sugar Grove,
| and a poor guard had to come out to keep an eye on us until 3am
| because we couldn't be left alone. We noted curious wooden
| gazebos positioned around a featureless meadow, hinting at
| significant manned infrastructure underground.
|
| Unlike the Green Bank Observatory from the above article, Sugar
| Grove was piggybacked on the National Radio Quiet Zone so the
| NSA could intercept intercontinental telecom traffic as a part
| of the ECHELON network. The cover story was that it was a run-
| of-the-mill AT&T site, but was an open secret for all the
| Pendleton County WV locals that it was a spy site. The base was
| also home to the best restaurant in the whole county, which
| isn't saying much for a single-traffic-light county.
|
| https://en.wikipedia.org/wiki/Sugar_Grove_Station
|
| https://en.wikipedia.org/wiki/ECHELON
| CobaltFire wrote:
| Yes; I was cleared to the level required (but not need to
| know) and the visit was approved by his (the base) CO. He was
| stationed there as a Crypto Tech, and though I couldn't see
| the really neat underground stuff I was mostly free above
| ground as long as I was chaperoned by him. He gave me quite
| the tour.
|
| The gazebos are there due to the underground facilities, yes.
| There is likely a whole lot more than even you realized.
|
| As for my impressions: I was a Security Manager for a more
| operational side of the Navy for years (later). I informed a
| lot of my edge case thinking with what I saw of how they
| handled things there. I don't know that I really want to go
| into more detail than that.
| veunes wrote:
| I can only imagine what it must have been like standing next to
| those giant dishes and realizing just how massive they really
| are
| nimish wrote:
| I wonder what signal processing methods exist to deal with
| terrestrial noise sources instead of relying on the brute force
| approach.
| drweevil wrote:
| Not sure what you mean by the brute force approach. The problem
| is that the terrestrial noise sources are many orders of
| magnitude stronger than the faint signals that the ultra-
| sensitive receivers are designed to receive, and easily
| saturate them. The only recourse is to excise any data taken
| during an RFI episode. It would be extremely difficult, if not
| impossible, to do science in many RF bands of interest were it
| not for the NRQZ.
| Aaron2222 wrote:
| Not who posted the parent comment, but "brute force approach"
| = having the NRQZ I'd imagine.
| drweevil wrote:
| I figured as much. The question about why it is needed
| brought to mind something I was told when I started work
| there, over three decades ago. It was something along the
| line that all the signal energy recorded by the
| observatory's telescopes integrated over their lifetimes
| amounted to less energy than is expended by one flea making
| one jump. I don't know exactly how accurate that is, but it
| does rather vividly illustrate the problem.
| rootbear wrote:
| In 2006 my friend and I decided to stop talking about visiting
| the NRAO and actually go. We picked a weekend and then discovered
| that that Sunday was the 50th Anniversary open house! There were
| special exhibits and more of the facilities were open to tours
| than on regular visitors days. I can highly recommend visiting if
| you get the chance.
|
| Coincidentally, my friend's last name is Blonder! And he's
| related to the Blonder-Tongue founder. According to my friend,
| all Blonders are related, the family name was originally
| Gottlieb, but was changed to something more Anglo sounding, to
| avoid anti-semitic discrimination, probably when they immigrated
| to the US from Russia.
| floatrock wrote:
| > Here he monitors the gross violations of the Quiet Zone and
| also looks at the local environment: powerline noise, illegal use
| of radios, etc. For example, at the time of my visit there, the
| amateur radio bands were being used improperly by a group of
| people and the signal was strong enough to overload the 140-foot
| telescope, so it became a serious problem... The likely action
| taken will be that he calls the FCC in to enforce the rules in
| place. After 20 years on the job, Wesley has built up a network
| of contacts he can call upon when he needs help. One of those
| contacts is the man in charge of the Enforcement Bureau at the
| FCC, whom Wesley knew when he was still a satellite technician.
|
| Always interesting to hear examples how effective coordination
| often comes down to networks of people-connections that get built
| up over time. Software folk often think it's simply automating
| whatever process -- I certainly thought that early on -- but more
| and more I'm seeing it's about knowing the person in the right
| role with the right experience. Your personal network is
| leverage.
|
| The last two sections about helping out a grumpy farmer with an
| old burned out amplifier and coordinating secret fly-overs with
| the Cheyenne Mountain guys are also great people-network stories.
| donohoe wrote:
| I wonder how many of his critical contacts at the FCC have been
| fired by Musk
| rkagerer wrote:
| It's a shame we don't better contain all the EM noise emanating
| from our modern vehicles.
|
| I'm dealing with this issue right now on my boat (EM noise from
| hydraulic trim pump for the drive leg is coupling to a power
| supply line running to a more sensitive electronic component).
| johnklos wrote:
| So there are good reasons, aside from reliability, efficiency and
| ease of repair, for having a 1981 Diesel Chevette with a 100%
| mechanical engine :)
| torstenvl wrote:
| Green Bank is great. I have ties to E WV and made a trip there
| one time after hiking Seneca Rocks. Highly recommended if you get
| a chance.
|
| https://ibb.co/N2RYW8vr
| watersb wrote:
| I spent two weeks there, during the commissioning of the Green
| Bank Telescope (GBT). Our team was designing the monitor and
| control system for an upgrade for another NRAO telescope, the
| Very Large Array in New Mexico. The team from the GBT led us
| through their design during the day; our nights sleeping in the
| on-site dormitory, complete with the break room where Frank Drake
| came up with his Drake Equation estimating the number of
| extraterrestrial civilizations...
|
| Those old diesel trucks!
|
| The GBT is so big, it's just wrong. Experiencing the forest moon
| of Endor, in real life.
|
| (The single-dish GBT is sensitive to near-field RFI, whereas the
| multi-dish Very Large Array is a bit more tolerant. The VLA isn't
| restricted to antiquated diesel vehicles. Although they do ask
| visitors to power off cell phones and refrain from any microwave
| ovens that RVs might bring in.)
| tjmc wrote:
| I wonder how they start them. Park at the top of a hill?
| johnklos wrote:
| That's one way, but I suspect that even if they did disconnect
| the alternators, they could just charge the batteries
| overnight.
|
| On the other hand, alternators should make _way_ less EM noise
| than ignition coils.
| nosmokewhereiam wrote:
| Netstumbler!
| silisili wrote:
| The NRAO should kickstarter a new, electronics free diesel
| fullsize.
|
| Not to build it, just to prove how much demand exists for it.
| Because this is something every truck guy I know has been asking
| for forever.
|
| There's even an online rebellion of sorts over the new Hilux not
| being available here.
| genewitch wrote:
| When has the hilux ever been available here? I've wanted one
| for over 20 years, but not enough to pay to import...
| silisili wrote:
| Not ever. But apparently there's some new model called the
| Champ that starts around 10k, and has people who want simple
| trucks raging out. For good reason, it's a solid looking
| simple truck.
| go-nil-why wrote:
| We'll need to fire all the industry plants in the EPA
| before we can legally have a small (fuel efficient) truck
| here in US. Our emissions laws were written by Big Truck.
| genewitch wrote:
| has this not happened yet? I don't have a twitter account
| so i can't ask
| fc417fc802 wrote:
| > electronics free diesel fullsize
|
| I'd happily settle for embedded computer free _anything_. Or
| even just not-cell-network-connected and no touchscreens. The
| bar has dropped quite low at this point.
| veunes wrote:
| An old-school, no-nonsense diesel truck with zero unnecessary
| electronics? I feel like it would get funded overnight
| preisschild wrote:
| many electronics actually improve safety a lot, so probably not
| a great idea.
| panstromek wrote:
| Since the unwanted interference is from sparkplug, I wonder -
| assuming it would contain no additional electrincs, could they
| get some EV? Or does the electric engine itself generate noise by
| necessity?
| genewitch wrote:
| EV are so noisy they talked about doing away with AM radio in
| the US because the EV jams it.
|
| I am unsure what would lead to this question...
| panstromek wrote:
| hm, yea, I guess it was a dumb question. Spinning magnets for
| sure must generate noise.
| p_l wrote:
| It's possible to deal with it, but one must _want_ to deal
| with it, plus the "costs" like increased weight, BOM, etc.
|
| EV makers don't want to and it's a problem even with the
| very low bar is consumer equipment
| panstromek wrote:
| yea, my question was more about whether this is more
| about the redundant additional electronics in newer cars,
| or just EV car problem in principle.
| p_l wrote:
| Mostly EV components - the motors and inverters that
| drive them can generate a lot of EM noise.
| namibj wrote:
| That's not because they have to, though; especially if
| quietness in a narrow band is required. It's just way cheaper
| and somewhat more efficient to abuse the motor as the
| inductor to filter the hard switching.
| genewitch wrote:
| explain how you make something quiet in a "narrow band"
| around things that are so sensitive that it was claimed
| that "if you integrated all of the signal power received by
| the antennas, it's less than the energy used by a flea to
| jump".
|
| not just at any given moment. In the career of whoever said
| that, the total power was that miniscule.
| mikewarot wrote:
| It's _possible_ to build a control system and inverters for an
| electric vehicle that don 't spam RFI everywhere, it won't be
| anywhere near as small, as all the filtering required is going
| to be quite sizeable. (And no, I'm not suggesting using
| analog/linear systems, that would be silly huge and get super
| hot)
|
| The motors are brushless, so if all of the drive power is low
| frequency and well filtered, it'll be nice and RF quiet.
| veunes wrote:
| The bit about the old diesel cars still being in service because
| modern ones generate too much RFI is both fascinating and a
| little surreal
| TrackerFF wrote:
| I live in a town that has some pretty huge military radars (S-
| and X-band radars), and while they are pointed away from the
| population - the side lobes still send out a periodic chirp that
| has the duration of exactly 10.5 seconds, and it is only audible
| in audio equipment.
|
| And for guys like me, that operate a home recording studio, it
| really fucking sucks.
|
| Another place I lived, there was this 7 kHz noise that would also
| get on top of any amplified source - almost drove me insane, and
| could never figure out what it was. It was some kind of RFI. At
| first I thought it was something related to the house, maybe a
| bad ground combined with some switching circuit.
|
| Turned off the mains breaker, and hooked up my guitar to a
| battery amplifier - same annoying noise was present. Tried
| shielded cables, tried cables in different lengths from longest
| to a short 5 cm patch cable, still there. Went outside, and it
| was present. No distribution transformer, gas meters, or smart
| meters in general.
|
| Also, back in the day, we'd get Soviet TV coming in waves -
| meaning that you'd get some periodic interference where your TV
| would show a combination of both. I think it was due to their
| huge over-the-horizon radars.
|
| (But I've never had any problems with RFI from cars!)
| plantain wrote:
| Are you in Alaska?
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