Ask MetaFilter questions tagged with interference

How do I shield an audio cable in my computer case which I cannot take out and replace?

aliasless — Mon, 28 Dec 2009 09:55:22 -0800

How do I shield an audio cable in my computer case which I cannot take out and replace? The cable running from my motherboard to the front headphone jack is unshielded, apparently. I constantly hear a high-pitched mosquito sound in my headphones, and static when my hard drive spins up.

What's a good DIY way to shield the cable? Foil tape? Some kind of mesh jacket? I can't replace it because that would require soldering knowledge, I think. However, I can unplug one end of the cable if needed.

FM Interference & Potential Coinkidink

JoeXIII007 — Sat, 26 Dec 2009 22:05:23 -0800

Heard some strange radio interference Christmas day, wondered if a hypothesis is correct in relating it to the local 'terror' attempt at DTW??? So the family had gotten home from a Christmas gathering, and someone checked the radio randomly to see what was on the low end of the FM spectrum (88-89, 88.7 and 89.1 to be exact), and we heard light static followed by some horrific beeping that could have came straight from a loud Atari game. Not quite bass, not quite tenor, just loud, obnoxious, and alternating (low then high, repeat). It did not last long.

Thus the question: what could this have been. We live within 30 minutes of Metro, so it was thought that since this noise had not been heard since 2001, it might have had something to do with the terror attempt. Otherwise, no clue, and would like to know for later reference.

Ideas?

My piano picks up the the radio

TrashyRambo — Tue, 29 Sep 2009 13:09:24 -0800

My new Casio digital piano picks up the radio. I think this is a bug not a feature. You can very faintly hear a music station coming out of one of the speakers (which is very distracting). Any ideas on how to fix it?

It's the buzz buzz buzz in the drum of the ear, or, making my amplifier a tinfoil hat to stop GSM noises from my phone.

Halle — Wed, 23 Sep 2009 06:22:38 -0800

It's the buzz buzz buzz in the drum of the ear, or, making my amplifier a tinfoil hat to stop GSM noises from my phone. Like many others, I have GSM buzz in my speakers. But, I frequently don't have the option of setting my phone to silent while I'm working, because I'm working on the phone. That leaves the options as a) not getting to listen to music while working, or b) letting hideous noises that come out of my speakers every hour at a much higher volume than the music make me aggro. So, I've done some research (and read the old and inconclusive GSM noise questions here in AskMe) and I've concluded that it's most likely my amplifier lacking shielding. I'm going to put ferrite chokes on my speaker and audio cables just in case, but the main plan of attack is to put a faraday cage around the amp since it's out of sight. What is a good way to construct the cage with the following specs:

1) blocks interference really well,
2) isn't terribly expensive,
3) will last/can be moved (i.e. alternatives to tinfoil),
4) has some possibility of heat dispersal so it doesn't kill the amp.
5) no negative electrical safety implications (I can't imagine what these could be but I thought I'd throw it in there in case there is anything I'm overlooking in this department).

Thank you!

Aside from the inconvenience, it ruins phone sex

notashroom — Wed, 13 May 2009 08:33:42 -0800

What can I do to help a friend with interference issues causing phone problems in her house? My friend has virtually no cell reception inside her house, so she still has a landline. She has two 2.4GHz cordless phones, neither of which works in the southwest corner of the house. They can initiate and receive calls, but there is very loud static that prevents either party from hearing.

That corner of the house (her bedroom and bath) is where the house's power line enters. I'm guessing this may be the origin of the interference, but I'm no engineer. She's tried various locations for the phone bases, with no appreciable difference (both within the room and in other upstairs rooms). The static dissipates immediately after leaving the bedroom, just a foot or two into the hallway and it's gone.

Other info, in case it's relevant:
- Under the bedroom is the garage, which does have a remote door opener.
- The computer is more than 20 feet away. There is no wireless.
- She has Dish Network. I don't remember where the satellite is, but it is possible that it is in direct proximity to the bedroom.
- In the bedroom within 24" of the wall corner where the power line enters (but approx. 4' below), are an LCD TV, Dish box, and iPod docking station.
- The building in question is a single-family house with over 30' of clearance on each side from neighbors. There is no nearby power substation or anything.

What, if anything, can I do to help her be able to use her phone in her bedroom?

Is the ticking on my new cordless phone a result of interference from my old wireless router?

IndigoRain — Sun, 15 Mar 2009 19:11:47 -0800

Is the ticking on my new cordless phone a result of interference from my old wireless router? I have an old (I'd guess about 5 years) D-Link DI-514 router that says it's on 2.4 GHz. I have a set of Panasonic model KX-TGA246W cordless phones that are also on 2.4 GHz and work fine.

However, I just bought a bottom-of-the-line ($9 at Wal-Mart) Uniden phone that claims 2.4GHz. On this new phone, on some calls (but not all) I hear a constant ticking in the background... like a clock but a little faster. I've tried changing the phone's channel to no avail. It still happens on some calls. The Uniden phone is at the other end of the house from the router. One of the Panasonic phones is literally 2 feet from the router and works fine with no ticking.

Is the wireless router frequency likely the culprit for the ticking noise? If so, do I buy a new phone or a new router? I can't find many 900MHz phones anymore in stores, should I go for a 5.8GHz one if it's not too expensive? What frequency are most new wireless routers today?

Through the luminiferous aether

strangecargo — Mon, 26 Jan 2009 15:05:55 -0800

RFInterferenceFilter: This is a continuation of this question. Summarizing: I'm experiencing a loud buzzing noise in my stereo, accompanied by interference from local FM radio stations. I've done more investigation and have eliminated my power as a (direct) cause of the noise. The original post has a more detailed description/history of my problem. After some investigation with an oscilloscope, I ended up with this image of my AC power superimposed over the noisy preamp output (close-ups here and here). My working theory at the time was that the hiccups at the top and bottom of the sine wave in the AC output were causing the corresponding jumps in preamp output (which would conveniently explain 120Hz buzzing). In order to test this theory, I got my hands on an AC power regenerator and tried powering my preamp with that. The noise didn't go away (and didn't really change). In the course of scratching my head at this development, I also discovered that the noise doesn't go away when I physically unplug the preamp and allow it to run for a few seconds from only the power left in the power supply reservoir capacitors. Of course, the noise goes away when the energy in the capacitors is used up.

So now I'm left with this: 60/120Hz buzzing and FM radio interference when everything is physically isolated from my AC power (ie: preamp has been totally unplugged, driving the inputs of a laptop running from batteries). This leads me to believe that the cause of the noise is RFI/EMI, and that the hiccups in my power are not the cause of my issues, but are instead also caused by whatever is causing the noise in my preamp, which would explain why they are temporally coincident. I'm still inclined to believe that this is somehow power-related, as the hiccups and my AC power are in perfect synchronization, but nothing as simple as the line-noise-sails-through-power-supply that I had initially hoped for.

I'm an engineer, but not an electrical one; I've managed to debug this problem to this point, but I'm pretty much out of my element here. I don't understand enough of the principles at work to figure out this issue past this point or what I can do to try and fix it. Suggestions, please!

Lite Rock, Less Talk? I'd like neither, please.

strangecargo — Thu, 15 Jan 2009 00:59:16 -0800

(Electronics|Stereo)filter: What is causing this infuriating noise in my preamp and how do I fix it? Links to sound files and long list of symptoms in extended. I have this preamp and ever since moving to my current apartment in San Francisco, it generates a really loud noise that sounds like a combination of 60 Hz hum and FM radio broadcasts. The noise is loudest when the volume knob is turned all the way down, but it doesn't go away when you turn the volume up. And this is what it sounds like when you go from zero gain to full gain and back. The noises don't sound that loud when played back on a computer, but that level of noise is pretty dang loud when sent to the input of a power amp.

The maybe pertinent facts (numbered because there are a lot of them):

1. I recorded the linked sound files by plugging in the output of the preamp into the line in of a MacBook Pro. No mixing or diddling with the file other than that.

2. You can clearly hear the station identifier for KOIT in the first sound file I linked. This is an FM station. What the heck? I was under the impression that FM was way too complicated for equipment to randomly pick up unless it was designed specifically to, you know, receive FM radio.

3. Changing the vacuum tubes inside the preamp doesn't change the nature of the noise.

4. I have other audio equipment (both solid-state and tubed) that doesn't make this sort of noise.

5. The noise is generated independent of what I have connected as an input or output (or if there's anything connected at all).

6. I can't seem to reproduce this noise outside of my apartment (friends' places, hifi shops, etc). Whenever I try, the preamp is noiseless and dead silent.

7. Physically moving the preamp around my apartment doesn't seem to change the noise either.

8. I live in an old apartment without grounding in most of the electrical sockets, but the noise doesn't change if I plug the preamp into a grounded outlet. I've checked that the grounded outlets in my apartment are indeed grounded with one of these devices.

9. I live sort of near Sutro Tower (but who in SF doesn't?). Wikipedia tells me that KOIT broadcasts from Sutro Tower. I also live right next to the N Judah MUNI line. Sometimes my lights dim when it goes by. I suspect the power is probably kind of dirty.

10. Using a different power cable doesn't do anything.

11. For what it's worth, here's a look at the circuitry inside the preamp.

I've been investigating this problem on and off for the last year or so and I still haven't figured out what's causing the problem. Do any electrical engineer types have an suggestions for further testing or solutions to this problem? I have a digital multimeter and oscilloscope at my disposal for the collection of further data.

I'm quite attached to this preamp (more so when it isn't making this noise), so please don't tell me to replace it.

USB Charger Static

mccarty.tim — Sat, 06 Dec 2008 15:49:08 -0800

My car's USB adapter makes staticy noises over the radio. Should I replace it, and if so, with what? When I got my car, I bought several car adapters, including a cellphone charger and a USB adapter, both cheapie generics from eBay megasellers. The problem is that my USB charger is what I use to run my GPS (which I bought used with a bad battery and defective car charger, so I use the USB adapter to run it instead), and whenever I plug it in to the USB adapter, it creates static, or maybe somehow grounds the signal so that less of the signal comes in. Can you tell I'm not an electronic engineer? Also, if I am really close to a reasonably high power station, I get little to no effect.

It seems to be largely based on where the cable is, and I've tried it with several cables with similar results. I did try it once with a USB cable that had a barrel type thing on the end, probably meant to control RF interference, but it only helped marginally. However, it came with a camera, and it was a small barrel type thing (I know it's a bead of some material inside, but I'm not that smart...). If the cable is closer to the head unit, the static is worse, but it's not as bad with the external antenna. However, that's probably because there's a metal bar in between the cable and the antenna on my PT Cruiser, so that's probably the station there.

My cellphone charger causes some trouble when I hold it close, but I keep my charging phone in the arm rest instead of near the radio, so it has little to no effect on radio signal.

I'd like to get a new USB charger, preferably with more ports so I can charge my GPS and iPod at the same time, or perhaps a firewire port as well for faster iPod charging, if the newer ones still support it (my Nano does, but not for data). Is there a model with less of an RF sent over the cables problem? Or is this an issue with my cables or radio? I have no trouble getting smaller radio stations from farther away when the USB charger is not plugged in, so I think the antenna is probably properly installed. For what it's worth, the radio is a Chrysler 2007 PT Cruiser stock REF radio, and I'm not entirely happy with it since it has a loose AUX port on the face, but I put up with it and I'm in no rush to replace it.

I've been looking at this, this, and this. I want it to be under $15, preferably under $10, and I might ask for it as a christmas gift, so if it has a distinctive brand name or shape, that makes it easier to ask for without having to get the wrong thing or feeling bad for asking for something really specific. I'm not too big on inverters, as I'm worried they'd be expensive and I'd start abusing them for bigger things and then pop a fuse in my car. I don't really need to daisychain another car adapter, since I have two ports and only really want to charge 3 gadgets in my car (GPS, phone, iPod), and rarely all at once.

The interference does not coordinate wtih any band of the radio, and I'm only trying it with FM, as I don't like any of the AM stations.

Microwave vs. Computer, and the Microwave is winning.

sol — Sat, 28 Jun 2008 06:43:08 -0800

The kitchen computer has a little trackpad/keyboard combo that sits atop of the microwave. When the microwave turns on, the trackpad stops working. Looking for suggestions on shielding, putting a filter in line with the cable, grounding, anything to help me cook and mouse at the same time. This has been going on for a while but last night, after some extended nuking of some delicious lasagna, the computer warned me that a USB device was not functioning properly and was disabled, forcing a restart of the whole thing to get the keyboard working again.

So what to do? I know about basic electronics from fixing guitars and such, but not the RF/Magnetic interference voodoo. I'm fully prepared to crack this thing open, get into ferrite beads, soldering, grounding wires, etc. if it will help. Yes, the problem goes away if I move the keyboard a few inches away from the microwave, but the way my kitchen is set up this is really the best spot for things.

Attention Tivo customers: Mars Needs Women

bondcliff — Wed, 04 Jun 2008 07:10:48 -0800

What is the purpose of this random noise my electronics are making? I first noticed this on my Tivo. I’d be sitting around, not even watching TV, when I’d hear a short (< 2 second) burst of “morse code.” Not beeps, but sort of a muted dit-dit-doot-doot-dit-dit. This would happen about once or twice a day. I assumed the hard drive was doing some sort of self check.

Then yesterday I was in a meeting at work when I heard the exact same noise (same pattern of dits and doots, as far as I can tell) coming from one of those starfish-type speaker phones. Nobody was talking on the phone. There goes my hard drive theory. Now I’m thinking perhaps it didn’t come from the Tivo, but perhaps a speaker near the Tivo.

Last night, I heard the same thing from one of my Squeezebox players, or rather from the speakers attached to it. The player was not playing music, though both the player and speakers were powered on, or at least in stand-by.

Now that I think about it, I’m pretty sure I’ve heard this noise on other electronic devices. It's definitely a digital-type signal, as opposed to static.

What the hell is happening? Is something else causing interference? Is there a common component inside these devices that is doing this? Why is the pattern always the same? Are my electronics communicating back to the mother ship, planning the revolution?

I’d prefer a technical explanation (“These devices all use a THX1138 chip, it’s the hammerflanger module recalibrating the DRADIS.”) over a guess, and I’d love to know I’m not the only one hearing this.

Can I install aftermarket iPod interfaces into my BMW?

desjardins — Mon, 28 Apr 2008 07:39:00 -0800

I have a 2003 BMW 325i. There is a sticker on my windshield warning me that aftermarket electronics (and cell phones) may interfere with the car's electronic system. For real? The dealer says they cannot install the factory iPod interface (it's only for 2004 and later). My fiance has a 2006 BMW X3 with the factory-installed iPod interface and I am insanely jealous. DO WANT. First off, I use my (Verizon, RAZR VM3) cell phone in the car regularly (I don't use bluetooth because it wasn't installed in the car and I'm not willing to pay for it). Am I secretly destroying some electronic component? My radio gets much poorer reception than other cars driving in the same area (I had a rental car for awhile, and I ride in my fiance's car all the time). We're 70 miles from Milwaukee and 50 miles from Chicago, and he can pick up FM stations from both cities, while I get static on many of them.

I saw this and I'm salivating over the prospect of being able to control my playlists. But, I don't want to "interfere with the electronic components," and I don't want to void my warranty (MaxCare from CarMax - the BMW original warranty has expired). Will installing the product above ourselves void my warranty?

By the way, I have Monster iCarPlay for iPod and it's intermittently staticky. I've tried the Belkin versions and they suck too. If it matters, my iPod is a 2nd gen Nano (8 gb) that I have no immediate plans to upgrade.

Yes, I realize the irony of asking the AskMe example question.

Avoiding DVI interference on stereo for Macbook

tonci — Fri, 25 Apr 2008 08:43:58 -0800

Macbook- DVI question: How to avoid "hum" sound interference on stereo cable with DVI/HDMI cable hooked in? I tried connecting my Macbook from the DVI port through adaptors to an HDMI cable to hook up to my projector for the first time and the video worked great. The problem is that when I plugged in the stereo cable into the Macboo's headphone jack to plug into my stereo it picked up lots of hum-sounding interference. Any ideas on how to remedy this problem?

Cable TV weirdness

Cosine — Tue, 04 Mar 2008 09:22:15 -0800

Why is my cable TV signal acting differently and is this just me/just my provider? For the past 2-3 months I have noticed some changes to my TV signal, I have plain cable but no cable box. I'm wondering if this makes sense to anyone else.

The changes are;

1. Commercials are now much, much louder than programs; since the dawn of time this has been true but in the past few months the difference has become so great that my wife and I have to dive for the remote whenever one comes on because it blasts out as twice the volume of the show we were watching.

2. Audio/video unsynced; more and more often this is happeneing, sometimes the audio is as much as a second out of sync with the video, this seems worse on some channels than others.

3. Shows cut off at the end; more and more often shows are cut off before they finish, the most consistant one is Letterman, the last 2-4 minutes of the show are replaced with any number of other shows that I have never heard of.

4. Digital type interference; sometimes the video but most often the audio is garbled in that "digital interference" way, just for a split second at a time, the most consistant case is the first split second of each commerical or each show when it comes back from commercial, there is always a little, quick glitch of garbled audio, it's so short my wife didn't even notice it until I pointed it out.

Is anyone out there seeing any of these symptoms or am I losing my mind.. or both? Perhaps they are getting sloppy due to the looming darkening of analogue cable?

iPod + car charger = BZZZZZZ???

steveminutillo — Wed, 05 Dec 2007 12:43:33 -0800

How can I listen to and recharge my iPod at the same time in my car without the audio quality sucking? I have a 2nd generation iPod and a car with an aux input for the stereo. I can plug my iPod into this input and listen to it though the car speakers and it works great! The problem comes when I want to recharge it while listening.

First I bought a DC to AC inverter at Radio Shack, and then plugged the iPod's AC adapter into it. The iPod was able to recharge, but when I listened to music while charging a loud and annoying HUMMMMMMMMMMMMMM sound came through the car's speakers.

I thought maybe the problem had something to do with the ridiculously overcomplicated DC/AC/DC conversion, so I went for the direct route: I bought this car firewire charger. This worked a little better, but instead of a loud hum, I get a BUZZZZZZZZZ sound which seems to go up and down in frequency in sync with the engine revolutions!

So where am I going wrong? Has anybody done this without causing audible interference?

There are four bars.

M Edward — Tue, 27 Nov 2007 20:11:46 -0800

What is going on with my cellphone? I have the LG Chocolate (first release) and it's been reliable and good so far, however, the last two days the battery has lasted exactly 2 minutes.

Every time I look at it the backlight is on. I've carried this thing in my pocket for a good year and a half and never had this problem. Also, the little mp3 symbol is appearing a lot more at the top of the screen--when you play mp3's the backlight is always on--yet no mp3's are playing.

So I took it home and charged it from completely dead yesterday. I thought maybe it was from being in my pocket that somehow I was turning it off and on. So today I left it in my desk drawer all day. When I went to grab it and leave it had a blinking battery light and halfway home it turned itself off: dead battery.

I just got a new job so now I am also carrying the Blackberry 7130e and working around a lot of wireless network devices that use radio cards.

Is electrical interference making my phone do weird things? I don't have bluetooth enabled. If it is some sort of interference can it be manipulated to remotely access options on my phone? That'd be cool. Or do I just need to buy a new battery?

Do I REALLY need to take offf my iPod during takeoff?

Sheppagus — Fri, 05 Oct 2007 11:53:16 -0800

Am I going to bring down the plane if I listen to my iPod during takeoff and landing? I'm familiar with the standard flight attendant instructions to remove and stow all electronic devices to avoid "interference."

At the risk of seeming overly dense, how could my iPod interfere with anything? And if it does cause interference, why is it okay to listen to it during the flight itself, but not during takeoff or landing? I remember during the 80s getting the same warning about my cassette player, which again, didn't seem to make much sense.

Am I dooming my fellow passengers if I keep my iPod playing during takeoff and landing?

Electromagnetism vs. The BBC

boosh — Sun, 16 Sep 2007 13:55:44 -0800

TV Signal Problem: Co-axial cable suffering EM interference (I think), and it only affects the good channels! I recently built a Home Theater PC and it works perfectly except for one thing: some of the TV channels suffer from terrible interference, ranging from stuttering to total loss of signal. I'm receiving UK Freeview (from the Crystal Palace transmitter 30-odd miles away) through a Hauppauge WinTV Nova Digital Freeview PCI card. The current cabling is standard co-ax from the roof aerial, which comes into the house and runs through a couple of boosters and then through whatever el-cheapo co-ax cable came with the boosters into the TV card. The same signal also goes direct into my digital TV and provides a flawless reception. The HTPC box is tucked into a corner behind the TV cabinet.

The whole BBC output is affected (i.e. BBC 1 through 4 and News24) plus a few others (Five Life, Five US and abc1 but I'm not really bothered about them). All of the other digital channels are absolutely fine through the TV card.

However... if I pull the HTPC out of the corner, so the co-axial cable is at full stretch and away from all the other cables and power supplies, the signal problem instantly disappears, and all of the channels get a flawless reception. This leads me to think that I might be getting some kind of EM interference when all the cables are bundled up together in the corner. It's not an issue with one particular co-ax cable, as I've tested 3 different ones (although they're all the same standard quality cables).

Repositioning the unit or the route of the cable is not really an option, so I guess that I need a cable with better shielding to keep the interference out (but please correct me if I'm wrong). I've done a load of googling and come across options like 'quad shield RG-6' and 'triaxial', but what do I actually need and where can I get it in the UK? My bullshit meter always goes haywire when I browse any site selling cables and interconnects, so recommendations would be greatly appreciated.

Brand new noise coming from G5 into audio signal

lockedroomguy — Fri, 07 Sep 2007 19:47:27 -0800

I have a Mac G5 and it is connected via the analog audio output port to my stereo receiver, and a new humming buzzing just started. I connected it last week so I could play music from the G5 through my stereo speakers. It worked fine. Today there is a loud humming noise that comes through the speakers whenever the G5 is selected as the stereo input. Any other stereo input does not have the humming noise. It's definitely an electrical type noise.

It's so loud that there is no point playing the music.

If I unplug the cable from the G5 and plug it into any other audio source, the humming goes away, so it's definitely the G5. It's not interference from a nearby object, because I can put a laptop next to the G5, and use it as the audio signal, and the humming goes away.

The noise is there whether the G5 is powered on or not. I've plugged it into different electrical outlets with no change.

The noise is still there if I move the audio out cable to the headphone jack of the G5.

There is no noise when playing sound through the G5 internal speaker.

There is a common problem with the G5 Mac power supply making noise that leaks into the audio signal, but that is a problem that is inherent in the power supply, not a problem that develops over time, so I don't think that's it.

There was no problem a week ago. I can't think of anything that changed since then.

Does my iPhone hate my Sennheiser noise cancelling headphones?

kathryn — Tue, 07 Aug 2007 08:45:13 -0800

My iPhone and my Sennheiser noise cancelling headphones are not playing nicely. Periodically, I get an annoying buzzing/interference noise when I'm listening to music on my iPhone and have noise cancellation switched on. My equipment:

Brand new iPhone
Older Sennheiser noise reducing headphones, PXC 250 model
Belkin iPhone adapter

I live in NYC. I sometimes get this interference while at my desk at work. I also consistently get this noise when waiting for the train, on the subway platform. It happens 100% of the time when an oncoming subway train is approaching. If an express train passes my station, I hear a horrible, loud buzzing sound for several seconds until the train passes.

My gut reaction is that it has to do with the iPhone searching for a cellular signal. Can I make the buzzing stop?

Soundcard interference but only over KVM?

cyrusdogstar — Tue, 10 Jul 2007 18:12:31 -0800

I need help figuring out a strange audio interference issue with my computer setup, involving headphones, a KVM, and an apparent contradiction. The setup: iMac, custom-built gaming PC, nice pair of headphones, plenty of cables. Until today, I had speakers hooked up to the iMac and the headphone jacked into the PC, and everything was fine. Today, wanting to use the headphones on both machines, I bought an ioGear KVM which includes audio switching, hooked it up, and now the PC - and only the PC - is generating irritating background noise.

So, with headphones on, I have the KVM set to the iMac. The connection goes headphones -> KVM -> KVM cable -> iMac. The sound is perfect. I then switch the KVM to the PC's port, and get a decently loud background hum/buzz noise, including various additional sounds when the mouse moves, hard disk spins up, network activity, etc.

Plugging the headphones straight into the PC results in perfect quality, as before. So if it's not the sound card (or the problem would exist with the direct connection) or the KVM cabling (or the problem would exist with both machines) then what is it?

Additional caveats: I think I can rule out nearby cable interference and the sound card, as both KVM connections have other cables nearby, and the issue happens with both my onboard and expansion sound cards (but to a lesser extent with the onboard). I also recall a similar issue with other KVMs in the past.

¿¿why so trippy??

garethspor — Sun, 08 Jul 2007 16:45:43 -0800

What kind of interference-pattern phenomenon have I got going on here? My interest was piqued by that representation of Danny Hillis's Thinking Machine architecture in an old back issue of Whole Earth Review. So I plotted out some images of large grids of evenly spaced points in 3-dimensional space and found all sorts of cool (what i believe you would call) 'interference patterns.' I then applied a simple gaussian blur to the images and animated their rotation, resulting in the trippy youtube video. (all images and video in the link from the main question)

Surely I'm not the first person to play with these sorts of images? Any math/art geeks out there wanna share some information on what I've got here?

Is this substation a problem?

ascullion — Mon, 04 Jun 2007 02:17:19 -0800

I'm considering buying a house that's right beside a small electrical substation (just a small path between it and the wall of the house). Are there any risks attached to this? I'm primarily concerned about two things..

1) Health: I've read plenty of stuff over the years about the health effects of living near electrical infrastructure, but never paid enough attention to know if they were just meaningless scare stories

2) Interference: Is there any risk of interference with electrical equipment, or with tv/radio reception, or with a wireless network, for example?

In relation to the actual substation - it's quite small, total area is no more than about 8 square feet. It gives off an audible buss, but nothing that you would be able to hear from inside the house, for example.

I know it's hard to generalise with this stuff, and that I'm not giving you much info about the nature of the substation, but I don't have anymore information at this stage. Any advice appreciated.

Satellite TV Interference

booksprite — Sun, 15 Apr 2007 02:32:52 -0800

I'm thinking of getting Satellite TV (Sky+). Does anyone know how susceptible it is to interference from signals from nearby mobile phone transmitters? If there is a problem, what are the best solutions?

le monde du bruit

mykescipark — Sun, 08 Apr 2007 18:58:27 -0800

RF Filter (literally): I'm using my trusty Sony ICF-2010 shortwave radio (1990 vintage) with a brand-new Edirol R-09 digital recorder. Unfortunately, once I hook up the R-09, it spits up digital noise all over the bands. In this case, the predominant noise is like a kind of fast chuffing, a trilling, outboard motor-like sound. The sound changes its rhythmic qualities depending on whether the unit is in standby (the chuffing) or in record mode (noise bursts seemingly whenever "packets" of data are being written to the flash card). It gets softer or louder as one touches or handles the unit - at its loudest when the unit is being handled, as the body acts as a conductor. At its absolute quietest, it simply acts as a noise floor which obliterates quieter signals and makes a significant sonic fingerprint on all but the most powerful of broadcasters.

This also happened with my Sony TCD-D7 and my Sony MZR70 Mini-Disc recorder, and not just on this radio: my tank-like Kenwood R-5000 also suffered from the ill effects of these digital recorders. Whether they use moving parts and motors (DAT, MD) or flash cards (MP3), each creates a distinctive brand of hashy noise. What can one implement to stop this egregious leakage?

I've tried all of the following:

- standard, off-the-shelf in-line and snap-on RF chokes;
- making the line extraordinarily long (up to 50') and moving the recording device far away from the radio;
- using a third device (such as a mixing board, analog cassette deck, etc.) as a "middle man" to offset any direct line-in interference;
- using both devices with their respective "wall warts" and with batteries, in combinations;
- calling both Universal Radio and Grove for expert advice.

In all cases, the noise just plows on through. I'm a bit vexed that nobody in the shortwave universe has figured this out by now. I'm not terribly solder-savvy, but I'm willing to learn to find a permanently workable solution. Any bright ideas, hive mind? Specifics, if you can...