Why you should never let anyone in your shop alone - Page 1
Forum section: electronics / general

author: Planobilly
author_rank: Regular Contributor
timestamp: September 03, 2016, 01:49:49 am
content: I finished the new build of a tube amp and a day or two later I turned the volume up and noticed it was oscillating. I worked for hours looking for the cause of the issue. After a while I looked like this...lolA few days before AT&T installed a new internet router in my shop. They placed it under my workbench. I was not there at the time.I finally found the router was the cause of all this greif. What a pain in the butt!!The lessons learned were don't doubt yourself, if you know you did stuff right and rechecked your work then look for some other cause to the issue. Don't let anyone in your shop alone!!Cheers,Billy

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2016, 01:54:20 am
content: That might suggest it doesn't meet EMI standards. Does it affect anything else close?

author: Planobilly
author_rank: Regular Contributor
timestamp: September 03, 2016, 02:05:49 am
content: Not after I killed it with my 12 gauge shot gun...lolJust joking. I have not done any investigation yet but it will get moved somewhere else. I am not sure what the FCC standards for a router are.Billy

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2016, 02:08:06 am
content: Quote from: Planobilly on September 03, 2016, 02:05:49 amIs it a combo LAN and wireless unit ?

author: jmctech
author_rank: Contributor
timestamp: September 03, 2016, 02:11:28 am
content: The WiFi radio in some of the routers AT&T uses will cause an audible clicking noise in speakers also. I work for them, I have had to move a few routers for interference issues.Sent from my SAMSUNG-SM-N920A using Tapatalk

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2016, 02:14:48 am
content: Quote from: jmctech on September 03, 2016, 02:11:28 amHow do you get away with installing devices that can do that?

author: jmctech
author_rank: Contributor
timestamp: September 03, 2016, 02:15:59 am
content: I have no clue I wondered the same thingSent from my SAMSUNG-SM-N920A using Tapatalk

author: jmctech
author_rank: Contributor
timestamp: September 03, 2016, 02:22:05 am
content: Which model is the modem that you have, I assumed it is the WiFi radio that causes the interference, most of the power supplies for our modems are linear, but they might have smps in the modem causing the problem.Sent from my SAMSUNG-SM-N920A using Tapatalk

author: helius
author_rank: Super Contributor
timestamp: September 03, 2016, 02:50:12 am
content: Quote from: tautech on September 03, 2016, 02:14:48 amFor some reason the $3T GSM industry hasn't been shut down yet. I blame corrupt regulators.

author: Ampera
author_rank: Super Contributor
timestamp: September 03, 2016, 06:33:41 am
content: Over in Albany area we have FiOS who also did their own wireless routers.When the people were there installing it the first thing we did was disable the modem's inbuilt router and used our own.Rn we have 2 DIR-655 routers and a wireless AP.And surprising enough our wireless network kinda sucks. 2.4 Ghz networking is stupid. I am aware as to why it's used, being FCC sanctioned for consumer use, but the 5.8 Ghz band has a ton more stable channels and supports faster 802.11 speeds.

author: CM800
author_rank: Frequent Contributor
timestamp: September 03, 2016, 06:39:20 am
content: Would it have much effect reporting it to FCC?

author: Ampera
author_rank: Super Contributor
timestamp: September 03, 2016, 06:48:28 am
content: Quote from: TCWilliamson on September 03, 2016, 06:39:20 amMaybe, but probably not. Like most US divisions they don't do a whole load of case by case stuff and focus more on major issues. If this is major? Idk.

author: tggzzz
author_rank: Super Contributor
timestamp: September 03, 2016, 07:54:40 am
content: Quote from: tautech on September 03, 2016, 02:14:48 amProbably because the transmitter is operating correctly, within specification and without generating EMI.The principle is that RF is picked up by a wire near the audio system's input, and is rectified by a non-linear device such as a "rusty bolt" or a semiconductor junction. For a constant power RF signal, the result is a constant DC shift, which won't be heard. For a pulsed signal, the shift will be pulsed and that will be amplified and heard.Classic example: the 217Hz ba-de-ba-de-ba-de-bzzzzz from a GSM cellphone near an old deafaid (absolutely deafening), or by any microphone such as another phone.The audio interference falls off as somewhere between r4and r8.

author: Howardlong
author_rank: Super Contributor
timestamp: September 03, 2016, 07:55:46 am
content: Although I am not casting aspersions one way or the other, the balanced approach is to consider not only the intentional radiator's EMC, but also the EMC of the affected device.I am sure there are many radio hams on this forum who have operated entirely legally, even on low power, who have at times unintentionally interfered with their own and their neighbours' electronics. Whether that is to do with the affected devices themselves, or, for modern consumer electronics, more often the installation itself, it can take some time to resolve, and needs a large dose of diplomacy.Having your average cellphone anywhere near many particularly older consumer audio devices and landline phones causes clicks that we've all heard for example.The natural reaction is understandably always to blame "what's changed", but sometimes the story isn't always as black and white as that.Maybe the router is at fault, or maybe that tube amp needs a little attention spent on EMC!

author: tggzzz
author_rank: Super Contributor
timestamp: September 03, 2016, 07:56:41 am
content: Quote from: helius on September 03, 2016, 02:50:12 amThat's mistaken. Blame physics and improperly shielded audio equipment.See my previous message for the explanation.

author: tggzzz
author_rank: Super Contributor
timestamp: September 03, 2016, 07:59:12 am
content: Quote from: CM800 on September 03, 2016, 06:39:20 amAbsolutely none whatsoever. The problem is inadequately shielded audio equipment rectifying and then amplifying pulses of RF energy.

author: tautech
author_rank: Super Contributor
timestamp: September 03, 2016, 08:04:14 am
content: Quote from: tggzzz on September 03, 2016, 07:54:40 amYes of course.My old iPhone 4S interferes with the audio on my PC when close to it, normally when it's hand shaking to my cell provider just before a call or text arrives. Thanks excusable IMO but for a permanently installed modem I'm not so sure. Yeah, the junction example you provide, well that's almost impossible to prevent except to move stuff away.

author: VK5RC
author_rank: Unknown
timestamp: September 03, 2016, 12:18:22 pm
content: Transmitting 7Mhz at about 50W with my transmissions all 'by the book' (in terms of harmonic suppression etc) I could open my neighbours garage door (and close it fortunately). Luckily he was out at the time. Never went on 7MHz again until I moved. Diplomacy always wins.Lots of gear is not well RFI hardened esp the older or cheaper stuff.Plasma TVs/crappy SWPSUs are deafening in RF terms often.

author: madires
author_rank: Super Contributor
timestamp: September 03, 2016, 01:12:26 pm
content: Quote from: TwoOfFive on September 03, 2016, 06:33:41 amI wouldn't use D-Link's WLAN stuff. It simply sucks, even the more expensive "professional" stuff. Better get a TP-Link supported by OpenWrt. Much better and stable.

author: Planobilly
author_rank: Regular Contributor
timestamp: September 03, 2016, 02:06:49 pm
content: For me the answer to the issue is simple, just relocate the router. I am sure it will interfere with my scope and perhaps other equipment.In hindsight, I should have moved the amp to another location. I did turn off the lights and the computer system. I have built and worked on many amps in this location without issue in the past. When starting up a new amp build for the first time, there is always the possibility of discovering issues with the build.Not realizing the router was even there was the real issue. Normally, if I have some issue with an amp I am able to come to the solution pretty quickly. It is much easier to find a fault than come to the conclusion that everything is correctly built.Tube amps are notorious for doing strange things and the causes are sometimes not so easy to find. I guess that fact had me running around in circles a lot longer than normal.Billy

author: Ampera
author_rank: Super Contributor
timestamp: September 03, 2016, 02:38:35 pm
content: Quote from: madires on September 03, 2016, 01:12:26 pmThe original DIR-655 802.11 N router was purchased by my dad who installed it to replace a god awful 802.11G router.And yea, I know. But I got the second DIR-655 free from someone who said it broke (It didn't)And while I would love to do so, routers aren't the sorta thing you can just get up and replace.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 03, 2016, 03:34:38 pm
content: Put the router in the microwave.If the radio waves penetrate the device then it must not be FCC compliant, thus solving your problem.

author: Ampera
author_rank: Super Contributor
timestamp: September 03, 2016, 04:41:14 pm
content: Good idea, but how do you plug it in?Unless you mean to make a router panini.

author: System Error Message
author_rank: Frequent Contributor
timestamp: September 03, 2016, 06:46:13 pm
content: i replaced all my networking equipment with my own, the modem, router, etc. When i replaced the ISP router with my own i lost 2ms of internet latency and thats significant. The router was very basic and seemed like it was well designed but it seems to have higher latencies than my modded 36 core router.I've heard of the horrors of american telecoms like at&t and other providers. Cable ISPs are usually greedy giving you really bad upload-download ratios. If in the UK Virgin media is a prime example advertising a 10-1 ratio but in practice it is 20-1 in order to keep you content happy but unable to properly utilise the network for your own use like your own vpn, file and other services that routers nowadays support.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 03, 2016, 07:13:45 pm
content: Quote from: System Error Message on September 03, 2016, 06:46:13 pmI have absolute shit internet, like 0.1MBs both ways. That's why I can't do youtube, I can barely play online games. Idk how much we pay for it though.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 03, 2016, 07:39:35 pm
content: For services that do intentional emission (e.g. WiFi, GSM, Dect) the power levels are quite high near the source. So it is not uncommon to see (or hear) interference, even with good quality gear. For example I have a Sony digital radio that pics up some signal form a neat by (e.g. < 0.5 m) GSM Phone, quite loud. My 1.st mobile phone (GSM based) even picked up some military radio signals - even when not making a call, when to close - so did the radio in the car. Must have been quite a strong signal.As the sending power is usually well checked, it is more likely that the audio amplifier is at fault and pics up more than it should be. It may also be that they are just to close together and interference is normal at this close range. So both units could be within EMC specs but just to close together.

author: Ampera
author_rank: Super Contributor
timestamp: September 03, 2016, 08:27:27 pm
content: Quote from: System Error Message on September 03, 2016, 06:46:13 pmAmerica is a big place. Bigger than the entire EU 2,3 or even 4 times over. To say the internet sucks anywhere in the US or to even generalize us is like saying internet everywhere in the EU sucks.I live in the Albany area of NY and we are a shithole compared to what we were. Albany has nothing in it, Schenectady has the open wound GE made when they left us and troy is a damned ghetto.And yet Verizon telecoms provides 90/90 Up down direct attach fiber with VoIP service and cable TV including some Clear QAM service for I think around 120-150 USD a month. That is pretty damned ace if you ask me. And in some places you can get Gigabit INTERNET for about the same price with FREE INCLUDED VoIP service and a 4 Tuner DVR from Google Fiber even though it's only in certain more southern cities.If you can get fiber, it's probably gonna be pretty good, but DSL/Cable TOTALLY sucks. You will get bottom rank speeds, no real upload, and unreliable service for a lot of money from people like TWC, who thenblast you when your contract is over. I seriously got about 24 Mbps down with them and an even sadder upload until FiOS came on the scene with blazing fast service.So really it depends on who you are, where you buy it, what year it is, and where you live, just like in Europe. However on a recent trip to Waldbrol, Germany to visit family, we had pretty good internet from T, so idk.

author: G7PSK
author_rank: Super Contributor
timestamp: September 03, 2016, 08:45:42 pm
content: In the good old days valve (tube) amplifiers were always in a metal box very often with the valves in their own metal can, all well earthed to boot, unlike the modern craze to have all the valves out in the open.

author: Nerull
author_rank: Frequent Contributor
timestamp: September 03, 2016, 09:54:40 pm
content: I'm curious how people expect a radio to work without emitting radio waves.If your tube amp picks up 2.4GHz transmissions and turns them into audio, that's really not the routers fault.

author: Planobilly
author_rank: Regular Contributor
timestamp: September 04, 2016, 07:11:36 pm
content: If you want to talk about who is at fault then it is simple. I am! I ordered the internet service. I did not supervise the installation of the the equipment in my shop. I built the amp in question. I lacked the skill set to find the answer to the issue in a short period of time. I did not provide sufficient shielding to prevent such issues.I take responsibility for events in my life and I am not dependent on governmental regulatory agencies to protect me. The "blame game" is seldom useful in dealing with issues. This idea that we should have cradle to grave protection provided by the various governments is counter productive at best in my less than humble opinion. At worst that idea provides for a false sense of security that can cause issues that are much more problematic that some frustration dealing with an amp issue.Perhaps because I have flown aircraft all over the planet and sailed boats single handed across oceans I have a different perspective on " who is at fault".Many products and services we buy in today's world are significantly less that perfect. For me to have the expectation that things I buy will always meet the regulatory requirements is uninformed at best.I learned a few new things while dealing with this issue. I would have prefered to get that education in a less painful way but such is life....lolCheers,Billy

author: VK5RC
author_rank: Unknown
timestamp: September 05, 2016, 12:12:58 pm
content: Gheeesz , if my internet speed was better my daughters would download even MORE, I couldn't afford it ! HiHi.With three teenager daughters, my shed/shack/lab is essential, it is not that infrequent my wife asks if she can join me out there!

author: System Error Message
author_rank: Frequent Contributor
timestamp: September 05, 2016, 01:04:34 pm
content: Quote from: VK5RC on September 05, 2016, 12:12:58 pmNot to mention you will need more storage to download more too

author: Jeff_Birt
author_rank: Regular Contributor
timestamp: September 05, 2016, 01:54:54 pm
content: The cable guy came and installed a new, faster, cable modem a few months ago. The old unit was the size of a book, the new unit is the size of a 1990's VCR! It blocks the RDP port and they won't admit the problem and I finally got tired of dealing with them and use a different program to remote in (which is not as nice as what is built into Windows).

author: System Error Message
author_rank: Frequent Contributor
timestamp: September 06, 2016, 01:15:09 pm
content: Quote from: Jeff_Birt on September 05, 2016, 01:54:54 pmYou can buy modems for cable. Netgear sells decent ones but the prices may not be to your liking. As long as it supports the configs used by your ISP you can use a different modem. There have been SFP modules for cable as well which is helpful to people like me who have really nice routers but i dont use cable because of their greed (here in UK virgin media has some weird speed management so if you download loads in a small amount of time your speed is throttled. their uploads are only half as claimed.)Here in UK even though BT only sells half of what virgin media offers with the same advertised uploads, but virgin media's upload speeds are half of claimed making BT's VDSL offering having 2x better upload. That upload to download ratio is very important as its a measure of how much can you actually utilise your own internet (like hosting your own personal vpn and file server on the router, streaming games) rather than being a content consumer only.

author: madires
author_rank: Super Contributor
timestamp: September 06, 2016, 01:54:09 pm
content: We all love those "x Mbps*" ads, with the "*" meaning "up to, if you're lucky".

author: rdl
author_rank: Super Contributor
timestamp: September 06, 2016, 03:23:03 pm
content: The monthly lease charge in this area for a modem from Comcast is about $8, but you can buy a modem for less than what a year of leasing will cost. That's what I call a "no brainer". I actually paid less than $70 for a Motorola (now Arris) SURFboard at the local Walmart store.

author: AG6QR
author_rank: Frequent Contributor
timestamp: September 06, 2016, 04:30:49 pm
content: Others have addressed the technical side, but legally, the router is almost certainly certified under part 15 of the FCC rules, and it probably carries a sticker on the bottom that says:"This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation."That means that, legally, part 15 devices are very low on the totem pole. If there are problems, the legal solution is to stop using the part 15 device unless and until the owner of the Part 15 device resolves the problem technically, perhaps by going back to the manufacturer. If it causes harmful interference, the owner of the device must shut it down and not operate it until the cause of the interference is corrected. If it receives interference that causes it to malfunction, the owner has to deal with it or shut it down -- the owner can't demand that the other device be shut down, or somehow reduce or eliminate the emissions that are causing the interference.When you are the owner of both the interfering device and the device receiving interference, this legality is pretty much moot. You can decide which device to shut down until the problem can be dealt with technically. It becomes more relevant when a Part 15 device has a conflict with a neighbor's device operating under a different part of the regulations, such as a ham radio station, or a business band radio, or a broadcaster, etc.

author: Planobilly
author_rank: Regular Contributor
timestamp: September 07, 2016, 04:57:17 am
content: Actually, this little RFI monster I now own will be a fun toy to play with. I have several friends who own several high dollar boutique guitar amps. They are entirely way too enamored of their expensive toys. They bring them over often singing the praises of their super cool stuff. Time to take them down a notch or two...lolNext time they come over I will have the router hid and point out how their high dollar amp really sounds like crap...lol Well...yes I know that is a diabolical plan but if you knew these guys you would surely see the humor in my plan...I feel pretty lucky actually. Not everyone has his own nefarious RFI generator...Cheers,Billy

author: Ampera
author_rank: Super Contributor
timestamp: September 07, 2016, 05:12:44 am
content: Quote from: Planobilly on September 07, 2016, 04:57:17 amIf you want to take it up a notch make an RFI generator and hide it in their house. Best prank ever.EDIT: Make sure they have a non RF phone or you have a way to turn it of remotely in an instant so if he needs to call 911/999/112 he is safe.