I'm guessing most people wouldn't even know to complain these days if theirs or their neighbors dishwasher started interfering with their TV or radio.
And TV's with their cable/internet/satellite connections and FM/satellite radios are a lot more immune to that stuff as well than 40 years ago. So I wouldn't be surprised if the rules don't change either. Bigger fish to fry as they say. -Dave -----Original Message----- From: Ted Eckert [mailto:[email protected]] Sent: Wednesday, August 27, 2014 9:14 AM To: [email protected] Subject: Re: [PSES] construction machinery in USA The rules made sense when they were drafted. Forty years ago, a dishwasher wouldn't have digital electronics and it would be unlikely to cause interference in receivers located more than a few meters away. The same dishwasher would be very loud during operation and you wouldn't be able to listen to the radio or TV in the kitchen where that dishwasher was operating. This was the rationale for many home appliances. The rules just haven't kept up with the changes. We now have appliances full of digital electronics and they make very little acoustic noise when operating. However, unless there are a lot of complaints to the FCC, the rules likely won't change. The United States has a history where people in denser residential environments, where you are more likely to be affected by a neighbor's appliance, are in larger cities where most commercial radio and television transmitters have stronger signals. In areas with fringe reception, people historically lived in single family housing that was spread out. The risk of being affected adversely by somebody else's appliance was lower. If my understanding of history is correct, we may even have the existence of the 2.4 GHz ISM band due to radiated emissions from microwave ovens. They operate at 2.4 GHz, and the early versions were a bit leaky. I've heard that this frequency was so polluted with noise in residential environments that it wasn't adopted by anybody for a specific purpose leaving it open to ISM applications. Ted Eckert Compliance Engineer Microsoft Corporation [email protected] The opinions expressed are my own and do not necessarily reflect those of my employer. -----Original Message----- From: Jim Hulbert [mailto:[email protected]] Sent: Wednesday, August 27, 2014 4:59 AM To: [email protected] Subject: Re: [PSES] construction machinery in USA A sidebar here. FCC Rules also exempt "A digital device utilized exclusively in an appliance, e.g., microwave oven, dishwasher, clothes dryer, air conditioner (central or window), etc.". These devices not only can be operated but are expected to be operated in residential areas. Rules don't always make sense. Jim Hulbert -----Original Message----- From: T.Sato [mailto:[email protected]] Sent: Wednesday, August 27, 2014 6:20 AM To: [email protected] Subject: Re: [PSES] construction machinery in USA On Wed, 27 Aug 2014 00:26:23 +0000, Ted Eckert <[email protected]> wrote: > The FCC is generally not concerned with unintentional emissions from > construction machinery. The general assumption is that a susceptible > receiver would not be operating in close proximity to the construction > equipment. It may no longer be a correct assumption, but that is the > basis. It will likely be true in some cases. I can't imagine a > Caterpillar 797 operating in a residential area. However, smaller > pieces of machinery might be used closer to susceptible receivers. The > rules have not kept up with technology and they are based on a time > when the most significant ignition source in a vehicle was the > distributor and when digital electronics did not exist in construction > equipment. Actually I guess so, but couldn't find the fact and the rationale. I also sent an inquiry about this to FCC, but had no response at this time. > The general assumption is that a susceptible receiver would not be > operating in close proximity to the construction equipment. It may no > longer be a corre ct assumption, but that is the basis. It will likely > be true in some cases. I can't imagine a Caterpillar 797 operating in > a residential area. However, smal ler pieces of machinery might be > used closer to susceptible receivers. The rul es have not kept up with > technology and they are based on a time when the most significant > ignition source in a vehicle was the distributor and when digital > electronics did not exist in construction equipment. Well, in the good old days, heavy machines were driven by diesel engines with no ECU, those arms were driven by oil pressure through manual valves and they usually don't have any electronic circuit, so I risk of EMC problems should negligible. However, these days, heavy machines may be equipped with electric/ electronic circuit including microprocessors, control circuits, inverter driven electric motors, sensors, etc., which can cause electromagnetic emission/immunity problems. Also, such heavy machines (smaller ones, if not Caterpillar 797!) may be used also in/near residential areas. General vehicles are still explicitly exempted by 47 CFR 15.103(a) and industrial machines are usually exempted by 47 CFR 15.103(b), but I couldn't find any exemption applicable to heavy machines in general. This raise me the question. > That being said, I'm not an expert in automotive EMC and I encourage > anybody with better information to amend or correct what I have > stated. (I would also like to know how you would run testing on a > Caterpillar 797. I don't think it would fit in many chambers.) If international standards are accepted, I think we can measure those emissions with CISPR 12 test method. Regards, Tom -- Tomonori Sato <[email protected]> URL: http://homepage3.nifty.com/tsato/ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> ________________________________ - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
