[PSES] EU - Medical device also used in homes
Members, I'm seeking opinions regarding the application of EU Directives for a device that is primarily intended for use as a medical device within physical therapy clinics and hospitals. It's clear that the MDD applies to the device and a reputable Authorized Representative company has already accepted the device and registered it within the EU. It is a very high-end and expensive exercise machine that is also offered for sale to home users (secondary market). Should the General Product Safety Directive also be applied? If so, then that would mean that the EMC Directive would also be applied. The DoC would state compliance with all three. I don't want to cloud this post with too much detail, but because it is declared not to have an 'essential performance', EMC immunity is not required per EN 60601-1-2. Only emissions. It's doesn't seem acceptable to market an electrical device to home users that hasn't had EMC immunity testing applied. Thanks in advance, Carl - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] EU - Medical device also used in homes
In message CANCKvwjd4c_D+fChmqA9mdzcn=f--6smysx40u8io94j5iv...@mail.gmail.com, dated Thu, 23 Feb 2012, Carl Newton emcl...@gmail.com writes: Should the General Product Safety Directive also be applied? If so, then that would mean that the EMC Directive would also be applied. The DoC would state compliance with all three. I think that the EMC Directive applies whether or not the GPS does. I don't see any grounds for exemption. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If 'QWERTY' is an English keyboard, what language is 'WYSIWYG' for? - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] EU - Medical device also used in homes
Medical devices are excluded from the scope of the EMCD per article 1(4) and MDD article 1(7) . Also, EN 60601-1-2, clause 5.2.2.9 a) addresses medical equipment that has no essential performance. Documentation must state that immunity testing was not performed if this is the case. I've concluded that the LVDD and EMCD should be applied to this device because it can also be sold to commercial fitness centers. At issue, however, is whether or not MDD, LVDD, and EMCD should be applied on one DoC. I received one off-line reply from a very reputable member source that believes that there should be two model numbers with separate DoCs. This has to be considered. I would appreciate any opinions on this matter. Thanks very much for all replies Carl On Thu, Feb 23, 2012 at 9:20 AM, John Woodgate j...@jmwa.demon.co.uk wrote: In message CANCKvwjd4c_D+fChmqA9mdzcn=F-**-6SMYsX40u8iO94J5iVgVQ@mail.** gmail.com f--6smysx40u8io94j5iv...@mail.gmail.com, dated Thu, 23 Feb 2012, Carl Newton emcl...@gmail.com writes: Should the General Product Safety Directive also be applied? If so, then that would mean that the EMC Directive would also be applied. The DoC would state compliance with all three. I think that the EMC Directive applies whether or not the GPS does. I don't see any grounds for exemption. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If 'QWERTY' is an English keyboard, what language is 'WYSIWYG' for? - --**--** 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 emc-p...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-**pstc.htmlhttp://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/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://listserv.ieee.org/**request/user-guide.htmlhttp://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/**listrules.htmlhttp://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] EU - Medical device also used in homes
In message CANCKvwj7BSUsPeRac1MJ=j5ljhq2q_+omdn0hp3_rb+e632...@mail.gmail.com, dated Thu, 23 Feb 2012, Carl Newton emcl...@gmail.com writes: At issue, however, is whether or not MDD, LVDD, and EMCD should be applied on one DoC. I received one off-line reply from a very reputable member source that believes that there should be two model numbers with separate DoCs. This has to be considered. I would appreciate any opinions on this matter. Yes, to properly control engineering changes (and perhaps changes to standards), you would be well-advised to have two model numbers and DoCs. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK If 'QWERTY' is an English keyboard, what language is 'WYSIWYG' for? - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
[PSES] Antenna Pattern for 2.4 GHz and 5GHz
Folks, I would like to get the antenna patterns for our 802.11 Access point Antenna's. I am looking for a Test lab in Bay Area (preferably) that has the facility to provide antenna patterns and schedule some days of test time (that is my estimate, but, we may need more/less depending on various factors). For each AP, a signal generator is connected to the antenna’s and the unit I rotated in one axis and then turned and rotated is the other axis to get the antenna pattern at the receiving antenna. I think in MIMO all the antenna’s may be energized simultaneously?. Any help in this regard is appreceiated. regards Christopher 408-470-4915 www.Aerohive.com - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Antenna Pattern for 2.4 GHz and 5GHz
Hi Christopher Check with UL CCS in Fremont, they have two antenna pattern test chambers. www.ccsemc.com Good luck, best regards Tom On Feb 23, 2012, at 1:22 PM, Christopher wrote: Folks, I would like to get the antenna patterns for our 802.11 Access point Antenna's. I am looking for a Test lab in Bay Area (preferably) that has the facility to provide antenna patterns and schedule some days of test time (that is my estimate, but, we may need more/less depending on various factors). For each AP, a signal generator is connected to the antenna’s and the unit I rotated in one axis and then turned and rotated is the other axis to get the antenna pattern at the receiving antenna. I think in MIMO all the antenna’s may be energized simultaneously?. Any help in this regard is appreceiated. regards Christopher 408-470-4915 www.Aerohive.com - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
[PSES] Wireless Telephone and Wireless Internet Clash
Hello All, We have a situation in our house. Two years ago our cable system went Chapter 7. So we signed up with an ISP that provides a wireless Internet connection. Radio and antenna are 40 feet up in the big tree out front of the house and operates at 915 MHz. The radio is connected to our router (in the basement wiring cabinet) via shielded CAT-5. The house is wired with CAT-5 in every room and all terminate at the wiring cabinet. The external power supply feeding power to the radio (POE) is located in the basement wiring cabinet right next to the routers EPS. We regularly have Internet problems, losing connection, extremely slow transfer rates, etc. It seems particularly bad between 6 and 10 pm (usually a few hours in that block of time). It is pretty consistent (almost daily). Our ISP pings every radio in the system every 15 seconds and plots the return time. Normally we run in the 10 to 20 msec range. But when it goes bad, ping times can exceed 3-5 SECONDS! Or sometimes it just cannot talk at all. Our radio power levels are always quite strong (-59 to -63 dBm), even when we cannot ping or pass data. The ISP compares my return response to another radio less than a mile away from me. Theirs is always rock steady, nary a ping over 30 msec. He showed me plots of both radio power levels and ping response times and it is very clear to me that my system is falling down a lot, to the point of not even being able to use it. The router is only a year old, the laptop is only 3 months old. We had these same problems with the old router and the old desktop too. The mains wiring is all less than 10 years old and mechanically screwed down rather than stripped and poked into the outlet, etc. I even went around to check connections and tightened some loose screws in the old part of the house two years ago. When I wired the house, I took extra care to keep good routing and separation of AC, CAT-5, and RF. All network and RF connectors are good quality and poor crimp connections were not tolerated. Everything is tight and in good order. The ISP says it is not the radio, but somehow the data is getting hosed before it can be modulated onto the carrier. He thinks it is something in my house causing the problem. He said he has seen problems before with wireless telephones, Blackberry's, motion detectors, and some other things. We do have a 900 MHz wireless telephone that is 5-7 years old. After my most recent conversation with the ISP, I decided to disconnect the 900 MHz wireless phone. I had not told the ISP and tonight he emailed me and asked what we had done. He said the system graphs had improved dramatically. Next week we are going to plug the phone back in and see if the problem repeats. My question(s) to the list are how do you explain this? Is it radiated as in two radios beating against each other or your more normal radiated EMI getting in the system hardware? Is it conducted on the mains or the network wiring? Where is the ingress occurring? Can the phone make enough EMI to trash the data getting into the radio? I will also be looking for a solution (besides trashing the phone). I have my ideas and opinions but will hold those for now. As always, I will be looking forward to the interesting comments, ideas, and solutions that come from you all. Thanks in advance for your replies. Best, Scott - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
[PSES] UL to Propose Suspension Withdrawal of UL 6500
To the List, For those of you with legacy A/V products certified to UL 6500, this may be welcome news. I learned in a phone call from UL today that a proposal to suspend the withdrawal of UL 6500 (and maybe some other standards too) will be mailed out to their clients in the next week or so. UL 6500 was planned to be withdrawn May 1, 2012. As I understand it, they will propose to suspend that withdrawal and to allow new product to continue to be certified to UL 6500 until May 1, 2013. Clients will have four weeks to provide UL comments. After that time, UL will have to decide if they actually suspend the withdrawal or not. Clients should look for that letter from UL soon. Regards, Scott - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com
Re: [PSES] Wireless Telephone and Wireless Internet Clash
Sounds like a simple fix; get a 2.4ghz or 5.8ghz cordless or 1.9ghz DECT phone. -Ken On 2/23/12, Scott Douglas sdoug...@radiusnorth.net wrote: Hello All, We have a situation in our house. Two years ago our cable system went Chapter 7. So we signed up with an ISP that provides a wireless Internet connection. Radio and antenna are 40 feet up in the big tree out front of the house and operates at 915 MHz. The radio is connected to our router (in the basement wiring cabinet) via shielded CAT-5. The house is wired with CAT-5 in every room and all terminate at the wiring cabinet. The external power supply feeding power to the radio (POE) is located in the basement wiring cabinet right next to the routers EPS. We regularly have Internet problems, losing connection, extremely slow transfer rates, etc. It seems particularly bad between 6 and 10 pm (usually a few hours in that block of time). It is pretty consistent (almost daily). Our ISP pings every radio in the system every 15 seconds and plots the return time. Normally we run in the 10 to 20 msec range. But when it goes bad, ping times can exceed 3-5 SECONDS! Or sometimes it just cannot talk at all. Our radio power levels are always quite strong (-59 to -63 dBm), even when we cannot ping or pass data. The ISP compares my return response to another radio less than a mile away from me. Theirs is always rock steady, nary a ping over 30 msec. He showed me plots of both radio power levels and ping response times and it is very clear to me that my system is falling down a lot, to the point of not even being able to use it. The router is only a year old, the laptop is only 3 months old. We had these same problems with the old router and the old desktop too. The mains wiring is all less than 10 years old and mechanically screwed down rather than stripped and poked into the outlet, etc. I even went around to check connections and tightened some loose screws in the old part of the house two years ago. When I wired the house, I took extra care to keep good routing and separation of AC, CAT-5, and RF. All network and RF connectors are good quality and poor crimp connections were not tolerated. Everything is tight and in good order. The ISP says it is not the radio, but somehow the data is getting hosed before it can be modulated onto the carrier. He thinks it is something in my house causing the problem. He said he has seen problems before with wireless telephones, Blackberry's, motion detectors, and some other things. We do have a 900 MHz wireless telephone that is 5-7 years old. After my most recent conversation with the ISP, I decided to disconnect the 900 MHz wireless phone. I had not told the ISP and tonight he emailed me and asked what we had done. He said the system graphs had improved dramatically. Next week we are going to plug the phone back in and see if the problem repeats. My question(s) to the list are how do you explain this? Is it radiated as in two radios beating against each other or your more normal radiated EMI getting in the system hardware? Is it conducted on the mains or the network wiring? Where is the ingress occurring? Can the phone make enough EMI to trash the data getting into the radio? I will also be looking for a solution (besides trashing the phone). I have my ideas and opinions but will hold those for now. As always, I will be looking forward to the interesting comments, ideas, and solutions that come from you all. Thanks in advance for your replies. Best, Scott - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: dhe...@gmail.com - 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 emc-p...@ieee.org 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:
Re: [PSES] Antenna Pattern for 2.4 GHz and 5GHz
Chris: I would be very careful about the physical and electrical setup of the access point. Although you could feed the access point’s antennas with a low-level CW signal from a signal generator, I think that the coax cables (even if you use very small diameter and very flexible coax) will have nasty effects on the antenna patterns. I would try to not use any external devices, but rather use the real signal from the access point’s intentional radiators. Now, I’m imagining this “access point” to be like a conventional wireless router, so it will have perhaps an unshielded Ethernet cable and a 2-wire small DC power cable from a wall-wart power pack. Yep, these cables will also have effects on your antenna patterns, so you will have to define a cable positioning protocol and make sure the cables don’t move around when the access point is being rotated around its axes. I’m also imagining the access point will probably not have nice isolation of its antennas from the rest of the access point (that is, plastic cases and antenna stalks that may have multiple angles of deployment). Let’s at least hope that the case doesn’t flex or twist as the access point is rotated through your measurement arc. And I assume that you only want to measure with matched polarizations. If all goes well, an ordinary spectrum analyzer can be used to monitor the amplitude. You can start with the access point sitting on a plastic tripod, and do a measurement cut 360 degrees around the Z axis. Then, you tilt by maybe 18 degrees on the X axis, and then do another 360 degree cut around the Z axis. You can do this by walking into your test chamber and just manually moving the tripod, but be very careful to not move anything else. Obviously, an automated antenna range is best, but you can substitute time for facilities. BTW, sometimes you might get better amplitude readings by setting the spectrum analyzer to zero-span and using video triggering. Also, I would prefer using a very directional measurement antenna, like a horn, so that I didn’t have to worry about sidelobe responses from a typical Biconical or Yagi. You can also spend a lot of time playing with varying positions of cables connected to the access point. If you are conservative, you might want to use the position that gives you the worst gain. OTOH, if you intend to depend on that FCC style wording (move everything around until something finally works better), then maybe you will want to use the best performance positioning combination. If you have two or three intentional RF emitters running at the same time, so long as none overload your spectrum analyzer, then you can do multiple measurements at multiple frequencies each time you move the physical position by one increment. Be prepared with a nice matrix to keep you from getting confused about what angle of which cut and which frequency you are measuring. I have done one frequency with several cuts in a half-day, so if you have two frequencies and want relatively fine data increments, then a couple of days sounds reasonable. Ed Price El Cajon, CA USA From: Christopher [mailto:cksal...@yahoo.com] Sent: Thursday, February 23, 2012 1:23 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] Antenna Pattern for 2.4 GHz and 5GHz Folks, I would like to get the antenna patterns for our 802.11 Access point Antenna's. I am looking for a Test lab in Bay Area (preferably) that has the facility to provide antenna patterns and schedule some days of test time (that is my estimate, but, we may need more/less depending on various factors). For each AP, a signal generator is connected to the antenna’s and the unit I rotated in one axis and then turned and rotated is the other axis to get the antenna pattern at the receiving antenna. I think in MIMO all the antenna’s may be energized simultaneously?. Any help in this regard is appreceiated. regards Christopher 408-470-4915 www.Aerohive.com - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher j.bac...@ieee.org David Heald dhe...@gmail.com -
Re: [PSES] Wireless Telephone and Wireless Internet Clash
Scott: My first guess would be that your phone is desensitizing the receiver in the modem in your tree. Since you have found interaction between your phone and the data link, you could either get a phone on a different frequency (further away from the 900 MHz link), or you could try to improves the link's RF budget. Do you really need the link in the tree? Could you get by with less coax and put the antenna on the peak of your roof? And maybe then the antenna won't have to look through wet foliage too? Less problems from squirrels and birds too. Ed Price El Cajon, CA USA -Original Message- From: Scott Douglas [mailto:sdoug...@radiusnorth.net] Sent: Thursday, February 23, 2012 7:57 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: [PSES] Wireless Telephone and Wireless Internet Clash Hello All, We have a situation in our house. Two years ago our cable system went Chapter 7. So we signed up with an ISP that provides a wireless Internet connection. Radio and antenna are 40 feet up in the big tree out front of the house and operates at 915 MHz. The radio is connected to our router (in the basement wiring cabinet) via shielded CAT-5. The house is wired with CAT-5 in every room and all terminate at the wiring cabinet. The external power supply feeding power to the radio (POE) is located in the basement wiring cabinet right next to the routers EPS. We regularly have Internet problems, losing connection, extremely slow transfer rates, etc. It seems particularly bad between 6 and 10 pm (usually a few hours in that block of time). It is pretty consistent (almost daily). Our ISP pings every radio in the system every 15 seconds and plots the return time. Normally we run in the 10 to 20 msec range. But when it goes bad, ping times can exceed 3-5 SECONDS! Or sometimes it just cannot talk at all. Our radio power levels are always quite strong (-59 to -63 dBm), even when we cannot ping or pass data. The ISP compares my return response to another radio less than a mile away from me. Theirs is always rock steady, nary a ping over 30 msec. He showed me plots of both radio power levels and ping response times and it is very clear to me that my system is falling down a lot, to the point of not even being able to use it. The router is only a year old, the laptop is only 3 months old. We had these same problems with the old router and the old desktop too. The mains wiring is all less than 10 years old and mechanically screwed down rather than stripped and poked into the outlet, etc. I even went around to check connections and tightened some loose screws in the old part of the house two years ago. When I wired the house, I took extra care to keep good routing and separation of AC, CAT-5, and RF. All network and RF connectors are good quality and poor crimp connections were not tolerated. Everything is tight and in good order. The ISP says it is not the radio, but somehow the data is getting hosed before it can be modulated onto the carrier. He thinks it is something in my house causing the problem. He said he has seen problems before with wireless telephones, Blackberry's, motion detectors, and some other things. We do have a 900 MHz wireless telephone that is 5-7 years old. After my most recent conversation with the ISP, I decided to disconnect the 900 MHz wireless phone. I had not told the ISP and tonight he emailed me and asked what we had done. He said the system graphs had improved dramatically. Next week we are going to plug the phone back in and see if the problem repeats. My question(s) to the list are how do you explain this? Is it radiated as in two radios beating against each other or your more normal radiated EMI getting in the system hardware? Is it conducted on the mains or the network wiring? Where is the ingress occurring? Can the phone make enough EMI to trash the data getting into the radio? I will also be looking for a solution (besides trashing the phone). I have my ideas and opinions but will hold those for now. As always, I will be looking forward to the interesting comments, ideas, and solutions that come from you all. Thanks in advance for your replies. Best, Scott - 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 emc-p...@ieee.org 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://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas emcp...@radiusnorth.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher:
