Re: [PSES] Wireless Telephone and Wireless Internet Clash
Scott The ISP says it is not the radio, but somehow the data is getting hosed before it can be modulated onto the carrier. They should be able to run some better remote diagnostics than that guess. Your received signal level isn't varying (and if it does it is nothing to do with what's in your house) - I suspect the signal-to-noise ratio is though - ask them if they can monitor that remotely. I think that you've identified the likely culprit as being you wireless telephone - but I'm wondering why it's behaviour changes for a few hours every evening? - is it just when someone's talking on it? The carrier's test should be just between their base station and your mast-head unit. Can you ping the masthead unit? Regards Charlie -Original Message- From: Scott Douglas [mailto:sdoug...@radiusnorth.net] Sent: 24 February 2012 03:57 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:
Re: [PSES] Antenna Pattern for 2.4 GHz and 5GHz
Is this test done in an semi-anechoic or full-anechoic setup and typically what is the distance between antennas? Is the receive antenna at one height or is it similar to site attenuation or antenna calibration? If one height, what is typical? I’ve never none this test before but I’ve always wanted to play around with it. The Other Brian From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ed Price Sent: Friday, February 24, 2012 1:16 AM To: emc-p...@ieee.org Subject: 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.ORGmailto: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.comhttp://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.orgmailto: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
Re: [PSES] Antenna Pattern for 2.4 GHz and 5GHz
Brian This test is typically done in a fully anechoic chamber with antennas aligned and near centre axis of chamber. Separation distance of 3-4 metres would be typical. Ideally the device under test is completely isolated on a non-conductive mount, but if you need to feed a signal to the EUT for test or calibration purposes then use a narrow co-ax cable that is loaded with ferrite sleeve. Equipment that needs to be in a radiated link to be exercised is typically configured so that its link is via one, or more, antennas that are on a plane perpendicular to the central axis. Regards Charlie From: Kunde, Brian [mailto:brian_ku...@lecotc.com] Sent: 24 February 2012 13:44 To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Antenna Pattern for 2.4 GHz and 5GHz Is this test done in an semi-anechoic or full-anechoic setup and typically what is the distance between antennas? Is the receive antenna at one height or is it similar to site attenuation or antenna calibration? If one height, what is typical? I’ve never none this test before but I’ve always wanted to play around with it. The Other Brian From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ed Price Sent: Friday, February 24, 2012 1:16 AM To: emc-p...@ieee.org Subject: 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.ORGmailto: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
Re: [PSES] EU - Medical device also used in homes
One of the large international (and NRTL) compliance labs is telling me that including the MDD, LVD, and EMCD on one DoC with one model number is the correct procedure in this case. I've researched this question in the Blue Book and I find this on page 35: Where several New Approach directives apply to a product, the manufacturer or the authorised representative can, basically, merge all the declarations into a single document. However, this is not possible if the directive provides for a specific form of the EC declaration of conformity (such as the Directive relating to personal protective equipment). Consequently, the EC declaration should also provide information on whether or not it covers only one directive. In such a case the declaration should include a reference to other directives in order to verify whether the manufacturer has followed all the Community legislation, or which legislation has been chosen during the transitional period. I don't believe that the MDD is requiring a specific type of DoC. Open to other opinions, of course. That said, I believe that the Blue Book supports the view that I can apply MDD, LVD, and EMCD to a product like this on one DoC. I can explain it in my 'Supplementary information' section. Carl On Thu, Feb 23, 2012 at 12:22 PM, John Woodgate j...@jmwa.demon.co.ukwrote: In message CANCKvwj7BSUsPeRac1MJ=J5LJhq2**q_+oMdN0HP3_rB+e632XtQ@mail.** gmail.com j5ljhq2q_%2bomdn0hp3_rb%2be632...@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.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
[PSES] optoisolators
Group, I would like to get some input on how 60950-1 people and others deal with 60950-1 2.10.5.4 Semiconductor devices: optoisolators We are dealing with the issue of option a) vs option b) to show compliance. The end goal is to identify that the component satisfies the following, a) - passes the TYPE TESTS and inspection criteria of 2.10.11; and - passes ROUTINE TESTS for electric strength during manufacturing, using the appropriate value of the test voltage in 5.2.2; or b) for an optocoupler only, complies with the requirements of IEC 60747-5-51), where the test voltages as specified in 5.2.6 (of IEC 60747-5-5): - the voltage V ini,a for TYPE TESTING and - the voltage V ini,b for ROUTINE TESTING, shall be the appropriate value of the test voltage in 5.2.2 of this standard. We do a routine electric strength test, and the parts are certified to standards older than IEC 60747-5-5. Experience on what option is being used in industry may give me some additional direction. Appreciate your input, as always. James Goedderz Sr. Principal Engineer-Product Safety Sensormatic Electronics, LLC 561.912.6378 Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of the company. This email and any attachments are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the sender immediately and delete any copies in your possession. - 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 CANCKvwj7_oiKDX=e7_q6q9j4g3v6v_zo7_gkkfy5+owbsbt...@mail.gmail.com, dated Fri, 24 Feb 2012, Carl Newton emcl...@gmail.com writes: One of the large international (and NRTL) compliance labs is telling me that including the MDD, LVD, and EMCD on one DoC with one model number is the correct procedure in this case. I've researched this question in the Blue Book and I find this on page 35 But you haven't got ONE product; you have two, one to which requirements for immunity have been applied and one to which they have not. They are also aimed at different markets. Consider that having two DoCs means one extra document among thousands associated with the products. -- 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] optoisolators
On 2/24/2012, Jim Goedderz wrote: I would like to get some input on how 60950-1 people and others deal with 60950-1 2.10.5.4 Semiconductor devices: optoisolators We are dealing with the issue of option a) vs option b) to show compliance. The end goal is to identify that the component satisfies the following, a) passes the TYPE TESTS and inspection criteria of 2.10.11; and passes ROUTINE TESTS for electric strength during manufacturing, using the appropriate value of the test voltage in 5.2.2; or b) for an optocoupler only, complies with the requirements of IEC 60747-5-51), where the test voltages as specified in 5.2.6 (of IEC 60747-5-5): the voltage V ini,a for TYPE TESTING and the voltage V ini,b for ROUTINE TESTING, shall be the appropriate value of the test voltage in 5.2.2 of this standard. Hi Jim: I believe that most designers simply choose an opto that already has appropriate approvals at the component level. That allows the manufacturer to avoid doing additional testing of the component. There are two types of opto approvals that will achieve this: 1) Optos that provide at least 0.4 mm thickness of solid insulation between the input and output, and have the requisite external creepage and clearance spacings on the opto package. In other words, they fully comply with the requirements for Supplementary or Reinforced insulation. This is the option that I prefer. 2) Optos that do not provide at least 0.4 mm thickness of solid insulation between the input and output, but have been tested by the manufacturer to comply with one of the options in clause 2.10.5.4. Either way there will likely be a routine electric strength test in production, but that is usually required anyway as a test for the overall isolation barrier in the product (not just the opto). Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) j...@randolph-telecom.com http://www.randolph-telecom.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
HI Scott, We had to move a 2.4 GHz cordless phone away from a nearby router and that solved a plethora of problems in our home. We then replaced that phone with a 900 MHz cordless oldie-but-goodie phone and the problems did not reappear. Good Luck, Art == On Thu, 23 Feb 2012, Scott Douglas 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:
Re: [PSES] Wireless Telephone and Wireless Internet Clash
metageek.net - inSSIDer and related h/w stuff; source at https://github.com/metageek-llc/inSSIDer-2 Assume that this is in North America which will be considered unlicensed ISM, so much @915MHz - zigbee, any 802.15.4 stuff(wireless mesh networking), weather station sensors, bluetooth, speacil weather radars, RFID, space alien zombie mind control base stations, etc. If there is mil in your area, may be tactical relay network (not certain if UL mil will deploy these system in CONUS at 915M). Brian -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of Arthur Michael Sent: Friday, February 24, 2012 10:32 AM To: Scott Douglas Cc: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Wireless Telephone and Wireless Internet Clash HI Scott, We had to move a 2.4 GHz cordless phone away from a nearby router and that solved a plethora of problems in our home. We then replaced that phone with a 900 MHz cordless oldie-but-goodie phone and the problems did not reappear. Good Luck, Art == On Thu, 23 Feb 2012, Scott Douglas 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/
Re: [PSES] Compliance engineering contacts at Plextor and Netgear
Dear All, Contact made to the relevant compliance people in Netgear and Plextor. Thanks for all your suggestions of where to look! Have a great weekend! Edward Quoting Mark Gandler markgand...@hotmail.com: Netgear: here here. Please take me off the February 21st most wanted list. Ed, just spoke to your colleague, help is on the way, just sign the NDA. BTW, getting these type of requests for test reports and certs are pretty common. Usually doesn't involve Interpol search, simple phone call to the front desk does the trick. Mark Gandler Netgear - 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
Re: [PSES] Wireless Telephone and Wireless Internet Clash
Other stuff was on my mind. sales engr - just read your post. me - so? sales engr - UL has a military branch? me - uh no, but they do run the secret labs for the space aliens. -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of Brian Oconnell Sent: Friday, February 24, 2012 12:25 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: [PSES] Wireless Telephone and Wireless Internet Clash metageek.net - inSSIDer and related h/w stuff; source at https://github.com/metageek-llc/inSSIDer-2 Assume that this is in North America which will be considered unlicensed ISM, so much @915MHz - zigbee, any 802.15.4 stuff(wireless mesh networking), weather station sensors, bluetooth, speacil weather radars, RFID, space alien zombie mind control base stations, etc. If there is mil in your area, may be tactical relay network (not certain if UL US mil will deploy these system in CONUS at 915M). Brian -Original Message- From: emc-p...@ieee.org [mailto:emc-p...@ieee.org]On Behalf Of Arthur Michael Sent: Friday, February 24, 2012 10:32 AM To: Scott Douglas Cc: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Wireless Telephone and Wireless Internet Clash HI Scott, We had to move a 2.4 GHz cordless phone away from a nearby router and that solved a plethora of problems in our home. We then replaced that phone with a 900 MHz cordless oldie-but-goodie phone and the problems did not reappear. Good Luck, Art == On Thu, 23 Feb 2012, Scott Douglas 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 -
Re: [PSES] Wireless Telephone and Wireless Internet Clash
Scott- I think Ed Price hit this one the head. At least one and probably both of your 900 MHz devices frequency hop. In theory, you would then have only a small loss in capacity during their infrequent collisions. What really happens is that the single-chip radios in these devices do not perform very well. The receivers are easily overloaded by out-of-channel signals. The transmitters put out a signal with noise sidebands that extend many channels outside of the channel in use. The upshot is that due to the rather marginal performance of these radio chips, signals that theoretically should not interfere with each other do interfere, especially when the two devices in question are close to each other. Cheers, Don From: Ed Price edpr...@cox.net To: EMC-PSTC@LISTSERV.IEEE.ORG Date: 02/23/2012 10:29 PM Subject:RE: [PSES] Wireless Telephone and Wireless Internet Clash Sent by:emc-p...@ieee.org 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
Re: [PSES] Wireless Telephone and Wireless Internet Clash
In my house, to get everything to play together nicely, I had to segregate the devices on different bands: -5.8Ghz cordless phone -900mhz (had to find old ones on ebay) wireless cameras for the baby room (newborn) -2.4ghz wi-fi for laptops and Nintendo Wii (and Nook, and iPod touch, etc) -908Mhz z-wave AC control devices (though part of the house could not be reached; used power line x-10 devices there). -Ken On 2/24/12, don_borow...@selinc.com don_borow...@selinc.com wrote: Scott- I think Ed Price hit this one the head. At least one and probably both of your 900 MHz devices frequency hop. In theory, you would then have only a small loss in capacity during their infrequent collisions. What really happens is that the single-chip radios in these devices do not perform very well. The receivers are easily overloaded by out-of-channel signals. The transmitters put out a signal with noise sidebands that extend many channels outside of the channel in use. The upshot is that due to the rather marginal performance of these radio chips, signals that theoretically should not interfere with each other do interfere, especially when the two devices in question are close to each other. Cheers, Don From: Ed Price edpr...@cox.net To: EMC-PSTC@LISTSERV.IEEE.ORG Date: 02/23/2012 10:29 PM Subject:RE: [PSES] Wireless Telephone and Wireless Internet Clash Sent by:emc-p...@ieee.org 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
Re: [PSES] Lead-free article
please define quite a mess When we caught onto the mess we were making almost 50 years ago, (remember?) then we started cleaning up our act. All sorts of regulations came out to change the behavior of Corporations and of each of us personally. The book Silent Spring by Rachel Carson (1962) is pointed to as the inflection point in attitudes and ideas. From then, we have been changing our behaviors for better responsibility of the environment, Corp and personal. So if you want mess look up what the '60's were like. My home town bay was declared by Jacques Cousteau as the deadest body of water in the world. The pollution on rivers caught on fire. The medians and sides of most roads were covered in trash tossed from cars, the product of the fast food industry Beaches were covered, and I have seen covered in some areas, 100 % in trash. The ground was not visible. But that was the '60's and 70's as we adjusted our behaviors and the Corp did too. There have been many exceptions since then. So the message has not yet covered 100%, for 100% of the time. You are right about the moderating effect of society, and that would be us. Those of us that work in some aspect of regulation Imagine where EMC - or the lack of - would be for our EM environment. Or just how safe our electrical products would be, without the Safety regulations from about 100 years ago. In all, we are moving in the right direction, and can move further, with careful consideration. The fear mongers among us can tip the balance back to the dark ages if we are not attentive. A point to note is that we survived a dreadful time of pollution during the '50's, '60's, '70's and are now in a much better place than those times. And we can improve!!! From: Anthony Thomson ton...@europe.com To: EMC-PSTC@LISTSERV.IEEE.ORG Sent: Monday, February 20, 2012 4:21 AM Subject: Re: [PSES] Lead-free article We’ve only really been making electronic goods for around 100 years, just a little over one single lifetime. I guess that production has grown roughly exponentially during that time and continues to do so as the world’s cultures steadilly become technology consumers and the already 'developed' world enjoys shorter and shorter technology replacement cycles. We’ve made quite a mess in just 100 years. Left unchecked, what would it be like in the next 100, 200, 500 years? Google image search ‘Blade Runner Cityscape’ ? I’m not a radical ‘Green’, not even a passive ‘Green’ but I am kind of thankful for their moderating effect on society. Tony - Original Message - From: John Woodgate Sent: 02/17/12 09:50 PM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] Lead-free article In message ca2031b25ecf4165abe4a98bb2bdc...@tamuracorp.com, dated Fri, 17 Feb 2012, Brian Oconnell oconne...@tamuracorp.com writes: And we cannot say that was just another unintended affect. I read the similar stuff from approx 2003 to 2005. So if the assertion that lead-free is not net-good for the planet is valid, what would it take to rescind? Or is this another permanent temporary tax? All this eco-stuff in Europe is driven by Green Party activists, mostly in Germany, I think. But they are elsewhere: I've met some in Netherlands. Because it's emotional and political, you don't get to change it by reasoning. If pollution, environmental toxins, etc. were really as deadly as is made out, we'd be extinct by now. The people of Cornwall, far west of England, say they thrive on the radon that comes from their volcanic rocks. That's a bit far the other way, but one may ponder that the last 50 years or so of anti-radon measures follow some 900 thousand years of human occupation with none. -- 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 - This message is from the IEEE Product Safety
Re: [PSES] Wireless Telephone and Wireless Internet Clash
I'm reminded that somewhere in the various regulations, that there is the comment noting that the limits are generally the minimum needed to ensure a reasonable expectation of performance or some such language. Then there is the caution that a better performance, beyond what the standards set, is encouraged. And the radio standards for unlicensed and unprotected products explain the situation you are in. From: Arthur Michael amich...@safetylink.com To: Scott Douglas sdoug...@radiusnorth.net Cc: EMC-PSTC@LISTSERV.IEEE.ORG Sent: Friday, February 24, 2012 1:31 PM Subject: Re: [PSES] Wireless Telephone and Wireless Internet Clash HI Scott, We had to move a 2.4 GHz cordless phone away from a nearby router and that solved a plethora of problems in our home. We then replaced that phone with a 900 MHz cordless oldie-but-goodie phone and the problems did not reappear. Good Luck, Art == On Thu, 23 Feb 2012, Scott Douglas 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
