Re: Considering a rooftop OATS
Hi Doug We looked at doing a 10m OATS but found that at 10m you didn't have a clear 10db margin from the relevant limit line in the standards, so we're aiming for a 3m site now with a raised platform so that cable trunking, turntable wont be too much trouble (I hope!) Richard EMC Resource Network - Original Message - From: Dave Heald davehe...@attbi.com To: POWELL, DOUG doug.pow...@aei.com Cc: EMC-PSTC (E-mail) emc-p...@ieee.org Sent: Saturday, April 27, 2002 7:43 AM Subject: Re: Considering a rooftop OATS Well, I can comment on the line of site interference issues: The cell tower, while nearby, only transmits in certain ranges. Unless the signals from the tower overload your measurement devices, this should be managable. To check for overload, play with different attenuators and look for an appropriate linear reduction in signal strength with each attenuator used. This can be done before it's too late. (i.e. when you do your antenna scan before presenting your proposal) The same goes for the building to building links. These should also be on defined bands (one near my old workplace was at 2.488GHz which really got in the way) but for the most part you should be able to get used to them and then roughly ignore them (don't entirely ignore them though - you may have an emission that is masked within an ambient). The only other really bad interference generators are HDTV and really strong local TV stations (and of course the FM radio band). All but the HDTV can be worked around with creative resolution bandwidth management - practice makes perfect is the best advice I can give. Unfortunately there is nothing you can do to get around the HDTV signals other than build yourself a precompliance anechoic chamber. Best Regards, Dave Heald POWELL, DOUG wrote: Greetings all, I am considering a proposal to build a pre-compliance OATS on the rooftop of our facility. I am interested in hearing any experiences along this line especially any unexpected difficulties that came up. I am considering a 10 meter site on a raised framework or platform with turntable. There are a number of air-conditioning units on the roof. If needed, I can place grounded chain-link fence around these as a sort of faraday cage. A binocular scan of the surrounding area reveals a power substation about 1/2 mile away. Other items in the area are a cell phone tower about 2 miles away and there are nearby office buildings with small dish antennas and the like. Some of these are undoubtedly site to site wireless data communication. I still need to get my antenna out on the roof and do a quick scan. The equipment to be testing is sometimes rather heavy and I need to consider an elevator or at least an equipment hoist over the edge of the roof. Additionally, I am considering some kind of a portable weatherproof enclosure over the turntable. Thanks in advance for your comments, -doug --- Douglas E. Powell, Compliance Engineer Advanced Energy Industries, Inc. Mail stop: 203024 1626 Sharp Point Drive Ft. Collins, CO 80525 970.407.6410 (phone) 970-407.5410 (fax) mailto:doug.pow...@aei.com --- _ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri
Re: Considering a rooftop OATS
TUV in San Diego had a roof top OATS. I would talk to them on the subject. Regards, Ron Chernus, Compliance Engineer DENSO Wireless POWELL, DOUG doug.pow...@aei.com on 04/26/2002 09:21:16 AM Please respond to POWELL, DOUG doug.pow...@aei.com To: EMC-PSTC (E-mail) emc-p...@ieee.org cc:(bcc: RON CHERNUS/LALAB) Subject: Considering a rooftop OATS Greetings all, I am considering a proposal to build a pre-compliance OATS on the rooftop of our facility. I am interested in hearing any experiences along this line especially any unexpected difficulties that came up. I am considering a 10 meter site on a raised framework or platform with turntable. There are a number of air-conditioning units on the roof. If needed, I can place grounded chain-link fence around these as a sort of faraday cage. A binocular scan of the surrounding area reveals a power substation about 1/2 mile away. Other items in the area are a cell phone tower about 2 miles away and there are nearby office buildings with small dish antennas and the like. Some of these are undoubtedly site to site wireless data communication. I still need to get my antenna out on the roof and do a quick scan. The equipment to be testing is sometimes rather heavy and I need to consider an elevator or at least an equipment hoist over the edge of the roof. Additionally, I am considering some kind of a portable weatherproof enclosure over the turntable. Thanks in advance for your comments, -doug --- Douglas E. Powell, Compliance Engineer Advanced Energy Industries, Inc. Mail stop: 203024 1626 Sharp Point Drive Ft. Collins, CO 80525 970.407.6410 (phone) 970-407.5410 (fax) mailto:doug.pow...@aei.com --- _ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
RE: Considering a rooftop OATS
Doug, Rooftop sites have a number of problems. I'm sure the folks who have actually built them can elaborate more, but one that jumps to mind is the fact that you will have a worse ambient than at ground level. The VHF and UHF signals that comprise the ambient tend to be line of sight, and raising yourself above the average terrain increases the distance at which transmitters may be received. Thus, you'll suffer interference from FM and television stations that are farther away than if you were at ground level. Ghery Pettit Intel -Original Message- From: POWELL, DOUG [mailto:doug.pow...@aei.com] Sent: Friday, April 26, 2002 9:21 AM To: EMC-PSTC (E-mail) Subject: Considering a rooftop OATS Greetings all, I am considering a proposal to build a pre-compliance OATS on the rooftop of our facility. I am interested in hearing any experiences along this line especially any unexpected difficulties that came up. I am considering a 10 meter site on a raised framework or platform with turntable. There are a number of air-conditioning units on the roof. If needed, I can place grounded chain-link fence around these as a sort of faraday cage. A binocular scan of the surrounding area reveals a power substation about 1/2 mile away. Other items in the area are a cell phone tower about 2 miles away and there are nearby office buildings with small dish antennas and the like. Some of these are undoubtedly site to site wireless data communication. I still need to get my antenna out on the roof and do a quick scan. The equipment to be testing is sometimes rather heavy and I need to consider an elevator or at least an equipment hoist over the edge of the roof. Additionally, I am considering some kind of a portable weatherproof enclosure over the turntable. Thanks in advance for your comments, -doug --- Douglas E. Powell, Compliance Engineer Advanced Energy Industries, Inc. Mail stop: 203024 1626 Sharp Point Drive Ft. Collins, CO 80525 970.407.6410 (phone) 970-407.5410 (fax) mailto:doug.pow...@aei.com --- _ This message, including any attachments, may contain information that is confidential and proprietary information of Advanced Energy Industries, Inc. The dissemination, distribution, use or copying of this message or any of its attachments is strictly prohibited without the express written consent of Advanced Energy Industries, Inc. --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list --- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@attbi.com For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on browse and then emc-pstc mailing list
