My understanding is that quite good correlation can be drawn between three and ten meter sites, as long as the EUT is in the far field of the antenna AND the antenna is in the far field of the EUT at both separation distances. However, if this is not the case, then you have problems.
---------- >From: "Brent Pahl" <bre...@dynarc.com> >To: "Ken Javor" <ken.ja...@emccompliance.com>, "Tudor, Allen" <allen_tu...@adc.com>, "EMC-PCST \(E-mail\)" <emc-p...@majordomo.ieee.org> >Subject: RE: Site Correlation >Date: Thu, Jan 11, 2001, 1:31 PM > > Hi Ken, > > Very true. I was simply looking at the question of which of the two listed > methods would work best, without taking into account the overall accuracy of > either method. No matter what you try, you will never get direct > correlation between a 10m OATS and a 3m chamber, but by utilizing one of the > listed methods, he may get a slightly clearer picture than he would without > any correction factors at all. The measurements from the 3m chamber will > always need to be taken with a grain of salt. > > Regards, > Brent > > -----Original Message----- > From: Ken Javor [mailto:ken.ja...@emccompliance.com] > Sent: Thursday, January 11, 2001 11:02 AM > To: Brent Pahl; Tudor, Allen; EMC-PCST (E-mail) > Subject: Re: Site Correlation > > > Have to take strong exception. If EUT is much larger than comb generator, a > correlation between sites using the comb generator will not work for the > larger EUT. Measurement antenna is in far field of comb generator on both > sites, but is more in the far field of the EUT at 10 m than at 3 m. > > ---------- >>From: "Brent Pahl" <bre...@dynarc.com> >>To: "Tudor, Allen" <allen_tu...@adc.com>, "EMC-PCST \(E-mail\)" > <emc-p...@majordomo.ieee.org> >>Subject: RE: Site Correlation >>Date: Thu, Jan 11, 2001, 11:31 AM >> > >> >> Allen, >> >> We just did this in our 3-meter lab using a comb generator. After >> interviewing several test labs, I found out that they use comb generator's >> occasionally to see if they are still properly calibrated. Evidently, a >> good comb generator will give a consistent output, give or take 0.5dB, > over >> it's lifetime. As long as the comb generator is consistently set up the >> same way every time (e.g. with power cord vs. on battery, same distance > from >> antenna, facing same direction), and the measurements are taken the same > way >> at the 10m site as they are in your 3m chamber (e.g. not maximizing at > every >> frequency vs. maximizing at every frequency, peak hold vs. continuous > run), >> you should get consistent results. In regards to the "vs." options listed >> above, I would recommend using the 1st option in all cases. >> >> Honestly, either a comb generator or a signal-generator/antenna should > both >> give you accurate results, but the comb generator reduces the number of >> variables you need to consider/double-check during setup. >> >> Best of luck, >> Brent >> >> >> -----Original Message----- >> From: owner-emc-p...@ieee.org [mailto:owner-emc-p...@ieee.org]On Behalf >> Of Tudor, Allen >> Sent: Thursday, January 11, 2001 5:58 AM >> To: EMC-PCST (E-mail) >> Subject: Site Correlation >> >> >> >> Greetings: >> >> What's the best way to correlate a pre-compliance chamber (smaller than a > 3m >> chamber) to a 10m anechoic chamber? Should I use a signal generator and >> antenna or should I use a comb generator? >> >> Would the answer be different if I were correlating the pre-compliance >> chamber to an OATS? >> >> Thanks in advance. >> >> >> Allen Tudor, Compliance Engineer >> ADC DSL Systems Inc. >> 6531 Meridien Dr. >> Raleigh, NC 27616 >> phone: 919.875.3382 >> email: allen_tu...@adc.com >> >> >> ------------------------------------------- >> This message is from the IEEE EMC Society Product Safety >> Technical Committee emc-pstc discussion list. >> >> 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: >> Jim Bacher: jim_bac...@mail.monarch.com >> Michael Garretson: pstc_ad...@garretson.org >> >> For policy questions, send mail to: >> Richard Nute: ri...@ieee.org >> >> >> >> >> ------------------------------------------- >> This message is from the IEEE EMC Society Product Safety >> Technical Committee emc-pstc discussion list. >> >> 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: >> Jim Bacher: jim_bac...@mail.monarch.com >> Michael Garretson: pstc_ad...@garretson.org >> >> For policy questions, send mail to: >> Richard Nute: ri...@ieee.org >> >> > ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. 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: Jim Bacher: jim_bac...@mail.monarch.com Michael Garretson: pstc_ad...@garretson.org For policy questions, send mail to: Richard Nute: ri...@ieee.org
