Re: Standard Gain Horn Antenna Calibration
In message 08bfa5ada9462e4f96e4a31a270fc86b198...@usa0300ms02.na.xerox.net, dated Thu, 14 Feb 2008, Spencer, David H david.spen...@xerox.com writes: During our labs last on-site ISO-17025 audit, I was informed by A2LA that the terms calibration, verification, and quality check all mean essentially the same thing. I think there are grounds to challenge that. From the IEC 'Electropedia', (FREE access at www.iec.ch): calibration set of operations which establishes, by reference to standards, the relationship which exists, under specified conditions, between an indication and a result of a measurement NOTE 1 – This term is based on the uncertainty approach. NOTE 2 – The relationship between the indications and the results of measurement can be expressed, in principle, by a calibration diagram. Source: [not the same as] VIM 6.11 [VIM is the International Vocabulary for Metrology] verification (of calibration) set of operations which is used to check whether the indications, under specified conditions, correspond with a given set of known measurands within the limits of a predetermined calibration diagram NOTE 1 – This term is used in the uncertainty approach. NOTE 2 – The known uncertainty of the measurand used for verification will generally be negligible with respect to the uncertainty assigned to the instrument in the calibration diagram. I can't claim that these are models of lucidity, but clearly the terms are not synonymous. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Standard Gain Horn Antenna Calibration
ALL, During our labs last on-site ISO-17025 audit, I was informed by A2LA that the terms calibration, verification, and quality check all mean essentially the same thing. To be clear, this was a discussion that centered around statements of measurement uncertainty, and I was trying to clear myself from having to state measurement uncertainty for items of which I was performing a verification of design parameters: LISN, CDN's NSA, etc. etc... My (failed) argument was that ISO-17025 only requires measurement uncertainty when performing a calibration. That when I reference CISPR 16 (or ANSI C63.4) for LISN VERIFICATION, I'm not performing a calibration, I'm performing a verification. I lawyer I am not; however, I assumed that if ISO-17025 says calibrations require measurement uncertainty then thou shalt state measurement uncertainty. ISO-17025 says nothing about verifications. Before I got struck down by the SITH Lords at A2LA, I did a bit a research, and found that the terms can be used interchangeably. I don't agree, because I look it the terms as degrees of how in depth an item's accuracy is verified. Personally, I think measurement uncertainty is a good thing. It's made our lab much more aware of possible variations in test results. Regarding annual calibration of antenna's, LISN's, CDN's, and other similar devices which are not prone to change year-over-year, regardless of whether the calibration is on-site or sent out, it's the price of doing business. Just my opinions and tangents on this subject. Regards Dave Spencer From: emc-p...@ieee.org on behalf of Gert Gremmen Sent: Thu 2/14/2008 3:50 PM To: Dennis Camell; John Woodgate; EMC-PSTC@LISTSERV.IEEE.ORG Subject: RE: Standard Gain Horn Antenna Calibration My opinion on calibration and verification, please comment: Calibration is the determination of the measurement deviations of a certain device by comparing to a better specified device. The determination includes an error calculation. Calibrations takes usually place within the specification limits defined by the manufacturer, and is repeated in a manufacturer specified interval. This is not mandatory however, and intervals may be adjusted if justified by calibration history or on your own risk. If a device goes out of specification a calibration may be followed by a justification process. After justification a new calibration is required. A proper calibration process provides a proven unbroken chain of other proper calibrations to an (inter)national standard. A common misunderstanding is that a calibration may be carried out by calibration labs only. While carrying out a very accurate calibration is a difficult process, an simple instrument can be calibrated by anyone having access to a better traceable calibrated instrument. It all comes down to a measuring deviations to the reference with a proven error margin. The difficult part is determining the new error, not measuring the deviation. A defective 1% voltmeter which shows 15% off, can be traceable calibrated if an error margin of 16% is noted in the calibration report. I do not recommend calibrating defective voltmeters, however. Ideally calibration should take place before and after each measurement. Only this way we can be absolutely sure we measured a correct value, In real life however, we assume that a decently constructed instrument will remain within spec in the recommended calibration interval. Verification is the routine type of calibration that is used to shorten the period of uncertainty that might happen if an instrument goes out of spec at a sudden time. Imagine your new voltmeter goes defective 2 weeks after calibration in a yearly calibration interval. You may produce faulty measurements during 50 weeks before you even notice (at the next calibration ) In a test lab that may implicate recall of hundreds of tested products. The verification process -if logged- may produce a very valuable trace of daily data showing how your instruments accuracy drifts in time, and will warn you early when odd things happen and reduce the time-period of faulty measurements. A verification happens on a subset of the calibration parameter set, because we presume that an instrument error will show in the selected subset. (if not we are in trouble) From a measurement practice point of view, logged verification is much more valueable then calibration. A nice thing of verification is that it can verify a full chain of equipment used in a test set up in a very short time. We use a small RF generator (comb type) to verify the daily performance of an emission measurement setup consisting of: A measurement table A fully anechoic room A receive antenna The antenna cabling The switch matrix The measuring receiver(s). The value of a number of peaks of the comb generator MUST be essentially the same every day, if not, one or more parts of the equipment may
Re: Standard Gain Horn Antenna Calibration
Gert, Thanks for the mini course Gert, nice to have it all in one place so clearly explained. best regards Tom On Feb 14, 2008, at 12:50 PM, Gert Gremmen wrote: My opinion on calibration and verification, please comment: Calibration is the determination of the measurement deviations of a certain device by comparing to a better specified device. The determination includes an error calculation. Calibrations takes usually place within the specification limits defined by the manufacturer, and is repeated in a manufacturer specified interval. This is not mandatory however, and intervals may be adjusted if justified by calibration history or on your own risk. If a device goes out of specification a calibration may be followed by a justification process. After justification a new calibration is required. A proper calibration process provides a proven unbroken chain of other proper calibrations to an (inter)national standard. A common misunderstanding is that a calibration may be carried out by calibration labs only. While carrying out a very accurate calibration is a difficult process, an simple instrument can be calibrated by anyone having access to a better traceable calibrated instrument. It all comes down to a measuring deviations to the reference with a proven error margin. The difficult part is determining the new error, not measuring the deviation. A defective 1% voltmeter which shows 15% off, can be traceable calibrated if an error margin of 16% is noted in the calibration report. I do not recommend calibrating defective voltmeters, however. Ideally calibration should take place before and after each measurement. Only this way we can be absolutely sure we measured a correct value, In real life however, we assume that a decently constructed instrument will remain within spec in the recommended calibration interval. Verification is the routine type of calibration that is used to shorten the period of uncertainty that might happen if an instrument goes out of spec at a sudden time. Imagine your new voltmeter goes defective 2 weeks after calibration in a yearly calibration interval. You may produce faulty measurements during 50 weeks before you even notice (at the next calibration ) In a test lab that may implicate recall of hundreds of tested products. The verification process -if logged- may produce a very valuable trace of daily data showing how your instruments accuracy drifts in time, and will warn you early when odd things happen and reduce the time-period of faulty measurements. A verification happens on a subset of the calibration parameter set, because we presume that an instrument error will show in the selected subset. (if not we are in trouble) From a measurement practice point of view, logged verification is much more valueable then calibration. A nice thing of verification is that it can verify a full chain of equipment used in a test set up in a very short time. We use a small RF generator (comb type) to verify the daily performance of an emission measurement setup consisting of: A measurement table A fully anechoic room A receive antenna The antenna cabling The switch matrix The measuring receiver(s). The value of a number of peaks of the comb generator MUST be essentially the same every day, if not, one or more parts of the equipment may be out of specs. That includes the comb generator, of course. The test takes 5 seconds, is automated in the test software (GPIB bus) and is carried out every day. We even made a setup consisting of a small send antenna remotely placed in the measurement room, that is fed by an external generator. It is used to quickly verify one frequency before the start of every measurement. Unfortuneately the propagated field in the test room is influenced by the EUT under test, so the verified values tend to fluctuate. It provides however, a safeguard against gross measurement errors before each and every test. It also allows us to verify the polarization of the antenna (still done by hand). Gert Gremmen ce-test, qualified testing bv _ Van: emc-p...@ieee.org namens Dennis Camell Verzonden: do 14-2-2008 19:49 Aan: 'John Woodgate'; EMC-PSTC@LISTSERV.IEEE.ORG Onderwerp: RE: Standard Gain Horn Antenna Calibration Hi John, Sure, I'll give it a try. Other opinions are welcome. Verification involves checking a device, etc. that it is within specification. This check is done with other calibrated device(s). Calibration starts like a verification, but could involve adjustments to the device if possible and a formal report with a traceable chain to some standard. Standard practice could be thought of as recommended practice or SOP. While this should improve the repeatability, accuracy may still be in question. By the way, Wikipedia has a good summary of the first two. Dennis Camell National Institute of Standards and Technology 325 Broadway, MS 818.02 Boulder, CO 80305 USA From: emc-p
RE: Standard Gain Horn Antenna Calibration
To all, I find the responses interesting and some I even agree with. If you wish to apply your passion on this topic, join a national or international standards body. For the USA, it is C63®. Its website is C63.org and this is a good place to get started. Off-topic: the mention of courtrooms reminds me of two famous lawyers, innuendo and conjecture. My apologies if this listing is against forum norms. Dennis Camell National Institute of Standards and Technology 325 Broadway, MS 818.02 Boulder, CO 80305 USA _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Thursday, February 14, 2008 1:52 PM To: Untitled Subject: Re: Standard Gain Horn Antenna Calibration, slightly off-topic response Awhile ago, a criminal case was appealed on the basis that the fingerprint method used to convict the defendant had an unquantified aspect to it in that no one could say how accurate fingerprinting analysis really was. This was not a case of a partial print requiring human judgment, but rather a philosophical point: How do you KNOW that no two fingerprints (or substitute snowflakes) are alike? If you can’t quantify it, no matter how much circumstantial evidence there is to support it, then you don’t have a usable technique. That was the basis of the appeal. I don’t know how it turned out, but the fact that the appeal was allowed after over one hundred years of using fingerprints to track down and convict criminals, tells you that there has been a philosophical shift in how people think about these things, and this calibration vs. basic theory issue seems to me to be part and parcel of the same thought process. Ken Javor Phone: (256) 650-5261 _ From: Derek Walton lfresea...@aol.com List-Post: emc-pstc@listserv.ieee.org Date: Thu, 14 Feb 2008 14:13:54 -0600 To: Dennis Camell cam...@boulder.nist.gov, emc-p...@ieee.org Subject: Re: Standard Gain Horn Antenna Calibration Hi all, calibration has been an issue with me for a long time: specifically where and when it makes sense. The std gain horn is a prime example. I wonder if there is any calibration process that can be used, that is actually more accurate than maintaining mechanical dimensions of a horn modelled in some form of NEC program. Damage aside of course. So, in the case of something simple like a Std gain horn WHICH IS more accurate, the NEC model using tight mechanical dimensions, or some test method with very large measurement errors? We seem to be driven more by metrologists that do not fully inderstand practical limits Curious in Rockford, IL USA. Derek Walton - Original Message - From: Dennis Camell mailto:cam...@boulder.nist.gov mailto:cam...@boulder.nist.gov To: emc-p...@ieee.org Sent: Thursday, February 14, 2008 9:36 AM Subject: RE: Standard Gain Horn Antenna Calibration Dear members and Grace, C63.5-2006 states that all antennas, including horns, need to be calibrated. The earlier version (2004) had a sentence saying it was unnecessary to calibrate standard gain horns, but that was removed. The calibration of horns is a current topic of discussion at the C63.5 working group meetings and changes should be made in the next revision. The working group is always looking for new participants, so if you are interested contact C63® or me. I like Ed Price’s comments below. To me it’s like the difference between standard practice, verification and calibration. One possible verification check is the use of S11 measurements of the horn in question. This could extend the calibration cycle but may not eliminate it. Oh, and connector savers do make it easier to fix connector problems by reducing the wear on the adaptor connector. On the use of different horns; SGH have single lobed patterns, I do not know if the DRG have the same pattern across all frequencies. Regards, Dennis Camell National Institute of Standards and Technology 325 Broadway, MS 818.02 Boulder, CO 80305 USA Tel: (303) 497-3214 Fax: (303) 497-6665 _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] mailto:emc-p...@ieee.org%5d On Behalf Of Ken Javor Sent: Wednesday, February 13, 2008 10:41 AM To: Price, Edward; Untitled Subject: Re: Standard Gain Horn Antenna Calibration Ed makes an excellent point regarding the coax-to-waveguide adapter. A simple way to protect against damage is the use of an external adapter used as a “connector-saver.” Ken Javor Phone: (256) 650-5261 _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] mailto:emc-p...@ieee.org%5d mailto:emc-p...@ieee.org%5d mailto:emc-p...@ieee.org%5d On Behalf Of Grace Lin Sent: Wednesday, February 13, 2008 6:38 AM To: emc-p...@ieee.org Subject: Standard Gain Horn Antenna Calibration Dear Members, Does a standard gain horn antenna (htt ://www.ets-lindgren.com/manuals/3160.pdf) need
Re: Standard Gain Horn Antenna Calibration, slightly off-topic response
Awhile ago, a criminal case was appealed on the basis that the fingerprint method used to convict the defendant had an unquantified aspect to it in that no one could say how accurate fingerprinting analysis really was. This was not a case of a partial print requiring human judgment, but rather a philosophical point: How do you KNOW that no two fingerprints (or substitute snowflakes) are alike? If you can’t quantify it, no matter how much circumstantial evidence there is to support it, then you don’t have a usable technique. That was the basis of the appeal. I don’t know how it turned out, but the fact that the appeal was allowed after over one hundred years of using fingerprints to track down and convict criminals, tells you that there has been a philosophical shift in how people think about these things, and this calibration vs. basic theory issue seems to me to be part and parcel of the same thought process. Ken Javor Phone: (256) 650-5261 _ From: Derek Walton lfresea...@aol.com List-Post: emc-pstc@listserv.ieee.org Date: Thu, 14 Feb 2008 14:13:54 -0600 To: Dennis Camell cam...@boulder.nist.gov, emc-p...@ieee.org Subject: Re: Standard Gain Horn Antenna Calibration Hi all, calibration has been an issue with me for a long time: specifically where and when it makes sense. The std gain horn is a prime example. I wonder if there is any calibration process that can be used, that is actually more accurate than maintaining mechanical dimensions of a horn modelled in some form of NEC program. Damage aside of course. So, in the case of something simple like a Std gain horn WHICH IS more accurate, the NEC model using tight mechanical dimensions, or some test method with very large measurement errors? We seem to be driven more by metrologists that do not fully inderstand practical limits Curious in Rockford, IL USA. Derek Walton - Original Message - From: Dennis Camell mailto:cam...@boulder.nist.gov mailto:cam...@boulder.nist.gov To: emc-p...@ieee.org Sent: Thursday, February 14, 2008 9:36 AM Subject: RE: Standard Gain Horn Antenna Calibration Dear members and Grace, C63.5-2006 states that all antennas, including horns, need to be calibrated. The earlier version (2004) had a sentence saying it was unnecessary to calibrate standard gain horns, but that was removed. The calibration of horns is a current topic of discussion at the C63.5 working group meetings and changes should be made in the next revision. The working group is always looking for new participants, so if you are interested contact C63® or me. I like Ed Price’s comments below. To me it’s like the difference between standard practice, verification and calibration. One possible verification check is the use of S11 measurements of the horn in question. This could extend the calibration cycle but may not eliminate it. Oh, and connector savers do make it easier to fix connector problems by reducing the wear on the adaptor connector. On the use of different horns; SGH have single lobed patterns, I do not know if the DRG have the same pattern across all frequencies. Regards, Dennis Camell National Institute of Standards and Technology 325 Broadway, MS 818.02 Boulder, CO 80305 USA Tel: (303) 497-3214 Fax: (303) 497-6665 _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Wednesday, February 13, 2008 10:41 AM To: Price, Edward; Untitled Subject: Re: Standard Gain Horn Antenna Calibration Ed makes an excellent point regarding the coax-to-waveguide adapter. A simple way to protect against damage is the use of an external adapter used as a “connector-saver.” Ken Javor Phone: (256) 650-5261 _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] mailto:emc-p...@ieee.org%5d mailto:emc-p...@ieee.org%5d On Behalf Of Grace Lin Sent: Wednesday, February 13, 2008 6:38 AM To: emc-p...@ieee.org Subject: Standard Gain Horn Antenna Calibration Dear Members, Does a standard gain horn antenna (htt ://www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. A standard gain or pyramidal horn, with a waveguide feed, is a mechanically simple device. After an initial calibration, it should maintain its values without drift unless mechanically deformed. How much the gain will change with mechanical distortion is unpredictable, so I doubt that period pictures could reasonably document the antenna's condition. A double-ridged horn adds more mechanical complexity, making real periodic calibration verifications even more important. And then there is the waveguide-to-coax transition found
RE: Standard Gain Horn Antenna Calibration
My opinion on calibration and verification, please comment: Calibration is the determination of the measurement deviations of a certain device by comparing to a better specified device. The determination includes an error calculation. Calibrations takes usually place within the specification limits defined by the manufacturer, and is repeated in a manufacturer specified interval. This is not mandatory however, and intervals may be adjusted if justified by calibration history or on your own risk. If a device goes out of specification a calibration may be followed by a justification process. After justification a new calibration is required. A proper calibration process provides a proven unbroken chain of other proper calibrations to an (inter)national standard. A common misunderstanding is that a calibration may be carried out by calibration labs only. While carrying out a very accurate calibration is a difficult process, an simple instrument can be calibrated by anyone having access to a better traceable calibrated instrument. It all comes down to a measuring deviations to the reference with a proven error margin. The difficult part is determining the new error, not measuring the deviation. A defective 1% voltmeter which shows 15% off, can be traceable calibrated if an error margin of 16% is noted in the calibration report. I do not recommend calibrating defective voltmeters, however. Ideally calibration should take place before and after each measurement. Only this way we can be absolutely sure we measured a correct value, In real life however, we assume that a decently constructed instrument will remain within spec in the recommended calibration interval. Verification is the routine type of calibration that is used to shorten the period of uncertainty that might happen if an instrument goes out of spec at a sudden time. Imagine your new voltmeter goes defective 2 weeks after calibration in a yearly calibration interval. You may produce faulty measurements during 50 weeks before you even notice (at the next calibration ) In a test lab that may implicate recall of hundreds of tested products. The verification process -if logged- may produce a very valuable trace of daily data showing how your instruments accuracy drifts in time, and will warn you early when odd things happen and reduce the time-period of faulty measurements. A verification happens on a subset of the calibration parameter set, because we presume that an instrument error will show in the selected subset. (if not we are in trouble) From a measurement practice point of view, logged verification is much more valueable then calibration. A nice thing of verification is that it can verify a full chain of equipment used in a test set up in a very short time. We use a small RF generator (comb type) to verify the daily performance of an emission measurement setup consisting of: A measurement table A fully anechoic room A receive antenna The antenna cabling The switch matrix The measuring receiver(s). The value of a number of peaks of the comb generator MUST be essentially the same every day, if not, one or more parts of the equipment may be out of specs. That includes the comb generator, of course. The test takes 5 seconds, is automated in the test software (GPIB bus) and is carried out every day. We even made a setup consisting of a small send antenna remotely placed in the measurement room, that is fed by an external generator. It is used to quickly verify one frequency before the start of every measurement. Unfortuneately the propagated field in the test room is influenced by the EUT under test, so the verified values tend to fluctuate. It provides however, a safeguard against gross measurement errors before each and every test. It also allows us to verify the polarization of the antenna (still done by hand). Gert Gremmen ce-test, qualified testing bv _ Van: emc-p...@ieee.org namens Dennis Camell Verzonden: do 14-2-2008 19:49 Aan: 'John Woodgate'; EMC-PSTC@LISTSERV.IEEE.ORG Onderwerp: RE: Standard Gain Horn Antenna Calibration Hi John, Sure, I'll give it a try. Other opinions are welcome. Verification involves checking a device, etc. that it is within specification. This check is done with other calibrated device(s). Calibration starts like a verification, but could involve adjustments to the device if possible and a formal report with a traceable chain to some standard. Standard practice could be thought of as recommended practice or SOP. While this should improve the repeatability, accuracy may still be in question. By the way, Wikipedia has a good summary of the first two. Dennis Camell National Institute of Standards and Technology 325 Broadway, MS 818.02 Boulder, CO 80305 USA From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Woodgate Sent: Thursday, February 14, 2008 10:55 AM To: emc-p...@ieee.org Subject: Re: Standard Gain Horn Antenna
RE: Standard Gain Horn Antenna Calibration
Dear members and Grace, C63.5-2006 states that all antennas, including horns, need to be calibrated. The earlier version (2004) had a sentence saying it was unnecessary to calibrate standard gain horns, but that was removed. The calibration of horns is a current topic of discussion at the C63.5 working group meetings and changes should be made in the next revision. The working group is always looking for new participants, so if you are interested contact C63® or me. I like Ed Price’s comments below. To me it’s like the difference between standard practice, verification and calibration. One possible verification check is the use of S11 measurements of the horn in question. This could extend the calibration cycle but may not eliminate it. Oh, and connector savers do make it easier to fix connector problems by reducing the wear on the adaptor connector. On the use of different horns; SGH have single lobed patterns, I do not know if the DRG have the same pattern across all frequencies for 18-40GHz. Regards, Dennis Camell National Institute of Standards and Technology 325 Broadway, MS 818.02 Boulder, CO 80305 USA Tel: (303) 497-3214 Fax: (303) 497-6665 _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Wednesday, February 13, 2008 10:41 AM To: Price, Edward; Untitled Subject: Re: Standard Gain Horn Antenna Calibration Ed makes an excellent point regarding the coax-to-waveguide adapter. A simple way to protect against damage is the use of an external adapter used as a “connector-saver.” Ken Javor Phone: (256) 650-5261 _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] mailto:emc-p...@ieee.org%5d On Behalf Of Grace Lin Sent: Wednesday, February 13, 2008 6:38 AM To: emc-p...@ieee.org Subject: Standard Gain Horn Antenna Calibration Dear Members, Does a standard gain horn antenna (http //www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. A standard gain or pyramidal horn, with a waveguide feed, is a mechanically simple device. After an initial calibration, it should maintain its values without drift unless mechanically deformed. How much the gain will change with mechanical distortion is unpredictable, so I doubt that period pictures could reasonably document the antenna's condition. A double-ridged horn adds more mechanical complexity, making real periodic calibration verifications even more important. And then there is the waveguide-to-coax transition found on many lower frequency horns. You can electrically damage the little post inside the waveguide by arcing or excess heat or mechanical shock. Also, this post is often mounted to the rear of the coax adapter, and damage to the connector (from a bad cable connector) can translate into physical damage to the post location. Everything in this area is very mechanically sensitive, and also invisible to the user. I keep all of my horn antennas, both coax and waveguide feed models, on periodic calibration. Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty Grace Lin graceli...@gmail.com wrote: Dear Members, Does a standard gain horn antenna (http //www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. Also, when measuring radiated emission, what is the difference between using a double ridge waveguide horn antenna (http://www.ets-lindgren.com/pdf/3117.pdf, http://www.ets-lindgren.com/manuals/3116.pdf) and a standard gain horn antenna (http://www.ets-lindgren.com/manuals/3160.pdf)? I can find a double ridge waveguide horn antenna to cover frequency range of 18-40GHz. For standard gain antennas, I need at least two to cover the same range (more calibration cost if calibration is required). Thank you and look forward to hearing from you. Best regards, Grace Lin - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. - Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html
RE: Standard Gain Horn Antenna Calibration
Hi John, Sure, I'll give it a try. Other opinions are welcome. Verification involves checking a device, etc. that it is within specification. This check is done with other calibrated device(s). Calibration starts like a verification, but could involve adjustments to the device if possible and a formal report with a traceable chain to some standard. Standard practice could be thought of as recommended practice or SOP. While this should improve the repeatability, accuracy may still be in question. By the way, Wikipedia has a good summary of the first two. Dennis Camell National Institute of Standards and Technology 325 Broadway, MS 818.02 Boulder, CO 80305 USA From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of John Woodgate Sent: Thursday, February 14, 2008 10:55 AM To: emc-p...@ieee.org Subject: Re: Standard Gain Horn Antenna Calibration In message 009401c86f1f$4e90c940$242fa...@bw.nist.gov, dated Thu, 14 Feb 2008, Dennis Camell cam...@boulder.nist.gov writes: To me it's like the difference between standard practice, verification and calibration. It would very likely help many people if you could reproduce the definitions of those terms here. They are often confused. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Standard Gain Horn Antenna Calibration
In message 00d501c86f3a$4c9c30f0$242fa...@bw.nist.gov, dated Thu, 14 Feb 2008, Dennis Camell cam...@boulder.nist.gov writes: Sure, I'll give it a try. Other opinions are welcome. Thanks. Verification involves checking a device, etc. that it is within specification. This check is done with other calibrated device(s). Calibration starts like a verification, but could involve adjustments to the device if possible and a formal report with a traceable chain to some standard. Standard practice could be thought of as recommended practice or SOP. While this should improve the repeatability, accuracy may still be in question. By the way, Wikipedia has a good summary of the first two. In UK, we hear a lot of stuff from academic faculties about Wikipedia being highly unreliable, so much so that they ban students from using it. That is contrary to my experience, but maybe they are mostly social scientists, in which field there is NO reliable material. (;-) -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Standard Gain Horn Antenna Calibration
Incoming inspection on a new antenna at EMC Compliance (always new for EMCC, i.e., used) consists of checking it out visually and then something close to an S11 measurement is made, without having a network analyzer. A directional coupler is used to measure forward and reverse power. If that ratio is commensurate with manufacturer’s specs on vswr, it’s a good antenna. It is true that the microwave DRG built to the mil ECOM drawing DL-ES-A-217311 (best known commercial model is EMCO 3115) has a double lobe with a null on center above 10 GHz. But the newer version EMCO 3117 which really doesn’t look like a horn at all is advertised to have a single lobe over the entire frequency range. Ken Javor Phone: (256) 650-5261 _ From: Dennis Camell cam...@boulder.nist.gov List-Post: emc-pstc@listserv.ieee.org Date: Thu, 14 Feb 2008 08:36:03 -0700 To: emc-p...@ieee.org Subject: RE: Standard Gain Horn Antenna Calibration Dear members and Grace, C63.5-2006 states that all antennas, including horns, need to be calibrated. The earlier version (2004) had a sentence saying it was unnecessary to calibrate standard gain horns, but that was removed. The calibration of horns is a current topic of discussion at the C63.5 working group meetings and changes should be made in the next revision. The working group is always looking for new participants, so if you are interested contact C63® or me. I like Ed Price’s comments below. To me it’s like the difference between standard practice, verification and calibration. One possible verification check is the use of S11 measurements of the horn in question. This could extend the calibration cycle but may not eliminate it. Oh, and connector savers do make it easier to fix connector problems by reducing the wear on the adaptor connector. On the use of different horns; SGH have single lobed patterns, I do not know if the DRG have the same pattern across all frequencies. Regards, Dennis Camell National Institute of Standards and Technology 325 Broadway, MS 818.02 Boulder, CO 80305 USA Tel: (303) 497-3214 Fax: (303) 497-6665 _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Wednesday, February 13, 2008 10:41 AM To: Price, Edward; Untitled Subject: Re: Standard Gain Horn Antenna Calibration Ed makes an excellent point regarding the coax-to-waveguide adapter. A simple way to protect against damage is the use of an external adapter used as a “connector-saver.” Ken Javor Phone: (256) 650-5261 _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] mailto:emc-p...@ieee.org%5d mailto:emc-p...@ieee.org%5d On Behalf Of Grace Lin Sent: Wednesday, February 13, 2008 6:38 AM To: emc-p...@ieee.org Subject: Standard Gain Horn Antenna Calibration Dear Members, Does a standard gain horn antenna (http //www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. A standard gain or pyramidal horn, with a waveguide feed, is a mechanically simple device. After an initial calibration, it should maintain its values without drift unless mechanically deformed. How much the gain will change with mechanical distortion is unpredictable, so I doubt that period pictures could reasonably document the antenna's condition. A double-ridged horn adds more mechanical complexity, making real periodic calibration verifications even more important. And then there is the waveguide-to-coax transition found on many lower frequency horns. You can electrically damage the little post inside the waveguide by arcing or excess heat or mechanical shock. Also, this post is often mounted to the rear of the coax adapter, and damage to the connector (from a bad cable connector) can translate into physical damage to the post location. Everything in this area is very mechanically sensitive, and also invisible to the user. I keep all of my horn antennas, both coax and waveguide feed models, on periodic calibration. Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty Grace Lin graceli...@gmail.com wrote: Dear Members, Does a standard gain horn antenna (http //www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. Also, when measuring radiated emission, what
Re: Standard Gain Horn Antenna Calibration
In message 009401c86f1f$4e90c940$242fa...@bw.nist.gov, dated Thu, 14 Feb 2008, Dennis Camell cam...@boulder.nist.gov writes: To me it?s like the difference between standard practice, verification and calibration. It would very likely help many people if you could reproduce the definitions of those terms here. They are often confused. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Standard Gain Horn Antenna Calibration
Dear members and Grace, C63.5-2006 states that all antennas, including horns, need to be calibrated. The earlier version (2004) had a sentence saying it was unnecessary to calibrate standard gain horns, but that was removed. The calibration of horns is a current topic of discussion at the C63.5 working group meetings and changes should be made in the next revision. The working group is always looking for new participants, so if you are interested contact C63® or me. I like Ed Price’s comments below. To me it’s like the difference between standard practice, verification and calibration. One possible verification check is the use of S11 measurements of the horn in question. This could extend the calibration cycle but may not eliminate it. Oh, and connector savers do make it easier to fix connector problems by reducing the wear on the adaptor connector. On the use of different horns; SGH have single lobed patterns, I do not know if the DRG have the same pattern across all frequencies. Regards, Dennis Camell National Institute of Standards and Technology 325 Broadway, MS 818.02 Boulder, CO 80305 USA Tel: (303) 497-3214 Fax: (303) 497-6665 _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Ken Javor Sent: Wednesday, February 13, 2008 10:41 AM To: Price, Edward; Untitled Subject: Re: Standard Gain Horn Antenna Calibration Ed makes an excellent point regarding the coax-to-waveguide adapter. A simple way to protect against damage is the use of an external adapter used as a “connector-saver.” Ken Javor Phone: (256) 650-5261 _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] mailto:emc-p...@ieee.org%5d On Behalf Of Grace Lin Sent: Wednesday, February 13, 2008 6:38 AM To: emc-p...@ieee.org Subject: Standard Gain Horn Antenna Calibration Dear Members, Does a standard gain horn antenna (http //www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. A standard gain or pyramidal horn, with a waveguide feed, is a mechanically simple device. After an initial calibration, it should maintain its values without drift unless mechanically deformed. How much the gain will change with mechanical distortion is unpredictable, so I doubt that period pictures could reasonably document the antenna's condition. A double-ridged horn adds more mechanical complexity, making real periodic calibration verifications even more important. And then there is the waveguide-to-coax transition found on many lower frequency horns. You can electrically damage the little post inside the waveguide by arcing or excess heat or mechanical shock. Also, this post is often mounted to the rear of the coax adapter, and damage to the connector (from a bad cable connector) can translate into physical damage to the post location. Everything in this area is very mechanically sensitive, and also invisible to the user. I keep all of my horn antennas, both coax and waveguide feed models, on periodic calibration. Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty Grace Lin graceli...@gmail.com wrote: Dear Members, Does a standard gain horn antenna (http //www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. Also, when measuring radiated emission, what is the difference between using a double ridge waveguide horn antenna (http://www.ets-lindgren.com/pdf/3117.pdf, http://www.ets-lindgren.com/manuals/3116.pdf) and a standard gain horn antenna (http://www.ets-lindgren.com/manuals/3160.pdf)? I can find a double ridge waveguide horn antenna to cover frequency range of 18-40GHz. For standard gain antennas, I need at least two to cover the same range (more calibration cost if calibration is required). Thank you and look forward to hearing from you. Best regards, Grace Lin - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. - Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.org Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send
Re: Standard Gain Horn Antenna Calibration
In message 317772.86647...@web39603.mail.mud.yahoo.com, dated Wed, 13 Feb 2008, Bill Owsley wdows...@yahoo.com writes: I hear tell that a standard gain horn is defined by it's construction and is used as the standard for calibrating other antennas. Maybe that's why it's called a standard gain horn ??? That may be so: it would be better to use the word 'calculable' for such devices rather than 'standard'. Calculable devices are very attractive, because you can often make them out of simple materials. Obviously, they won't be as accurate as one made by a national metrology laboratory, which might be within +/-10^-6 or better, but if you can get within 0.5 dB for a few dollars, you've won. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk For very important information, please turn over. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Standard Gain Horn Antenna Calibration
Ed makes an excellent point regarding the coax-to-waveguide adapter. A simple way to protect against damage is the use of an external adapter used as a “connector-saver.” Ken Javor Phone: (256) 650-5261 _ From: Price, Edward ed.pr...@cubic.com List-Post: emc-pstc@listserv.ieee.org Date: Wed, 13 Feb 2008 09:36:00 -0800 To: emc-p...@ieee.org Conversation: Standard Gain Horn Antenna Calibration Subject: RE: Standard Gain Horn Antenna Calibration _ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Grace Lin Sent: Wednesday, February 13, 2008 6:38 AM To: emc-p...@ieee.org Subject: Standard Gain Horn Antenna Calibration Dear Members, Does a standard gain horn antenna (http //www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. A standard gain or pyramidal horn, with a waveguide feed, is a mechanically simple device. After an initial calibration, it should maintain its values without drift unless mechanically deformed. How much the gain will change with mechanical distortion is unpredictable, so I doubt that period pictures could reasonably document the antenna's condition. A double-ridged horn adds more mechanical complexity, making real periodic calibration verifications even more important. And then there is the waveguide-to-coax transition found on many lower frequency horns. You can electrically damage the little post inside the waveguide by arcing or excess heat or mechanical shock. Also, this post is often mounted to the rear of the coax adapter, and damage to the connector (from a bad cable connector) can translate into physical damage to the post location. Everything in this area is very mechanically sensitive, and also invisible to the user. I keep all of my horn antennas, both coax and waveguide feed models, on periodic calibration. Ed Price ed.pr...@cubic.com mailto:ed.pr...@cubic.com mailto:ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Standard Gain Horn Antenna Calibration
I hear tell that a standard gain horn is defined by it's construction and is used as the standard for calibrating other antennas. Maybe that's why it's called a standard gain horn ??? Grace Lin graceli...@gmail.com wrote: Dear Members, Does a standard gain horn antenna (http //www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. Also, when measuring radiated emission, what is the difference between using a double ridge waveguide horn antenna (http://www.ets-lindgren.com/pdf/3117.pdf, http://www.ets-lindgren.com/manuals/3116.pdf) and a standard gain horn antenna (http://www.ets-lindgren.com/manuals/3160.pdf)? I can find a double ridge waveguide horn antenna to cover frequency range of 18-40GHz. For standard gain antennas, I need at least two to cover the same range (more calibration cost if calibration is required). Thank you and look forward to hearing from you. Best regards, Grace Lin - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - Bill You can say what you want about the South, but you never hear of anyone retiring and moving North!!! _ Looking for last minute shopping deals? http://us.rd.yahoo.com/evt=51734/*http //tools.search.yahoo.com/newsearch/category.php?category=shopping Find them fast with Yahoo! Search. - --- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: Standard Gain Horn Antenna Calibration
_ From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Grace Lin Sent: Wednesday, February 13, 2008 6:38 AM To: emc-p...@ieee.org Subject: Standard Gain Horn Antenna Calibration Dear Members, Does a standard gain horn antenna (http //www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. A standard gain or pyramidal horn, with a waveguide feed, is a mechanically simple device. After an initial calibration, it should maintain its values without drift unless mechanically deformed. How much the gain will change with mechanical distortion is unpredictable, so I doubt that period pictures could reasonably document the antenna's condition. A double-ridged horn adds more mechanical complexity, making real periodic calibration verifications even more important. And then there is the waveguide-to-coax transition found on many lower frequency horns. You can electrically damage the little post inside the waveguide by arcing or excess heat or mechanical shock. Also, this post is often mounted to the rear of the coax adapter, and damage to the connector (from a bad cable connector) can translate into physical damage to the post location. Everything in this area is very mechanically sensitive, and also invisible to the user. I keep all of my horn antennas, both coax and waveguide feed models, on periodic calibration. Ed Price mailto:ed.pr...@cubic.com ed.pr...@cubic.com WB6WSN NARTE Certified EMC Engineer Technician Electromagnetic Compatibility Lab Cubic Defense Applications San Diego, CA USA 858-505-2780 (Voice) 858-505-1583 (FAX) Military Avionics EMC Is Our Specialty - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: Standard Gain Horn Antenna Calibration
Grace, horn antennas need to be calibrated at least once. Since they have no active elements or baluns, you can recalibrate them by taking pictures of them and guaranteeing that they have not received any damage within the last year (dents, scratches, etc.). We calibrate our horns every year but auditors have told me that we really don't need to. I don't know about your standard gain horn question as we only use double ridge. Bob Heller 3M EMC Laboratory, 76-1-01 St. Paul, MN 55107-1208 Tel: 651- 778-6336 Fax: 651-778-6252 = Grace Lin gracelinnj@gmail .com To Sent by: emc-p...@ieee.org emc-p...@ieee.org cc Subject 02/13/2008 08:44 Standard Gain Horn Antenna AMCalibration Dear Members, Does a standard gain horn antenna ( http://www.ets-lindgren.com/manuals/3160.pdf) need to be calibrated when used for radiated emission measurement? A sales representative keeps telling me that calibration is not required for this type of antennas. This is against my understanding that all antennas for radiated emission measurement must be calibrated. Also, when measuring radiated emission, what is the difference between using a double ridge waveguide horn antenna ( http://www.ets-lindgren.com/pdf/3117.pdf, http://www.ets-lindgren.com/manuals/3116.pdf) and a standard gain horn antenna (http://www.ets-lindgren.com/manuals/3160.pdf)? I can find a double ridge waveguide horn antenna to cover frequency range of 18-40GHz. For standard gain antennas, I need at least two to cover the same range (more calibration cost if calibration is required). Thank you and look forward to hearing from you. Best regards, Grace Lin - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald: emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
