Is it possible that the correction factors you got from RefRad* cannot give the same good results when measuring real EUT? In other words, different EUT would probably need different correction factors. I'm just curious.
*RefRad is a comb generator produced by EMCo - a part of ETS now. Barry Ma --------------- On Wed, 12 January 2000, [email protected] wrote: Barry, Thank you for your comment. What we are trying to do is establish better correlation between the chamber and OATS so we minimize our time in the heat, humidity, rain and bugs (South Florida) at the OATS. We are not trying to replace the OATS with the chamber. We have recently been evaluating a REFRAD for correlation purposes. So far the results with the REFRAD factors have been very good. The emission in the chamber was 7 dB off from the OATS value, but this correlated to within 1 dB of what was predicted by the REFRAD. I admit our sample universe is small at this time with only a handful of emissions to compare to. But these first results are promising. Don Umbdenstock Sensormatic ---------- From: Barry Ma[SMTP:[email protected]] Reply To: Barry Ma Sent: Tuesday, January 11, 2000 5:55 PM To: [email protected] Cc: [email protected] Subject: RE: Chamber and OATS Coorelation Mirko, I happen to have a copy of CISPR 16-1 at hand. Clause 16.6 "Open area site validation procedure" reads: ... The deviation between a measured NSA value and the theoretical value shall not be used as a correction for a measured EUT field strength. This procedure shall be used only for validating a test site. ... The above statement is not followed by any explanation. What do you think the reason is? My guess is that there are lot of factors causing inaccurate E-field measurement. The collective result of those factors cannot be simply corrected by changing antenna factors. At the end of your message, however, you stressed on "for a specific test setup". May we try this "illegal" correction procedure with caution only "for a specific test setup" and for a specific frequency range? Hopefully it might be worthwhile to try. Barry Ma Anritsu Company Morgan Hill, CA ----------- On Tue, 11 January 2000, "Matejic, Mirko" wrote: Richard, You could improve correlation by adjusting chamber antenna factors for a correlation differences which you can get from NSA measurements one at OATS the other in the chamber with a fixed antenna height. You could also determine correlation differences by comparing measured field strength levels from battery powered comb generator. Fixed vs. 1-4m antenna height among other factors will always create unpredictable correlation for a specific test setup. Mirko Matejic ______________________________________________________________ Free Internet Access from AltaVista: Get it, share it & win! http://freeaccess.altavista.com/pika/www/initweb.jsp --------- This message is coming from the emc-pstc discussion list. To cancel your subscription, send mail to [email protected] with the single line: "unsubscribe emc-pstc" (without the quotes). For help, send mail to [email protected], [email protected], [email protected], or [email protected] (the list administrators).
