Joe, Our laboratory was used to compare readings in the low-end, specifically 30 MHz. to 90 MHz. on an OEM product In particular the OEM customer who maintains 10m indoor anechoic facilities claimed that our customer was failing the CISPR22B limits by 5-6dB in the above freq. range. After taking our own readings and comparisions with 3 different OATS in a 1.5 day turnaround we showed a 1.8 - 2.5 dB correlation between the OATS!!!!!! The meter reading at all three sites indicated a passing margin of 3-4dB using the identical product and configuration previously tested in the Anehoic Chamber. All OATS test sites used contained different test, equipment, ground structure, ambients. etc. Of course only 3 or 4 frequencies were observed for this comparison but we found our OATS correllation from site to site to be extremely good in this case.
In my opinion, for engineering purposes only the 10m chamber is ideally suited for accomplishing the task of high volume testing. Zero ambients, and automated testing is the only way to fly. However, with all the improving absorber technology as such I still believe for correlation and repeatability there is no equal to the 10m OATS, especially for those located in a low ambient environment. Our faclity is located deep within a canyon at the base of a 4000 foot mountain in So. Cal near a creek bed. The floor noise is excellent and the ambients are low. Line noise is non-existent. Our customers see many advantages. Hope this helps. Regards, SJK --------- 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).
