We have a PMM 7000 precompliance receiver that we use for all kind of EMC testing. However we recently had a CE failure at a test house that surprised us as we didn't see it on our setup. That made us start poking around and we came up with two potential issues:
1) In the 150kHz - 30 MHz region the minimum step size for the receiver is 10kHz. The RBW is set to 9kHz as per CISPR. Is that not an issue? If the filter was perfect then it would leave narrow bands between the "bins". Perhaps the steepness of the cutoff of the filter is not that steep? Anybody got any thoughts?
2) We have seen significant differences in results sometimes with different dwell times. I wondered if this could be the issue. I struggled to get a straight answer out of the test house as to what we should use. I guess as long as it needs to be to see worst case? Any advice?