I have a board that is failing radiated EMC tests. There are narrowband spikes with 50 MHz intervals (300 MHz, 350 MHz, 400 MHz, etc.)
I believe it has something to do with a clock (I suspect so since 50 MHz seems to be the "base frequency" and that is a very even number).
EMC chamber time is very expensive so I thought I would look for the problem with near-field probes. I have access to a spectrum analyzer, but I haven't used these probes much before.
So what is the logical choice when one is looking for this 50 MHz clock (might be some internal clock on some chip since I have no such crystal on the board), H-field or E-field probes?
What are the two types of probes usually used for? Some example? Is one for current and the other for voltage?