spectrum analyser or oscilliscope. R&S vs Siglent, Rigol, other.

[loki42]

I'm wondering if my R&S RTM3004 (COM, all options) is suitable with the FFT stuff for basic pre compliance with a LISN or if something like the FPC1500 would be a good addition. Is there other options i should look at? I won't be using it a lot and it's right next to my computer so I'd be happy with USB based systems as well. I enjoy the R&S UI / general vibe but also have Agilent / Keysight gear and open to others. Are there hardware agnostic EMC software like R&S Elektra? Is it worth it for occasional use?

[loki42]

I've also got some rigol gear so I'm open to Siglent & Rigol too or other options.

[Kean]

For conducted emissions with a LISN you are generally doing from 9kHz or 150kHz up to 30MHz, so it doesn't require an expensive SA.
I mostly use a Rigol DSA815 with Tekbox TBLC08 AC LISN and occasionally with a TBTC2 TEM Cell.  For higher frequency measurements I have a SignalHound SA44B.

For software I use the Tekbox EMCview which works with various Rigol, Siglent, & low-end R&S SAs (license is tied to the SA serial number).
https://www.tekbox.com/product/emcview-pc-software-emc-compliance-testing/

Not sure about the FFT suitability, but it seems to me that it would be too limited due to the lack of scope dynamic range even with 10-bits, let alone other features in an SA with EMI filter.

[nctnico]

IMHO a spectrum analyser will be more convenient and it has the required dynamic range. For conducted emissions, the limits are ball park -50dBuV which is a signal level that is below what you can measure with a common DSO.