I really like my Rigol DSA-815TG and use it a lot, but I’m far from an expert in the field. I understand the basics (OK, a bit more than that), but realistically I hardly scratched the surface of working with them.
If you are a regular visitor of my blog, you will have noticed many reviews in which the Rigol played a major part. There are many more uses for a spectrum analyzer though, and one of them is testing / calibrating filters and cavities – if you have the tracking generator option, that is. Even a simple cookie jar has a resonance frequency, as is demonstrated in this blog post.
Great fun. Nice set of formulas there to memorize and use too. Actually, EDN’s website as a whole is worth multiple visits.