Old thread but I don’t get to look at this board as often as I like. It was a rainy Sunday afternoon and I saw this. I have been using a Rigol DSA815 for a number of years to do NRSC measurements. It does have 300 Hz. RBW and peak hold. What is not so good is the phase noise to get to -80 dBc for measurements beyond +/- 75 kHz., especially since no video filtering can be used. The spec sheet shows RWB from 10 Hz to 1 MHz in a 1-3-10 sequence:
The solution for the phase noise issue is a Chris Scott AM notch filter to notch the fundamental for the measurements beyond +/- 75 kHz.
While I agree that the Rigol DSA815 might not be the as capable as other SAs, it is capable enough for NRSC with some additional equipment. BTW, before the Rigol, I was using a Tek 2712 which had the same issue with phase noise.