I have a loaned Keysight E4403B, so I used the opportunity to play a little with it.
Here are three Youtube videos, that show the same CATV signal on:
- Keysight E4403B
- Siglent SSA3021X
- Rohde & Schwarz CRTU
- Start Frequency = 50 MHz
- End Frequency = 850 MHz
- Span = 800 MHz
- RBW = 1 MHz and 0.1 MHz
- RBW/VBW = 0.1
An intersting fact, at least to me: on the third video, if you increase volume, you will hear a chirping from the E4403B right in the beginning. Then I turn off the AUTO ALIGNMENT and the chirping is gone. Turns out that this is a normal behaviour and what you are hearing is the RF Frontend aligning itself at the end of each sweep, which results in relays clicking.
More info about this: Why is there a "chirping" noise coming out of my ESA Series Spectrum Analyzer?
I mention it, because it was driving me crazy - I feared that after repairing the PSU, there was some other fault...