As to the tests; for cable loss & for bad fittings for the most part.
Damping can be measured from one end, if the other end is open or shorted (i.e. 100% reflection), and if it is granted that no other reflections occur along the cable (e.g. due to defects, or bad matching). Both, the forward and reflected wave are attenuated by the damping. Therefore the one-way damping is 1/2 of the observed |S11| (in dB) then. If there are other reflections too, besides from the open/shorted far end, then it becomes difficult to separate their contributtions to S11, and damping is no longer |S11|/2, of course.
Scalar return loss measurements are basically possible without VNA, but in addition to SA and tracking generator a directional coupler/bridge (with good directivity) ist required.
This method (and its limitations) was recentyl discussed here:
https://www.eevblog.com/forum/rf-microwave/can-a-siggensadirectional-coupler-be-used-as-a-poor-mans-scalar-analyzer/[ For this purpose, Siglent obviously offers
this kit as accessory for the SSA. 20dB directivity is a bit meager, though. For a scalar analyzer, good directivity is essential (for a VNA this is less important, since the vector error correction can compensate it mathematically). ]
If the aim is to localize a bad connector, or a cable damage somewhere in the middle (i.e. "discance to fault"), then you need TDR. Traditionally, TDR is done in the time domain (-> fast pulse generator + fast scope), but alternatively it can be also calculated from S11 measurement in the frequency domain via IDFT. The S11 measurements must be
vector measurements, though. It is not possible to calculate it from scalar measurements (i.e. magnitude only). Chapers 1-5 in this
application note give an overview how it basically works. The presentation of the results may vary between different VNA models, but the underlaying principle is basically the same. It is also possible to calculate an impedance profile (i.e. impedance vs. distance) from the S11 measurements (no magic either -- just a variation of low-pass step processing). NanoVNA V2 firmware supports this display mode, too. I don't know if the Siglent SVA does?