S-Points, are they useful

The S-Meter in an Amateur Radio Receiver/Transceiver is an indicator for the received signal strength (Strength Meter). On HF, signal strength 9 (S9) has been defined to be an input power of -73dBm @ 50Ω (dBm is power expressed as decibels relative to 1mW). This is a level of 50µV (microvolts) measured at the antenna input port. Each step between S-Units corresponds to a difference of 6dB. 6dB is equivalent to a power ratio of four and a voltage ratio of two. (S-Point History)

The term S-Unit/point is used to refer to the amount of signal strength that move the S-Meter indicator from one marking to the next, i.e. it moves by one S-Point/unit. On Amateur Radio equipment, most S-Meter markings are from S1 to S9, with marking above S9 in 10dB steps.

To be able to add meaning to the S-Meter report, I believe, Amateur Radio Operators should know how the S-Meter of the radio equipment is tracking against the IARU standard. Quite a few Amateur Radio Operators either don't seem to care or don't understand the value of having an instrument that can track precise. Let's consider the below.

• Profiling a couple of antennas by listening to the background noise.  On antenna one we see a noise level of S4 (-103dBm). Switching to the second antenna we see that the S-Meter indicates S6 (-91dBm). We could now conclude that there is a noise difference between ant1 and ant2 of 12dB.
• Checking the front to back ratio of a Beam (Yagi/Uda) Antenna. Receiving the signal from the front of the antenna the meter reads S9. Turning the antenna 180 degree, i.e. pointing the back of the beam to the signal source, the meter reads S5. This would indicate a nice 24dB(4 S-point = 4*6dB = 24dB) front to back ratio of the Antenna.
• Comparing receiver prowess, i.e. using a receive splitter to split the receive signal equally to compare receivers. If receiver-1 is displaying a S3 and receiver-2 is displaying S7 on the same signal. 

We can clearly see that if we do not know what our S-Meter really is displaying, every above scenario becomes guess work and would most likely lead us astray.

 

So to come back to the question at hand, I'd say since Amateur Radio is a Technical Hobby it would be nice to provide and receive a correct S-Value report, one that is trackable to a standard. An even better report would be SNR (one for the future).

However, if one uses the Radio for NET chats and contesting, then who cares if the S-value is S9 or S9+20dB or S5 for that matter.

Would it then not be more appropriate to say the quality of your signal at my station is Q5 or Q4, i.e. going back to the old Q(SA) system. One can always ask for an S-value, but what would be the usefulness in a value that does not track to a standard.