As an electrical engineer I learned that “all digital devices comprise analog components”.  This has remained true even as quantum effects are now being utilized in computational logic gates (they are defined by analog wave functions).

Radio waves, especially those used by amateur radio operators, are analog signals transmitted and received by oddly shaped and configured pieces of conducting metal parts known as “antennas”.  And the techniques to couple a useful signal to them are part of the arcane art and science of amateur radio.  The sharing of this knowledge is a big part of the ham radio community ethos. 

So I should not have been surprised to receive an email asking for help with “s-meter calibration” of an antenna.  It was addressed to my dad, who died in 2016, but whose email address has been set to forward everything to me.  I get occasional messages from this account, but with diminishing frequency, and usually from some company or service he had subscribed to, but for which there was no “unsubscribe”.  In this case however, it was from one of his fellow ham radio acquaintances looking for advice.