So the tester can exercise everything in one session instead of one
control per build: RF and mic gain, squelch, preamp, attenuator, NB, NR,
AGC, filter width, antenna, RIT/XIT with a clear, and the keyer speed.
The analogue scales differ between an Elecraft and a Kenwood — RF gain
000-250, mic 000-060, squelch 000-029 against 0-255 — so each is mapped
through its own full scale and shown as a percentage. Using one rig's
range on the other silently halves or doubles every setting.
Antenna only appears when the radio answers AN: a K3 without the internal
ATU has one socket, and a switch that goes nowhere is worse than none.