DJ11DLN
Member
Probably tradition. Unwritten rules from back in the day had sideband on the upper channels (and sometimes channel 16). Not sure why LSB is preferred over USB.
When I was active (long ago) it was 16, 17, 18 and 36-40, but it was convention rather than a rule. Everybody used LSB, never any valid reason given. Maybe people wanted to be different since Hams typically use USB.
I heard later that the sidebanders had claimed 31-40 as well as 14-18 and would fry the ears of anyone with the temerity to key up on AM in "their" territory...but that was mid- or late-1980s, after I'd left the game. Never understood that...when I was still active a lot of sidebanders had moved into the freeband above 40. You definitely met a lot fewer idiots and a******s up there!