Why is it LSB below 10MHz and USB over 10MHz?
From a student: “Why is lower sideband used below 10MHz, and upper sideband used over 10MHz?”
When early SSB radios were built, it was technically challenging to create upper sideband, and so it was cheaper and easier to make radios using lower sideband. Nowadays, this isn’t such a big deal, but the convention has stuck. So, it’s now a historic reason.