It seems that there is a firmware doing SSB (I don't understand if it's real SSB or something emulated).
Anyway, the radio chip of UV-K5 is able to manage distinct I-Q signal, so it just a matter of implementing SSB via software.
SSB requires more sophisticated frontend than FM because the channel is smaller and reuqires less noise. There are HF radios that use a simple signal generator, but then need a complicated frontend to be able to received anything. The cheap SDR HF radios are $500 when SDR VHF handhelds are cheap like this one.
