What about long-term stability?

Simple room temperature crystal oscillators don’t really have good enough long-term stability for consistent SSB/CW operation at above, say 1.3GHz, or for JT44 operation at above 432MHz.

Simple room temperature crystal oscillators don’t really have good enough long-term stability for consistent SSB/CW operation at above, say 1.3GHz, or for JT44 operation at above 432MHz.