How stable do our microwave LOs need to be?

SSB/CW need short-term frequency accuracies of ±50Hz
current narrowband ‘digital’ modulation schemes such as JT44 need around 3Hz.
at 148GHz that equates to 1 part in 3.109 for SSB/CW and 1part in 5.1010 for JT44!
even at 10GHz we need 1 part in 2.108 for SSB/CW and around 1part in 3.109 for JT44!

SSB/CW need short-term frequency accuracies of ±50Hz