Hot from the K3UK Sked page. "Breaking news from ARRL. They concur that ROS is a spread spectrum mode and as such is not allowed by the FCC on bands below 222 MHz."
I had just been giving ROS another try with my K3 and 40W this time, and managed to complete contacts on 20m with Alabama and Washington State. Neither of these are locations I would expect to work under current conditions using another mode. As soon as the announcement was posted on the site it all went quiet.
My sympathies to my fellow digimode enthusiasts in the USA. It has always struck me as ironic that hams in the land of the free have to operate under more rigid controls than those of us in "socialist" Europe.