27635 USB 1830-1845 + UTC

[R4002]

Hearing some sort of polytone "jingle" on 27635 USB.  Usually when the band is open, this frequency is occupied by truckers operating freeband (since it is CB channel 19 with the flick of the bandswitch on export/"10-meter" radios).  Today, however, I've been hearing this weird polytone transmission every few minutes.  Great variation in signal strength as well.  Right now its around S3 but it was a clear S7 about 10 minutes ago (1640 UTC).  

I can hear some USB voice traffic underneath it from time to time.  Anybody know what this is?  I'm thinking its just some sort of elaborate noise toy that somebody is running with high power and/or an awesome antenna but wanted to get a second opinion by more experienced ops (or somebody who can look at it on a SDR waterfall/spectrograph

Edit:  Now at 1654 UTC it has shot up to S9.

[refmo]

This is a popular frequency for ROS mode digital chat, which is almost sure to be what you were hearing.
Googling ROS digital mode should point you toward a free decoder you can use for receive and transmit.