While listening to OTR on 6770 kHz AM, I can hear several conversations (often both sides of the conversation at once) on the following frequencies:
6760 kHz USB, 6789 kHz LSB, 6790 kHz USB, 6801 kHz USB
6790 kHz USB has been logged several times in the past, and is likely part of the Rural Radiotelephone Service (RRTS). 6789 kHz LSB is also extremely active as is 6760 kHz USB