Sounds like a Canadian NDB (non-directional beacon).

(Mike Andrews) writes:

William Mutch wrote:

What I'm hearing is some strange signal which seems to have a
surpressed carrier on 500.0 and sidebands both above and below at about
6 khz intervals...ie +/-6, 12, 18, getting radidly weaker as they get
further from 500 khz. They are modulated A-2, MCW, with what seems to
be code with three characters...a dit, a short dah, and a long dah send
in the format {long dah, two dits, variable number of short dahs (n= 3
to ~20), long dah, pause} with timing like a busy signal on a landline
phone.

Are you really in the Finger Lakes area, or somewhere else?
(specify:_______________________)

?? Any one else with a lowfer RCVR wanna take a listen and see if
they can hear it ?? I've been hearing it from 0000z to about 0300z.

?? anyone have any idea what this might be ??

I'll fire up the FRG-100 and maybe some other gear, and take a listen
from central .ok.us; not sure what if anything will be audible here.

--
Mike Andrews

Tired old sysadmin