In the US, the segment 50.0-50.1 is CW only (auto beacons are only allowed in 50.6-50.8 range...manned beacons can be anywhere)...outside the US, in those countries where 6m is authorized, they could allow data or other non voice modes..
However, it could be a pulse from a PC or other device with some digital clock timer in it...CPUs are bad about putting noise out into the low VHF bands....
I agree with Mark...if its 24/7, its likely something local to you or the neighborhood..depending on how strong it is, it could be in violation of Part 15...(it isnt send only prime numbers is it??
Chris
WB5ITT