Ridge, that is definitely the Korean numbers station V24. 5115 kHz is one of their regular frequencies (currently 4600, 4900, 5115, 6215, and 6310 kHz) but the mode of transmission is AM, not USB. Often though the audio is a little low, so USB or LSB can sometimes works best.
The same message will be repeated tomorrow at the same time, on the same freq.
Re the page Brandon linked to, I have let that one get waaaayyy out of date, but some of the core information is still good. I really need to update that one and the one on HFU.
A recent schedule for prediction can be found here:
http://token_radio.home.mchsi.com/V24_M94_latest_sched.jpg
You can see from that sched that your 1400 reception on 5115 kHz was right on schedule. My prediction chart works out to be about 90% accurate each month, there are normally some missed times lots and a couple of time slots are every other month instead of monthly.
And yep, that background noise was/is a Chinese OTHR, or OTH-B. A regular feature on that freq, there most mornings.
T!