Within a few minutes, I positively identified the broadcast from the phrases "BBC World Service" and "BBC News". BBC's current frequency guide for Southeast Asia matches the data on short-wave.info, confirming broadcasts originating in both Thailand and Singapore on 9740 kHz. I'm assuming that I'm receiving the stronger of the two signals (which is from Thailand). In this case, Nahkon Sawan, Thailand to San Francisco, California represents a reception distance of approximately 7900 mi / 12700 km.
Links relevant to BBC's Thailand relay: