A Spectrogram of the Signal
During the QRP To The Field Contest on April 28th, 2001 I noticed a broadband interference throughout the CW portion of the band. A day later and it was still there. Judging by the fading a phasing characteristics it is obvious that the emission was arriving at my location via skywave from some long distance away. The signal peaked at an S9 and considering that the emission was broadband in nature this indicated that the power of the transmission was considerable. I am very familiar with most all natural occurring emissions and I suspect that this one is man made.
I can't know for sure without further investigation but I suspect that the signal was a spurious emission from a powerful shortwave broadcast transmitter (DRM?). The spectrum of the signal was roughly 50 kHz wide and it occasionally drifted out of the bottom of the 20m band and then it would come back.
The following recording was made on April 30, 2001 at 0023 UTC on 14.009 MHz.