Yes, that is a possible answer. There were 2 jammers active last night in the 40 meter band, one was on 7140 kHz and one was on 7180 kHz, two weaker ones, probably unintentional, were on 7100 and 7220 kHz. They all started at 0335 UTC and went off air about 0505 UTC. Their actual 3dB width was only about 10 kHz, but naturally they covered a lot more bandwidth further down the power range, depending on how strong they were at your location you might have heard them up to 30+ kHz in width.
MrMomB only mentioned the 7180 kHz signal, so I was after more information to see if this jammer was a possible consideration. There was a Chinese BPSK radar in the same frequency range that is also a possibility, and there has been some true wideband data, about 24 Khz wide, showing up in that freq range.
T!