The last day or two I noticed an annoying QRM signal on the SDR recordings, around 6920, and way too close to 6925. Thinking back to any recent electronic devices added around the house, I remembered that we just got a new electric kettle, and I plugged in the DVD player the other day, to watch some discs from Netflix. Sure enough, it was the DVD player. Just turning it into standby mode was enough to get rid of the QRM.
Perhaps my new system should be to immediately run the SDR whenever we add any sort of electric device to the house, and verify that it doesn't cause QRM, rather than having to hunt for the offender after the fact.