Interesting! I have been plagued by a similar QRM for over three years, which seems to be centred on the 14MHz band. It is distributed over an area of a couple of miles mainly by the telephone lines.
Failed Wart: Post Mortem... Its dc-o/p is modulated with 100pps pulses. These contain an RF-burst envelope, chirping from MF to HF. System had been working fine for 3yrs - then owner lost sync & B/B
Might be of general interest... Severe MW pulses with mains PRF, common-mode via BT-lines throughout village [300yds from MF antenna]. Two Belkin Wireless Routers powered-up, but no Sync LED & no B/B