Ever since I started hanging up antennas here, I've been plagued with a terrible, pulsing, interference across 40m.
Walking around with a short wave radio seemed to show that it was coming from somewhere near my house. It seemed to come from the mains, it was very strong near our meter box which has some suspiciously new meters in it. I could hear it at the next power pole down the street but not at my neighbor's meter box.
I decided to turn off the power to the house and while walking around looking for things that should be shut down before turning off the power I noticed the signal got very strong near a TEAC DVB receiver, model DV-B420.
When I unplugged it, the broadband, pulsing signal vanished.
What's worse is that this box makes the interference even when turned "off". As with many modern appliances, there is no true "off", it just stops putting out video. My guess is that it's a little switching power supply that just keeps going. Thankfully, this device isn't required at our place any more.
Some searching reveals that I am not alone in noticing interference from these devices.