Interference on WWV

What's up with WWV? for the past few days, there's a very loud buzzing noise on WWV frequencies of 5, 10, 15, and 20MHz. 2.5 MHz sounds fine (during the appropriate hours, of course). This noise completely covers the voice and signal. What might account for this? If it were some sort of local interference, I would assume all other shortwave frequencies would be affected, but no. CHU Canada comes in fine, as well as all the HF utility stations that I monitor. This occurs on all my shortwave equipment, not just one radio, from Airspy HF+ to Icom IC-R70 and CommRadio CR-1a.

I just took a peek at 10 Mhz.. There is a noticeable buzzing sound there, but I'm pretty sure in my case, it's local.

I went up to 15 Mhz and can't hear Fort Collins at all right now (17:40 UTC).. But WWVH is coming in nicely from Hawaii. I don't hear a buzz on that signal.

No buzzing on any of the WWV freq's here in the PNW.

I use the WWV frequencies weekly to check WSJT-X digital demod software calibration.

2.5, 5, 10, 15, 20 and even the 25MHz frequency are all coming in clear in the Northwest without any issues.

10MHz is clear as a bell here in Northern Illinois..

It does sound like local interference. But why wouldn't nearby frequencies be affected? Could it just be a coincidence that I hear it on all WWV frequencies?

EDIT: I just checked again, and now the interference is gone. In the case of 5 MHz, there is some sort of interference that spans from approximately 4975 to 4995 khz, and it's shifting back and forth, sometimes moving over 5000 khz.

Sometimes a STANAG-4285 signal will show up on their freq. But I'm leaning towards local RFI such as a Plasma TV or something, since nobody else seems to be hearing it.

UPDATE: Solved

Turns out it was the 12 volt "wall wart" transformer that powers my Wellbrook Loop antenna. I swapped it out for a different one and the noise disappeared.

Should I assume that the original wall wart developed a defect, and I should trash it to avoid future issues with something else?