K3 Noise Blanker Magic

So many things to love about the K3, but chief among them is the noise blanker. I have an almost constant S7 to S9 noise level (from the power transformer that is about 30 feet away from my antenna, I suspect) and the K3 takes it pretty much in stride.

This example was recorded earlier this morning (UTC; last night local time) listening to IS0HFE in Sardinia calling CQ on 40m. I worked him a few minutes later before I lost him to QSB. I honestly don't know that I'd have even heard him on most other radios I've used in the past -- certainly not the JST-245 which despite being my second favorite rig ever had a noise blanker that was practically useless.

In hindsight I wish I'd done a side-by-side comparison with the Flex 1500. I've had no luck finding a NB setting with the Flex that removes this level of noise without completely distorting the signal. I'll chalk it up to operator incompetence until I know for sure, but I'm pretty sure I've tried every imaginable setting in PowerSDR and it hasn't come close to the K3 yet.

The more pressing question is, how do I get rid of this noise? There are times it goes away all on its own (when it's raining a lot, it seems... unless that's just a coincidence). It was quiet a few weeks ago until (of course) NAQP CW weekend, and I had to deal with this for the entire contest. I've been meaning to head outside with a portable receiver and a loop antenna to see if I can't get a fix on the noise and confirm that it's the transformer but I've had other pressing matters of late. And if it is the transformer, how do I approach the utility company in order to get results?

But for now, I just push the NB button and the noise drops to a level at which I can at least hear some of the weaker signals, though the noise level remains S5-S6 at the best of times.