Arriving today: a shiny new 70cm Yagi antenna suitable for tracing the source of this godforsaken noise. I'm pretty sure I know which utility pole it's coming from, but having a very directional antenna will hopefully clinch it. Time to learn some t-hunt skills, though in this case the transmitter is likely an accidental spark-gap operated by PG&E.
Picked up a new Kenwood TH-D75a too. Not strictly necessary for this exercise (I already had a D72), but I've had my eye on this sweet little HT for a while and this is a good excuse.