All, I know this is a bit off-topic, but I thought it was worth mentioning since it has to do with HF digital in a round about way. I recently started hearing strong interference on HF just before sundown. It would continue into the night and quit around sunrise. A faulty streetlight came to mind so I set out to look for one with a portable AM radio. My HF antennas indicated that the noise was coming from the east so that narrowed things down a bit.
I started checking telephone poles in the direction of the noise expecting to find a streetlight that was arcing / flickering, but instead, I found one that was simply not working. I checked it out anyway and was pleasantly surprised to hear the AM portable come alive with a loud buzz as I walked near it. I certainly thought I found what I was looking for - although it did seem odd that the light itself wasn't showing signs of trouble. Long story short, I gave the pole number to the town and they fixed the streetlight - the noise is gone! I checked it several times since and all is quiet. If you're experiencing this type of problem, and the timing of the noise has streetlight written all over it, you may be able to find it easier than you think. This is not the first time the little AM portable saved the day. I've had several line noise problems over the years and I've been able to track them down every time - some take a few days, others take a few minutes. A better way to go would be to use a small hand-held 2 meter Yagi with an HT capable of AM mode. That would give you real DF capability. Of course, once you find the noise, you'll have to call on the local power authority to fix the problem. We're fortunate to have an RFI investigator working for the Long Island Power Authority who happens to be a ham himself. He's fixed many line noise problems in the past and has even tracked down a neighbors electric bike charger that was causing horrendous RFI. He found it within an hour and informed the home owner about the noise. It pays to do a little investigating on your own if you intend to call your local power authority to investigate a noise problem. Keep a log that shows when the noise comes and goes as well as the direction it seems to be coming from. A recording can help narrow down the type of interference. Best of all, getting rid of the noise makes it easier to copy your favorite digital modes! Good hunting... Tony -K2MO