How to find the noisy poles
The very best detection equipment, the professional tools that should be purchased used by utilities, can be found at Radar Engineers. However, it isn’t financially practical for the average ham to own such devices.
I have found that the best way to find noisy poles is to get the general direction(s) from your VHF beam (2m or 6m) at home, OR to drive around in your car with an omni antenna and a radio on 6m or 2m AM (or SSB). Doing it on HF might work, but the noise general travels further on HF, so using HF probably won’t get you as close to the source as VHF will. Then, you can get out of the car and use a handheld antenna to find the offending pole(s). Generally speaking, it may be best to hunt for the noise on the highest frequecy on which you can hear the noise.
I have had very good success using the Yaesu FT-50 and FT-60 HTs, sometimes an Icom IC-2720 in the car, since they have AM. (Note: don’t bother if the rig is FM-only.) For antennas, you can make your own beam if you wish, but I have found the Arrow Antennas units to be very good. Specifically, the 3-element 2m beam does a very decent job on 2m, but I have also found that the 7-element 70cm beam (picture shown below) is simply superb, if you can get close enough to the noise to hear it on 70cm, because it is so directional. I put the rig on a 440MHz freq in mode AM, and the buzzing-hunting doesn’t take as long. See my 1-minute video for a very brief demo.
You can also use loops, hand-held broadcast-band AM radios, etc. Some guys have success with the MFJ-852 unit. I would still suggest, however, that a mobile or handheld 2m/70cm rig on AM with the Arrow beams cannot be beat without spending a boatload of money.
Look at the suspect pole from at least 2, preferably 3, different directions. Then look the pole over visually. You might tap on it with your hand — though some folks suggest not doing that — I would say to obey the law, make sure to be safe, and don’t hit it with your hammer, your pickup, or anything like that. When you smack it with your hand and the noise audibly changes, you know you’ve found a problem. Write down the pole #, and the address and specific location, and supply that info to your utility; see the how to contact your utility link.
If the wooden pole is rotten, and in need of replacing, count yourself fortunate! Tell the utility, and they very well might need to replace the entire pole, which means all new hardware, and no more noise.
This is a picture of the Arrow 7-element 70cm beam: