A few years back, I was having a serious problem with loud interference on the AM bands. It was a loud buzz that nearly stretched across the entire dial. Sometimes it was there, sometimes it wasn't... but usually there more often than not. This applied to both battery operated and house current sets.

One evening while listening (no interference at this particular moment), my phone rang... it was my neighbor across the street. I turned the radio down some and spoke to her for a few minutes. During our conversation, she was trying to look something up in a book. She told me, "hold on... lemme turn on the light." At that moment, that damn buzz came in loud and clear! WTF??? I asked her to turn off the light for a moment (this really confused her as to why I'd want her to turn off the light). She did so, and the buzz stopped. Mystery solved!

The light she was using was one of those bright pole lamps with the dimmer... they were popular for catching drapes on fire. I was really amazed that the light in her living room was causing the buzz in my radio from across the street!

I've installed a couple of dimmer switches... I have one here at home for the living room light, and one at my camp for the front porch light. Both are the type that appear to be a normal wall switch, but dim the light as you move it downward.

Here at home, the switch does not seem to interfere with my radio... unless you get really close to it... say about a half foot or so. At my camp, the dimmer switch there will cause such a loud buzz that you can't listen to the radio... and even if I move to the opposite side of the house! It's loud!!!

I never thought to try taking the radio outside with the light on... and see how far away I have to be from the house before the buzz starts to fade away. I will check that this weekend when I go there.

Has anyone else here had mystery interference... and finally figured out where it was coming from? :scratch2:

I have power line noise that started a few years ago. I found it out by holding a battery powered transistor radio and tuning it to an unused spot on the dial, and walking up and down the street. I have semi-high tension power lines about 50 feet from my house. It's just about killed any AM or shortwave reception to the point that I didn't even bother putting up an outdoor wire. I just packed the DX-440 away, and don't hardly use AM on my Yamaha tuna.
Tom

I have it! But it was pretty easy to figure out.

The traffic control signals at the intersection a couple hundred feet from my living room. On certain stations you can clearly hear the "walk" signals flashing and changes from green-yellow-red.

It probably would have perplexed me for a longer period of time, but I experienced the same effect several years ago at a pay phone outside my place of employment. I could watch the lights change and hear the static and buzzing change pitch in the receiver. :scratch2:

My previous house had reception somwhat akin to running the antenna through a microwave oven. Jaunting around the neighborhood I found a corner a few blocks away that for some reason completely flooded the band with harsh noise. Nothing unusual power line wise, never figured that one out, but it still does it when I drive past that spot...