Mapping QRM

QRM, or man-made interference is a problem for amateur radio.
After all - you aren't going to be able to work an S5 signal if you've got S7 of background noise.
Common sources of QRM are plasma TVs, cheap switched-mode power supplies, cheap broadband-over-powerline adapters, and now more recently solar panel inverters.

Often the best way to locate the source of QRM is to take a cheap AM radio, and walk/drive around your neighbourhood until the signal is very strong. Then you have the dubious pleasure of knocking on a door, and trying to explain the problem.

I don't know whether it will prove useful, but I've written a little Android app which can record the signal from a receiver. I've only tested it with a Yaesu FT-817 and FT-857D, but it works sufficiently well. You will need to have a USB CAT cable for your radio, as well as an adaptor to be able to plug it into your phone (commonly called a USB OTG (On The Go) cable)

You can find more information and the QRM Mapper app.