FWIW, you may wish to add a 50Hz notch filter as well. If you're in North America 50Hz noise won't be as much of an issue, but if your receiver is sensitive enough there's likely still enough of it floating around from various DC-AC inverters and the like. Of course, if you've got a good enough tuner you can likely just measure the noise in that "band" yourself.

Re: using a pipeline as an antenna - I wonder how difficult (or illegal) it would be to use mains power lines. My RF-foo is only marginally above white-belt, but I'd imagine that a fair amount of low frequency signal would make it through the transformers.