There is another possibility (even though I still think it was EMI from the power lines), and it could explain the interference even with a 2.4 GHz system. There could be cable TV RF running next to the power lines. Cable TV RF can boradcast into the upper portion of the UHF frequency band which is 300 MHz to 3 GHz. A degraded cable or connector could cause the RF to broadcast out through the damaged area. I have first hand experience with this. When I was a young technician back in Cape May, NJ we had a problem once where we were getting a strange static coming over on channel 23 and 83 on our VHF marine band radios. After checking the small boat station's comms station as well as all of the boats, myself and another technician came up with an idea to locate the where the interference was coming from. We installed a KDF-538 (CGr will know what this is ) direction finder in one of our vehicles. We then drove all around the base and were able to locate the source of the interference just outside the front gate, but we didn't know what cdould be out there causing the interference. The FCC sent out a representative and they confirmed the problem was where we thought it was. This resulted in a technician from Comcast Cable coming out, investigating and finding failing weatherproofing and a bad connector on one of there lines. Once the connector was replaced, the interference was gone on channel 23 and 83. Just food for thought and I felt like sharing a little sea story [8D].

Brett