Bob,
It is possible that the power lines are an issue but check everything else first.
Which firmware version are you using ?
Do you have a high rate of CRC errors or discards ?
What is the signal quality ? ( run the antenna alignment test)
Anything close to the frensel zone ? what showed up in your site survey as potenial problems ?
How long is your coax at both ends.
What do you see in the channel activity test ? Have you selected the least congested channel ?
Has this always happened since it was installed or just started
I know this is a lot of questions but these are the first things you need to check when you troubleshoot bridge links
