Yeap the 25s filter well , Sounds like you have the noise pretty bad then 55 that would surely make it rough on me as well , I can just wish you the best of luck in hopes you can figure out something for yourself there. As was said before , there's a good possiblity of a antenna change might be of a serious help to you ? You may not got rid of all of it , but enough for you to be a little bit more comfortable with your radios receive. They say the Wilson 1Ks and 5Ks can help a lot in situations like your own . I run a 5K drill through in my car and yes I have engine noise through my antenna , and I can here my electric fan when it comes on depending on how quit it is out there , I capped the hot wire of the fan but it really didn't help much , maybe a little , but not much. other then that , I just run my noise blankers on the radio and it is good enough for me , if it wasn't ? I truly doubt I would be using it very much at all. (The blankers work good enough in my case , I feel very lucky because I know it could always be worse.)