I have dishnet but in my area my locals are not available in hi def. So I put up a large antenna in my attic and much to my surprise, I was able to get all my locals. All the towers are about 20 miles away and nearly all in the same area. My signal strength is from a high 90s on CBS to a low of 70-74 on Fox. Everything is working very well and I suspect I should be satisfied but sometimes my Fox signal fades and I lose the picture and sound. Usually only for a brief period but it is rather annoying. Is there a way to boost or amplify the signal?