I have a Outdoor VHF-Hi/UHF Scanner Antenna Model: 20-176 from Radio Shack mounted on a 2x4 set about 5' above the eave of my house. I have a metal roof, so I know it can cause interference. I can receive our local weather net frequency using a rubber duck or a telescopic antenna on the scanner. When I switch to the outdoor antenna I can take the squelch completely off and hear the transmissions through static, if I switch to the indoor antenna's they come in loud and clear. What can I do to improve the outdoor antenna's reception?