Re: the coax from the antenna to your scanner.
Buy the best coax you can afford!
You can have the most amazing antenna on a 200 foot tower. You can purchase the best VHF/UHF/SHF receiver in the world. But, it will all be at the mercy of the coax that runs between the two!
The cable should be made by Belden (THE best, IMHO!) At a minimum, I would use RG-8x. If possible, the jacket should be non-contaminating
and the core should be solid, but foam will be okay as long as you're buying Amphenol. The center conductor should be stranded, not solid. The connectors should be silver teflon and manufactured by Amphenol. Chances are with most base station scanners, you will need a BNC connector at the radio end. Depending upon the antenna itself, you may need to have a PL-259 ( http://www.dxengineering.com/ShowProdImage.asp?URL=http://www.dxengineering.com/images/prod/pl-259_prod.jpg
) or BNC ( http://en.wikipedia.org/wiki/Image:BNC_connector.jpg
). Again, the connector should be silver teflon by Amphenol.
The coax run itself should be as short as possible between the radio and the antenna. DX Engineering can make you a custom cable to the exact length you need. This way, you're getting great cable, real RF connectors that have been properly soldered onto the cable (and NOT crimped!). Here's their page with the RG-8X: http://www.dxengineering.com/Products.asp?ID=239&SecID=127&DeptID=33
Please, please, please, avoid cheapy coax found at RS and CB shops. It tends to be inferior and just doesn't last!