antenna discone scanning

I'm looking for some advice from others that know better than me with antennas. Is it worth it to have 2 separate antennas for VHF/UHF and 800 Mhz? This will be for a base application and in the attic. I have an all-band mobile with a ground plane currently using as my base on a 10-foot mast...

Much to my surprise, when I went on the roof my 10+ year old RS discone antenna was missing 3 1/2 radials, and probably has been for years...since I recently upgraded my scanner from a pro2006 to a bcd996xt I thought I'd also upgrade my antenna and cable as well. I have 75' of LMR400 (to...