I'm looking to install dual band mobile with a single antenna output (something like a FT-7900). My question is what sort of antenna is required? Currently I have a scanner with a Larsen tri-band antenna on a lip mount and a commercial UHF radio with a 1/4 wave antenna on a lip mount. I'd like to leave both in place and add the new dual-band, but don't want to add another antenna. Do I need to diplex, or can I splice into the tri-band antenna? If I need to do either what is the suggestion for the components needed to do that? Is it sufficient to add a BNC "T" to the scanner line to use the dual band radio?