antenna options for a jeep in heavy brush...

i just bought the midland mxt400 radio. VERY VERY new to this! me and my hunting partners have garmin 520 radios so this type of radio in my jeep will make for a good device for me.
I have a CB in my jeep. the antenna deploys out of the rear qtr panel into a big chrome ball attached to a spring and a 14’ antenna. WOULD LOVE TO USE THIS BUT I’M TOLD IT WON’T WORK. i think i need a uhf 450-470 MHz antenna???
what antennas can i use to replace this antenna? use the same hole? in a lot of brush w this jeep so the spring loaded setup is awesome!
HELP a rookie out w some simple english so i can get it running. web links to product would be cool too??? :eek:

At 400mhz antenna length should be 6in or less
Please note that the Wavelength at 400mhz is .66 meters which equates to 25.74 in. The higher the frequency the shorter the antenna length.
The lower the frequency the longer the antenna.

Antenna peak signal is at ? wavelength

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