Its easy if they share the same feedpoint. You can first make the 6" 460MHz element stick straight out of the connector then attach the 3 1/4" 800MHz element right where the 6" element first exits the connector but first bring the 800 element sideways for maybe 3/4" then bend it straight up. The whips will interact a bit and should be tuned but your dimensions should be close enough to work.
I was doing basically the same thing about an hour ago modifying an AOR SA-7000 to improve FM broadcast and NOAA 162MHz weather.
I threw away the stock mystery loaded whip which doesn't resonate anywhere I needed it and replaced with a 32" whip tuned to 98MHz with a secondary 16" whip tuned to 162MHz attached to the same feedpoint with a tiny SS hose clamp and it bends away from the long whip about 2" before going straight up.
I measured the stock antenna at 162MHz then after modification and 162MHz weather came up about 12dB over the stock whip, which is not a trivial amount and it proves the two whips can coexist.
Originally Posted by dave3825
I think you misread my post..
The ground plane I made is for 460MHz and the center element is only 6'' long.
I would like to know where to add the 3 1/4 800MHz element, if this will even work..