[TowerTalk] inserting tuned coax length to help match vertical antenna

[Jamie WW3S]

Trying to help the local club get a better match on their 2/440/6m 
triband antenna, 2 and 440 are great, the swr is a little on on 6m, 
52.680, a little more than 3:1 or so, We have access to the feedline at 
the base of the tower, but no access to climb the cell tower we are 
co-located on.  Is it possible to insert either a 1/4 or 1/2 wave piece 
of coax, tuned to 52.68, to help match the feedline a bit better?