antenna modification

Hello everybody, I have a DB201 UHF and I would like to convert it to VHF. Does any of you have try that? If yes, - How you did you extended the radiation element? - How did you seal again the epoxy in the middle of the antenna? - Did you use the same impedance adapter? or it has to be...

As a random project, I decided to modify a cheap/unused 144/430 MHz Nagoya NA-771 antenna I had lying around to work best on 700 MHz. I cut the element down to about 7.27" to perform ideally on 772 MHz (middle of the 700 MHz repeater output range) as per KD4SAI's Antenna Calculator. Question is...