Hello!  If you want to make your j-pole a dual bander, just extent the long 
element to 61" and it will work great on 2 meters and 440mhz.
I have one that tunes down just fine on both bands.  I put a brass bolt in 
he
short leg and soldered a nut under the cap so I can tune it without moving 
he
coax connections.
I don't know if another section can be added to get more gain. Haven't tried 
that yet!!
73 de Stan
KC5BFA
--- GEcho/386 1.11+
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