i was told not to use a spring under a 10k .
http://www.worldwidedx.com/predator...pring-under-10k-monkey-made-type-antenna.html
does it flop around or have any issues 15 ?
You can use a Pot Belly spring like is used with the 102" Whips, on the short shafts like a 6,9, or 12" shaft, and it will work just fine with the Single Coil 10K's...But don't use a spring on longer shafts like the 17,22, and 27" because it will flop around from wind drag off the coil...
Also I would not use a spring on the Dual Coil 10K's either, for the same reason...Too much wind drag, even with the short shafts.