Hi John,
The ubiquitous J-Pole is an antenna often extolled as a 'beginners' antenna and is actually frustratingly far from such. (Usually praised for 2m VHF operations.)
Dimensions and materials used can become quite critical (especially at VHF but even so at 10/11m) with it also being sensitive to it's surroundings. It looks easy to simply 'slide' the feed line up/down the 1/4 wave matching stub for good SWR but this can be difficult with a simple wire constructed arrangement. You can guarantee a 'calculated' feed point measurement will only ever be in the ball park if at all but who knows, you may get lucky.
For CB/11m operation it's going to be almost 8m (26 foot) long and you may experience difficulty mounting it especially when constructed from wire.
There are far easier antennas to make such as the common dipole and for end fed solutions the shrouded dipole or otherwise known as the T2LT. The latter can be mounted to any non-metallic pole you'd like for erecting and I've even seen examples where they're hung up in trees etc.
Never wanting to put someone off from experimenting feel free to have a go at it but just be aware that it might all become a bit frustrating.
Someone's bound to come along and claim that they're the "best-thing-since-sliced-bread" but if you've never seen sliced bread before everything is amazing.

(Heck, even a wet finger in the back of your radio will pick up signals but doesn't make for a good antenna!)
Hope that helps.
All the best,
Victor