This antenna is my go-to antenna for 2m or VHF commercial communication. It does not have any theoretic gain, but it can be tuned PERFECTLY. I would rather have a flat SWR than gain any day.
The design is very simple, and easy to build. If you have the supplies, it takes about half an hour. Some people say you need a 1:1 balum, but in my experience this is only true if you solder a larger coax direct to the antenna (like LMR400/RG8). If you use RG 58 or equivalent for a few feet, you should have no problem with tuning.
4_ Feet 1/4" Copper Tubing (used for fridge water line).
6_ Feet 3/4" PVC Pipe
2_ 3/4" PVC "T"s
1_ Coax with PL259 (Or whatever you want) on one end.
Start with (2) 19" pieces of copper tubing. Split your coax and leave about 1" pigtails on it. Solder the center to one piece of tubing, and the braid to the other.
Use zip ties to secure the elements to your PVC "T". Tune with an SWR meter. (If you don't have access to one, trim both elements to 18 3/8".)
Make sure the coax goes away from the elements at a right-angle for at least 20".