Here is an easy to make J-Pole antenna, easily constructed and tuned in an afternoon.
All that’s really needed:
- 450 Ohm ladderline (300 twinlead works too)
- a length of coax
- PL-259 Connector (or connector of choice)
- a piece of string
- Razor blade or sharp knife
- measuring tape
- solder/soldering iron
- electrical tape or silicone
- String or fishing line
I’ve constructed many of these, for extending the range of a handheld or for a quick and dirty way to extend a mobile for field operations. A little re-enocing at the top and coax junction to support the coax weight allows it ti be hauled to the top of a tree via a fishing pole or slingshot yields some fantastic results with just an HT. I’ve pushed as much as 65 watts through them on FM using the 450 ohm ladderline with no visible issues.. YMMV.
A little math to calculate lengths to construct a GREAT scanner antenna tuned for particular bands is also possible.
Here is a link to a .pdf from QST that lists the details of construction, theory of operation and other nice to know stuff.