I'm looking to make a directional antenna in the 215 to 218 MHz band
(215 if that's too broad), used for location of dementia patients who
have wandered away from their caregivers. I'm a volunteer with an
organization that locates these people. They wear a tiny transmitter
which emits a chirp that can be heard from 1-2 miles on the ground and
8-10 miles via helicopter.


You might do a bit of research on the equipment that various animal
tracking organizations use. They tend to use the 215 - 218 MHz band for
tracking various animal species, and the equipment should suit your needs
also.


Ed K7AAT