On 4/8/2017 8:19 AM, Gareth's Downstairs Computer wrote:
When you consider the reduction in the size of antennae when going
from dipoles et al to magnetic loops, I wonder why those
on wildlife safaris who have attached beacons to animals
use full size yagi-udas to track the animals?

Surely the same reduction in size should be possible
with mag loops for VHF?

A magloop antenna has limited gain, but more importantly the direction
finding has to be done by pointing a null, losing the signal. So if
your signal is not strong to begin with the null is hard to use.

Still, the Yagi-Uda antenna design can pick up a much weaker signal
because of the significant gain. A magloop doesn't even have the gain
of a simple dipole.

--

Rick C