Cat Automation (not quite HA)

["AZWoody" <Reply@xxxxxxxxxxxxxx>]

I've got a cat that likes to wander. (1-2 block range)

I try to get him inside before dark, but I don't always have any luck in
finding him.

I was wondering if anyone knew of a small (he's only 10 lbs) transmitter
that could be attached to his collar which could be used in locating him.
I'd use something with a directional antenna, to at least determine the
proper direction to go looking for him.  (HAM bands ok.  Been studying for
my license for other reasons).

Any other ideas would also be appreciated (keeping him inside is not an
option)