The Walston device can be used to find you model up to 20 miles away.

BTW there are some other brands out there somewhat like the Walston.

You have a three element Yagi directional antenna that will point to the airplane when the signal is loudest.

The little transmitter only gives out a a "click" about ever 2 seconds.

The click has to be nulled out except when you are directed right at the target. So as you get closer to your plane, you will have to turn the gain of the receiver down so as to stay right on track.

The Walston and others like it were intended for Free Flight type Gliders, Gas, and rubber powered models. Also model rocket guys use them. Where I fly R/C there are a group of S.A.M. old timers that fly and some of these guys have the transmitter type retrieval systems.

I've practiced some with mine but have never lost a plane while actually using the retrieval system.

My wife hid a transmitter in a junk box in the far corner of the house, I found the little thing with the antenna. It only weighs a couple grams.