Scott in Aztlan wrote:

Suppose you were participating in a search for a hidden radio transmitter, only
instead of the usual radio receiver with a directional antenna you have a
receiver with an omnidirectional antenna and a GPS receiver.

What is the reason for the constraint? I have used loops at frequencies
from a couple hundred Hertz up to 30MHz and I know they work even
higher. Why not use a loop?

There are a lot of factors besides distance affecting signal strength.
You would have to use an approximation to the inverse square law and
look at the area described by drawing circles from each reading. The
area common to all the circles would be your guess. You would then want
to get closer and repeat.

Ted