You can build an antenna with a cardiod pattern, which has a wide range but a very deep, narrow null at one end. When you see the signal strength dip off, the transmitter has to be aligned with the null (sort of, there are also multipath issues to consider)
But, doing this requires you can move freely to track the transmitter. Hunting a transmitter on Russian soil by non-Russian entities might not be viewed very kindly :)
And the location probably wouldn't be too surprising. I remember reading that some number station transmitter was tracked down to a Russian military base. Pretty much where you'd expect it to be.
You can build an antenna with a cardiod pattern, which has a wide range but a very deep, narrow null at one end. When you see the signal strength dip off, the transmitter has to be aligned with the null (sort of, there are also multipath issues to consider)
But, doing this requires you can move freely to track the transmitter. Hunting a transmitter on Russian soil by non-Russian entities might not be viewed very kindly :)