Crazy George wrote:
"The reason Hams can`t do this are two-fold:
1. Space
2. Money."

That`s usually true.

I don`e think anyone has mentioned Doppler or Quasi-Doppler DF systems
yet. I`ve seen hams using them but I have no experience with them.

Servo Corporation of America claims to have supplied over 350
Quasi-Doppler radio direction finding systems to the U.S. FAA and they
are used in airports throughout the U.S.A.

The angle at which a VHF signal wavefront passes over a small forest of
antenna elements is determined to give a bearing toward the transmitter.

It has been generally found that for radio direction finding that the
larger the antenna, the better the performance.. But, in the case of two
spaced antennas, the spacing must not exceed 1/2-wavelength to avoid
ambiguities. Peak error from an Adcocvk Array is 11.4 degrees, says
Servo Corp. Their Doppler Systems, they say, are much better.

I see what I suppose are Doppler antenna systems on the trunk lids of
police cars.

Best regards, Richard Harrison, KB5WZI