I thought it was interesting that they mention using a yagi.
For hunting a strong signal, the traditional tool is antenna with a deep null such a loop antenna. The reason for this is because the null at a point can be very deep relative to the average response-- e.g. maybe a small directional antenna has 10dB difference between the front and the side, but a small antenna engineered to have a deep null can easily have 40+ dB of isolation between a null and the side. To search for a signal using a null you aim until the signal goes away and you go in that direction. :)
And it's easy to construct antennas with only two (or one) null.
For a directional antenna like a yagi you have various reflections hitting the antennas sidelobes, making it harder to read.
For hunting a strong signal, the traditional tool is antenna with a deep null such a loop antenna. The reason for this is because the null at a point can be very deep relative to the average response-- e.g. maybe a small directional antenna has 10dB difference between the front and the side, but a small antenna engineered to have a deep null can easily have 40+ dB of isolation between a null and the side. To search for a signal using a null you aim until the signal goes away and you go in that direction. :)
And it's easy to construct antennas with only two (or one) null.
For a directional antenna like a yagi you have various reflections hitting the antennas sidelobes, making it harder to read.