david8858
I am a technical instructor in radio frequency techniques at an engineering establishment and can clarify that the single reflector is placed 1/4 wavelength behind the driven element (dipole) and is slightly more than 1/2 wavelength long. The directors are placed at 1/4 wavelength intervals in front of the driven element and are slightly shorter than 1/2 wavelength long. Each additional director will add approximately 1 dB of gain to the aerial system. Oh, and it matters not if it is used as a transmit or receive aerial it will work as both. For caravanners the thing to do is check that it has reasonable gain, is pointed in the right direction and at the correct polarity.
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