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[chileflora]

I was wondering what would have happen if two dipole elements would be placed very close to the focus of a dish antenna.

I am flying FPV and the question relates to the idea of installing two video
transmitters on the airplane, one running on 5.6 the other on 5.8 Ghz. The frequency separation is more than enough so as not to cause interference.

On the receiving end I use dish antennas, usually something like 30 dbi (60 x 90 cm). From experience, there is very little to none change in the quality of reception if I move antenna by up to 1°. The standard dipole is located at about 30 cm. form the main reflecting surface, so 1° at this distance is equal to 5 mm.

My question is: if I put two dipole elements, each leading to a separate Receiver, and separate them by let us say 7-8mm, 4 mm to one side from the centerline, and 4 mm to the other side from the centerline, would I have same quality of reception, or it will degrade, and if so, by how much?