Hello Guys! Hope all is well with everyone.
I was doing some reading on dish antennas and came across a paper written by a ham operator. www.packratvhf.com/Article_9/Dish_Not.pdf‎

In it he says how for a parabolic "mesh" antenna the holes must be less than 1/10 of a wavelength in diameter, at the highest operating frequency. Would you guys know why it is necessary for the holes to be less than 1/10 of a wavelength in diameter?
Thank You

 

Radio waves pass through openings in metallic surfaces. How much passes through vs how much is reflected is a function of the aperture size and shape. The 1/10 figure is a rule-of-thumb for the aperture size where some of the wave leaks through. For a dish, you want complete reflection. At some hole edge-length, the sharp edges likely scatter the radio wave, screwing up the focusing of the energy into the feed.

 

MikeML is correct.Accordenly to the receiption or receiving frequency,mesh antennas behaving as "strainers"!!!!