Spindler antenna for receiving MMDS television. Scheme, description

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Spindler antenna for receiving MMDS television. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Television antennas

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For receiving MMDS television, mesh parabolas with a gain (as required) of 18-24 dB are usually used. It is quite difficult to make such an antenna on your own, given that it has different curvature in the horizontal and vertical planes. Therefore, in places where the signal strength of the MMDS TV signal is not bad, it is quite possible to use antennas that are easier to manufacture. The drawing of this antenna was obtained with the help of my Action to recalculate the dimensions of the Spindler antenna. For the antenna traverse, I took a bar of fiberglass 10x10x880 mm (cut off from the sheet). All elements are made of 3 mm capillary tube and hammered into a traverse.

The traverse is longer than the calculated one, because I additionally inserted 6 more directors, bringing their number to 30. The antenna gain in this embodiment should be about 17,5 dB, which almost corresponds to the smallest of the standard parabolas. U-bend loop made of 75 ohm cable 2 mm in diameter. I made the connection to the converter with a 50-ohm silver-plated cable in fluoroplastic insulation 5 mm in diameter, because, after transformation, the input impedance of the antenna is closer to 50 ohms than to 75! The antenna works well, but when I tried to calculate its parameters in the wonderful MMANA program, I could not get the expected results. What is the reason and where the error I have not yet figured out.

About the program for recalculating the dimensions of the Spindler antenna. She's under DOS. The picture below is the result of her work. Exit from the program is provided only after receiving the drawing, by Esc. I would redo it, but the original was not preserved. Therefore, I describe this as a feature of the program.

(click to enlarge)

Author: E.Shustikov, UO5OHX ex RO5OWG; Publication: shustikov.by.ru

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