I just wanted to ask the reason for having two loops in a QFH antenna. and what is the advantage of having them oriented the way they are?
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You might want to consider asking on Amateur Radio Stack Exchange. – Puk Mar 24 '22 at 06:50
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The elements in a QFH antenna are spiral-wrapped because the electromagnetic waves they are designed to receive are circularly polarized. The slightly larger spiral wrap is a reflector element which renders the antenna insensitive to signals coming from sources off to the sides of the antenna on the ground and doubles its sensitivity to signals coming from above it in the sky.
niels nielsen
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Thanks for the answer. As a follow up, is there anything special about the larger loop when it comes to its design other than its size that made it a reflector? – Elias Solomon Mar 25 '22 at 08:46
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two things are important: that its dimensions be scaled up about about 2% to 5% relative to the inner helix, and that it be not electrically connected to the inner helix but instead left "floating"- unless otherwise specified by the designer. – niels nielsen Mar 25 '22 at 16:40