Ryan Malloy
41114373b9
Diátaxis-structured documentation for 406 MHz SARSAT beacon reception: - Tutorials: signal chain walkthrough - Guides: antenna setup, message decoding - Reference: block API, signal format - Explanation: Cospas-Sarsat system overview Includes extracted images from official Cospas-Sarsat specifications (LFS).
187 lines
8.0 KiB (Stored with Git LFS)
XML
187 lines
8.0 KiB (Stored with Git LFS)
XML
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<!-- Title -->
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<text x="300" y="35" text-anchor="middle" font-size="22" font-weight="700" fill="#1a1a2e">
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QFH Antenna for 406 MHz
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</text>
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<text x="300" y="58" text-anchor="middle" font-size="13" fill="#666">
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Quadrifilar Helix — RHCP Satellite Reception
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</text>
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<!-- Main antenna structure -->
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<g transform="translate(300, 380)" filter="url(#shadow3d)">
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<!-- PVC support mast -->
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<!-- Left arm going up and curving -->
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C 80,-120 92,-180 92,-240"
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C 86,-220 50,-260 0,-260"
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<!-- Small helix loop 1 (front) -->
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C 75,-120 88,-175 88,-230"
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<!-- Small helix loop 2 (back) -->
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C 78,-212 45,-248 0,-248"
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<!-- Feed point connector -->
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<!-- Coax cable -->
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<text x="-20" y="295" font-size="10" fill="#666">RG-58 / RG-213</text>
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<text x="470" y="285" font-weight="600">260 mm</text>
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<text x="470" y="300" font-size="10" fill="#888">(Large loop H)</text>
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<text x="280" y="510" font-weight="600">185 mm</text>
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<text x="272" y="525" font-size="10" fill="#888">(Large loop W)</text>
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<!-- Small loop indicator -->
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<text x="115" y="285" fill="#3498DB" font-weight="600" transform="rotate(-90, 115, 285)">250 mm (Small H)</text>
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QFH Dimensions for 406.025 MHz
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<text x="15" y="8" fill="#333" font-weight="500">Large Loop:</text>
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<text x="95" y="8" fill="#555">185 mm W × 260 mm H</text>
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<text x="15" y="8" fill="#333" font-weight="500">Small Loop:</text>
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<text x="95" y="8" fill="#555">178 mm W × 250 mm H</text>
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<text x="15" y="8" fill="#333" font-weight="500">Conductor:</text>
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<text x="95" y="8" fill="#555">6-10 mm copper or aluminum tube</text>
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<text x="15" y="8" fill="#333" font-weight="500">Support:</text>
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<g transform="translate(300, 45)" font-size="12">
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<g fill="#e74c3c">
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<text x="15" y="8" fill="#333" font-weight="500">Twist:</text>
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<text x="95" y="8" fill="#555">½ turn (180°)</text>
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<text x="15" y="8" fill="#333" font-weight="500">Polarization:</text>
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<text x="95" y="8" fill="#555">RHCP (Right-Hand)</text>
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<text x="15" y="8" fill="#333" font-weight="500">Impedance:</text>
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<text x="95" y="8" fill="#555">~50Ω (self-matching)</text>
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<rect x="0" y="0" width="8" height="8" rx="2"/>
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<text x="15" y="8" fill="#333" font-weight="500">Gain:</text>
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<text x="95" y="8" fill="#555">~3 dBic at zenith</text>
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</g>
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</g>
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<!-- Design note -->
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<text x="300" y="690" text-anchor="middle" font-size="10" fill="#888" font-style="italic">
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Self-phasing design — loops at 90° provide circular polarization without external phasing network
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