176 lines
13 KiB
HTML
176 lines
13 KiB
HTML
<!doctype html>
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<html lang="en">
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<head>
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<meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1">
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<title>HBOX v6 — Antenna Chain</title>
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<style>
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:root { color-scheme: light dark; }
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body { margin: 0; padding: 20px; font: 14px/1.5 system-ui, sans-serif;
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background: light-dark(#fafaf8, #16181d); color: light-dark(#1c1e21, #e4e6e9); max-width: 1020px; margin-inline: auto; }
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h1 { font-size: 19px; margin: 0 0 4px; }
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p.lead { margin: 0 0 22px; color: light-dark(#555, #9aa0a8); }
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figure { margin: 0 0 30px; }
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svg { max-width: 100%; height: auto; display: block; }
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figcaption { font-size: 12.5px; color: light-dark(#555, #9aa0a8); margin-top: 8px; max-width: 62em; }
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.rf { color: #3b82f6; } .dc { color: #e08a1f; }
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b.k { font-weight: 600; }
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</style>
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</head>
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<body>
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<h1>How the GNSS antenna connection works</h1>
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<p class="lead">One coax does two jobs at once: <span class="rf"><b>RF comes down</b></span> from the antenna to the receiver, and <span class="dc"><b>3.3 V goes up</b></span> the same cable to power the amplifier inside the antenna.</p>
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<figure>
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<svg viewBox="0 0 980 400" role="img" aria-label="GNSS signal chain: active antenna outside the enclosure, SMA bulkhead through the wall, pigtail to the board U.FL, then bias tee and DC block feeding the ZED-F9P. RF flows right to left into the receiver; 3.3 V flows left to right up the same coax into the antenna's LNA.">
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<defs>
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<marker id="aRF" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse">
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<path d="M0,0 L10,5 L0,10 z" fill="#3b82f6"/>
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</marker>
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<marker id="aDC" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse">
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<path d="M0,0 L10,5 L0,10 z" fill="#e08a1f"/>
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</marker>
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</defs>
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<!-- ======== PCB zone ======== -->
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<rect x="14" y="60" width="392" height="240" rx="8" fill="none" stroke="currentColor" stroke-width="1.4"/>
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<text x="26" y="84" font-size="13" font-weight="600" fill="currentColor">EinarBoard v6 (PCB)</text>
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<!-- F9P -->
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<rect x="30" y="130" width="104" height="70" rx="4" fill="none" stroke="currentColor" stroke-width="1.6"/>
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<text x="82" y="158" font-size="12.5" font-weight="600" text-anchor="middle" fill="currentColor">ZED-F9P</text>
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<text x="82" y="174" font-size="11" text-anchor="middle" fill="currentColor">RF_IN</text>
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<text x="82" y="190" font-size="11" text-anchor="middle" fill="currentColor">VCC_RF 3.3 V</text>
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<!-- DC block C143 -->
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<line x1="134" y1="150" x2="176" y2="150" stroke="#3b82f6" stroke-width="2" marker-start="url(#aRF)"/>
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<line x1="182" y1="138" x2="182" y2="162" stroke="currentColor" stroke-width="2"/>
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<line x1="190" y1="138" x2="190" y2="162" stroke="currentColor" stroke-width="2"/>
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<text x="186" y="128" font-size="11" text-anchor="middle" fill="currentColor">C143 100 nF</text>
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<text x="186" y="115" font-size="10.5" text-anchor="middle" fill="currentColor">DC block: RF passes, DC stops</text>
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<!-- node to U.FL -->
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<line x1="190" y1="150" x2="330" y2="150" stroke="#3b82f6" stroke-width="2"/>
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<circle cx="252" cy="150" r="3.2" fill="currentColor"/>
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<!-- bias tee L21 -->
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<path d="M252 150 v22 m0 0 a6 6 0 0 1 0 12 a6 6 0 0 1 0 12 a6 6 0 0 1 0 12 v14" fill="none" stroke="#e08a1f" stroke-width="2"/>
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<text x="264" y="196" font-size="11" fill="currentColor">L21 68 nH</text>
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<text x="264" y="210" font-size="10.5" fill="currentColor">bias tee: DC passes,</text>
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<text x="264" y="223" font-size="10.5" fill="currentColor">RF blocked</text>
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<!-- DC from VCC_RF -->
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<path d="M134 186 h84 v36 h34" fill="none" stroke="#e08a1f" stroke-width="2"/>
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<line x1="252" y1="222" x2="252" y2="156" stroke="#e08a1f" stroke-width="0" />
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<text x="150" y="240" font-size="11" fill="#e08a1f">3.3 V, ≤50 mA</text>
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<!-- ESD -->
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<line x1="306" y1="150" x2="306" y2="184" stroke="currentColor" stroke-width="1.4"/>
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<path d="M298 184 h16 l-8 14 z" fill="none" stroke="currentColor" stroke-width="1.4"/>
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<line x1="298" y1="198" x2="314" y2="198" stroke="currentColor" stroke-width="1.6"/>
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<line x1="300" y1="203" x2="312" y2="203" stroke="currentColor" stroke-width="1.2"/>
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<line x1="303" y1="208" x2="309" y2="208" stroke="currentColor" stroke-width="1"/>
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<text x="320" y="192" font-size="11" fill="currentColor">D27 ESD 0.5 pF</text>
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<!-- U.FL -->
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<circle cx="352" cy="150" r="16" fill="none" stroke="currentColor" stroke-width="1.6"/>
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<circle cx="352" cy="150" r="4" fill="currentColor"/>
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<text x="352" y="106" font-size="11.5" font-weight="600" text-anchor="middle" fill="currentColor">J12</text>
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<text x="352" y="120" font-size="11" text-anchor="middle" fill="currentColor">U.FL</text>
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<!-- ======== pigtail ======== -->
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<path d="M368 150 C 420 150 430 150 470 150" fill="none" stroke="currentColor" stroke-width="5" opacity="0.28"/>
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<line x1="368" y1="150" x2="470" y2="150" stroke="#3b82f6" stroke-width="2"/>
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<text x="419" y="132" font-size="11" text-anchor="middle" fill="currentColor">pigtail 10–15 cm</text>
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<!-- ======== enclosure wall ======== -->
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<rect x="470" y="40" width="18" height="330" fill="currentColor" opacity="0.16"/>
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<text x="479" y="30" font-size="11.5" font-weight="600" text-anchor="middle" fill="currentColor">enclosure wall</text>
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<!-- bulkhead SMA -->
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<rect x="458" y="138" width="44" height="24" rx="3" fill="none" stroke="currentColor" stroke-width="1.8"/>
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<line x1="452" y1="134" x2="452" y2="166" stroke="currentColor" stroke-width="3"/>
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<line x1="508" y1="134" x2="508" y2="166" stroke="currentColor" stroke-width="3"/>
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<text x="480" y="184" font-size="11.5" font-weight="600" text-anchor="middle" fill="currentColor">SMA bulkhead</text>
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<text x="480" y="198" font-size="10.5" text-anchor="middle" fill="currentColor">nut + gasket seal (IP)</text>
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<text x="480" y="212" font-size="10.5" text-anchor="middle" fill="currentColor">takes the torque, not the PCB</text>
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<!-- ======== outside ======== -->
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<line x1="508" y1="150" x2="640" y2="150" stroke="#3b82f6" stroke-width="2"/>
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<path d="M508 150 C 560 150 580 150 640 150" fill="none" stroke="currentColor" stroke-width="5" opacity="0.28"/>
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<text x="574" y="132" font-size="11" text-anchor="middle" fill="currentColor">antenna cable (SMA macho)</text>
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<!-- active antenna -->
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<rect x="640" y="92" width="240" height="120" rx="8" fill="none" stroke="currentColor" stroke-width="1.6"/>
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<text x="760" y="82" font-size="12.5" font-weight="600" text-anchor="middle" fill="currentColor">Active GNSS antenna (outside, clear sky)</text>
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<rect x="660" y="112" width="80" height="34" rx="3" fill="none" stroke="currentColor" stroke-width="1.4"/>
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<text x="700" y="133" font-size="11" text-anchor="middle" fill="currentColor">patch L1/L2</text>
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<rect x="780" y="112" width="66" height="34" rx="3" fill="none" stroke="currentColor" stroke-width="1.4"/>
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<text x="813" y="133" font-size="11" text-anchor="middle" fill="currentColor">LNA</text>
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<line x1="740" y1="129" x2="780" y2="129" stroke="#3b82f6" stroke-width="2" marker-end="url(#aRF)"/>
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<line x1="846" y1="129" x2="874" y2="129" stroke="#3b82f6" stroke-width="2"/>
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<path d="M874 129 v21 h-234 v0" fill="none" stroke="#3b82f6" stroke-width="2"/>
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<text x="762" y="172" font-size="10.5" text-anchor="middle" fill="currentColor">the LNA runs on the 3.3 V that arrives up the coax</text>
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<text x="762" y="196" font-size="10.5" text-anchor="middle" fill="currentColor">ground plane / metal surface under the antenna kills reflections</text>
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<!-- satellites -->
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<path d="M690 34 l-14 22 M710 30 l-6 26 M732 34 l4 22" stroke="#3b82f6" stroke-width="1.6" fill="none" marker-end="url(#aRF)"/>
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<text x="712" y="24" font-size="11" text-anchor="middle" fill="currentColor">L1 / L2 from satellites</text>
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<!-- flow legend arrows -->
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<line x1="640" y1="290" x2="140" y2="290" stroke="#3b82f6" stroke-width="2.4" marker-end="url(#aRF)"/>
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<text x="390" y="282" font-size="12" text-anchor="middle" fill="#3b82f6">RF signal → down the coax → into RF_IN</text>
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<line x1="140" y1="330" x2="640" y2="330" stroke="#e08a1f" stroke-width="2.4" marker-end="url(#aDC)"/>
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<text x="390" y="352" font-size="12" text-anchor="middle" fill="#e08a1f">3.3 V DC → up the same coax → powers the antenna's LNA</text>
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</svg>
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<figcaption><b class="k">Fig. 1 — the same piece of coax carries both directions.</b> On the board, L21 (the bias tee) injects 3.3 V onto the antenna side of the line — an inductor passes DC but looks like a wall to 1.5 GHz RF, so the injection doesn't disturb the signal. C143 (the DC block) does the mirror job: RF passes into the receiver, DC cannot. Result: the antenna's built-in amplifier gets its power with zero extra wires, which is why the F9P <i>requires</i> an active antenna and why J12's little circuit exists.</figcaption>
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</figure>
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<figure>
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<svg viewBox="0 0 980 300" role="img" aria-label="Top view of the cabinet: the PCB's GNSS U.FL at the bottom-left corner and LTE U.FL at the right edge run short pigtails to two SMA bulkheads on the enclosure wall, mounted at least 20 cm apart. The GNSS antenna mounts high with clear sky; the LTE whip mounts on the opposite side.">
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<!-- cabinet -->
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<rect x="150" y="50" width="560" height="220" rx="10" fill="none" stroke="currentColor" stroke-width="1.8"/>
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<text x="430" y="40" font-size="12.5" font-weight="600" text-anchor="middle" fill="currentColor">HBOX cabinet (top view)</text>
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<!-- PCB -->
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<rect x="230" y="90" width="400" height="140" rx="4" fill="none" stroke="currentColor" stroke-width="1.3" stroke-dasharray="5 4"/>
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<text x="430" y="110" font-size="11.5" text-anchor="middle" fill="currentColor">EinarBoard v6 — 140 × 100</text>
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<circle cx="252" cy="208" r="7" fill="none" stroke="currentColor" stroke-width="1.5"/>
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<text x="252" y="232" font-size="10.5" text-anchor="middle" fill="currentColor">J12 GNSS</text>
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<circle cx="608" cy="130" r="7" fill="none" stroke="currentColor" stroke-width="1.5"/>
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<text x="608" y="112" font-size="10.5" text-anchor="middle" fill="currentColor">J13 LTE</text>
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<line x1="269" y1="196" x2="591" y2="142" stroke="currentColor" stroke-width="1" stroke-dasharray="3 4"/>
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<text x="430" y="182" font-size="10.5" text-anchor="middle" fill="currentColor">≈149 mm apart on the board</text>
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<!-- pigtails to wall -->
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<path d="M245 208 C 200 208 190 200 160 190" fill="none" stroke="currentColor" stroke-width="2.2" opacity="0.55"/>
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<path d="M615 130 C 660 130 680 122 700 116" fill="none" stroke="currentColor" stroke-width="2.2" opacity="0.55"/>
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<!-- bulkheads -->
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<rect x="142" y="180" width="16" height="20" fill="none" stroke="currentColor" stroke-width="1.8"/>
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<rect x="702" y="106" width="16" height="20" fill="none" stroke="currentColor" stroke-width="1.8"/>
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<text x="128" y="216" font-size="10.5" text-anchor="end" fill="currentColor">SMA bulkhead</text>
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<text x="732" y="100" font-size="10.5" fill="currentColor">SMA bulkhead</text>
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<!-- separation arrow -->
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<line x1="150" y1="286" x2="710" y2="286" stroke="currentColor" stroke-width="1.4" marker-start="url(#aSep)" marker-end="url(#aSep)"/>
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<defs>
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<marker id="aSep" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse">
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<path d="M0,0 L10,5 L0,10 z" fill="currentColor"/>
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</marker>
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</defs>
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<text x="430" y="280" font-size="11.5" font-weight="600" text-anchor="middle" fill="currentColor">antennas ≥ 20 cm apart — the #1 defence against the modem deafening the GNSS</text>
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<!-- external antennas -->
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<line x1="100" y1="190" x2="142" y2="190" stroke="#3b82f6" stroke-width="2"/>
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<circle cx="84" cy="190" r="15" fill="none" stroke="#3b82f6" stroke-width="1.8"/>
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<circle cx="84" cy="190" r="4" fill="#3b82f6"/>
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<text x="84" y="164" font-size="10.5" text-anchor="middle" fill="currentColor">GNSS antenna</text>
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<text x="84" y="222" font-size="10.5" text-anchor="middle" fill="currentColor">highest point,</text>
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<text x="84" y="234" font-size="10.5" text-anchor="middle" fill="currentColor">clear sky</text>
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<line x1="718" y1="116" x2="760" y2="116" stroke="currentColor" stroke-width="2"/>
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<line x1="760" y1="116" x2="760" y2="66" stroke="currentColor" stroke-width="2.6"/>
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<text x="792" y="86" font-size="10.5" fill="currentColor">LTE whip</text>
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</svg>
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<figcaption><b class="k">Fig. 2 — where each piece lives.</b> The board carries only the two U.FL receptacles, placed at opposite corners. Short pigtails jump to SMA bulkheads that clamp through the enclosure wall — the nut and gasket keep the seal, and any torque from screwing antennas on lands in the wall, never in the PCB's solder joints. Outside, the antennas separate further: GNSS up high with open sky, the LTE whip away from it.</figcaption>
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</figure>
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</body>
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</html>
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