Statistical resolution limit (SRL) — closest two targets tellable apart vs SNR · hover a point (session 014z DF model)
10.0 dBi (PML) · F/B 17.9 dB · S11 −33 dB @ 915 · Zin 49+j2 Ω — DIRECT 50 Ω, no matching network · BW(−10 dB) 86 MHz · HPBW 58° · side 83 mm, spacing 46 mm (0.14λ, sets R: +1.7 Ω/mm) · reflector 350×250 copper-clad FR4 · 2 mm Cu wire bent from ONE 680 mm piece (bottom centre = continuous bend, ends meet at top pad) · braid collar bonded 360° to plate + 5-bead ferrite choke (balun) · solder pads, bending template DXF · CM check (explicit coax): bare −27.5 dB / collar bond −61 dB / λ/4 sleeve −49 dB @915 — the reflector bond IS the balun workhorse · WIND→FEM (OpenFOAM RANS + CalculiX): Cd 1.23, 59 N @30 m/s (133 N @45) · 1.6 mm plate on a 40×40 mm centre clamp bows 11 mm at the corners @30 m/s → Δspacing ≈2.2 mm → ΔR +3.7 Ω, Δf −0.7 MHz — match holds (linear FEM, conservative) · σvM 27 MPa (≈16× FR4 margin) · @45 m/s corners flap ~25 mm — use a full-width mast plate / 3 mm substrate for permanent outdoor mounts · FUSELAGE MOUNT (fixed-wing, vertical, flow along the 350 mm side): cruise drag only 0.6-0.7 N @30 m/s · sideslip turns it into a fin: |Fy| 20 N @β=10° / 27 N @β=15°, mount moment 3.4 N·m · plate bows 5.1 mm @β=15° → ΔR +1.7 Ω — RF-benign · beam points sideways; reflector shields the airframe · F/worst-3D-lobe 17.0 dB
⬗ stack-up: 2 mm solid Cu wire element in air · reflector: single-side copper-clad FR4 1.6 mm, 350×250 mm