gerber quasi-Yagi, 915 MHz, single copper layer on FR4 1.6 mm - SMA-ON-PCB variant.
.gtl top copper (reflector+strips+driven+rear-tab ground pour = one piece;
     isolated SMA pin pad; 2 floating directors)
.gko board outline (uploaded-set flared shape, 6 routed windows + balun slit)
.drl Excellon: SMA pin 1.5 + 4 posts 1.7 (5.08 mm square; the official
     KiCad footprint SMA_Amphenol_132134_Vertical) + 2x zip-tie 3.0
     + jumper centre 1.0 / shield tack 1.6 at the emitter

ASSEMBLY
1. Mount an Amphenol 132134 (or equivalent 4-post 6.35 mm-sq flange SMA
   jack) on the BOTTOM face at (-23.5, -6): pin up through the board to
   the round pad, posts soldered to the top-side pour. The pin is OFFSET
   from the tab centre onto the y=-6 run line on purpose - the stiff
   RG-402 then needs no bends at all.
   The jack points DOWN - along the stand; use a straight cable plug.
2. Cut ~82 mm of RG-402 (0.141" semi-rigid). Solder the centre to the pin
   pad. Lay it flat in ONE STRAIGHT run at y=-6: pour -> reflector ->
   along the return strip to the -y arm base. Tack the shield to the
   copper every ~15-20 mm (marked X on the preview) and at the -y arm pad.
3. At the emitter the exposed centre conductor jumps the 2 mm slot to the
   +y arm pad (drill 1.0). Keep the jump short and straight.
4. The 58 mm slit (short at the reflector, open at the driven element) is
   the balun - do NOT bridge it with the jumper or solder.
4b. 915-CENTRING TRIM: as-built (drive at the real solder crossing) the
   antenna resonates ~892 MHz. Trim 1.7 mm off EACH driven-arm TIP
   (l_drv 135.4 -> 132) to centre 915.0: S11 -30.5 dB, Zin 52+2j
   (FDTD PML_8, SMA + lambda/2 cable). Sensitivity ~5-6 MHz per mm of
   l_drv; trim symmetrically, measure, sneak up on it. Do NOT try to
   retune by moving the solder crossing instead: that knob only spans
   res 872-892 and is already at its maximum at x=58.
5. Clamp the stand at the reflector centre; zip-tie the cable down the
   stand (holes at (-26, +-14) take a backup tie on the tab).
FDTD-verified (openEMS PML_8): connector+jumper and a lambda/2 cable on
the stand leave resonance/S11/gain/F-B essentially unchanged - see
gerber_yagi_sma.json in the gallery card.
