gerber quasi-Yagi, 915 MHz, 1 copper layer on FR4 1.6 mm - PIGTAIL variant
(NO board connector; the coax is captive and exits through the board).
.gtl top copper (reflector+strips+driven+SOLID tab pour = one piece; 2 dirs)
.gko board outline (uploaded-set flared shape, 6 routed windows + balun slit)
.drl Excellon: pigtail exit 6.5 @ (-23.5, -6) + 2x zip-tie 3.0
     + jumper centre 1.0 / shield tack 1.6 at the emitter

ASSEMBLY
1. One continuous RG-402 run (~82 mm on-board + pigtail length as needed;
   lambda/2 on the stand FDTD-verified benign, longer is fine). The exit
   hole is OFFSET to the y=-6 run line on purpose: the whole on-board run
   is straight and the quarter-bend at the hole is the cable's ONLY bend.
2. Solder the centre to the +y arm pad at the emitter (drill 1.0); tack the
   shield at the -y arm base and every 15-20 mm along the return strip
   (y=-6), the reflector and the tab pour - same X marks as the SMA build.
3. At (-23.5, -6) bend the coax DOWN (radius >= 8.0 mm - start the bend
   ~8 mm before the hole) and pass it through the exit hole. Solder the
   shield to the pour ALL AROUND the hole rim - this is the ground bond the
   FDTD model assumes, and the main strain relief.
4. Route the pigtail down the stand and zip-tie it (backup ties: the two
   3.0 holes at (-26, +-14)). Terminate at the radio end only (SMA plug or
   direct solder).
5. The 58 mm slit (short at the reflector, open at the driven element) is
   the balun - never bridge it.
5b. 915-CENTRING TRIM (same as the SMA build): as-built the antenna
   resonates ~892 MHz (drive at the real solder crossing). Trim 1.7 mm
   off EACH driven-arm TIP to centre 915.0 (S11 -30.5 dB, Zin 52+2j;
   FDTD PML_8 with cable). ~5-6 MHz per mm of total driven length.
Trade-off vs the SMA build: no mating interface (~0.05-0.1 dB less loss, no
connector cost/height) but the cable is captive - re-cabling means
desoldering. RF is identical (PML_8 FDTD: same resonance/gain/F-B as the
SMA build; see gerber_yagi_pigtail.json).
