Sweep 700–1250 MHz with the cable connected as you'll fly it. Read VSWR at the three band points, the frequency of the deepest dip, and — if your calibration plane is at the pads — the resistance at 915.
Re-measure with the same cable and setup, then type the two numbers above.
| Recipe | Cuts | Copper ends | VSWR 895 / 915 / 935 | R@915 Ω | Deep dip | Gain | F/B |
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Ranges span laminate εr 4.4–4.8 — the whole spread your board could be, since a crossed board only tells you εr is 4.4 or above, never which value. Simulated with openEMS (MUR), floating tip islands included, on the produced rail geometry. The reflector pair alone does nothing (VSWR stays 3.5); D2 alone does nothing; scraping the loop bridges measures worse; the original tap pads stay.