Before You Measure: VNA Pre-Check
- Warm-up: Allow 30–60 minutes for VNA frequency reference to stabilize
- Cable inspection: No kinks, bends, or damaged connectors
- Connector cleaning: IPA wipe on all SMA connectors (male and female) — most common source of calibration error
- Torque: SMA connectors to 0.9 N·m (8 in-lbs) — not over-torqued
Calibration Best Practices
Cal at room temperature (20–25°C); if lab varies >5°C, recalibrate Cal kit: use same connector type as DUT (SMA-m, SMA-f, 2.92mm) Verify after cal: connect 50Ω Load → S11 should be <−40 dB If S11 > −35 dB after calibration: dirty connector or worn standard
During Measurement
- Do not flex or move cables after calibration — phase shifts invalidate cal
- Terminate all unused DUT ports in matched 50Ω loads (not open!)
- For active DUT (LNA, PA): apply DC bias before connecting to VNA
- Source power: use −10 to −20 dBm for passives, −25 to −30 dBm for active devices
- Set IF bandwidth based on measurement time: 1 kHz for best accuracy, 10 kHz for quick check
Exporting for RF View
File → Save → Touchstone → .s2p Select: DB format, R=50 Name: partnum_condition_date.s2p (e.g., SFECF1G8_25C_20250115.s2p) Transfer to Android → open in RF View → instant analysis
RF View: Every good VNA measurement ends with a clean .s2p file. Load in RF View for Auto Match, Monte Carlo, and multi-file comparison. Free on Android.