THE DESIGN BRIEF

You're spending $15K on chamber time when a $3K mobile setup could catch your failures early. FCC Part 15 mobile test equipment gives you radiated and conducted emissions measurements against actual limits — not just relative readings.

Here's your threshold: if mobile gear shows you're within 3 dB of limits at your desk, you're probably failing in the chamber. The correlation isn't perfect, but it's close enough to save you iterations. Run conducted emissions from 150 kHz to 30 MHz on your power leads first — that's where most commercial designs fail. For radiated, sweep 30 MHz to 1 GHz at 3m if you've got the space, 1m if you don't. Apply the distance correction factor: 20 log(3/1) = 9.54 dB.

The new CISPR 11 (2024 revision) tightened ISM equipment limits by 2-3 dB in some bands. If you're designing medical gear under IEC 60601-1-2, those CISPR 11 limits feed directly into your compliance matrix.

• • CS115 bulk cable injection: Now tested to 200 MHz per MIL-STD-461G, up from 150 MHz in previous revisions
• • CISPR 25 automotive: Still the baseline for vehicle EMC alongside ISO 11451/11452 — no updates but OEMs are adding custom requirements above 6 GHz
• • CE101 audio-frequency: 30 Hz–150 kHz on power leads remains the most common MIL failure mode
• • Shielding ROI: 20-30 dB improvement typical for conformal shields on switching regulators above 100 MHz

• • IEC 60601-1-2 Edition 5.0: Expected late 2026 with stricter immunity requirements for life-critical medical devices
• • Automotive mmWave: CISPR 25 supplement under development for 24-77 GHz radar systems

Have you run CS115 bulk cable injection to 200 MHz per MIL-STD-461G? Reply with what frequency killed you — I'm collecting field data.

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