The Nine Fives Blog

Field notes on RF test automation, instrumentation, and building simple, networked, driverless test equipment.

Attenuator running the new firmware 4.7.0, already showing the Nine Fives splash screen 5.20 seconds after PoE is applied

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Using LLMs to unleash the embedded Linux beast

How I gave Claude a power switch, a serial cable and a camera, and it took our attenuator from 21 seconds to 5.6 seconds between power-on and a usable screen.

October 20, 2026

HFSS animation of the electric field on the semi-circular three-section Wilkinson divider over one RF cycle

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How to vibecode a Wilkinson divider

How I used Claude Opus 5.5 with Qucs-S, openEMS and HFSS to design a 6–18 GHz multi-section Wilkinson power divider, from schematic to EM-verified layout.

October 5, 2026

Simulated surface current density on a coplanar waveguide with ground, animated over one RF cycle

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Transmission Line Tuning w/ HFSS

Using HFSS to tune a transmission line

July 9, 2026