I took my magnetometer (magnetic field detector) out of the magnetic noise of the city this morning, and onto the slopes of Table Mountain (pictured). The goal was to see whether it was stable in a magnetically quiet environment, and to quantify its performance. It was stable. Also, sensitivity greatly increased in the "quiet". It reliably picked up a tiny neodymium button (⌀ 6 mm by 2 mm) at 1.27 metres. OBSERVATION: But there is a problem. There are two channels -- so configured for stability. Move one sensor in relation to the other by mere micrometres, and the magnetometer picks it up. This means that it would need an extremely rigid frame. I shall also look at switching one channel in and out.