Wife E claims that I am building a bomb. In fact I am housing my magnetometer in a length of concrete pipe -- the device should not vibrate, even slightly. It is one thing to design the electronics, quite another to build the machine. To modify the pipe, I first tried a standard hacksaw -- but needed a carborundum rod instead -- and what needs to be embedded in the pipe is quite complex. Then I lost all of my data last week. I had to find data for a standard magnetic field and re-test. OBSERVATION: In the re-test, it reliably detected a small neodymium magnet at 2.7 metres in a "noisy" urban environment. On the basis of a standard Ø 3/8" by 1/8" magnet, that would be 2.43 nanotesla sensitivity. However, my test magnet is a smaller Ø 9 mm by 2.5 mm -- therefore the sensitivity is much better than that. It would offer stiff competition for most devices on the market today. But it is designed to detect magnetic fields, not measure them. It is a detector, for finding things.