article

A hodograph is a technology for visual identification of the VDI number (counting starts from the vertical axis). The further to the right (more positive) the slope of the hodograph, the larger the detected object and the more noble its metal. For example, small colored items are displayed on the hodograph as a ray, whereas iron objects, medium or large in size, take the form of a loop.

We propose to explore how the AKA metal detector hodograph reacts to different types of targets. For the test, we will use the Intronic STF with a 9x12 coil and a frequency range of 5-40 kHz.

Keep in mind that using a different coil may change the VDI number, as higher frequencies will result in a higher VDI value.

Three hodographs are displayed on the device's screen:

Low frequency - 5 kHz;

D-hodograph - shows deviations from the vertical axis, with positive (non-ferrous metal targets) or negative (iron) values.

High frequency - 40 kHz.