Multilayer PCBs, especially when designed for RF, may have many layers of ground; even the signal layers typically have ground flooded on them. ... The via spacing was set to 200 mils, this ...

Many readers are certainly familiar with the process for home-etching of PCBs: it’s considered very straightforward, if a little involved, today. This was not the case in my youth, when I fir… ...

Earth is made up of several layers: the lithosphere, asthenosphere, lower mantle (also known as mesospheric mantle), outer core and inner core.

Astronomers have creatively used a radio telescope to see in 3-D, allowing them to detect the existence of tubular plasma structures in the inner layers of the magnetosphere surrounding the Earth.