Editing Direction finding (section)

==== Transistor preamplifiers ====
Transistors suitable for microwave frequencies became available towards the end of the 1950s. The first of these was the [[metal oxide semiconductor field effect transistor]] (MOSFET). Others followed, for example, the [[metal-semiconductor field-effect transistor]] and the [[high electron mobility transistor]] (HEMT). Initially, discrete transistors were embedded in [[stripline]] or [[microstrip]] circuits, but [[microwave integrated circuit]]s followed. With these new devices, low-noise receiver preamplifiers became possible, which greatly increased the sensitivity, and hence the detection range, of DF systems.