Tuesday, November 30, 2010

Lesson 14: General Class Exam Course G3C

Here is the 14th lesson in the General Class series.  This lesson covers the G3C questions and ionosphere propagation.  Nothing too earth shattering to remember in this lesson.  A few things to reflect on, though.

The order of the ionospheric layers which impact propagation, and which you need to know for the exam, from lowest to highest are the D, E, F1 and F2 layers.  The D layer only exists during daylight hours.  As the sun goes down, the D layer disappears.  This is important to know because the D layer will absorb most signals below 10 MHz.  This limits daytime propagation for the lower HF frequencies to ground wave propagation only.

The F2 layer is the highest layer of the ionosphere which impact signal propagation.  Because it is the highest layer, signal which are bounced off of it tend to reach the farthest distances on the earth's surface.

Hope you enjoy the lesson!