Using NIST’s Shortwave Broadcast Signals to Experience and Understand Ionospheric Radio Propagation

We discuss the use of NIST's high-frequency (HF) broadcast signals to enable undergraduate engineering students to experience and thereby better understand how the ionosphere can enable transcontinental wireless communication. We will demonstrate this phenomenon using signals of opportunity such as NIST's 5 and 10 MHz time/frequency broadcasts. Also discussed is how the D-layer absorbs signals below 8 MHz and thus inhibits long distance transcontinental sky-wave radio propagation during the daylight hours.