Crawley Amateur Radio Club

Radio propagation through the ionosphere is one of the great gifts nature gives to anyone with an antenna and a receiver. While most of us are familiar with the F layer's role in long-distance HF communication, the E layer — and especially its unpredictable cousin, Sporadic E — deserves its own detailed look. This piece covers both the traditional, well-behaved E layer and the wild, VHF-opening phenomenon known as Sporadic E, with an eye to what it means for CARC members working HF and VHF from here in West Sussex. Part One: Traditional E Layer Propagation What Is the E Layer? The E layer is a region of the ionosphere located roughly 90 to 150 km (56 to 93 miles) above the Earth's surface. It sits below the F layer and above the D layer, forming one of several ionized layers that make radio propagation possible. The "E" designation comes from the original naming convention used by physicist Edward Appleton, who studied the layers using "electric" wave ...