On Google+, Bob, K0NR posted,
Interesting question from a 10-year-old student in the ham radio class today: Why do we always talk about the D, E and F layers of the ionosphere…are there A, B or C layers? I don’t know the answer to that one.
Now, I’d always heard that the reason the lowest layer is the D layer is because when scientists first started studying the ionosphere, they found these three layers and postulated that they would find three layers below them, i.e. the A, B, and C layers. They did not find them, but never went back and relabeled ones that they did find.
I posted this as a reply, and Bob asked if I had a reference. Well, I Googled all over for one, but came up empty. Do any of you know if this explanation is true, or if this is a ham radio urban legend?
Dan KB6NU says
Ethan, KG8U, emailed me the following:
Bob K0NR says
Dan and Ethan,
Thanks for the information!
Bob
Curt/KF5KGN says
Yes, thank you!
Robert Kellogg says
Appleton recalled [1], “The story of how I came to give the names D, E and F is really a simple one. In the early work with broadcasting wavelength, I obtained reflections from the Kennelly-Heaviside layer and I used on my diagrams the letter E for the electric vector of the down coming wave. When I found in winter 1925 that I could get reflections from a higher and completely different layer, I used the letter F for the electric vector of the down coming wave. Then about the same time I got occasionally reflections from a very low height and so naturally used the letter D for the electric vector of the returning waves. Then I suddenly realized that I must name these discrete layers and being rather fearful of assuming any finality about measurements, I felt I ought not to call these layers A, B, and C, since there might be undiscovered layers, both below and above them. I therefore felt that the original designations for the electric field vector D, E and F might be used for the layers themselves”
[1] R. Silberstein, “The Origin of the Current Nomenclature for the Ionospheric Layers”, J. Atmos. Terr. Physics. (JATP 0259), p.382
Dan KB6NU says
Thanks for the citation!
PeteS says
C layer found!
https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0CCQQFjABahUKEwjS48CO6pvJAhUDORoKHS09CkM&url=http%3A%2F%2Fonlinelibrary.wiley.com%2Fdoi%2F10.1029%2FJA085iA06p03037%2Fabstract&usg=AFQjCNHTpsA_4FGxw0HRoM1q0e1WfSWUBA