The Ionosphere and what to do with it

Before embarking on this in-depth study of the ionosphere it is essential to brief the absolute beginner on the basics of cosmology and planetarianism. This may appear to be complicated as indeed it is. Moving along quickly, there is only one basic fact which has to be remembered by the novice and that is that the sun moves around the earth in a 364-day geostationary orbit. When this fact is firmly established in the brain everything else will seem simple.

The Earth may be imagined to be a tennis-ball. (You may prefer to think of it as an orange, but this will soon go rotten when exposed to ultra-violent rays as we will soon see.) There are several layers surrounding the Earth in space and these are all named after famous letters of the alphabet, such as D etc. When Sir George Appleside invented the ionosphere in 1776 the world used the Gregorian aphabet and the letters A, B, and C did not then exist.

There are seven of these alphabetical layers in all, the afore-mentioned D-layer, the E-layer, and five F-layers called F, F1, F2, LU(F) and MU(F). Of these the D-layer may be completely disregarded as it runs in a counter-clockwise orbit around the equator during the winter solstice, is non-ionised and will not refract magnetic energy. (Kirchhoff's third law of unilateral refraction.)

The E-layer (the 'E' stands for 'Emitter') is more highly ionised than the Base and Collecter and thus is said to be forward-biased. However, this only occurs on the peaks of the crystal-lattice structure and is thus termed 'sporadic'. This Sporadic-E occurs during the summer months and is therefore predictable.

Now we move on to the interesting subject of all those F-layers. Starting from the Earth's surface the first we come to is the LU(F) or the 'Low Unstable F-layer'. Because of the massive accumulations of hydrogen, neon and fluon in this layer it is extremely unstable and, note this well, should never be subjected to radio-waves which are not thoroughly supervised. The use of spark transmissions is expressly forbidden.

The next layer is the F-layer which, to coin a phrase, 'traps' radio signals. An eminent scientist once calculated that if it could be possible to permanently position an aerial (or antenna) within the F-layer it would have to be about 300 miles high. This is amazing.

The F1-layer is known colloquially as the 'binary layer'. This is because it is continually in the F1 state unless a negative pulse from a transmitter triggers it into F0. As such it is useful for on/off keying systems or binary data streams. Experimental use of an off/off keying system has been used with the F1-layer but because, as anticipated, the layer did not switch to its 0 state, no receiving station could swear that the signal had not been received. However the work goes on.

Next comes the F2-layer. This is negatively ionised with respect to the F1-layer and, to use technical jargon, 'catches' signals which would have otherwise 'escaped'. These 'escape rays' are doomed to permanently circle the earth once every twenty-four hours and may be sometimes heard as fading on the medium-wave after dark.

The MU(F) lor 'Maximum Unstable F-layer' acts as a sort of ionised fence and prevents signals between 2 and 2,000,000 Mhz. from escaping from the Earth's gravitional pull. In some respects this is a good thing because, in technical terminology, some signals are 'zoomed back' to Earth. However, because the MU(F)-layer repels signals in the EHF and SHF spectra it means that all satellites must be put into orbit inside this layer. This makes it extremely tricky when sending up a new satellite and it may necessitate the use of complicated mathematical instruments such as slide-rules and protractors, or even set-squares, so the launch can be calculated correctly.

The reader will be pleasantly surprised to learn that he or she has now mastered the ionosphere. However, there are one or two bits which are additional and should be well noted. The first of these bits is information on sun-spots. These were first noticed by Neil Armstrong in 1969. It may be remembered that he was the first human being to set foot on the sun and he is famous for his well-known humourous saying, "This is one small spot for a man". Well, the spot he so casually joked about was the famous sun-spot which has been affecting sub-normal D-layer non-propagation ever since.

The next thing to note is back-scatter. This term refers to small pieces of signals which 'come off' the back of the aerial, bounce rapidly off the LU(F)-layer accelerating all time time. Passing through the D-layer they change phase, and because they are moving so quickly, actually catch up with the signals which left the front of the aerial. Because the two signals are not out of phase, one is 'sucked into' the other and they both disappear. This accounts for the well-known phenomenon where no signals can be heard on some frequencies for some of the time.

There is no need to remember anything about ultra-violent rays except that too many of them rot oranges. (See above.) Reference to oranges brings us naturally onto the subject of aerials and where you can stick them.