hcarter333
commented
1 year ago Here's how to grab the image: https://stackoverflow.com/a/32330832/1429266
Which resides at https://prop.kc2g.com/renders/current/mufd-normal-now.svg
Here's more infor on ionograms: https://en.wikipedia.org/wiki/Ionosonde#Ionogram
Here's the text from the original Nature article: A Radio Method of Estimating the Height of the Conducting Layer. IN a recent note we have outlined a method of estimating the height of the conducting layer by means of radio waves (M. A. Tuve and G. Breit, Terr. Mag., vol. 30 (I92S), pp. rs-I6). Through the co-operation of the U.S. Naval Bellevue, Anacostia, D.C., we have obtamed defimte indications of reflections such as would take place from the layer and some estimates of its height. The method used consists in sending out interrupted high frequency wave-trains and observing the wave-form of the received signal. Each wave-train received manifests itself as a temporary rise in the detector current of the receiving set. One particular wave-train at the transmitter gives rise to two received wave-trains at the receiver if a single reflection takes place. One of these trains travels over the ground and the other by way of the layer. Thus the detector current is forced to rise at two different times by the same wave-train from the transmitter and an oscillogram of the detector current shows two humps generally of unequal size. The transmitter was operated with a soo-cycle plate current supply so that a of 71·3 wave-length was emitted durmg a part of each posrttve half of the cycle. A succession of single humps is thus emitted. (We have made sure of this by observing the wave form at the same time at the transmitting and the receiving stations.) The re-ceiving station was located 7 miles away from the transmitter in a general direction north, the Potomac River and the City of Washington being between the two stations. We have observed the received wave-form visually and photographically. Double and triple humps were observed on some days, though practically single ?umps were obse::ved on Marked variations m the relative posttion and amph-tude of the humps were observed during ro-minute observation periods. The retardation of the secondary humps with respect to the primary is of the ?rder of r /1700 second, which corresponds to a retardation over a length of rough! y I I o miles and a distance of the layer of the order of so miles. humps spond to Ioo miles. The ongm of tnple rs not clear. The possibilities of a wavy surface m the layer and successive reflections suggest themselves. Experiments on other wave-lengths with different receivers and transmitters and m drfferent locatwns seem valuable. We are hoping that such experiments will be performed by others as well as Some experiments at 6oo _metres wer.e performed. m co-operation with the Radro Corporation of. Amenca, the distances between the two statwns bemg about rso and roo miles. No definite indication of the presence of the layer was found in these cases. G. BREIT. M.A. TuvE. Department of Terrestrial Ma&netism, Carnegie Institution of Washmgton, Washington, D.C. K2
This will enable tracking the progression of the maximum usable frequency vs the QSOs/spots from the Rockmite.