Photographic Records Showing the Variations of the Virtual Height of Reflection as a Function of the Radio Frequency
The standard (analog) ionosonde produces photographic records known as ionograms, which show the variations of the virtual height of reflection as a function of the radio frequency. The frequency band normally used is from about 1 MHz to about 20 MHz though some ionosondes operate down to about 0.20 MHz and up to 30 …