The frequency of 38.2 MHz is reserved for research. A method of quantifying the amount of scintillation present. The effect is the same as the visible twinkling of stars due to variations in the atmosphere. Scintillation is readily identified in the data. Scintillation is most easily explained by analogy to a diffraction grating.
Ionospheric irregularities are the equivalent of the diffraction grating.
The received signal is then the sum of signal from multiple paths. As the path lengths change the signal varies due to constructive and destructive interference, hence the star twinkles. In other words, scintillation is variations in amplitude, phase, polarization and angle of arrival of a radio wave upon passing through the ionosphere, such as would occur with a satellite signal. It is also important how big the area is that is affected by the temperature change. Generally, the requirements the antenna system has to fulfil in order to achieve the required spatial resolution are harder to fulfil than the requirements for a reasonable sensitivity.