Fig. 11From: MF and HF radar techniques for investigating the dynamics and structure of the 50 to 110 km height region: a reviewThe average height profile of returned signal to noise (SNR) for 1 year of observations for one receiver channel for O-mode on the Davis Station MF radar (after McIntosh 2010). Note the rapid increase in SNR between 80 and 82 km, which corresponds to a gradient of 18 dB in 2 km. This rapid increase in returned power with height was the rationale for using two sampling regimes and two gain settings on some older radarsBack to article page