Dependence of drift rate on frequency fitted according to power laws using coefficients a and b. The fits derived from the observations of Morosan & Gallagher (2018), Dorovskyy et al. (2017), and McConnell (1982) are plotted in green, blue, and red, respectively. The black fit takes into account the orange (UTR-2 data), grey (LOFAR data from Morosan & Gallagher 2018), and red (data from McConnell 1982) points to provide, for the first time, a collective analysis of this dependence using multiple instruments.