The relation of F2 layer noon critical frequency with magnetic dip and geomagnetic latitude is studied for constant values of solar zenithal angle. The constant-x plots show two maxima situated on the two sides of the magnetic equator. An asymmetry between the northern and southern hemispheres is also revealed. For chosen values of solar zenith distance the ratio of noon fF2 at sunspot maximum to that at sunspot minimum is studied in relation to magnetic dip. The ratio is found to vary with magnetic dip displaying a minimum to the north of the magnetic equator
