Fc = (Sqrt[20*30]);
Print[]
Print["Center frequency = "<>ToString[Round[Fc,0.01]]<>" MHz  (geometric mean from 20 to 30 MHz)"]
u=Table[{"  "<>ToString[PaddedForm[x,{3,1},NumberPadding->{"","0"}]]<>" MHz   ",
ToString[PaddedForm[Round[((Fc-x)/Fc) 360,0.1],{4,1},NumberPadding->{"","0"}]]<>"°  ",
ParametricPlot[{Sin[t],Sin[t+(π/2)+((Fc-x)/Fc) 2 π]},{t,0,2 π},PlotRange->1.05,Axes->True,ImageSize->{200,200},PerformanceGoal->"Quality"],
ToString[PaddedForm[Round[((Sqrt[Sin[(π/4)]^2+Cos[(π/4)+((Fc-x)/Fc) 2 π]^2])/(Sqrt[Sin[((3 π)/4)]^2+Cos[((3 π)/4)+((Fc-x)/Fc) 2 π]^2])),0.001],{4,3},NumberPadding->{"","0"}]]},
{x,15,30,1}];
v=Prepend[u,{"Frequency","Degrees Offset Phasing"<>FromCharacterCode[13]<>"from 24.49 MHz","Lissajous Figure","Axial Ratio - INCORRECT!"}];
Grid[v,Frame->All]

(Sqrt[Sin[(π/4)]^2+Sin[(π/4)+(π/2)+(((Sqrt[20*30])-18)/(Sqrt[20*30])) 2 π]^2])//N