OH1TV   OH1O   OH1WX
	Critical frequency foF2-limited local QSO on 14.2MHz
		When F2 layer height = 250km
		Ionogram	Shortest			Corresponds to 3000km
		foF2	distance	TOA		MUF	TOA
		3.87	3500	0.1		12.2	2.5
		4.0	2680	4.3		14.5	2.5
		4.5	1950	9.7		16.3	2.5
		5.0	1600	13.4		18.2	2.5
		6.0	1194	19.6		21.8	2.5
		7.0	945	25.3		25.4	2.5
		8.0	768	30.8		29.0	2.5
		9.0	630	36.5		32.7	2.5				TOA = antenna take off angle
		10.0	515	42.4		36.3	2.5
		11.0	414	48.9		39.9	2.5				Critical frequency foF2 link
		12.0	319	56.2		43.6	2.5
		13.0	221	65.2		48.2	2.5
		13.70	136	74.2		49.7	2.5
		14.0	0	90.0		50.8	2.5
		MHz	km	deg		MHz	deg
		Observations:
		Band is closed when foF2 is less than 3.9MHz
		Very short ,few tens of kilometers, QSO via F2 is possible when foF2 is 14MHz or more
		QSO down to 1000km is possible via F2  when foF2 is 6.7MHz
		QSO may still be possible via other propagation modes like back scatter, F1 etc.
		Back											28.4.2012