VHF Propagation identification determined by Min/Max distances (V3.0)

 

VHF Propagation identification determined by Min/Max distances (V3.0)
Distance	Less than 110km	110-400km	400-800km	800-2350km	2350-4700km	4700-8000km	Over 8000km
Propagation type	Line of Sight (LOS)	Tropo Scatter (TRS)
		Tropo Ducting (TRD)				TRD + Es
		Aurora (AU)
		Aircraft Scatter (AS)	Sporadic-Es (ES)		Sporadic-Es (ES) x2 hops	Sporadic-Es (ES)x3 hops	Sporadic-Es + TEP
			Meteor Scatter (MS)		Trans Equatorial Propagation (TEP)
						F2 Layer reflection (F2)
Required conditions or assists with ID	True Line of Sight is up to 50km, but can be extended by height i.e. elevation ASL or by refraction (LOS)	Stable High Air Pressure, as often seen with fog (TRD)	Raspy distorted tone & audio distortion (AU)	April to September with peak in June, small opening in December possible near Equinox (ES)	Sea path required for longest rare distances (TRD)		Often misidentified as ES alone on DXcluster, which is impossible. Main distance component is TEP and both stations need to be on opposite sides of Magnetic Equator
		Typically around 4 minutes duration (AS)	Mostly short duration pings of seconds or shorter, but can be minutes (MS)		Stations need to be either side of Magnetic Equator (TEP)	Favours Autumn to Spring months during Solar Cycle Peaks, approx every 11 years