50MHz Propagation forthe Millennium Year :50MHz Propagation forthe Millennium Year Magic Maths Myths and Legends Steve Reed G0AEV - UKSMG Annual Meeting, Sandown, Feb 2000


The 6m DX Propagation Equation(according to G0AEV!) :Maths + Legends - Myths Magic ____________________________________ =50 The 6m DX Propagation Equation(according to G0AEV!)


Legends - Trends from Old Data :egends Legends - Trends from Old Data


Legends :Legends Legendary Sources Previous cycle logs and recollections of experienced 6m operators. Raw data. Published compilations and reviews (e.g. in Six News, the Six and Ten Report) Recent 50 MHz trends and analogous 28 MHz data. “The past is the key to the future”.


Some events from Cycle 22 :Some events from Cycle 22 25/2/89 G4UPS to VS6 and JA (1st G QSO) 11/11/89 Widespread opening to Americas 28/4/91 G4IFX to CE (possible Es assisted) 8/2/92 Major opening to VK Most wished for in 2000? An opening to ZL!


Europe-VK contacts 1988-1992(Data from VK5LP) :Europe-VK contacts 1988-1992(Data from VK5LP) Six News, August 1999


G-VK contacts 1988-1992(Data from VK5LP) :G-VK contacts 1988-1992(Data from VK5LP)


50 MHz in 1999Days with openings per month :50 MHz in 1999Days with openings per month Data compilation by G3USF


NCDXF 28 MHz BeaconsOctober 1999 :NCDXF 28 MHz BeaconsOctober 1999


Legends : Summary :Legends : Summary Information from actual events - the raw data on what is possible and when. Trends (season, time, solar activity levels) where openings are relatively common Indications where openings are rare or at a lower frequency Not so helpful for “exceptional” events as insufficient data available.


Myths - Mainly about MUF :Myths - Mainly about MUF Myths


MUF Calculations :MUF Calculations f > f0 / sin  IONOSPHERE  f = f0 / sin  (classical MUF) f=f0 (critical frequency) D h f = f0 * SQRT[(D2/4h2) + 1]


Skip Geometry :Skip Geometry IONOSPHERE Footprint size increases with distance from Tx Tx


MUF and other measures :MUF and other measures f0F2 - Critical Frequency MOF - maximum observable frequency or Classical MUF Median MUF - MUF reached on 50% of days HPF - MUF reached on 10% of days (rule of thumb HPF = 1.15 * Median MUF) All these measures are “path-specific”


Comparison of 1999 Solar Indices :Comparison of 1999 Solar Indices


Late 1999 DX on 6mPropagation v Solar Indices :Late 1999 DX on 6mPropagation v Solar Indices


Late 1999 DX on 6mPropagation v Critical Frequencies :Late 1999 DX on 6mPropagation v Critical Frequencies


MUF map :MUF map


Great circle paths : G - VK & ZL :Great circle paths : G - VK & ZL


Myths - Solar Indices,Ionisation and Propagation :Myths - Solar Indices,Ionisation and Propagation Daily spots and flux indices only an approximate guide to levels of ionisation Daily critical frequency / MUF data only an approximate guide to propagation conditions Poor correlations on a day-by-day basis. Good conditions correlate with periods of high solar activity. Peak conditions may occur after peak solar activity.


Maths - A Scientific Approach :Maths - A Scientific Approach MATHS


Predictions :Predictions Uses international smoothed sunspot data MUF is determined on a path basis taking into account the best skip configuration. Includes signal to noise ratio calculations Ionospheric models limited to HF - at 50 MHz predictions of MUF are indicative. Probabilities reduced when geomagnetic effects included.


MUF : MARCH 12z SSN=140 :MUF : MARCH 12z SSN=140


MUF : MARCH 12z SSN=100 :MUF : MARCH 12z SSN=100


MUF : MARCH 12z SSN=200 :MUF : MARCH 12z SSN=200


MUF : MARCH 06z SSN=140 :MUF : MARCH 06z SSN=140


MUF : MARCH 09z SSN=140 :MUF : MARCH 09z SSN=140


MUF : MARCH 15z SSN=140 :MUF : MARCH 15z SSN=140


MUF : MARCH 18z SSN=140 :MUF : MARCH 18z SSN=140


MUF : MARCH 21z SSN=140 :MUF : MARCH 21z SSN=140


MUF : MARCH 00z SSN=140 :MUF : MARCH 00z SSN=140


MUF : DEC & JUN 12z SSN=140 June in red - December in green :MUF : DEC & JUN 12z SSN=140 June in red - December in green


HPF v SSN : MARCH G-VK/ZL :HPF v SSN : MARCH G-VK/ZL


Maths : Summary :Maths : Summary Predictions using computer calculations give: Probabilities for individual circuits Illustrate patterns and trends relating to Season Time of day Solar activity levels Quantitative relative measures


Magic - The DX Ingredient :Magic - The DX Ingredient Magic $ $ $ $ $ $ $


Magic Ingredients :Magic Ingredients Propagation mechanisms not easily predicted Mixed Modes Auroral enhancements Side scatter TEP and chordal hops Long path


MUF : NOV 09z SSN=140London Tx in red Tokyo Tx in green :MUF : NOV 09z SSN=140London Tx in red Tokyo Tx in green


Mixed Modes :Mixed Modes Sporadic E. Es-F2 links are common. Events at equinoxes especially important. Es often required for UK access to TEP circuits. Auroral E. For northerly paths (e.g. to JA?) Auroral backscatter. Rare (e.g. GM3WOJ to CX in ?1991) Meteor scatter. Rare (e.g. G3IMW reception of VE1YX 15/11/99)


Calculations + Observations Destinations East of UK : SSN=140 :Calculations + Observations Destinations East of UK : SSN=140 DU=Manila, JA=Tokyo, VK2=Sydney, VK6=Perth, VU=Delhi, ZL=Auckland


Calculations + Observations Destinations West of UK : SSN=140 :Calculations + Observations Destinations West of UK : SSN=140 CE=Santiago, KL7=Anchorage, VE7=Vancouver, VP8 Falklands, W6=San Francisco


What are the Chances? :What are the Chances? Depends on cycle amplitude, timing of the peak(s), activity and action levels, and luck! At SSN=140 Certain: all of Africa, most of South America, eastern seaboard of North America Very Likely: VK6 CE Far East (DU VR2 9V) Quite Likely: VK2, JA, W6 Unlikely: KH6, KL7, ZL G0AEV tip: late summer evening long path!


G0AEV’s Equation Explained:Predictions of 50MHz DX (The Magic) is the addition of Calculations (The Maths) with Observations (The Legends) while understanding the Theory (The Myths) :Maths + Legends - Myths Magic ____________________________________ =50 G0AEV’s Equation Explained:Predictions of 50MHz DX (The Magic) is the addition of Calculations (The Maths) with Observations (The Legends) while understanding the Theory (The Myths)