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Cycle 24 Status – and Much More

Cycle 24 Status – and Much More. Carl Luetzelschwab K9LA k9la@arrl.net. Topics. Quick review of August 2009 presentation Recent data Solar min review Cycle 24 status Cycle 24 looking ahead Seasonal effects on propagation Four relevant Cycle 24 questions Two other topics Effect of trees

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Cycle 24 Status – and Much More

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  1. Cycle 24 Status – and Much More Carl Luetzelschwab K9LA k9la@arrl.net PVRC Webinar 18 & 21July 2012 K9LA

  2. Topics • Quick review of August 2009 presentation • Recent data • Solar min review • Cycle 24 status • Cycle 24 looking ahead • Seasonal effects on propagation • Four relevant Cycle 24 questions • Two other topics • Effect of trees • Best height for an antenna PVRC Webinar 18 & 21July 2012 K9LA

  3. Quick review of August 2009 presentation PVRC Webinar 18 & 21July 2012 K9LA

  4. August 2009 Webinar We were at solar min – how long would it last? PVRC Webinar 18 & 21July 2012 K9LA

  5. August 2009 Webinar From Dr. David Hathaway (MSFC, 2009) • We’d been seeing Cycle 24 sunspots for about a year and a half • But Cycle 24 hadn’t started ramping up yet PVRC Webinar 18 & 21July 2012 K9LA

  6. August 2009 Webinar • Prior to this July 2009 prediction, ISES had been carrying two predictions • One for a “high” cycle (140) • One for a “low” cycle (90) • Long duration solar minimum led to decision to go with “low” cycle prediction International Space Environment Service PVRC Webinar 18 & 21July 2012 K9LA

  7. Most recent data PVRC Webinar 18 & 21July 2012 K9LA

  8. Recent Solar Minimums Longest of our lifetimes PVRC Webinar 18 & 21July 2012 K9LA

  9. All Solar Minimums We’ve had similar minimums – even longer minimums (assuming our data is good back then) Average duration ~ 37 months PVRC Webinar 18 & 21July 2012 K9LA

  10. Next Max vs Previous Solar Min Looks like we’re headed for a small cycle PVRC Webinar 18 & 21July 2012 K9LA

  11. First Sunspot of Cycle 24 PVRC Webinar 18 & 21July 2012 K9LA

  12. Current Cycle 24 Data • Solar min around December 2008 • Cycle 24 slow to start its ascent • Have we reached Cycle 24’s peak or is this just a temporary lull? PVRC Webinar 18 & 21July 2012 K9LA

  13. In Terms of 10.7 cm Solar Flux Similar trends PVRC Webinar 18 & 21July 2012 K9LA

  14. Geomagnetic Field Activity • Still quieter than 1996 solar minimum – too quiet? • Where is 160-Meters? • Are we seeing the effect of galactic cosmic rays? PVRC Webinar 18 & 21July 2012 K9LA

  15. Cycle 24 vs Cycle 23 • For a short time Cycle 24 rate of ascent was comparable to Cycle 23 • But Cycle 24 was slower to start – tends to indicate lower cycle PVRC Webinar 18 & 21July 2012 K9LA

  16. Current Predictions 90 60 International Space Environment Service Marshall Space Flight Center PVRC Webinar 18 & 21July 2012 K9LA

  17. A Very Early Prediction If only it were true! PVRC Webinar 18 & 21July 2012 K9LA

  18. Seasonal effects PVRC Webinar 18 & 21July 2012 K9LA

  19. Seasonal Effects • With the smoothed sunspot number hovering around 60 (smoothed 10.7 cm solar flux around 120) beginning in August 2011, seasonal effects become noticeable for 10m propagation • Let’s look at the MUFs along two paths at a smoothed sunspot number of 60 • W3 to EU, to JA, and to S. America • G to Eastern EU, to W4, and to JA PVRC Webinar 18 & 21July 2012 K9LA

  20. W3 to EU • October thru December good for 10-Meters • Summer months worst PVRC Webinar 18 & 21July 2012 K9LA

  21. W3 to JA • October best for 10-Meters • Summer months worst PVRC Webinar 18 & 21July 2012 K9LA

  22. W3 to S America • September thru April good for 10-Meters • Thanks to the robust equatorial ionosphere • Summer months worst PVRC Webinar 18 & 21July 2012 K9LA

  23. G to Eastern Europe • October thru February best for 10-Meters • Summer months worst PVRC Webinar 18 & 21July 2012 K9LA

  24. G to W4 • October thru February good for 10-Meters • Summer months worst PVRC Webinar 18 & 21July 2012 K9LA

  25. G to JA • October best for 10-Meters • Summer months worst PVRC Webinar 18 & 21July 2012 K9LA

  26. Last Fall vs This Spring • Decrease in monthly mean solar activity resulted in leveling off of the smoothed value • As we moved from Fall/Winter to the Spring, seasonal effects came into play • In general, 10-Meters for CQ WW and ARRL 10M good, ARRL DX and CQ WPX not so good • This Fall – 10-Meters should be good • But we need a more active Sun to help with 10-Meter propagation next Spring! PVRC Webinar 18 & 21July 2012 K9LA

  27. Four FAQs PVRC Webinar 18 & 21July 2012 K9LA

  28. #1 - Two Peaks for Cycle 24? • Cycle 19, 20, and 21 didn’t show much of a second peak • Cycle 22 and 23 did show a definite second peak • Cycle 23’s second peak made 6-Meter DXers very happy in the Winter of 2001 Cycle 24 could have a second peak PVRC Webinar 18 & 21July 2012 K9LA

  29. #2 - 6-Meter F2? • Paths not involving the equatorial ionosphere are very unlikely with the current Cycle 24 prediction • TEP is still possible • If F2 does happen away from the equator, it would be most likely during the Spring, Fall, and Winter of 2013 • Sporadic E should still be there • Late morning and early evening in the Summer • Early evening in December PVRC Webinar 18 & 21July 2012 K9LA

  30. Recent 6m Opening - W7 to EU 29 June 2012 Probably not F2 – most likely Es foF2 ~ 4.7 MHz F2 MUF ~ 17.4 MHz foEs > 9.5 MHz Es MUF > 50 MHz PVRC Webinar 18 & 21July 2012 K9LA

  31. #3 - Disappearing Sunspots? • W. Livingston and M. Penn measured the maximum strength of magnetic fields of sunspots • Strength has been declining since 1992 • Need about 1500 gauss for sunspots to be visible • Extrapolating their data says sunspots will disappear by 2016 extrapolation PVRC Webinar 18 & 21July 2012 K9LA

  32. 2012 Update Slope the same as previous plot – vertical axis in this plot is expanded So what if sunspots disappear? Remember that sunspots are a proxy for the true ionizing radiation (EUV), which still appears to be alive and well PVRC Webinar 18 & 21July 2012 K9LA

  33. Sunspot Number vs Solar Flux If sunspots are disappearing, we might expect to see a decrease in the correlation of smoothed sunspot number and smoothed 10.7 cm solar flux Cycle 23/24 data Also impacts propagation predictions using smoothed sunspot number PVRC Webinar 18 & 21July 2012 K9LA

  34. #4 - Another Maunder Minimum? • Maunder Minimum - lack of sunspots from 1645-1715 • The three cycles before Maunder Minimum showed a smooth decrease in group sunspot number • It’s generally agreed that the Sun is “slowing down” • Cycles 22, 23, and 24 exhibit a smooth decrease, too • What Cycle 24 does and duration of solar min between Cycle 24 and 25 may suggest where we’re headed • It very well may be there will still be an ionosphere PVRC Webinar 18 & 21July 2012 K9LA

  35. Trees and HF propagation PVRC Webinar 18 & 21July 2012 K9LA

  36. Trees and HF • All of my antennas look through trees on headings from Northwest thru South • Is this a problem? PVRC Webinar 18 & 21July 2012 K9LA

  37. Trees and HF – Two Issues • Foliage (leaves) • Use the work of Tamir and Krevsky PVRC Webinar 18 & 21July 2012 K9LA

  38. Foliage • Conductivity much more significant than permittivity • Mid latitude woods • Minor effect at LF • More effect as frequency increases • But my trees are deciduous – probably very minor effect in winter PVRC Webinar 18 & 21July 2012 K9LA

  39. Trunk (Chunk of Lossy Dieletric) • Technical Correspondence, Nov 1991 QST • 75m vertical in pine trees • Distances • High voltage portion too close to trunk • Try to keep high voltage portion greater than .023 wavelengths from trunk • These experiments were with wire parallel to tree trunk • Beverage antenna probably more forgiving PVRC Webinar 18 & 21July 2012 K9LA

  40. Best antenna height PVRC Webinar 18 & 21July 2012 K9LA

  41. Best Height for Antenna • Elevation statistics in the ARRL Antenna Book CD from N6BV’s work • Example: Indianapolis to six areas of the world and to the US Indianapolis to the world on 10-Meters PVRC Webinar 18 & 21July 2012 K9LA

  42. Antenna Patterns 5-element 10m monobander over average ground PVRC Webinar 18 & 21July 2012 K9LA

  43. Elevation Statistics + Patterns • Best “compromise” height is ~ 1.5 wavelengths (50 ft) • Agrees with W2PV’s analysis in his book Yagi Antenna Design • Need to stack antennas to cover all the angles PVRC Webinar 18 & 21July 2012 K9LA

  44. Summary • Cycle 24 has leveled off • Is this temporary or are we at the peak? • Next several months will give us a clue • Cycle 24 has a decent chance of two peaks • Would likely prolong propagation on the higher bands • 6M F2 propagation probably restricted to equatorial ionosphere • Sunspots may disappear, but EUV will likely still be there • Too early to tell if we’re headed for another Maunder Minimum • Even if we are, maybe it doesn’t matter with respect to propagation • Expect good 10-Meter contest season for CQ WW and ARRL 10M • ARRL DX and CQ WPX next spring need more solar activity • Don’t worry too much about trees – especially in the winter • Try to put your antenna at the “optimum” height PVRC Webinar 18 & 21July 2012 K9LA

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