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Propagation Topics

Propagation Topics. Carl Luetzelschwab K9LA k9la@arrl.net http://mysite.ncnetwork.net/k9la. A Little About K9LA. Novice license WN9AVT in October 1961 Selected K9LA in the mid 1970s Interested in propagation, antennas, DXing , and contesting NCJ Editor from 2002-2007

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Propagation Topics

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  1. Propagation Topics Carl Luetzelschwab K9LA k9la@arrl.net http://mysite.ncnetwork.net/k9la FRC 9 Nov 2010 - K9LA

  2. A Little About K9LA • Novice license WN9AVT in October 1961 • Selected K9LA in the mid 1970s • Interested in propagation, antennas, DXing, and contesting • NCJ Editor from 2002-2007 • My wife is Vicky AE9YL – it helps that she kind of understands this ham radio thing • BSEE 1969 and MSEE 1972 from Purdue • RF design engineer by profession FRC 9 Nov 2010 - K9LA

  3. What We’ll Cover • Solar Minimum and Cycle 24 • Recent Science News • F2 Region Variability • Propagation Predictions • 160m Fundamentals • 10m Opening to EU on October 11 • Old QSL Quiz FRC 9 Nov 2010 - K9LA

  4. Solar Minimum and Cycle 24 FRC 9 Nov 2010 - K9LA

  5. Our Recent Solar Min Pretty unusual, right? FRC 9 Nov 2010 - K9LA

  6. A Look At All Recorded History Note the cyclic nature Recent solar min certainly unusual in our lifetime, but not that unusual over all recorded history FRC 9 Nov 2010 - K9LA

  7. Cycle 24 Progress • Solar min in December 2008 • Smoothed sunspot number and smoothed solar flux steadily rising ever since (in spite of the ups-and-downs of the monthly mean values) FRC 9 Nov 2010 - K9LA

  8. Latest NOAA Prediction Max smoothed sunspot number of 90 and max smoothed solar flux of 140 in early 2013 Kind of looks like the actual results are a bit behind the predictions FRC 9 Nov 2010 - K9LA

  9. More Predictions Over 55 predictions in the scientific literature Range from a smoothed sunspot number of 40 to 185 Somebody is going to get it right! FRC 9 Nov 2010 - K9LA

  10. When Will 15m and 10m Be Back? • Let’s assume the NOAA prediction is correct • 15m needs a smoothed sunspot number of about 25 (smoothed solar flux of 85) for consistent F2 propagation • We’re probably there now • CQ WW PH was consistently good • CQ WW CW should be, too • 10m needs a smoothed sunspot number of about 50 (smoothed solar flux of 100) for consistent F2 propagation • I hope we get there in early 2011 • ARRL DX contests in February and March 2011 have the potential of being good (more than just Carib and S Amer) FRC 9 Nov 2010 - K9LA

  11. Our Very Own Prediction out of phase with solar min duration Long solar min points to a smaller cycle “cycles” – Schwabe 11 yrs Hale 22 yrs Gleissberg 88 yrs De Vries 205 yrs Halstatt 2300 yrs (from Be10 and/or C14) FRC 9 Nov 2010 - K9LA

  12. A Recent Prediction Annales Geophysicae, 28, 1463–1466, 2010 www.ann-geophys.net/28/1463/2010/ doi:10.5194/angeo-28-1463-2010 Size of the coming solar cycle 24 based on Ohl’s Precursor Method, final estimate R. P. Kane Instituto Nacional de Pesquisas Espacias, INPE C.P. 515, 12201-970 Sao Jose dos Campos, SP, Brazil • Maximum smoothed sunspot number of 58 +/- 25 • That’s lower than the NOAA prediction • 10m will suffer FRC 9 Nov 2010 - K9LA

  13. Recent Science News FRC 9 Nov 2010 - K9LA

  14. #1 - No More Sunspots? • Measured the magnetic fields of sunspots for the past 17 years, and data indicates sunspot magnetism is on the decline • Sunspots seem to form only if the magnetic field is stronger than about 1500 gauss • Solar magnetic fields may become too weak to form sunspots after 2016 or so • The technique looks at a spectral line emitted by iron atoms in the Sun's atmosphere FRC 9 Nov 2010 - K9LA Livingston and Penn, EOS, July 2009

  15. #2 - Collapsing Atmosphere FRC 9 Nov 2010 - K9LA

  16. Data Pt Arguello ionosonde shows downward trends for both foF2 and hmF2 Other ionosondes show a mixed bag of results The conclusion: More analysis is needed Details: November 2010 WorldRadio Online column FRC 9 Nov 2010 - K9LA

  17. #3 - Storm Warnings FRC 9 Nov 2010 - K9LA

  18. #4 - Lower Ionosphere • Space is just a little bit closer, BBC News, 21Dec08, news.bbc.co.uk/2/hi/science/nature/7794834.stm • NASA: Ionosphere not where it should be, UPI, 17Dec08, www.tinyurl.com/3p2pcs • These press releases are somewhat misleading • What’s not real clear is the data is for equatorial latitudes • Not understanding this leads to the erroneous conclusion that the worldwide ionosphere is lower - ionosonde data shows no such trend • Details: “Is the Ionosphere Really Lower?” at mysite.ncnetwork.net/k9la under Timely Topics link FRC 9 Nov 2010 - K9LA

  19. F2 Region Variability FRC 9 Nov 2010 - K9LA

  20. A Look at Ionosonde Data MUF varied from a low of just under 10 MHz to a high of just above 20 MHz This is due to the daily variation of solar radiation, right? FRC 9 Nov 2010 - K9LA

  21. Not Quite • August 2009 • Zero sunspots • Constant solar flux • Solar radiation creates ionization • But two other issues contribute to the final ionization • Magnetic field activity • Events in the lower atmosphere coupling up to the ionosphere • Thankfully the E region is more predictable – it’s under direct solar control • Solar activity • Solar zenith angle August 2009 FRC 9 Nov 2010 - K9LA

  22. Another Subtle Effect The worldwide ionosphere is not necessarily “in step” FRC 9 Nov 2010 - K9LA

  23. Propagation Predictions FRC 9 Nov 2010 - K9LA

  24. How Do You Model the Ionosphere? • It should be obvious that plugging in today’s sunspot number or today’s 10.7 cm solar flux does not tell us what the F2 region of the ionosphere is doing today • The developers of the model of the ionosphere for propagation prediction recognized this • They were forced to implement a statistical model • Thus our propagation predictions are statistical over a month’s time frame • The correlation between what the Sun is doing and what the ionosphere is doing is based on a smoothed solar index and monthly median ionospheric parameters FRC 9 Nov 2010 - K9LA

  25. Review of Correlations MUF could be anywhere from 17 MHz to 28 MHz at a solar flux of 170 Bottom line: We do not have daily predictions Median is predicted – use with variability tables to determine other probabilities FRC 9 Nov 2010 - K9LA

  26. So What Does All This Mean? • Let’s do a prediction for CQ WW CW • We’ll do it for 15m from Philly to Europe (DL) • We’ll use VOACAP • 1 KW • 13 dBi Yagis • I used a smoothed sunspot number of 36 (from http://www.swpc.noaa.gov/ftpdir/weekly/Predict.txt) FRC 9 Nov 2010 - K9LA

  27. Results 15m 10m Median MUF MUF • On half the days of the month at 1400 UTC, the MUF will be at least 25.6 MHz • On 89% of the days of the month at 1400 UTC, the MUF will be at least 21.0 MHz • On 27% of the days of the month at 1400 UTC, the MUF will be at least 28.0 MHz • Signal Strength • The median signal strength on 15m at 1400 UTC is -103 dBW (-73 dBm = S9) • The median signal strength on 10m at 1400 UTC is -142 dBW (-112 dBm = S1) UTC Unfortunately we don’t know which days will be the good ones Rule of thumb – MUF can vary about the median by one band and signal strength can vary about the median by a couple S-units on any given day in the one-month period FRC 9 Nov 2010 - K9LA

  28. 160m Fundamentals FRC 9 Nov 2010 - K9LA

  29. Interesting Question Is propagation on 160m different than propagation on, say, 10m? Most would answer “Yes” FRC 9 Nov 2010 - K9LA

  30. “No” Is Also A Good Answer • An electromagnetic wave on 1.8 MHz follows the same laws of physics as an electromagnetic wave on 28 MHz • What “laws of physics” should we look at? • The three that tell us • Refraction (inversely proportional to the square of the frequency) • Absorption (inversely proportional to the square of the frequency) • Polarization (Earth’s magnetic field plays critical role) FRC 9 Nov 2010 - K9LA

  31. Ray Trace on 10m • O-wave and X-wave pretty much follow the same path • Index of refraction approximately the same • X-wave bends a bit more • Apogee approx 240 km • Hops to 4000 km • O-wave and X-wave pretty much incur the same amount of absorption • Approx 2 dB per hop • O-wave and X-wave are circularly polarized On 10m the O-wave and X-wave propagate approximately equally FRC 9 Nov 2010 - K9LA

  32. Ray Trace on 160m • O-wave and X-wave do not follow the same path • Index of refraction significantly different • X-wave bends more • Apogee approx 170 km for O-wave • Hops limited to < 3000 km • O-wave and X-wave do not incur the same amount of loss • Absorption significantly different • X-wave usually considered to be out of the picture when operating frequency is near the electron gyro-frequency • ranges from .7 to 1.7 MHz worldwide • Approx 17 dB per hop • Polarization of O-wave tends towards elliptical (vertical) at mid to high latitudes 160m - shorter hops 160m - more lossy hops 160m – only one characteristic wave propagates FRC 9 Nov 2010 - K9LA

  33. Multi-hop on 160m • Based on previous slides, multi-hop propagation on 160m is via hops that are short and lossy • “Short” is relative – but it’s not 4000 km hops like on 10m • Per our present understanding of the lower ionosphere, at night a 1500 Watt signal with quarter-wave verticals on both ends can go about 10,000 km before being below the noise level of our receiving system (usually limited by external noise) • Daytime limit around 1000 km FRC 9 Nov 2010 - K9LA

  34. This Suggests Another Mode Distances greater than 10,000 km are likely due to ducting in the electron density valley above the nighttime E region peak Ducting incurs less loss due to less transits through the absorbing region and less ground reflections Key issues: what controls entry into the duct, what controls staying in the duct, what controls exiting the duct? FRC 9 Nov 2010 - K9LA

  35. galactic cosmic rays NM7M’s Work with GCRs • Galactic cosmic rays are mostly very high energy protons coming in from all directions – day and night • Quiet magnetic field (solar min) lets more in – more ionization in the lower ionosphere • Active magnetic field (solar max) keeps them out – less ionization • GCR measurement on Earth (and thus impact to ionosphere) is out of phase with solar cycle FRC 9 Nov 2010 - K9LA

  36. solar min -------- solar max ------- CGRs and the Valley • NM7M’s theory is that galactic cosmic rays play an important role in the valley formation, and thus ducting • At solar maximum, not many GCRs ionizing the valley – nice and deep • Extremely long distance DXing best at solar max • NM7M has some interesting plots of QSO distance vs GCR decrease, but there is conflicting data • At solar minimum, too many GCRs ionizing valley – fills up more and all we have left is lossy multi-hop FRC 9 Nov 2010 - K9LA

  37. W4DR Observationspersonal e-mail, late December 2009 “I have been DXing on 160 since 1970, with for the most part above-average antennas. During this present sun spot minimum (the last 2 years and especially the last 8 weeks) I have worked more polar path stations, Zones 17, 18, 19 and 23 plus some 40's than I have in the previous 37 years. This included my first ever zone 23 on Dec 12. On the other hand I have not worked any long path or bent path SE Asians in the last 4-5 years.” N4IS and K1ZM recently reported long-haul DX into SE Asia Suggests that 160m propagation over the poles is best at solar min, and long distance DXing may need a bit more geomagnetic field activity to keep GCRs out FRC 9 Nov 2010 - K9LA

  38. 10m Opening to EU on Oct 11 FRC 9 Nov 2010 - K9LA

  39. The Path • East Coast reported good 10m opening to EU on Oct 11 • PJ2T also reported this • No data from Goose Bay • So we don’t know what was happening on the East Coast end • El Arensillo (Spain) gives a good picture on the Europe end FRC 9 Nov 2010 - K9LA

  40. Ionosonde Data Something happened on or before the 11th FRC 9 Nov 2010 - K9LA

  41. Space Weather • It is likely that the gradual increase followed by a gradual decrease in the K index played a role in this 10m opening • Ionization targets at F2 region altitudes (oxygen atoms) can be re-distributed in the atmosphere due to an elevated K index FRC 9 Nov 2010 - K9LA

  42. Old QSLsorWhat Deleted Entity Is It? FRC 9 Nov 2010 - K9LA

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