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PVRC Webinar - 20Jan10 - K9LA 160m Propagation Carl Luetzelschwab K9LA

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Presentation on theme: "PVRC Webinar - 20Jan10 - K9LA 160m Propagation Carl Luetzelschwab K9LA"— Presentation transcript:

1 PVRC Webinar - 20Jan10 - K9LA 160m Propagation Carl Luetzelschwab K9LA

2 PVRC Webinar - 20Jan10 - K9LA What Were Going to Cover Foreword Foreword Fundamental physical truths Fundamental physical truths Normal propagation Normal propagation Interesting observations Interesting observations 160m predictions (or lack thereof!) 160m predictions (or lack thereof!) Summary Summary This presentation will be on the PVRC website visit click on the PVRC Webinars link at the top

3 PVRC Webinar - 20Jan10 - K9LA Cycle 24 Update - Sunspots Cycle 24 sunspot activity appears to be increasing

4 PVRC Webinar - 20Jan10 - K9LA Cycle 24 Update - Ap Geomagnetic field is the quietest weve ever seen

5 PVRC Webinar - 20Jan10 - K9LA Foreword Theres still a lot we dont know about 160m propagation Theres still a lot we dont know about 160m propagation The biggest area where we lack a good of understanding appears to be the lower ionosphere – i.e., the D region and lower E region The biggest area where we lack a good of understanding appears to be the lower ionosphere – i.e., the D region and lower E region –We really dont have any day-to-day parameters tied to this area of the ionosphere Thus dont expect this presentation to be The Secrets of 160m Revealed Thus dont expect this presentation to be The Secrets of 160m Revealed Recommendation – to better understand propagation on 160m, be very active on topband Recommendation – to better understand propagation on 160m, be very active on topband

6 PVRC Webinar - 20Jan10 - K9LA Oler and Cohen Article in CQ CQ, March 1998, Part 1, pp CQ, March 1998, Part 1, pp CQ, April 1998, Part 2, pp CQ, April 1998, Part 2, pp Oler and Cohen article is highly recommended reading Oler and Cohen article is highly recommended reading –Follow-up: Ducting and Spotlight Propagation on 160 Meters, K9LA, CQ, December 2005, pp 22-29

7 PVRC Webinar - 20Jan10 - K9LA Fundamental Physical Truths

8 PVRC Webinar - 20Jan10 - K9LA What Does It Take to Make a QSO? Enough ionization to refract signal back to Earth Enough ionization to refract signal back to Earth –MUF not a problem on 1.8 MHz even in the dead of night at solar minimum overhead Sun

9 PVRC Webinar - 20Jan10 - K9LA Ray Tracing vs Elevation Angles path across the northern tier of the US at solar minimum around midnight E region still comes into play at night at low elevation angles E region still comes into play at night at low elevation angles –foE approximately 0.4 MHz at night Angles below approximately 7 can be refracted back to Earth by the E region Angles below approximately 7 o can be refracted back to Earth by the E region

10 PVRC Webinar - 20Jan10 - K9LA What Does It Take to Make a QSO? Strong enough signal to be readable Strong enough signal to be readable –Ionospheric absorption on 1.8 MHz is the real problem – too much and signal is below your noise floor (which is usually not your receiver MDS) 1.8 MHz S3 S5 S7 S1 low noise receiving antenna are very helpful for serious DXing

11 PVRC Webinar - 20Jan10 - K9LA Refraction and Absorption Refraction and absorption are inversely proportional to the square of the frequency Refraction and absorption are inversely proportional to the square of the frequency Thus for a given electron density profile Thus for a given electron density profile –The lower the frequency, the more the refraction (bending) –The lower the frequency, the more the absorption 160m RF is bent the most and incurs the most absorption

12 PVRC Webinar - 20Jan10 - K9LA Ray Tracing on 28 MHz o-wave and x-wave pretty much follow the same path o-wave and x-wave pretty much follow the same path –Index of refraction approximately the same –X-wave bends a tiny bit more o-wave and x-wave pretty much incur the same amount of loss o-wave and x-wave pretty much incur the same amount of loss –Absorption approximately the same Apogee ~ 240 km Apogee ~ 240 km on higher HF bands, o-wave and x-wave propagate approximately equally

13 PVRC Webinar - 20Jan10 - K9LA Ray Tracing on 1.8 MHz O-wave and x-wave do not follow the same path O-wave and x-wave do not follow the same path –Index of refraction significantly different –x-wave bends more O-wave and x-wave do not incur the same amount of loss 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 ranges from.7 to 1.7 MHz worldwide Apogee for o-wave ~ 170 km Apogee for o-wave ~ 170 km –160m wave doesnt get as high into the ionosphere Generally only the o-wave is useful on 160m, and polarization at mid to high latitudes on 160m tends towards elliptical ( vertical)

14 PVRC Webinar - 20Jan10 - K9LA Multi-hop on 160m Based on previous slides, multi-hop propagation on 160m is via hops that are short and lossy Based on previous slides, multi-hop propagation on 160m is via hops that are short and lossy –Short is relative – but its not 3000 or 4000 km hops like on the higher frequencies 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) 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 – 1500 km

15 PVRC Webinar - 20Jan10 - K9LA This Suggests Ducting Distances at and greater than 10,000 km are likely due to ducting in the electron density valley above the nighttime E region peak Ducting does not incur loss due to multiple transits through the absorbing region and loss due to multiple ground reflections

16 PVRC Webinar - 20Jan10 - K9LA Normal Propagation

17 PVRC Webinar - 20Jan10 - K9LA Common Darkness Best place for 160m RF is in the dark ionosphere Best place for 160m RF is in the dark ionosphere –Concept of common darkness along a path came from W4ZV in his 1991 Proceedings of Fine Tuning article and his 13 Jan 97 topband reflector post K9LA sunsetSTØ sunrise 4 hours and 25 minutes of common darkness maps from W6ELProp

18 PVRC Webinar - 20Jan10 - K9LA Signal Enhancements Most prevalent on the western end of the path when the eastern end is around sunrise Most prevalent on the western end of the path when the eastern end is around sunrise –can bring a signal from no copy (below your noise) to perfect Q5 copy for tens of minutes Similar enhancements reported on the eastern end of the path when the western end is around sunset Similar enhancements reported on the eastern end of the path when the western end is around sunset Enhancements believed to be tied to ducting Enhancements believed to be tied to ducting Ducting (specifically getting out of the duct) may also have a lot to do with spotlight propagation Ducting (specifically getting out of the duct) may also have a lot to do with spotlight propagation VE7DXR recording of Meyerton (South Africa) shortwave station showing ~13 dB enhancement Meyerton sunrise

19 PVRC Webinar - 20Jan10 - K9LA Skewed Paths Dont always assume a great circle path - remember the lower the frequency, the more the wave refracts (both in the vertical plane and in the horizontal plane) If theres going to be a skewed path, 160m is the most likely band The auroral oval is probably the most likely cause of skewed paths Image from Skewed Paths to Europe on the Low Bands, K9LA, CQ, August 1999

20 PVRC Webinar - 20Jan10 - K9LA Spike in the K Index Better opportunity for ducting ??? Better opportunity for ducting ??? –From A modeling study of ionospheric conductivities in the high-latitude electrojet regions, Zhang, et al, Journal of Geophysical Research, Vol 109, April 2004 Less absorption due to higher electron temperatures causing more recombination ??? Less absorption due to higher electron temperatures causing more recombination ??? –From Frictionally heated electrons in the high-latitude D region, Brower, et al, Journal of Geophysical Research, Vol 114, December 2009 Many observations of enhanced propagation across the high latitudes right before (or concurrent with) a spike in the K index Many observations of enhanced propagation across the high latitudes right before (or concurrent with) a spike in the K index Includes improved propagation on the AM broadcast band Includes improved propagation on the AM broadcast band Mechanism may be tied to an increased ionospheric E-field Mechanism may be tied to an increased ionospheric E-field

21 PVRC Webinar - 20Jan10 - K9LA Gray Line N6FF to A61AJ N6FF to A61AJ –Nov 29, 1999 at 1455 UTC (N6FF sunrise) N6FF heard A61AJ best from the southwest N6FF heard A61AJ best from the southwest –SW on sunrise end, SE on sunset end Suggests long path, but true great circle path has too much daylight Suggests long path, but true great circle path has too much daylight Is it a skewed path? Is it a skewed path? –Wheres the skew point? What path did the RF follow? What path did the RF follow? Are we fooled by short path? Are we fooled by short path?

22 PVRC Webinar - 20Jan10 - K9LA Interesting Observations some of them make you wonder about our age-old beliefs

23 PVRC Webinar - 20Jan10 - K9LA Propagation Along the Terminator 3Y0X (Feb 06) worked 287 Zone 4 stations from 0210 UTC (image on left) to 0901 UTC (image on right) 3Y0X (Feb 06) worked 287 Zone 4 stations from 0210 UTC (image on left) to 0901 UTC (image on right) Path only near terminator at 3Y0X end – and path gets away from the terminator quickly Path only near terminator at 3Y0X end – and path gets away from the terminator quickly Note that this is short path

24 PVRC Webinar - 20Jan10 - K9LA Propagation Along the Terminator 3Y0X worked 8 Zone 20 stations (YO, SV, LZ) from UTC (image on left) to 0522 UTC (image on right) 3Y0X worked 8 Zone 20 stations (YO, SV, LZ) from UTC (image on left) to 0522 UTC (image on right) Path closer to the terminator – and not perpendicular Path closer to the terminator – and not perpendicular Note that this is short path

25 PVRC Webinar - 20Jan10 - K9LA Propagation Along the Terminator 3Y0X only worked 1 JA at 0819 UTC 3Y0X only worked 1 JA at 0819 UTC Path pretty much along the terminator Path pretty much along the terminator Note that this is short path This data indicates that gray line propagation on 160m on the short path is not efficient This data indicates that gray line propagation on 160m on the short path is not efficient –Our model of the ionosphere agrees with this data But our model also says that Marconis feat never should have happened – may be just a high latitude issue But our model also says that Marconis feat never should have happened – may be just a high latitude issue And that VY2ZM on PEI never should have heard the 100 Watt GB3SSS Poldhu beacon on 1.96 MHz – same high latitude issue And that VY2ZM on PEI never should have heard the 100 Watt GB3SSS Poldhu beacon on 1.96 MHz – same high latitude issue Theres something going on that we dont understand Theres something going on that we dont understand

26 PVRC Webinar - 20Jan10 - K9LA Solar Max vs Solar Min Is solar minimum really the best time for 160m? Is solar minimum really the best time for 160m? –Geomagnetic field is quieter 160m appears to be best at solar minimum if your path goes through the auroral oval 160m appears to be best at solar minimum if your path goes through the auroral oval path from IV3PRK to # of QSOs result North America East Coast % of QSOs at K < 3 North America Midwest 67 96% of QSOs at K < 3 North America West Coast % of QSOs at K < 2 IV3PRK to North America

27 PVRC Webinar - 20Jan10 - K9LA W8JI at Solar Maximum But there appears to be a lot of DX to be worked at solar maximum But there appears to be a lot of DX to be worked at solar maximum W8JI from September 1999 through July 2002 W8JI from September 1999 through July 2002 –Cycle 23 peak –Smoothed sunspot number > 100 Over 5,000 DX QSOs Over 5,000 DX QSOs –Almost 200 countries –All 40 CQ Zones low latitude paths mid latitude paths high latitude paths ~ 1450 QSOs ~ 2700 QSOs ~ 975 QSOs VK (71%), NA (13%), north SA (8%), Oceania (6%), north AF (2%) south & central EU (87.5%), ZL (8%), south SA (2.8%), Mideast (1.4%), south AF (0.3%) JA (54%), north EU (42%), Asia (3%), KL7 (1%) 60% in winter 8% in summer 16% in fall 16% in spring

28 PVRC Webinar - 20Jan10 - K9LA NM7Ms Work with GCRs Galactic cosmic rays are mostly very high energy protons coming in from all directions – day and night 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 Quiet magnetic field (solar min) lets more in – more ionization in the lower ionosphere Active magnetic field (solar max) keeps them out Active magnetic field (solar max) keeps them out GCR measurement on Earth and impact to ionosphere is 180 o out of phase with solar cycle GCR measurement on Earth and impact to ionosphere is 180 o out of phase with solar cycle galactic cosmic rays

29 PVRC Webinar - 20Jan10 - K9LA CGRs and the Valley NM7Ms theory is that galactic cosmic rays play an important role in the valley formation, and thus ducting NM7Ms 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 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 At solar minimum, too many GCRs ionizing valley – fills up more and all we have left is lossy multi-hop solar min solar max

30 PVRC Webinar - 20Jan10 - K9LA Recent W4DR Observations personal , late December 2009 I have been DXing on 160 since 1970, with for the most part above- average antennas. 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. 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. On the other hand I have not worked any long path or bent path SE Asians in the last 4-5 years. tends to confirm that 160m propagation across the poles is best at solar minimum, and long distance DXing per NM7Ms hypothesis may need a bit more geomagnetic field activity

31 PVRC Webinar - 20Jan10 - K9LA North Magnetic Pole is Moving As the north magnetic pole moves even farther north, will 160m propagation from the West Coast to Europe improve?

32 PVRC Webinar - 20Jan10 - K9LA 160m Predictions (or lack thereof!)

33 PVRC Webinar - 20Jan10 - K9LA Predictions Our propagation predictions typically cover 3 – 30 MHz Our propagation predictions typically cover 3 – 30 MHz –There are additional variables that impact frequencies below 3 MHz (e.g., electron gyro-frequency), and I believe they are not all identified yet Several studies in the past used 10.7 cm solar flux and the A index Several studies in the past used 10.7 cm solar flux and the A index –No good daily correlation seen Bring in space weather parameters Bring in space weather parameters –Do your own evaluation OH2BO (way up north) monitors solar wind speed and dynamic pressure OH2BO (way up north) monitors solar wind speed and dynamic pressure NZ4O (formerly KN4LF) outlines parameters on his web site NZ4O (formerly KN4LF) outlines parameters on his web site –I personally believe we havent identified all the important parameters Correlation to AM broadcast propagation Correlation to AM broadcast propagation –N6RK recently brought this up on the topband reflector –May be localized effect or may be widespread effect –My analysis when we lived in Texas (1980s) didnt show any consistent results There were days with enhanced 160m propagation but not enhanced AM broadcast propagation There were days with enhanced 160m propagation but not enhanced AM broadcast propagation

34 PVRC Webinar - 20Jan10 - K9LA Summary – Transmit & Receive Transmit Transmit –Put up the best transmit antenna you can Start with inverted-vee or inverted-L or shunt-fed tower Start with inverted-vee or inverted-L or shunt-fed tower Progress to arrays Progress to arrays –An amplifier is very helpful on 160m Again, start small – for example, AL-811 Again, start small – for example, AL-811 Move up to 1000 Watts or legal limit Move up to 1000 Watts or legal limit Receive Receive –Youll probably start with your transmit antenna –Improve your reception ability by implementing directional arrays Directionality is what makes them low noise Directionality is what makes them low noise –Dont rule out horizontally polarized antennas for receive

35 PVRC Webinar - 20Jan10 - K9LA Summary - Propagation Polar paths should generally be great now and for the next year or so Polar paths should generally be great now and for the next year or so Extremely long-distance paths may be hurt by this deep solar minimum Extremely long-distance paths may be hurt by this deep solar minimum Understand the concept of common darkness and learn how to determine it Understand the concept of common darkness and learn how to determine it Watch for signal enhancements around sunrise and sunset Watch for signal enhancements around sunrise and sunset Be very active to catch spotlight propagation to your area Be very active to catch spotlight propagation to your area In general vertical polarization will work best In general vertical polarization will work best –But you cant have too many antennas on 160m (who first stated that?) Dont shy away from elevated K-indices Dont shy away from elevated K-indices –Can provide skewed paths around the auroral zone –Can provide enhanced paths across the high latitudes Remember southwest at sunrise and southeast at sunset along the long path (even if we dont understand it, take advantage of it) Remember southwest at sunrise and southeast at sunset along the long path (even if we dont understand it, take advantage of it) Dont shy away from solar maximum Dont shy away from solar maximum –Even though S9+ signals on 10m are easier to deal with, be tough and stay on 160m

36 PVRC Webinar - 20Jan10 - K9LA CQ WW 160 CW January 30 and 31 January 30 and 31 Quote from WW9R on the SMC reflector Quote from WW9R on the SMC reflector –With all the low band propagation here of late, this should be a real barn burner... –With all the low band propagation here of late, this should be a real barn burner... Keep an eye on geomagnetic field activity (thru Ap) Keep an eye on geomagnetic field activity (thru Ap) –I think a little bit can be good, but a lot can be bad It might be helpful to have low-noise receive capability over the pole It might be helpful to have low-noise receive capability over the pole If you have QSOs greater than 12,000 km, Id like to hear about them – If you have QSOs greater than 12,000 km, Id like to hear about them –

37 PVRC Webinar - 20Jan10 - K9LA Reading Material ON4UNs propagation and receive antenna chapters in his Low-Band DXing series ON4UNs propagation and receive antenna chapters in his Low-Band DXing series –5 th Edition should be available later this year –Lots of practical information Web sites with space weather info and 160m content Web sites with space weather info and 160m content –W8JIhttp://www.w8ji.com –W4ZVhttp://users.vnet.net/btippett/images/W4ZV.htm –IV3PRKhttp://www.iv3prk.it –NZ4Ohttp://www.solarcycle24.org –NW7UShttp://www.hfradio./org –K9LAhttp://mysite.verizon.net/k9la –Cary Olerhttp://www.spacew.com (is there still 160m info?) Apologies to any I missed !

38 PVRC Webinar - 20Jan10 - K9LA Q & A This PowerPoint file will be at


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