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PVRC Webinar Mar 9, 2011 PVRC Webinar Mar 9, 2011 K9LA K9LA Selected Topics in Selected Topics in Propagation Propagation Carl Luetzelschwab K9LA Carl Luetzelschwab K9LA [email protected] [email protected]

Selected Topics in Propagation

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Selected Topics in Propagation. Carl Luetzelschwab K9LA [email protected] What We’ll Cover in This Session. An Update on Cycle 24 Will it be an underachiever? The M-Factor Some theory about one of the basic parameters of the ionosphere Sunspots and Solar Flux During Cycle 23 - PowerPoint PPT Presentation

Text of Selected Topics in Propagation

  • PVRC Webinar Mar 9, 2011 K9LASelected Topics in PropagationCarl Luetzelschwab [email protected]

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAWhat Well Cover in This SessionAn Update on Cycle 24Will it be an underachiever?The M-FactorSome theory about one of the basic parameters of the ionosphereSunspots and Solar Flux During Cycle 23An interesting anomaly not sure what it says yetIonosphere-Ionosphere ModesTheres more than multi-hop out there

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAAn Update on Cycle 24

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LALatest DataminimumSmoothed 10.7 cm solar flux is still rising

    PVRC Webinar Mar 9, 2011 K9LA

    Chart1

    83.483.6

    76.782.3

    75.581.2

    8980.6

    80.980.5

    76.580.2

    75.880

    79.480.1

    77.880

    74.379.1

    86.378.2

    84.577.8

    83.577.5

    77.776.9

    72.276

    72.475.3

    74.474.3

    73.773.3

    71.672.7

    69.172.1

    6771.8

    67.571.8

    69.671.4

    78.570.8

    74.370.3

    71.169.9

    72.969.8

    70.269.8

    68.469.8

    65.969.4

    65.768.8

    66.368.6

    67.168.4

    68.368.2

    68.668.3

    69.268.5

    69.868.7

    7068.8

    69.269

    69.769.3

    70.569.7

    68.670.2

    68.271

    67.472.1

    70.573.3

    72.374.1

    73.674.5

    76.874.9

    81.175.5

    84.776.5

    83.377.5

    75.978.3

    73.879

    72.679.7

    79.980.1

    79.780.6

    81.1

    81.6

    82.5

    84.3

    83.7

    94.6

    M

    A

    M

    J

    J

    A

    S

    O

    N

    D

    monthly mean

    smoothed

    2006 2007 2008 2009 2010 2011

    10.7 cm Solar Flux

    Solar Min Between Cycle 23 and 24 and Cycle 24 Ascentin terms of 10.7 cm solar flux

    sunspot numbers

    monthly meansmoothed

    YRMOCycle 23Cycle24

    2006J15.321

    2006F4.919

    2006M10.617

    2006A30.217

    2006M22.317

    2006J13.916

    2006J12.215

    2006A12.916

    2006S14.416

    2006O10.514

    2006N21.413

    2006D13.612

    2007J16.812

    2007F10.712

    2007M4.511

    2007A3.410

    2007M11.79

    2007J12.18

    2007J9.77

    2007A66

    2007S2.46

    2007O0.96

    2007N1.76

    2007D10.15

    2008J2.50.84.2

    2008F2.13.6

    2008M9.33.3

    2008A2.50.43.5

    2008M2.90.33.2

    2008J3.43.2

    2008J0.82.8

    2008A0.52.7

    2008S0.40.72.3

    2008O0.32.61.9

    2008N4.11.75

    2008D0.81.7

    2009J0.21.11.8

    2009F0.80.61.9

    2009M0.60.12

    2009A0.60.62.2

    2009M2.92.3

    2009J2.62.7

    2009J3.53.6

    2009A04.8

    2009S4.36.2

    2009O4.67.1

    2009N4.27.6

    2009D10.88.3

    2010J13.19.3

    2010F18.610.6

    2010M15.412.3

    2010A7.914

    2010M8.815.5

    2010J13.516.4

    2010J16.116.8

    2010A19.617.4

    2010S25.2

    2010O23.5

    2010N21.6

    2010D14.5

    2011J19

    2011F29.4

    2011M

    2011A

    2011M

    2011J

    2011J

    2011A

    2011S

    2011O

    2011N

    2011D

    sunspot numbers

    &A

    Page &P

    Cycle 24 monthly mean

    Cycle 23 monthly mean

    smoothed

    2006 2007 2008 2009 2010 2011

    Sunspot Number

    Solar Min Between Cycle 23 and 24, and Cycle 24 Ascentin terms of sunspot number

    solar flux

    YRMOmonthly meansmoothed

    2006J83.483.6

    2006F76.782.3

    2006M75.581.2

    2006A8980.6

    2006M80.980.5

    2006J76.580.2

    2006J75.880.0

    2006A79.480.1

    2006S77.880.0

    2006O74.379.1

    2006N86.378.2

    2006D84.577.8

    2007J83.577.5

    2007F77.776.9

    2007M72.276.0

    2007A72.475.3

    2007M74.474.3

    2007J73.773.3

    2007J71.672.7

    2007A69.172.1

    2007S6771.8

    2007O67.571.8

    2007N69.671.4

    2007D78.570.8

    2008J74.370.3

    2008F71.169.9

    2008M72.969.8

    2008A70.269.8

    2008M68.469.8

    2008J65.969.4

    2008J65.768.8

    2008A66.368.6

    2008S67.168.4

    2008O68.368.2

    2008N68.668.3

    2008D69.268.5

    2009J69.868.7

    2009F7068.8

    2009M69.269.0

    2009A69.769.3

    2009M70.569.7

    2009J68.670.2

    2009J68.271.0

    2009A67.472.1

    2009S70.573.3

    2009O72.374.1

    2009N73.674.5

    2009D76.874.9

    2010J81.175.5

    2010F84.776.5

    2010M83.377.5

    2010A75.978.3

    2010M73.879.0

    2010J72.679.7

    2010J79.980.1

    2010A79.780.6

    2010S81.1

    2010O81.6

    2010N82.5

    2010D84.3

    2011J83.7

    2011F94.6

    2011M

    2011A

    2011M

    2011J

    2011J

    2011A

    2011S

    2011O

    2011N

    2011D

    solar flux

    &A

    Page &P

    monthly mean

    smoothed

    2006 2007 2008 2009 2010 2011

    10.7 cm Solar Flux

    Solar Min Between Cycle 23 and 24 and Cycle 24 Ascentin terms of 10.7 cm solar flux

  • PVRC Webinar Mar 9, 2011 K9LALatest Dataminimum

    PVRC Webinar Mar 9, 2011 K9LA

    Chart2

    J15.321

    F4.919

    M10.617

    A30.217

    M22.317

    J13.916

    J12.215

    A12.916

    S14.416

    O10.514

    N21.413

    D13.612

    J16.812

    F10.712

    M4.511

    A3.410

    M11.79

    J12.18

    J9.77

    A66

    S2.46

    O0.96

    N1.76

    D10.15

    0.82.54.2

    F2.13.6

    M9.33.3

    0.42.53.5

    0.32.93.2

    J3.43.2

    J0.82.8

    A0.52.7

    0.70.42.3

    2.60.31.9

    4.1N1.75

    0.8D1.7

    1.10.21.8

    0.60.81.9

    0.10.62

    0.60.62.2

    2.9M2.3

    2.6J2.7

    3.5J3.6

    0A4.8

    4.3S6.2

    4.6O7.1

    4.2N7.6

    10.8D8.3

    13.1J9.3

    18.6F10.6

    15.4M12.3

    7.9A14

    8.8M15.5

    13.5J16.4

    16.1J16.8

    19.6A17.4

    25.2S

    23.5O

    21.6N

    14.5D

    19J

    29.4F

    MM

    AA

    MM

    JJ

    JJ

    AA

    SS

    OO

    NN

    DD

    Cycle 24 monthly mean

    Cycle 23 monthly mean

    smoothed

    2006 2007 2008 2009 2010 2011

    Sunspot Number

    Solar Min Between Cycle 23 and 24, and Cycle 24 Ascentin terms of sunspot number

    sunspot numbers

    monthly meansmoothed

    YRMOCycle 23Cycle24

    2006J15.321

    2006F4.919

    2006M10.617

    2006A30.217

    2006M22.317

    2006J13.916

    2006J12.215

    2006A12.916

    2006S14.416

    2006O10.514

    2006N21.413

    2006D13.612

    2007J16.812

    2007F10.712

    2007M4.511

    2007A3.410

    2007M11.79

    2007J12.18

    2007J9.77

    2007A66

    2007S2.46

    2007O0.96

    2007N1.76

    2007D10.15

    2008J2.50.84.2

    2008F2.13.6

    2008M9.33.3

    2008A2.50.43.5

    2008M2.90.33.2

    2008J3.43.2

    2008J0.82.8

    2008A0.52.7

    2008S0.40.72.3

    2008O0.32.61.9

    2008N4.11.75

    2008D0.81.7

    2009J0.21.11.8

    2009F0.80.61.9

    2009M0.60.12

    2009A0.60.62.2

    2009M2.92.3

    2009J2.62.7

    2009J3.53.6

    2009A04.8

    2009S4.36.2

    2009O4.67.1

    2009N4.27.6

    2009D10.88.3

    2010J13.19.3

    2010F18.610.6

    2010M15.412.3

    2010A7.914

    2010M8.815.5

    2010J13.516.4

    2010J16.116.8

    2010A19.617.4

    2010S25.2

    2010O23.5

    2010N21.6

    2010D14.5

    2011J19

    2011F29.4

    2011M

    2011A

    2011M

    2011J

    2011J

    2011A

    2011S

    2011O

    2011N

    2011D

    sunspot numbers

    &A

    Page &P

    Cycle 24 monthly mean

    Cycle 23 monthly mean

    smoothed

    2006 2007 2008 2009 2010 2011

    Sunspot Number

    Solar Min Between Cycle 23 and 24, and Cycle 24 Ascentin terms of sunspot number

    solar flux

    YRMOmonthly meansmoothed

    2006J83.483.6

    2006F76.782.3

    2006M75.581.2

    2006A8980.6

    2006M80.980.5

    2006J76.580.2

    2006J75.880.0

    2006A79.480.1

    2006S77.880.0

    2006O74.379.1

    2006N86.378.2

    2006D84.577.8

    2007J83.577.5

    2007F77.776.9

    2007M72.276.0

    2007A72.475.3

    2007M74.474.3

    2007J73.773.3

    2007J71.672.7

    2007A69.172.1

    2007S6771.8

    2007O67.571.8

    2007N69.671.4

    2007D78.570.8

    2008J74.370.3

    2008F71.169.9

    2008M72.969.8

    2008A70.269.8

    2008M68.469.8

    2008J65.969.4

    2008J65.768.8

    2008A66.368.6

    2008S67.168.4

    2008O68.368.2

    2008N68.668.3

    2008D69.268.5

    2009J69.868.7

    2009F7068.8

    2009M69.269.0

    2009A69.769.3

    2009M70.569.7

    2009J68.670.2

    2009J68.271.0

    2009A67.472.1

    2009S70.573.3

    2009O72.374.1

    2009N73.674.5

    2009D76.874.9

    2010J81.175.5

    2010F84.776.5

    2010M83.377.5

    2010A75.978.3

    2010M73.879.0

    2010J72.679.7

    2010J79.980.1

    2010A79.780.6

    2010S81.1

    2010O81.6

    2010N82.5

    2010D84.3

    2011J83.7

    2011F94.6

    2011M

    2011A

    2011M

    2011J

    2011J

    2011A

    2011S

    2011O

    2011N

    2011D

    solar flux

    &A

    Page &P

    monthly mean

    smoothed

    2006 2007 2008 2009 2010 2011

    10.7 cm Solar Flux

    Solar Min Between Cycle 23 and 24 and Cycle 24 Ascentin terms of 10.7 cm solar flux

  • PVRC Webinar Mar 9, 2011 K9LAReview of the PredictionsThese are from the Solar Cycle 24 PredictionPanel (NOAA, NASA, ISES, and other personnel)1409090

    PVRC Webinar Mar 9, 2011 K9LA

  • The Latest PredictionThere may be an updated prediction (lower) from the Solar Cycle 24 Prediction PanelPVRC Webinar Mar 9, 2011 K9LA

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAMarshall Space Flight CenterSimilar prediction to Kane, Size of the coming solar cycle 24 based onOhls Precursor Method, final estimate, Annales Geophysicae, July 201059A lot of evidence pointing to small Cycle 24

    PVRC Webinar Mar 9, 2011 K9LA

  • But . . . . . . .Not everyone agrees that Cycle 24 will be so smallRecent prediction in Solar PhysicsMaximum of 131 +/- 20Maximum in July 2012 +/- 4 monthsFrom R. S. Dabas and Kavita Sharma, Prediction of Cycle 24 Using Geomagnetic Precursors: Validation and Update, Solar Physics, Vol 266 No 2, pp 391-403, July 2010This would be good for the higher bands and for 6m F2If Cycle 24 is a small one, though, 6m F2 propagation will take the biggest hitThank goodness for summer E region propagationPVRC Webinar Mar 9, 2011 K9LA

    PVRC Webinar Mar 9, 2011 K9LA

  • Predictions in GeneralOver 60 predictions for Cycle 24Maximum smoothed sunspot number from 40 to 185Common forecasting methodsStatistical methods: length of Cycle n correlated to maximum of Cycle n+1, maximum R12 correlated to minimum R12Generally gives low Cycle 24Geomagnetic precursor methods: Ap, aa, and number of magnetically disturbed days correlate to next maximumUnfortunately can give widely varied answers depending on assumptionsPolar field precursor method: strength of Suns polar field correlates to next cycleGives small Cycle 24Solar dynamo method: the conveyor belt theoryUnfortunately can give widely varied answers depending on assumptionsSummary of forecasting methods from K. J. Li, et al, A brief review on the presentation of cycle 24, the first integrated solar cycle in the new millennium, Annales Geophysicae, 29, 341-348, 2011PVRC Webinar Mar 9, 2011 K9LA

    PVRC Webinar Mar 9, 2011 K9LA

  • Recent NASA NewsResearchers Crack the Mystery of the Missing SunspotsSolar scientists claim theyve developed a new computer model of the sun's interior that gets the physics right for all three aspects of the sunspot generation process --the magnetic dynamo, the conveyor belt, and the buoyant evolution of sunspot magnetic fieldsMaybe this will help narrow down the range of the forecasted maximum smoothed sunspot numberPVRC Webinar Mar 9, 2011 K9LAKeep an eye on NASA Headline News, http://www.solarcycle24.com, http://www.swpc.noaa.gov, and http://spaceweather.comhttp://science.nasa.gov/science-news/science-at-nasa/2011/02mar_spotlesssun/

    PVRC Webinar Mar 9, 2011 K9LA

  • ARRL DX CW and PHPVRC Webinar Mar 9, 2011 K9LA1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1 2 3 4 5 6 7 8FebMarIts headed in the right direction!ARRL DX CWARRL DX PH

    PVRC Webinar Mar 9, 2011 K9LA

  • ARRL DX CW and PHPVRC Webinar Mar 9, 2011 K9LARecent solar activity helped ARRL DX PH the mostARRL DX CWARRL DX PHred line is one-day running average1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 1 2 3 4 5 6 7 8FebMar28 MHz21 MHz

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAThe M-FactorNo, not this M

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAWhat Is The M-Factor?The M-Factor (MUF factor) relates the MUF (maximum useable frequency) to the critical frequencyMUF = M-Factor x Critical FrequencyM-Factor and critical frequency (along with other parameters) are measured by ionosondesM-Factor is one over the sine of the angle between the ray and the ionosphere (also known as the secant law as 1/sine = secant)sine of this angleIf the angle = 90o (vertically incident), then the M-Factor equals 1 and the MUF = the critical frequencyionosphere

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAApply It To The IonosphereionosphereEarthThus the M-Factor = 1 sine (1o) = 57Wow if the critical frequency is 5 MHz, then the MUF would be 285 MHzBut hold on the Earth-ionosphere system isnt flat its spherical = 1o = 1o

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAThe Real Earth-Ionosphere SystemionosphereEarthheight now matters lets assume 300 kmNow the M-Factor = 1 sine (17.5o) = 3.3MUF for this F2 region scenario is about 3 times the critical frequency = 1o = 17.5o

    PVRC Webinar Mar 9, 2011 K9LA

  • M-Factor vs Height and AnglePVRC Webinar Mar 9, 2011 K9LAThis calculation assumes specular (mirror-like) reflection over an infinitely short distance the real-world is refraction over a spherical distance The higher the layer, the longer the hop distance for a given angle

    But the higher the layer, the lower the M-Factor (lower MUF) for a given angle

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LARule of 3 and Rule of 5For the F2 region with low angles, the MUF is approximately 3 times the critical frequencyIonosondes report the M-Factor for a 3000 km hopM(3000)F2 or M(D) where D = 3000 kmFor the E region with low angles, the MUF is approximately 5 times the critical frequencyClose enough for sporadic E, tooAllows you to estimate the MUF only knowing the critical frequency

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LASunspots and Solar FluxDuring Cycle 23

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAWhy Use Smoothed Solar Indices?Reason #1: Daily data (and even monthly mean data) is spiky - hard to tell whats happening

    Reason #2: The best correlation between what the Sun is doing and what the ionosphere is doing is through a smoothed solar index - this is the basis on which the statistical model of the ionosphere for our propagation predictions was developed

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAEarly CorrelationEquation from texts on the ionosphere: SF12 = 63.75 + .728 SSN12 + .00089 SSN122 (the 12 subscript denotes smoothed values)Side note - there is very little correlation between daily 10.7 cm solar flux and daily sunspot number

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAMore DataSome more scatter about the trend line, but still pretty good.

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAInclude Cycle 23In terms of smoothed sunspot number, second peak is a bit lowerIn terms of smoothed solar flux, second peak is definitely higherWe had much better 6m F2 propagation during the second peakCycle 23 dataApril 2000Nov 2001

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAWhy The Anomaly?Dr. Leif Svalgaard (member of the Cycle 24 Prediction Panel) has several opinionsThe sunspot counting procedure or observers have changed with resulting artificial changes of the sunspot number (as they have in the past)There are changes in the Suns corona or chromosphere accounting for additional 10.7 cm emissionPenn and Livingstons observations (Penn, M. J. and W. Livingston, Temporal Changes in Sunspot Umbral Magnetic Fields and Temperatures, The Astrophysical Journal, 649, L45-L48, 2006 September 20) suggest that sunspots have been getting warmer during the last decade, leading to a decreased contrast with the surrounding photosphere and hence lessened visibility, possibly resulting in an undercount of sunspotsNo definite answer (yet!)Visit http://www.leif.org/research and select item 1020 for detailsCheck out my Propagation columns in the forthcoming May 2011 and June 2011 issues of WorldRadio Online for more on thishttp://www.worldradiomagazine.com/WRO is free !

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAIonosphere-Ionosphere Modes

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAMulti-Hop Can Have LimitsOn the lower bands there may be too much absorption for multi-hop the signal is too weakOn the higher bands the MUF may not be high enough to refract the ray back to Earth for multi-hop the ray goes out into spaceionosphereEarth

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAHigher MUF & Less AbsorptionAre there modes that could give a higher MUF and/or lesser absorption?Yes - there appear to be three of themChordal hopDuctPedersen Ray

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAChordal HopExample TEP (trans-equatorial propagation)K6QXY to ZL on 6mRay trace from Proplab Promonthly median resultsHigh density of electrons on either side of geomagnetic equatorExtremely long hop approximately twice a normal hopOnly two transits through the absorbing regionNo ground reflectionsLiterature says MUF is approximately 1.5 times normal F2 hoprefractionrefractionhelps MUF and absorptionarea of higher electron densityarea of higher electron density

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LADuctRequires upper and lower boundary for successive refractionsNeed entry and exit criteria - small range of anglesNo transits through the absorbing regionNo ground reflectionsLow grazing angles with ionosphere higher MUFBelieved to allow extremely long distance QSOs on 160mhelps MUF and absorption

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAPedersen RayNot a lot in the literature on the Pedersen RayComment from Ionospheric Radio (Davies, 1990)Across the North Atlantic, occurrence tends to peak near noon at the midpointOne would surmise that the ionosphere needs to be very stable for a ray to exactly parallel the Earth for long distancesProbably no help with MUF biggest advantage appears to be with lower absorption due to less transits of the absorbing region and no ground reflection losseshelps absorption1 and 2 are low-angle paths3 is medium-angle path4 and 5 are high-angle Pedersen Ray paths6 goes thru the ionosphere

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAA Detailed 20m AnalysisK2MO (AA2AE at the time) to ZS5BBO on July 5, 2003 at 1230 UTC on 20m SSB via long path

    K2MO reported that ZS5BBOs signal was around S7 (~ -83 dBm)

    Long path from W2 starts off in daylight, goes into darkness, and ends in daylight

    Short path has high MUF but marginal signal strength due to absorption

    Long path signal strength from ZS predicted to be -125 dBmAbout 40 dB shy of S7Short path 12,700 kmLong path 27,300 km

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAThe Ionosphere Along the LPNote the tilts in the ionosphere at dawn (W2 end) and at dusk (ZS end)

    Tilt can refract the ray so that it encounters the ionosphere at more of a grazing angle (i.e., a higher MUF)

    Good entry/exit criteria for ductVK5

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LARay Trace from W2 EndProplab Pro can only ray trace out to 20,000 km (half way around)

    Do two ray tracesOne from W2 end (pictured)One from ZS end (not pictured)

    Ray trace from ZS end shows similar ducting

    Signal strength now estimated to be -89 dBmClose to observed -83 dBm

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LAThe Big PictureMy crude picture on the left shows chordal hops as the ionosphere-ionosphere modeProplab Pro data indicates the K2MO-to-ZS5BBO QSO was ductingEasier to draw chordal hops!Youve probably seen a similar picture in the propagation literature. Ionosphere-ionosphere modes are our friends

    PVRC Webinar Mar 9, 2011 K9LA

  • PVRC Webinar Mar 9, 2011 K9LASummaryI hope you learned somethingThis webinar will be on the PVRC web sitehttp://www.pvrc.org/webinar/webinars.htmThe slides will also be at http://mysite.ncnetwork.net/k9laFollow-up webinars: More Selected Topics in PropagationSuch as noise, 10m long path, effect of the Moon on HF propagation, trans-equatorial propagationE-mail me if you have a specific [email protected] visit http://mysite.ncnetwork.net/k9laThanks to Ken K4ZW and to the PVRCAnd now . . . . . . . . . . . Q/A

    PVRC Webinar Mar 9, 2011 K9LA

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