Propagation Topics

FRC 9 Nov 2010 - K9LAFRC 9 Nov 2010 - K9LA

Propagation TopicsPropagation Topics

Carl Luetzelschwab K9LACarl Luetzelschwab K9LA

[email protected]@arrl.nethttp://mysite.ncnetwork.net/k9lahttp://mysite.ncnetwork.net/k9la


A Little About K9LAA Little About K9LA

• Novice license WN9AVT in October Novice license WN9AVT in October 19611961

• Selected K9LA in the mid 1970sSelected K9LA in the mid 1970s• Interested in propagation, Interested in propagation,

antennas, DXing, and contestingantennas, DXing, and contesting• NCJ Editor from 2002-2007NCJ Editor from 2002-2007• My wife is Vicky AE9YL – it helps My wife is Vicky AE9YL – it helps

that she kind of understands this that she kind of understands this ham radio thingham radio thing

• BSEE 1969 and MSEE 1972 from BSEE 1969 and MSEE 1972 from PurduePurdue

• RF design engineer by professionRF design engineer by profession


What We’ll CoverWhat We’ll Cover

• Solar Minimum and Cycle 24Solar Minimum and Cycle 24

• Recent Science NewsRecent Science News

• F2 Region VariabilityF2 Region Variability

• Propagation PredictionsPropagation Predictions

• 160m Fundamentals160m Fundamentals

• 10m Opening to EU on October 1110m Opening to EU on October 11

• Old QSL QuizOld QSL Quiz


Solar Minimum and Cycle Solar Minimum and Cycle 2424


Our Recent Solar MinOur Recent Solar Min

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months from descent below a smoothed sunspot number of 20

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between Cycles 18 and19 (Apr 1954)between Cycles 19 and20 (Nov 1964)between Cycles 20 and21 (Jun 1976)between Cycles 21 and22 (Sep 1986)

between Cycles 22 and23 (Oct 1996)between Cycles 23 and24Cycle 24 prediction

Pretty unusual, right?


A Look At All Recorded A Look At All Recorded HistoryHistory

Historical Solar Minimum Periods

0 10 20 30 40 50 60 70 80 90 100

1 & 22 & 33 & 44 & 55 & 66 & 77 & 88 & 9

9 & 1010 & 1111 & 1212 & 1313 & 1414 & 1515 & 1616 & 1717 & 1818 & 1919 & 2020 & 2121 & 2222 & 2323 & 24

sola

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number of months with smoothed sunspot number below 20

Recent solar min certainly unusual in our lifetime, but not that unusual over all recorded history

Note the cyclic nature


Cycle 24 ProgressCycle 24 Progress

• Solar min in December 2008Solar min in December 2008• Smoothed sunspot number and smoothed solar Smoothed sunspot number and smoothed solar

flux steadily rising ever since (in spite of the flux steadily rising ever since (in spite of the ups-and-downs of the monthly mean values)ups-and-downs of the monthly mean values)

Solar Minimum Between Cycle 23 and 24in terms of sunspot number

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Cycle 24 monthly mean

Cycle 23 monthly mean

smoothed

Solar Minimum Between Cycle 23 and 24in terms of 10.7 cm solar flux

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smoothed


Latest NOAA PredictionLatest 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


More PredictionsMore Predictions

Over 55 predictions in the scientific literatureRange from a smoothed sunspot number of 40 to 185Somebody is going to get it right!


When Will 15m and 10m Be When Will 15m and 10m Be Back?Back?

• Let’s assume the NOAA prediction is correctLet’s assume the NOAA prediction is correct• 15m needs a smoothed sunspot number of about 15m needs a smoothed sunspot number of about

25 (smoothed solar flux of 85) for consistent F2 25 (smoothed solar flux of 85) for consistent F2 propagationpropagation– We’re probably there nowWe’re probably there now– CQ WW PH was consistently goodCQ WW PH was consistently good– CQ WW CW should be, tooCQ WW CW should be, too

• 10m needs a smoothed sunspot number of about 10m needs a smoothed sunspot number of about 50 (smoothed solar flux of 100) for consistent F2 50 (smoothed solar flux of 100) for consistent F2 propagationpropagation– I hope we get there in early 2011I hope we get there in early 2011– ARRL DX contests in February and March 2011 have the ARRL DX contests in February and March 2011 have the

potential of being good (more than just Carib and S potential of being good (more than just Carib and S Amer)Amer)


Our Very Own PredictionOur Very Own Prediction

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Next Solar Max vs Duration of Previous Solar Min

R2 = 0.5815

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months at solar minimum (smoothed sunspot number < 20)

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Long solar min points to a smaller cycle

out of phase with solar min duration

“cycles” – Schwabe 11 yrs Hale 22 yrs Gleissberg 88 yrs De Vries 205 yrs Halstatt 2300 yrs (from Be10 and/or C14)


A Recent PredictionA Recent PredictionAnnales 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. KaneInstituto Nacional de Pesquisas Espacias, INPE C.P. 515, 12201-970 Sao Jose dos Campos, SP, Brazil

• Maximum smoothed sunspot Maximum smoothed sunspot number of 58 +/- 25number of 58 +/- 25

• That’s lower than the NOAA That’s lower than the NOAA predictionprediction

• 10m will suffer10m will suffer


Recent Science Recent Science NewsNews


#1 - No More Sunspots?#1 - No More Sunspots?• Measured the magnetic Measured the magnetic

fields of sunspots for the fields of sunspots for the past 17 years, and data past 17 years, and data indicates sunspot indicates sunspot magnetism is on the magnetism is on the declinedecline

• Sunspots seem to form Sunspots seem to form only if the magnetic field only if the magnetic field is stronger than about is stronger than about 1500 gauss1500 gauss

• Solar magnetic fields may Solar magnetic fields may become too weak to form become too weak to form sunspots after 2016 or sosunspots after 2016 or so

• The technique looks at a The technique looks at a spectral line emitted by spectral line emitted by iron atoms in the Sun's iron atoms in the Sun's atmosphereatmosphere

Livingston and Penn, Livingston and Penn, EOS, July 2009EOS, July 2009


#2 - Collapsing Atmosphere#2 - Collapsing Atmosphere•• July 15, 2010 July 15, 2010 -- A Puzzling Collapse of Earth's Upper AtmosphereA Puzzling Collapse of Earth's Upper Atmosphere

““NASANASA--funded researchers are monitoring a big event in our planet's funded researchers are monitoring a big event in our planet's atmosphere. High above Earth's surface where the atmosphere meetatmosphere. High above Earth's surface where the atmosphere meets s space, a rarefied layer of gas called space, a rarefied layer of gas called ‘‘the thermospherethe thermosphere’’ recently recently collapsed and now is rebounding again.collapsed and now is rebounding again.””““The collapse happened during the deep solar minimum of 2008The collapse happened during the deep solar minimum of 2008--20092009——a fact which comes as little surprise to researchers. The a fact which comes as little surprise to researchers. The thermosphere always cools and contracts when solar activity is lthermosphere always cools and contracts when solar activity is low. In ow. In this case, however, the magnitude of the collapse was two to thrthis case, however, the magnitude of the collapse was two to three ee times greater than low solar activity could explain.times greater than low solar activity could explain.””

•• What is the impact to HF radio?What is the impact to HF radio?–– Look at hmF2 (height of peak F2 ionization)Look at hmF2 (height of peak F2 ionization)–– Look at foF2 (F2 region critical frequency)Look at foF2 (F2 region critical frequency)


DataData

Pt Arguello ionosonde shows downward trends for both foF2 Pt Arguello ionosonde shows downward trends for both foF2 and hmF2and hmF2

Other ionosondes show a mixed bag of resultsOther ionosondes show a mixed bag of results

The conclusion: More analysis is neededThe conclusion: More analysis is needed

Details: November 2010 WorldRadio Online columnDetails: November 2010 WorldRadio Online column


#3 - Storm Warnings#3 - Storm Warnings•• July 16, 2010 July 16, 2010 -- Space Weather Turns into an International ProblemSpace Weather Turns into an International Problem

“If forecasters are correct, the solar cycle will peak during the years around 2013. And while it probably won't be the biggest peak on record, human society has never been more vulnerable. The basics of daily life—from communications to weather forecasting to financial services—depend on satellites and high-tech electronics. A 2008 report by the National Academy of Sciences warned that a century-class solar storm could cause billions in economic damage.”

• Space weather affects–– Astronauts in spaceAstronauts in space–– SatellitesSatellites–– GPSGPS–– Power grids on EarthPower grids on Earth–– OverOver--thethe--pole airline flightspole airline flights–– Propagation (commercial, military, Amateur Radio)Propagation (commercial, military, Amateur Radio)


#4 - Lower Ionosphere#4 - Lower Ionosphere• Space is just a little bit closerSpace is just a little bit closer, ,

BBC News, 21Dec08, BBC News, 21Dec08, news.bbc.co.uk/2/hi/sciencnews.bbc.co.uk/2/hi/science/nature/7794834.stme/nature/7794834.stm

• NASA: Ionosphere not where it NASA: Ionosphere not where it should beshould be, UPI, 17Dec08, , UPI, 17Dec08, www.tinyurl.com/3p2pcswww.tinyurl.com/3p2pcs

• These press releases are somewhat misleadingThese press releases are somewhat misleading• What’s not real clear is the data is for What’s not real clear is the data is for equatorialequatorial latitudes latitudes• Not understanding this leads to the erroneous conclusion that the Not understanding this leads to the erroneous conclusion that the

worldwide ionosphere is lower - ionosonde data shows no such worldwide ionosphere is lower - ionosonde data shows no such trendtrend

• Details: “Is the Ionosphere Really Lower?” at Details: “Is the Ionosphere Really Lower?” at mysite.ncnetwork.net/k9la under Timely Topics link mysite.ncnetwork.net/k9la under Timely Topics link


F2 Region F2 Region VariabilityVariability


A Look at Ionosonde DataA Look at Ionosonde Data

Wallops Island, 1700 UTC, August 2009

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median MUF = 15.75

MUF varied from a low of just under 10 MHz to a high of just above 20 MHzThis is due to the daily variation of solar radiation, right?


Not QuiteNot Quite• August 2009August 2009

– Zero sunspotsZero sunspots– Constant solar fluxConstant solar flux

• Solar radiation creates Solar radiation creates ionizationionization

• But two other issues But two other issues contribute to the final contribute to the final ionizationionization– Magnetic field Magnetic field

activityactivity– Events in the lower Events in the lower

atmosphere coupling atmosphere coupling up to the ionosphereup to the ionosphere

• Thankfully the E Thankfully the E region is more region is more predictable – it’s predictable – it’s under direct solar under direct solar controlcontrol– Solar activitySolar activity– Solar zenith angleSolar zenith angle

August 2009


Another Subtle EffectAnother Subtle EffectWallops Island vs Boulder, 1700 UTC, August 2009

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Wallops Boulder

Wallops median MUF = 15.75 MHz

Boulder median MUF = 16.14 MHz

The worldwide ionosphere is not necessarily “in step”


Propagation PredictionsPropagation Predictions


How Do You Model the How Do You Model the Ionosphere?Ionosphere?

• It should be obvious that plugging in today’s It should be obvious that plugging in today’s sunspot number or today’s 10.7 cm solar flux does sunspot number or today’s 10.7 cm solar flux does not tell us what the F2 region of the ionosphere is not tell us what the F2 region of the ionosphere is doing todaydoing today

• The developers of the model of the ionosphere for The developers of the model of the ionosphere for propagation prediction recognized thispropagation prediction recognized this

• They were forced to implement a statistical modelThey were forced to implement a statistical model• Thus our propagation predictions are statistical Thus our propagation predictions are statistical

over a month’s time frameover a month’s time frame• The correlation between what the Sun is doing and The correlation between what the Sun is doing and

what the ionosphere is doing is based on a what the ionosphere is doing is based on a smoothed solar index and monthly median smoothed solar index and monthly median ionospheric parametersionospheric parameters


Review of CorrelationsReview of Correlations

Correlation Between Daily MUF and Daily Solar Flux3000 km MUF over Canberra, December 1982, 0300 UTC

R2 = 0.0423

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daily solar flux

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Correlation Between Monthly Median MUF and Smoothed Solar Flux3000 km MUF over Canberra, December months, 0300 UTC

R2 = 0.8600

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Bottom line: We do not have daily predictionsMedian is predicted – use with variability tables to determine other probabilities

MUF could be anywhere from 17 MHz to 28 MHz at a solar flux of 170


So What Does All This So What Does All This Mean?Mean?

• Let’s do a prediction for CQ WW CWLet’s do a prediction for CQ WW CW

• We’ll do it for 15m from Philly to Europe (DL)We’ll do it for 15m from Philly to Europe (DL)

• We’ll use VOACAPWe’ll use VOACAP– 1 KW1 KW– 13 dBi Yagis13 dBi Yagis

• I used a smoothed sunspot number of 36 I used a smoothed sunspot number of 36 (from (from http://www.swpc.noaa.gov/ftpdir/weekly/Predict.txt))

http://www.swpc.noaa.gov/ftpdir/weekly/Predict.txt

http://www.swpc.noaa.gov/ftpdir/weekly/Predict.txt


ResultsResults

MUFMUF

• On half the days of the month at 1400 UTC, the On half the days of the month at 1400 UTC, the MUF will be at least 25.6 MHzMUF will be at least 25.6 MHz

• On 89% of the days of the month at 1400 UTC, On 89% of the days of the month at 1400 UTC, the MUF will be at least 21.0 MHzthe MUF will be at least 21.0 MHz

• On 27% of the days of the month at 1400 UTC, On 27% of the days of the month at 1400 UTC, the MUF will be at least 28.0 MHzthe MUF will be at least 28.0 MHz

UTC

Median MUF 15m 10m

Signal StrengthSignal Strength

• The median signal The median signal strength on 15m at strength on 15m at 1400 UTC is -103 dBW 1400 UTC is -103 dBW (-73 dBm = S9)(-73 dBm = S9)

• The median signal The median signal strength on 10m at strength on 10m at 1400 UTC is -142 dBW 1400 UTC is -142 dBW (-112 dBm = S1)(-112 dBm = S1)

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


160m Fundamentals160m Fundamentals


Interesting QuestionInteresting Question

Is propagation on 160m Is propagation on 160m different than propagation on, different than propagation on, say, 10m?say, 10m?

Most would answer “Yes”Most would answer “Yes”


““No” Is Also A Good AnswerNo” 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)


Ray Trace on 10mRay Trace on 10m• O-wave and X-wave pretty O-wave and X-wave pretty

much follow the same pathmuch follow the same path– Index of refraction Index of refraction

approximately the approximately the samesame

– X-wave bends a bit X-wave bends a bit more more

– Apogee approx 240 kmApogee approx 240 km– Hops to 4000 kmHops to 4000 km

• O-wave and X-wave pretty O-wave and X-wave pretty much incur the same much incur the same amount of absorptionamount of absorption

– Approx 2 dB per hopApprox 2 dB per hop

• O-wave and X-wave are O-wave and X-wave are circularly polarizedcircularly polarized

On 10m the O-wave and X-wave propagate approximately equally


Ray Trace on 160mRay Trace on 160m• O-wave and X-wave O-wave and X-wave do notdo not

follow the same pathfollow the same path– Index of refraction Index of refraction

significantly differentsignificantly different– X-wave bends moreX-wave bends more– Apogee approx 170 km Apogee approx 170 km

for O-wavefor O-wave– Hops limited to < 3000 Hops limited to < 3000

kmkm

• O-wave and X-wave O-wave and X-wave do notdo not incur the same amount of incur the same amount of lossloss

– Absorption significantly Absorption significantly differentdifferent

– X-wave usually X-wave usually considered to be out of considered to be out of the picture when the picture when operating frequency is operating frequency is near the electron gyro-near the electron gyro-frequencyfrequency

• ranges from .7 to ranges from .7 to 1.7 MHz worldwide1.7 MHz worldwide

– Approx 17 dB per hopApprox 17 dB per hop

• Polarization of O-wave tends Polarization of O-wave tends towards elliptical (vertical) at towards elliptical (vertical) at mid to high latitudesmid to high latitudes

160m - shorter hops 160m - more lossy hops160m – only one characteristic wave propagates


Multi-hop on 160mMulti-hop on 160m

• Based on previous slides, multi-hop Based on previous slides, multi-hop propagation on 160m is via hops that are propagation on 160m is via hops that are short and lossyshort and lossy– ““Short” is relative – but it’s not 4000 km hops Short” is relative – but it’s not 4000 km hops

like on 10mlike on 10m• Per our present understanding of the lower Per our present understanding of the lower

ionosphere, at night a 1500 Watt signal ionosphere, at night a 1500 Watt signal with quarter-wave verticals on both ends with quarter-wave verticals on both ends can go about 10,000 km before being can go about 10,000 km before being below the noise level of our receiving below the noise level of our receiving system (usually limited by external noise)system (usually limited by external noise)– Daytime limit around 1000 kmDaytime limit around 1000 km


This Suggests Another ModeThis Suggests Another Mode

STØRY to K9LAMarch 22, 20030330 UTC

Wave refracts successively between the top of the E region peak and the lower portion of the F region


Wave refracts successively between the top of the E region peak and the lower portion of the F region

STØRY

K9LA


STØRY

K9LA



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?


NM7M’s Work with GCRsNM7M’s Work with GCRs• Galactic cosmic rays are mostly Galactic cosmic rays are mostly

very high energy protons coming very high energy protons coming in from all directions – day and in from all directions – day and nightnight

• Quiet magnetic field (solar min) Quiet magnetic field (solar min) lets more in – more ionization in lets more in – more ionization in the lower ionospherethe lower ionosphere

• Active magnetic field (solar max) Active magnetic field (solar max) keeps them out – less ionizationkeeps them out – less ionization

• GCR measurement on Earth (and GCR measurement on Earth (and thus impact to ionosphere) is out thus impact to ionosphere) is out of phase with solar cycleof phase with solar cycle

Smoothed Sunspot Number and Calgary GCR Count

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-82

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-84

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-86

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galactic cosmic rays

http://en.wikipedia.org/wiki/File:Atmospheric_Collision.svg


CGRs and the ValleyCGRs and the Valley• NM7M’s theory is that NM7M’s theory is that

galactic cosmic rays play galactic cosmic rays play an important role in the an important role in the valley formation, and thus valley formation, and thus ductingducting

• At solar maximum, not At solar maximum, not many GCRs ionizing the many GCRs ionizing the valley – nice and deepvalley – nice and deep– Extremely long distance Extremely long distance

DXing best at solar maxDXing best at solar max– NM7M has some NM7M has some

interesting plots of QSO interesting plots of QSO distance vs GCR decrease, distance vs GCR decrease, but there is conflicting databut there is conflicting data

• At solar minimum, too At solar minimum, too many GCRs ionizing valley many GCRs ionizing valley – fills up more and all we – fills up more and all we have left is lossy multi-hophave left is lossy multi-hop

solar min --------solar max -------


W4DR ObservationsW4DR Observationspersonal e-mail, late December 2009personal e-mail, 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) 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 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.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-On the other hand I have not worked any long path or bent path SE Asians in the last 4-5 years.”5 years.”

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

N4IS and K1ZM recently reported long-haul DX into SE Asia


10m Opening to EU on Oct 1110m Opening to EU on Oct 11


The PathThe Path

• East Coast East Coast reported reported good 10m good 10m opening to opening to EU on Oct EU on Oct 1111

• PJ2T also PJ2T also reported reported thisthis

Arensilloionosonde

Goose Bay ionosonde

• No data from Goose BayNo data from Goose Bay– So we don’t know what was happening on the East Coast So we don’t know what was happening on the East Coast

endend• El Arensillo (Spain) gives a good picture on the Europe El Arensillo (Spain) gives a good picture on the Europe

endend


Ionosonde DataIonosonde Data

El Arensillo Ionosonde3000 km hop, October 2010

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Something happened on or before the 11thSomething happened on or before the 11th


Space WeatherSpace Weather

• It is likely that the gradual increase followed by a gradual decrease in It is likely that the gradual increase followed by a gradual decrease in the K index played a role in this 10m openingthe K index played a role in this 10m opening

• Ionization targets at F2 region altitudes (oxygen atoms) can be re-Ionization targets at F2 region altitudes (oxygen atoms) can be re-distributed in the atmosphere due to an elevated K indexdistributed in the atmosphere due to an elevated K index


Old QSLsOld QSLsoror

What Deleted Entity Is What Deleted Entity Is It?It?










SummarySummary

• Cycle 24 is likely to be a small oneCycle 24 is likely to be a small one– Along with the next couple of cycles Along with the next couple of cycles

• Carefully read and evaluate science newsCarefully read and evaluate science news• We don’t have daily predictionsWe don’t have daily predictions• 160m is still a tough band to understand160m is still a tough band to understand

– For more on propagation on 160m, visit For more on propagation on 160m, visit http://mysite.ncnetwork.net/k9la, and click on , and click on the 160m link on the leftthe 160m link on the left

• Keep an eye on 10mKeep an eye on 10m

http://mysite.ncnetwork.net/k9la


Q & Q & AA

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