fort wayne dx convention july 2015 solar impact on propagation carl luetzelschwab ft wayne, in...

Fort Wayne DX Convention July 2015Fort Wayne DX Convention July 2015

Solar Impact on Solar Impact on PropagationPropagation

Carl LuetzelschwabCarl LuetzelschwabFt Wayne, INFt Wayne, IN

[email protected] (e-mail)[email protected] (e-mail)http://k9la.us (web site)http://k9la.us (web site)


Who Am I?Who Am I? Began as an SWL in 6Began as an SWL in 6thth grade grade Mom and Dad bought me a National NC-60 Mom and Dad bought me a National NC-60

Special receiverSpecial receiver 31m and 25m were my best bands31m and 25m were my best bands

• NC-60 had adequate sensitivity and decent bandspread NC-60 had adequate sensitivity and decent bandspread for those frequenciesfor those frequencies

““Licensed” thru Popular Electronics as WPE9BQHLicensed” thru Popular Electronics as WPE9BQH WN9AVT in October 1961 (just turned 14)WN9AVT in October 1961 (just turned 14)

• Selected K9LA in 1977Selected K9LA in 1977 Still like to SWL with vintage receiversStill like to SWL with vintage receivers

• NC-60NC-60• Drake 2B with additional crystalsDrake 2B with additional crystals• Have an SX-100 (general coverage) that needs workHave an SX-100 (general coverage) that needs work


Solar Impact on PropagationSolar Impact on Propagation

Let’s divide AM broadcast frequencies to Let’s divide AM broadcast frequencies to 30 MHz into three segments30 MHz into three segments• Above about 16 MHzAbove about 16 MHz

MUF-driven bandsMUF-driven bands

• AM broadcast up to about 9 MHzAM broadcast up to about 9 MHz Absorption-driven bandsAbsorption-driven bands

• Between 9 MHz and 16 MHzBetween 9 MHz and 16 MHz Transition bandsTransition bands

We’ll also review disturbances to We’ll also review disturbances to propagationpropagation


MUF-Driven BandsMUF-Driven Bandsabove about 16 MHzabove about 16 MHz

Ionospheric absorption is Ionospheric absorption is inversely proportional to the inversely proportional to the square of the frequencysquare of the frequency• The higher the frequency, the The higher the frequency, the

lower the ionospheric lower the ionospheric absorptionabsorption

• Minimal absorption on these Minimal absorption on these frequenciesfrequencies

Amount of refraction is Amount of refraction is inversely proportional to the inversely proportional to the square of the frequencysquare of the frequency• The higher the frequency, the The higher the frequency, the

less the bendingless the bending• Need more ionization to Need more ionization to

refract RF back to Earthrefract RF back to Earth• Daytime!Daytime!

Size matters – the size of the Size matters – the size of the solar cycle, that is!solar cycle, that is!

daytime

the higher the frequency, the longer the hop and the less the absorption


All Solar CyclesAll Solar Cycles

Cyclic in natureCyclic in nature Three periods of larger cyclesThree periods of larger cycles Two periods of smaller cyclesTwo periods of smaller cycles Are we headed for a period of smaller cycles?Are we headed for a period of smaller cycles?

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Dalton Minimum


Duration of Solar MinimumsDuration of Solar Minimums

Three periods of short duration minimumsThree periods of short duration minimums Two periods of long duration minimumsTwo periods of long duration minimums Looks like we’re entering a third period of long minimumsLooks like we’re entering a third period of long minimums Note the relationship between this graph and the graph on Note the relationship between this graph and the graph on

the previous slidethe previous slide

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sola r m inim um be tw e e n indic a te d c yc le s

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Solar Max vs Previous Solar MinSolar Max vs Previous Solar Min

The longer the solar minimum, The longer the solar minimum, the smaller the next cyclethe smaller the next cycle

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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Cycle 24Cycle 24

Cycle 24 is the smallest in our lifetimesCycle 24 is the smallest in our lifetimes Early predictions for Cycle 25 say it may be even smaller!Early predictions for Cycle 25 say it may be even smaller!

• Not good for the higher frequenciesNot good for the higher frequencies

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months after minimum

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cm s

fCycle 23 Cycle 24


Grand Solar MinimumGrand Solar Minimum

Are we going to have another Maunder Minimum?Are we going to have another Maunder Minimum? Fact: we can’t see sunspots when the magnetic field around them Fact: we can’t see sunspots when the magnetic field around them

is less than about 1500 Gaussis less than about 1500 Gauss From 1998 thru 2010 the magnetic field around sunspots From 1998 thru 2010 the magnetic field around sunspots

appeared to be headed towards 1500 Gauss, but the decrease appeared to be headed towards 1500 Gauss, but the decrease appears to have leveled offappears to have leveled off


Summary of MUF-Driven BandsSummary of MUF-Driven Bands We may not have many opportunities on the We may not have many opportunities on the

higher frequencies during the next several cycleshigher frequencies during the next several cycles Regardless, best seasons for the northern Regardless, best seasons for the northern

hemisphere are the fall, winter and spring monthshemisphere are the fall, winter and spring months Daytime is best, but several hours past sunset is Daytime is best, but several hours past sunset is

okay due to slow F2 region recombinationokay due to slow F2 region recombination Comment about sunspots and 10.7 cm solar fluxComment about sunspots and 10.7 cm solar flux

• Both are proxies for true ionizing radiationBoth are proxies for true ionizing radiation F region: 10-100 nmF region: 10-100 nm E region: 1-10 nmE region: 1-10 nm D region: 0.1-1.0 nm and 121.5 nmD region: 0.1-1.0 nm and 121.5 nm

• Daily sunspot number or 10.7 cm solar flux does Daily sunspot number or 10.7 cm solar flux does notnot correlate well with what the ionosphere is doing todaycorrelate well with what the ionosphere is doing today

• Longer term correlation is best – smoothed solar index Longer term correlation is best – smoothed solar index and monthly median ionospheric parametersand monthly median ionospheric parameters


Absorption-Driven BandsAbsorption-Driven Bandsbelow about 9 MHzbelow about 9 MHz

Again, ionospheric Again, ionospheric absorption is inversely absorption is inversely proportional to the square proportional to the square of the frequencyof the frequency• The lower the frequency, The lower the frequency,

the higher the absorptionthe higher the absorption• Maximum absorption on Maximum absorption on

these frequenciesthese frequencies• Nighttime!Nighttime!

Again, amount of refraction Again, amount of refraction is inversely proportional to is inversely proportional to the square of the frequencythe square of the frequency• The lower the frequency, The lower the frequency,

the more the bendingthe more the bending• Don’t need more ionization Don’t need more ionization

to refract RF back to Earthto refract RF back to Earth

nighttime

The lower the frequency, the shorter the hop and the more the loss – caveat for loss at LF


A Limit to Multi-HopA Limit to Multi-Hop Since the lower frequencies have hops that are shorter and Since the lower frequencies have hops that are shorter and

incur more loss (even at night), worldwide reception must incur more loss (even at night), worldwide reception must be via multi-hop (many successive hops)be via multi-hop (many successive hops)

But there’s a problem – each hop takes its toll on signal But there’s a problem – each hop takes its toll on signal strength due to ionospheric absorption and ground strength due to ionospheric absorption and ground reflection lossreflection loss

How far can low frequency RF go before it’s below the noise How far can low frequency RF go before it’s below the noise level at a receiving station (usually defined by atmospheric level at a receiving station (usually defined by atmospheric and/or man-made noise)and/or man-made noise)

It’s easy to estimate this using the Friis transmission It’s easy to estimate this using the Friis transmission equationequation• P(rcv) = P(xmt) + Gain(xmt ant) + Gain(rcv ant) – (free space path loss) P(rcv) = P(xmt) + Gain(xmt ant) + Gain(rcv ant) – (free space path loss)

– (absorption) – (gnd refl loss) – (polarization mismatch)– (absorption) – (gnd refl loss) – (polarization mismatch) On 1.8 MHz with 1.5 kW and 0 dBi antennas, signal goes On 1.8 MHz with 1.5 kW and 0 dBi antennas, signal goes

below the average noise level at around 10,000 kmbelow the average noise level at around 10,000 km• This is why ducting is invokedThis is why ducting is invoked


Ducting MechanismDucting Mechanism Natural mechanism Natural mechanism

for ducting in the dark for ducting in the dark ionosphereionosphere• Electron density valley Electron density valley

above the E region above the E region peakpeak

RF refracts RF refracts successively between successively between the top of the E the top of the E region and the lower region and the lower F regionF region

RF in the duct avoids RF in the duct avoids ionospheric ionospheric absorption and absorption and ground reflection ground reflection losseslosses


Ducting ExampleDucting Example Ray trace is from Ray trace is from

Sudan (STØRY) to Fort Sudan (STØRY) to Fort Wayne (K9LA)Wayne (K9LA)

Ray tracing shows it is Ray tracing shows it is easy to get into a duct, easy to get into a duct, but getting out of a but getting out of a duct in the dark duct in the dark ionosphere with ray ionosphere with ray tracing is not easytracing is not easy• May require May require

irregularities that we irregularities that we know are there but are know are there but are not in the modelnot in the model

• The ionosphere is not The ionosphere is not homogeneoushomogeneous

Ducting likely occurs Ducting likely occurs from AM broadcast thru from AM broadcast thru MFMF

ducting increases the limit imposed by multi-hop


Signal EnhancementsSignal Enhancements Another way to get out Another way to get out

of a duct is to of a duct is to encounter a tilted encounter a tilted ionosphere around ionosphere around sunrise (and maybe sunrise (and maybe sunset)sunset)

The result is a The result is a significant increase in significant increase in signal strength for a signal strength for a short period of time short period of time when the signal comes when the signal comes out of the ductout of the duct

Sunrise enhancement of 3QD (Australia) at Victoria, BC on 1548 KHz on May 14, 1998

from “Medium-Frequency Sunrise Enhancements”, Nick Hall-Patch, QEX, July/August 2001 (reprints available)


Solar Minimum Best, Right?Solar Minimum Best, Right? Old adage is the Old adage is the

low frequency low frequency bands are best at bands are best at solar minimumsolar minimum

For paths near the For paths near the terminator, that’s terminator, that’s probably correct as probably correct as ionizing radiation ionizing radiation can scatter into the can scatter into the dark ionospheredark ionosphere

For paths well in For paths well in darkness, solar max darkness, solar max is similar to solar is similar to solar minmin

Can solar min be Can solar min be too deep? Perhaps!too deep? Perhaps!• Impact of GCRsImpact of GCRs

Lower Ionosphere Electron DensityDecember 15, 40N/60W, 0200 UTC

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1.000E+04

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electrons per cubic meter

hei

gh

t (k

m) Cycle 24 max

(SSN=80)without GCRsadditional dueto GCRs

GCRs contribute to absorption


Summary of Absorption-Driven BandsSummary of Absorption-Driven Bands

Nighttime (dark ionosphere) is bestNighttime (dark ionosphere) is best Always check around sunrise/sunset on Always check around sunrise/sunset on

both ends of the pathboth ends of the path Back when WOWO on 1190 KHz here in Back when WOWO on 1190 KHz here in

Fort Wayne was 50,000 Watts and a Clear-Fort Wayne was 50,000 Watts and a Clear-Channel, they received reception reports Channel, they received reception reports from Indiafrom India• WOWO selected antenna site for best ground WOWO selected antenna site for best ground

conditions (highest conductivity)conditions (highest conductivity)

For more on ducting and enhancements, read “Ducting and Spotlight Propagation on 160m”, Carl Luetzelschwab, CQ, December 2005 (reprints available)


Transition BandsTransition BandsBetween 9 MHz and 16 MHzBetween 9 MHz and 16 MHz

Not as dependent on MUF as the higher Not as dependent on MUF as the higher frequency bandsfrequency bands

Not as dependent on absorption as the Not as dependent on absorption as the lower frequency bandslower frequency bands

They are essentially good at solar min and They are essentially good at solar min and at solar max, and during the day and at solar max, and during the day and during the nightduring the night

My two favorite SWL bands (31m and My two favorite SWL bands (31m and 25m) and 19m fall into this range25m) and 19m fall into this range• These three bands are good all-around These three bands are good all-around

frequencies for international SWLingfrequencies for international SWLing


Disturbances to PropagationDisturbances to Propagation

In March 2002, NOAA defined three In March 2002, NOAA defined three categories of disturbances to propagation categories of disturbances to propagation – G, S, R– G, S, R

All three are caused by CMEs/coronal All three are caused by CMEs/coronal holes and big solar flaresholes and big solar flares


Three CategoriesThree Categories GG refers to refers to GGeomagnetic Stormseomagnetic Storms

• Caused by gusts in solar wind from CMEs (coronal mass Caused by gusts in solar wind from CMEs (coronal mass ejections) and high speed streams from coronal holesejections) and high speed streams from coronal holes

• Can cause auroral absorption, auroral-E, depleted F Can cause auroral absorption, auroral-E, depleted F regionregion

SS refers to refers to SSolar Radiation Stormsolar Radiation Storms• Caused by energetic protons from big solar flaresCaused by energetic protons from big solar flares• Can increase D region absorption in the polar cap (PCA)Can increase D region absorption in the polar cap (PCA)

R refers to refers to RRadio Blackoutsadio Blackouts• Caused by electromagnetic radiation from big solar flaresCaused by electromagnetic radiation from big solar flares

X-ray flares (.1-1 nm wavelengths) of X or M classX-ray flares (.1-1 nm wavelengths) of X or M class• Can increase D region absorption on daylight side of Can increase D region absorption on daylight side of

EarthEarth For all three, scale is 1 to 5For all three, scale is 1 to 5

• 1 is minor and 5 is extreme, and correspond to specific 1 is minor and 5 is extreme, and correspond to specific criteriacriteria

• Details at Details at http://www.swpc.noaa.gov/Data/info/WWVdoc.htmlhttp://www.swpc.noaa.gov/Data/info/WWVdoc.html


The Big PictureThe Big PictureX-ray radiation from solar flare – absorption on the daylight side of the Earth Protons from solar

flare – absorption in the polar cap

Geomagnetic storms – depressed F region MUFs at high and mid latitudes both day and night

Geomagnetic storms – auroral absorption, auroral ionization

X marks the spot – the North magnetic poleX


ImpactImpact In order of “least” impact to “most” impactIn order of “least” impact to “most” impact

• Radio blackout (R)Radio blackout (R) No warning, but usually short duration – an hour or twoNo warning, but usually short duration – an hour or two Lower frequencies impacted longerLower frequencies impacted longer Only affects daylight side of EarthOnly affects daylight side of Earth

• Solar radiation storm (S)Solar radiation storm (S) A couple hours warning, can last a day or twoA couple hours warning, can last a day or two Only affects propagation across the polar capOnly affects propagation across the polar cap

• Geomagnetic storm (G)Geomagnetic storm (G) A day or two warning, can last for daysA day or two warning, can last for days Adversely affects high and mid latitude ionosphere both Adversely affects high and mid latitude ionosphere both

day and nightday and night Can enhance low latitude ionosphereCan enhance low latitude ionosphere

In general we want G, S, R ratings to be 1 or lessIn general we want G, S, R ratings to be 1 or less


Mitigation for DisturbancesMitigation for Disturbances

low freqs.

Australia.


June 22/23 DisturbancesJune 22/23 Disturbances The high K indices The high K indices

are the result of a are the result of a CME or coronal holeCME or coronal hole• Could have adverse Could have adverse

impact on F2 regionimpact on F2 region When you see the K When you see the K

index that high for index that high for multiple 3-hr multiple 3-hr periods, you have to periods, you have to wonder about solar wonder about solar radiation storms and radiation storms and radio blackouts due radio blackouts due to a concurrent big to a concurrent big flareflare

www.swpc.noaa.gov/products/planetary-k-index


June 22/23 Disturbances - CMEJune 22/23 Disturbances - CME

First halo CME June 18 at First halo CME June 18 at 1724 UTC1724 UTC

Second halo CME June 19 Second halo CME June 19 at 0845 UTCat 0845 UTC

Third, and fastest, halo Third, and fastest, halo CME June 21 at 1900 UTCCME June 21 at 1900 UTC

The third CME caught up The third CME caught up with the earlier two to with the earlier two to add to the disturbanceadd to the disturbance

www.swpc.noaa.gov/products/products/lasco-coronograph


June 22/23 Disturbances – F2 RegionJune 22/23 Disturbances – F2 Region Depleted F2 Depleted F2

region at all region at all latitudes in latitudes in northern northern hemispherehemisphere

Depleted F2 Depleted F2 region at high and region at high and mid latitudes in mid latitudes in southern southern hemispherehemisphere

Remember this is Remember this is a model based on a model based on how the K index is how the K index is developing – developing – should be able to should be able to confirm with confirm with ionosonde dataionosonde data

www.swpc.noaa.gov/products/storm-time-empirical-ionospheric-correction


June 22/23 Disturbances - AuroraJune 22/23 Disturbances - Aurora

Watch it here – the Watch it here – the orange-red area is orange-red area is where where visiblevisible aurora aurora is likely to occur – is likely to occur – caused by low energy caused by low energy electronselectrons

It tells us nothing It tells us nothing about radio aurora about radio aurora from high energy from high energy electrons electrons

www.swpc.noaa.gov/products/aurora-30-minute-forecast


June 22/23 Disturbances - ElectronsJune 22/23 Disturbances - Electrons

These measurements These measurements are at geosynchronous are at geosynchronous altitudesaltitudes

When the K index goes When the K index goes up, electrons trapped up, electrons trapped in the magnetosphere in the magnetosphere are releasedare released

Guided to the high Guided to the high latitudes by magnetic latitudes by magnetic field linesfield lines

Precipitating electrons Precipitating electrons (that cause auroral (that cause auroral displays) do not displays) do not directly come from the directly come from the SunSun

www.swpc.noaa.gov/products/goes-electron-flux


June 22/23 Disturbances – Xray FluxJune 22/23 Disturbances – Xray Flux

bunch of big flaresbunch of big flares

M2.0 M2.6

M3.8

M6.5

M1.1

www.swpc.noaa.gov/products/goes-x-ray-flux


June 22/23 Disturbances – Proton FluxJune 22/23 Disturbances – Proton Flux

started increasing early on June 21started increasing early on June 21www.swpc.noaa.gov/products/goes-proton-flux


June 22/23 Disturbances – Absorption June 22/23 Disturbances – Absorption and Radio Blackoutsand Radio Blackouts

Increased absorption from protons funneling into the polar Increased absorption from protons funneling into the polar cap – solar radiation storm (A)cap – solar radiation storm (A)

Increased absorption from electromagnetic radiation on Increased absorption from electromagnetic radiation on dayside of Earth – radio blackout (B)dayside of Earth – radio blackout (B)

A

A

B

www.swpc.noaa.gov/products/d-region-absorption-predictions-d-rap


SummarySummary SWLing on the higher frequencies may not SWLing on the higher frequencies may not

be productive for the next several solar be productive for the next several solar cyclescycles

SWLing on the lower frequencies should SWLing on the lower frequencies should generally be good due to a small cyclegenerally be good due to a small cycle• May be dependent on how smallMay be dependent on how small

Impact of GCRsImpact of GCRs SWLing on the middle frequencies should SWLing on the middle frequencies should

be just finebe just fine Lots of space weather data available to Lots of space weather data available to

assess disturbances to propagationassess disturbances to propagation

fort wayne dx convention july 2015 solar impact on propagation carl luetzelschwab ft wayne, in...

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