Kamloops ARC Nov 2015 K9LA The Sun, the Ionosphere and HF Propagation Carl Luetzelschwab K9LA

Kamloops ARC Nov 2015 K9LA Who Is K9LA? Received Novice license (WN9AVT) in Oct 1961 Received Novice license (WN9AVT) in Oct 1961 Selected K9LA in 1977 Selected K9LA in 1977 Interests include Interests include PropagationPropagation DXingDXing ContestingContesting Playing with antennasPlaying with antennas Vintage equipmentVintage equipment DXpeditions include YK9A (Syria, 2001), OJ0 (Market Reef, 2002) and ZF (Cayman Islands, many times) DXpeditions include YK9A (Syria, 2001), OJ0 (Market Reef, 2002) and ZF (Cayman Islands, many times) Wife is Vicky AE9YL/ZF2YL Wife is Vicky AE9YL/ZF2YL Viking Ranger II HQ-170A

Kamloops ARC Nov 2015 K9LA Some of My Favorite Movie Stars

Kamloops ARC Nov 2015 K9LA But This Is My Favorite Star

Kamloops ARC Nov 2015 K9LA Some Facts About the Sun Radiates energy at many wavelengths Radiates energy at many wavelengths Highest intensity is at visible light wavelengths ( nm) Highest intensity is at visible light wavelengths ( nm) Wavelengths that ionize the atmosphere ( nm) are much shorter than visible light Wavelengths that ionize the atmosphere ( nm) are much shorter than visible light Visible light has nothing to do with the ionization process – not enough energy Visible light has nothing to do with the ionization process – not enough energy Same for 10.7 cm solar fluxSame for 10.7 cm solar flux wavelength in nm Solar Radiation Spectrum intensity Ionizing wavelengths.1 to 100 nm 10.7 cm The shorter the wavelength, the more the energy (Planck’s Law)

Kamloops ARC Nov 2015 K9LA Early Ionospheric Studies 1901 – Marconi hears Poldhu 1901 – Marconi hears Poldhu 1902 – Kennelly (US) & Heaviside (UK) independently suggest that the Earth’s upper atmosphere consists of an electrically conducting region (the Kennelly-Heaviside layer) 1902 – Kennelly (US) & Heaviside (UK) independently suggest that the Earth’s upper atmosphere consists of an electrically conducting region (the Kennelly-Heaviside layer) 1925 – Appleton finds conclusive evidence of a conducting region by measuring arrival angles of nearby transmitter 1925 – Appleton finds conclusive evidence of a conducting region by measuring arrival angles of nearby transmitter 1925 – Breit and Tuve confirm existence of reflecting region with the first ionosonde ( s wept-frequency upward-looking radar) 1925 – Breit and Tuve confirm existence of reflecting region with the first ionosonde ( s wept-frequency upward-looking radar) Watson-Watt coins the term “ionosphere” Watson-Watt coins the term “ionosphere” 1927 – Sharp decrease in critical frequency (measured by an ionosonde) seen during solar eclipse – deduce that solar radiation forms the ionosphere 1927 – Sharp decrease in critical frequency (measured by an ionosonde) seen during solar eclipse – deduce that solar radiation forms the ionosphere 1928 – Pettit ties sunspots to solar radiation – the more sunspots, the more radiation 1928 – Pettit ties sunspots to solar radiation – the more sunspots, the more radiation

Kamloops ARC Nov 2015 K9LA Sunspots Sunspots are the result of magnetic fields in the Sun that erupt through the surface, forming a huge magnetic loop Sunspots are the result of magnetic fields in the Sun that erupt through the surface, forming a huge magnetic loop The solar surface in this area cools significantly, causing this area to be darker The solar surface in this area cools significantly, causing this area to be darker The area around the sunspot emits radiation at wavelengths that ionize the atmosphere The area around the sunspot emits radiation at wavelengths that ionize the atmosphere Sunspots (and 10.7 cm solar flux) are a proxy for the true ionizing radiationSunspots (and 10.7 cm solar flux) are a proxy for the true ionizing radiation

Kamloops ARC Nov 2015 K9LA Solar Cycle Average length (A to C) is 11 years Average length (A to C) is 11 years Average rise time (A to B) is 4 yearsAverage rise time (A to B) is 4 years Average fall time (B to C) is 7 yearsAverage fall time (B to C) is 7 years Solar cycle may have two peaks Solar cycle may have two peaks We measure solar cycles using a smoothed solar index to “smooth out” the spikiness of daily and monthly mean values We measure solar cycles using a smoothed solar index to “smooth out” the spikiness of daily and monthly mean values The maximum value varies The maximum value varies Smoothed solar index could be smoothed sunspot number or smoothed 10.7 cm solar flux

Kamloops ARC Nov 2015 K9LA Two Peaks Cycles 21, 22, 23 and now 24 had a second peak Cycles 21, 22, 23 and now 24 had a second peak What does this mean? What does this mean? Good question!Good question!

Kamloops ARC Nov 2015 K9LA Recorded History Three periods of large cycles, two periods of small cycles Three periods of large cycles, two periods of small cycles Looks like we’re headed for some small solar cycles Looks like we’re headed for some small solar cycles Corroborating evidence is cycle max vs duration of previous minCorroborating evidence is cycle max vs duration of previous min Dalton minimum Cycle 1 began in 1755

Kamloops ARC Nov 2015 K9LA Duration of Cycle Minimums On the left is the duration of solar minimums On the left is the duration of solar minimums Out-of-phase with plot on previous slideOut-of-phase with plot on previous slide On the right is a scatter diagram of months at solar minimum vs magnitude of next peak On the right is a scatter diagram of months at solar minimum vs magnitude of next peak The longer the duration of solar minimum, the smaller the next cycle The longer the duration of solar minimum, the smaller the next cycle

Kamloops ARC Nov 2015 K9LA Early History Carbon-14 (and Beryllium-10) are proxies for solar activity Carbon-14 (and Beryllium-10) are proxies for solar activity Tied to galactic cosmic raysTied to galactic cosmic rays Are we headed for another Maunder Minimum? Are we headed for another Maunder Minimum? Some say yes, most say no – duration of minimum between Cycle 24 and 25 should give us a hint of where we’re headedSome say yes, most say no – duration of minimum between Cycle 24 and 25 should give us a hint of where we’re headed Cycles 5,6,7 the most well known minimum (~ ) Positive  14C is solar minimum Negative  14C is solar maximum

Kamloops ARC Nov 2015 K9LA Solar Cycle 24 Status Blue vertical bars are monthly means Blue vertical bars are monthly means Red line is smoothed value Red line is smoothed value First peak in early 2012 – second peak in mid 2014 First peak in early 2012 – second peak in mid 2014

Kamloops ARC Nov 2015 K9LA The Atmosphere Atmosphere is most often defined by temperature (yellow line) Atmosphere is most often defined by temperature (yellow line) Terrestrial weather is in the troposphere and lower stratosphere Terrestrial weather is in the troposphere and lower stratosphere Ionosphere starts in the mesosphere Ionosphere starts in the mesosphere

Kamloops ARC Nov 2015 K9LA The Ionosphere Remember that ionizing radiation is at wavelengths between.1 and 100 nm Remember that ionizing radiation is at wavelengths between.1 and 100 nm The shorter the wavelength, the more the energy The shorter the wavelength, the more the energy The more the energy, the lower it gets into the atmosphereThe more the energy, the lower it gets into the atmosphere F region above ~ 160 km F region above ~ 160 km nm wavelengths (EUV) nm wavelengths (EUV) E region from ~ km E region from ~ km 1-10 nm wavelengths (soft x-rays)1-10 nm wavelengths (soft x-rays) D region from ~ km D region from ~ km.1-1 nm wavelengths (hard x-rays).1-1 nm wavelengths (hard x-rays) R is the smoothed sunspot number R=0 is solar minimum R=200 is solar maximum

Kamloops ARC Nov 2015 K9LA Critical Frequency and MUF Ionosondes measure the critical frequencies of the ionosphere Ionosondes measure the critical frequencies of the ionosphere Critical frequency of a region is the frequency at which the RF pulse does not return to Earth (it goes through the region)Critical frequency of a region is the frequency at which the RF pulse does not return to Earth (it goes through the region) Ionosondes report critical frequencies for the E, F1 and F2 regions (and sporadic E when present)Ionosondes report critical frequencies for the E, F1 and F2 regions (and sporadic E when present) Using spherical geometry, we can estimate the maximum frequency that will propagate over a given path at a given time Using spherical geometry, we can estimate the maximum frequency that will propagate over a given path at a given time

Kamloops ARC Nov 2015 K9LA Critical Frequency Example As the elevation angle is lowered from 90 o, higher frequencies are refracted back to Earth As the elevation angle is lowered from 90 o, higher frequencies are refracted back to Earth The highest frequency that is refracted back to Earth when launched at a low elevation angle is about 3 times the critical frequency The highest frequency that is refracted back to Earth when launched at a low elevation angle is about 3 times the critical frequency This is the maximum useable frequency (MUF) This is the maximum useable frequency (MUF) In this example, the MUF would be about 24 MHz In this example, the MUF would be about 24 MHz F region 3 MHz8 MHz ionosonde varies its frequency

Kamloops ARC Nov 2015 K9LA Variability of the Ionosphere The ionosphere varies significantly The ionosphere varies significantly Over a solar cycle - most ionization at solar maximumOver a solar cycle - most ionization at solar maximum Monthly – Fall months best in northern hemisphereMonthly – Fall months best in northern hemisphere Throughout the day – max around noon, min before dawnThroughout the day – max around noon, min before dawn The ionosphere is affected by disturbances to propagation The ionosphere is affected by disturbances to propagation Our understanding of the ionosphere is statistical in nature over a month’s time frame Our understanding of the ionosphere is statistical in nature over a month’s time frame Thus our propagation predictions are statistical in nature over a month’s time frameThus our propagation predictions are statistical in nature over a month’s time frame We do not have a daily model of the ionosphereWe do not have a daily model of the ionosphere

Kamloops ARC Nov 2015 K9LA The Bands Our bands fall into three categories Our bands fall into three categories 160m, 80m, 40m: these bands are very dependent on ionospheric absorption160m, 80m, 40m: these bands are very dependent on ionospheric absorption Best during the night and best at solar minimum Best during the night and best at solar minimum 15m, 12m, 10m: these bands are very dependent on the MUF15m, 12m, 10m: these bands are very dependent on the MUF Best during the day and best at solar maximum Best during the day and best at solar maximum 30m, 20m, 17m: these are transition bands30m, 20m, 17m: these are transition bands Not entirely dependent on absorption Not entirely dependent on absorption Not entirely dependent on MUF Not entirely dependent on MUF Hold up well throughout a solar cycle Hold up well throughout a solar cycle

Kamloops ARC Nov 2015 K9LA Space Weather Current weather parameters and assessment of band conditions

Kamloops ARC Nov 2015 K9LA What We Desire Solar activity Solar activity In general we desire a high sunspot number (0-200) and a high 10.7 cm solar flux (65-300)In general we desire a high sunspot number (0-200) and a high 10.7 cm solar flux (65-300) Openings vs 10.7 cm solar fluxOpenings vs 10.7 cm solar flux 10m: long-term solar flux > m: long-term solar flux > m: long-term solar flux > 75 12m: long-term solar flux > 75 15m: long-term solar flux > 50 15m: long-term solar flux > 50 Geomagnetic field activity Geomagnetic field activity In general we desire A < 7 and K < 2In general we desire A < 7 and K < 2 A and K are measures of the deviation of the Earth’s magnetic field from quiet conditions A and K are measures of the deviation of the Earth’s magnetic field from quiet conditions A is a daily index, K is a 3-hour index A is a daily index, K is a 3-hour index

Kamloops ARC Nov 2015 K9LA What Bands Are Open? Since we don’t have a daily model of the ionosphere, knowing the 10.7 cm solar flux does not pin down the MUF for a given path at a given time Since we don’t have a daily model of the ionosphere, knowing the 10.7 cm solar flux does not pin down the MUF for a given path at a given time We can use propagation predictions to give a statistical view of what the best band would be for the desired path We can use propagation predictions to give a statistical view of what the best band would be for the desired path W6ELProp is a user-friendly propagation prediction program that is a free downloadW6ELProp is a user-friendly propagation prediction program that is a free download Visit the Tutorials link at for info about W6ELProp (how to download it, set it up and interpret the results)Visit the Tutorials link at for info about W6ELProp (how to download it, set it up and interpret the results)

Kamloops ARC Nov 2015 K9LA Listen Real-Time! The IARU/NCDXF beacon project has a beacon on 20m, 17m, 15m, 12m and 10m in 18 countries worldwide The IARU/NCDXF beacon project has a beacon on 20m, 17m, 15m, 12m and 10m in 18 countries worldwide Each beacon transmits for 10 seconds – so in 3 minutes you can assess worldwide openings on a band Each beacon transmits for 10 seconds – so in 3 minutes you can assess worldwide openings on a band for details for details

Kamloops ARC Nov 2015 K9LA Use Real-Time Spots Select LF-HF or VHF & up Select LF-HF or VHF & up Select band Select band Select geographical area Select geographical area Spots are shown for the designated time period Spots are shown for the designated time period from

Kamloops ARC Nov 2015 K9LA Modes of Propagation Most of our HF QSOs are made via the true great circle short path Most of our HF QSOs are made via the true great circle short path Other HF propagation modes exist Other HF propagation modes exist Long pathLong path Skewed pathSkewed path Scatter path (implies loss = weak signal)Scatter path (implies loss = weak signal) Path could be via F region, E region, E s region, auroral ionization, equatorial ionization (TEP), etc Path could be via F region, E region, E s region, auroral ionization, equatorial ionization (TEP), etc

Kamloops ARC Nov 2015 K9LA Noise Usually a problem on the lower bands (160m and 80m) Usually a problem on the lower bands (160m and 80m) Two categories Two categories Man-madeMan-made AtmosphericAtmospheric Mitigation for Mitigation for Man-made noise – check your house and neighbor’s house, work with power companyMan-made noise – check your house and neighbor’s house, work with power company Atmospheric noise – use low-noise receive antennasAtmospheric noise – use low-noise receive antennas

Kamloops ARC Nov 2015 K9LA Disturbances to Propagation

Kamloops ARC Nov 2015 K9LA Disturbances – The Big Picture Worst is geomagnetic storm – several days to a week Worst is geomagnetic storm – several days to a week Caused by CME or coronal holeCaused by CME or coronal hole Solar radiation storm – couple days Solar radiation storm – couple days Radio blackout – couple hours Radio blackout – couple hours both caused by big solar flare

Kamloops ARC Nov 2015 K9LA Solar Flares Emit lots of radiation at x-ray wavelengths (very short) Emit lots of radiation at x-ray wavelengths (very short) Biggest is X-Class Biggest is X-Class Next down is M-Class Next down is M-Class Next down is C-Class Next down is C-Class Least is B-Class Least is B-Class Visit explanation for details of disturbances to propagation Visit explanation for details of disturbances to propagation

Kamloops ARC Nov 2015 K9LA Summary The Sun radiates at many wavelengths The Sun radiates at many wavelengths nm is important for the ionosphere nm is important for the ionosphere Looks like we’re headed for some smaller solar cycles Looks like we’re headed for some smaller solar cycles How small is the questionHow small is the question Ionosphere varies significantly day-to-day Ionosphere varies significantly day-to-day Forces us to use a statistical modelForces us to use a statistical model Several ways to assess band conditions Several ways to assess band conditions Use them to help your operating habitsUse them to help your operating habits