Propagation Forecast
Propagation conditions during July have been fairly calm, especially from the 25th with the A index at 5 and the K index at 2. After a slight fluctuation on the 1st August, conditions will remain the same until the 7th when there will be another disturbance which will last until the 14th and will peak on the 8th with the A index at 20 and the K index at 5. Things will then remain calm until the 10th August with the A index rising to 10 and the K index to 3. The worst days will be 7th to the 12th and also the 18th.
The solar flux however will remain at 2 during the first week in August, rising to 5 by the 8th and settling back to 3 by the 18th. (http://www.wm7d.net)
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is generally poor to fair. (www.dxlc.com)
Solar Cycle 24 Prediction
June 27, 2008 During the annual Space Weather Workshop held in Boulder, CO in May, 2008, the Solar Cycle 24 Prediction Panel released an update to the prediction for the next solar cycle. In short, the update is that the panel has not yet made any changes to the prediction issued in April, 2007. The panel predicted solar minimum to occur in March, 2008. The panel expects the solar cycle to reach a peak sunspot number of 140 in October, 2011 or a peak of 90 in August, 2012.
The 2008 Perseid Meteor Shower 12th August.
"Peaking on August 12th, it should be a good show. "The time to look is during the dark hours before dawn on Tuesday, August 12th," says Bill Cooke of NASA's Meteoroid Environment Office at the Marshall Space Flight Center. "There should be plenty of meteors--perhaps one or two every minute.
The source of the shower is Comet Swift-Tuttle. Although the comet is far away, currently located beyond the orbit of Uranus, a trail of debris from the comet stretches all the way back to Earth.
Crossing the trail in August, Earth will be pelted by specks of comet dust hitting the atmosphere at 132,000 mph. At that speed, even a flimsy speck of dust makes a vivid streak of light when it disintegrates--a meteor! Because, Swift-Tuttle's meteors streak out of the constellation Perseus, they are called "Perseids.
Serious meteor hunters will begin their watch early, on Monday evening, August 11th, around 9 pm when Perseus first rises in the northeast. This is the time to look for Perseid Earthgrazers--meteors that approach from the horizon and skim the atmosphere overhead like a stone skipping across the surface of a pond." (NASA Science News http://science.nasa.gov/headlines/ )
Thanks to Ken Fletcher and Mike Terry for regular updates. Links can be found on my web page.
Saturday, 26 July 2008
Thursday, 19 June 2008
July 2008
Propagation Forecast
The second half of June will have seen 2 minor disturbances. On the 19th and 20th. The A index was at 10 and the K at 3, returning to ‘normal’ by the 21st with the A index at 5 and the K index at 2, until the 25th to the 27th with the A index peaking at 10 on the 26th. ‘Normal ‘ conditions will prevail until July 3rd to the 5th, with the A index again peaking at 10 on the 4th July. Things will remain ‘normal until 11th July with another disturbance until at least the 14th, the worst day being the 12th, with the A index peaking at 15 and the K index at 4.
Sunspots and Global Warming
The Spórer minimum (1420-1570) The Maunder minimum (1745-1615), and the Dalton Minimum (1790 to 1830) have coincided with a time when Earth’s climate was colder than average. The correlation has generated hypotheses that low solar activity produces cooler than average global temperatures, though a specific mechanism by which solar activity results in climate change has not been established.
Like the subsequent Maunder Minimum, the Spörer Minimum coincided with a time when Earth's climate was colder than average. This correlation has generated hypotheses that low solar activity produces cooler than average global temperatures, though a specific mechanism by which solar activity results in climate change has not been established.
Here is an interesting article in the Belfast Telegraph by Dr David Whitehouse (12 May 2007):
Can the Sun Save Us from Global Warming? (Low Sunspot Activity)
"Something is happening to our Sun. It has to do with sunspots, or rather the activity cycle their coming and going signifies. After a period of exceptionally high activity in the 20th century, our Sun has suddenly gone exceptionally quiet. Months have passed with no spots visible on its disc.
We are at the end of one cycle of activity and astronomers are waiting for the sunspots to return and mark the start of the next, the so-called cycle 24. They have been waiting for a while now with no sign it's on its way any time soon.
Sunspots – dark magnetic blotches on the Sun's surface – come and go in a roughly 11-year cycle of activity first noticed in 1843. It's related to the motion of super-hot, electrically charged gas inside the Sun – a kind of internal conveyor belt where vast sub-surface rivers of gas take 40 years to circulate from the equator to the poles and back. Somehow, in a way not very well understood, this circulation produces the sunspot cycle in which every 11 years there is a sunspot maximum followed by a minimum. But recently the Sun's internal circulation has been failing. In May 2006 this conveyor belt had slowed to a crawl – a record low. Nasa scientist David Hathaway said: "It's off the bottom of the charts... this has important repercussions for future solar activity." What's more, it's not the only indicator that the Sun is up to something.
Astronomers called it the "Maunder Minimum." It was an astonishing discovery: our Sun can change. Between 1645 and 1715 sunspots were rare. About 50 were observed; there should have been 50,000.
Ever since the sunspot cycle was discovered, researchers have looked for its rhythm superimposed on the Earth's climate. In some cases it's there but usually at low levels. But there was something strange about the time when the sunspots disappeared that left scientists to ponder if the sun's unusual behaviour could have something to do with the fact that the 17th century was also a time when the Earth's northern hemisphere chilled with devastating consequences."
THE SUN'S CHILLY IMPACT ON EARTH
A new NASA computer climate model reinforces the long-standing theory that low solar activity could have changed the atmospheric circulation in the Northern Hemisphere from the 1400s to the 1700s and triggered a "Little Ice Age" in several regions including North America and Europe. Changes in the sun's energy was one of the biggest factors influencing climate change during this period, but have since been superceded by greenhouse gases due to the industrial revolution. (NASA News).
(Thanks to Ken Fletcher and Mike Terry for regular updates). Links to the full articles are on my website. http://www.jameswelsh.org.uk
The second half of June will have seen 2 minor disturbances. On the 19th and 20th. The A index was at 10 and the K at 3, returning to ‘normal’ by the 21st with the A index at 5 and the K index at 2, until the 25th to the 27th with the A index peaking at 10 on the 26th. ‘Normal ‘ conditions will prevail until July 3rd to the 5th, with the A index again peaking at 10 on the 4th July. Things will remain ‘normal until 11th July with another disturbance until at least the 14th, the worst day being the 12th, with the A index peaking at 15 and the K index at 4.
Sunspots and Global Warming
The Spórer minimum (1420-1570) The Maunder minimum (1745-1615), and the Dalton Minimum (1790 to 1830) have coincided with a time when Earth’s climate was colder than average. The correlation has generated hypotheses that low solar activity produces cooler than average global temperatures, though a specific mechanism by which solar activity results in climate change has not been established.
Like the subsequent Maunder Minimum, the Spörer Minimum coincided with a time when Earth's climate was colder than average. This correlation has generated hypotheses that low solar activity produces cooler than average global temperatures, though a specific mechanism by which solar activity results in climate change has not been established.
Here is an interesting article in the Belfast Telegraph by Dr David Whitehouse (12 May 2007):
Can the Sun Save Us from Global Warming? (Low Sunspot Activity)
"Something is happening to our Sun. It has to do with sunspots, or rather the activity cycle their coming and going signifies. After a period of exceptionally high activity in the 20th century, our Sun has suddenly gone exceptionally quiet. Months have passed with no spots visible on its disc.
We are at the end of one cycle of activity and astronomers are waiting for the sunspots to return and mark the start of the next, the so-called cycle 24. They have been waiting for a while now with no sign it's on its way any time soon.
Sunspots – dark magnetic blotches on the Sun's surface – come and go in a roughly 11-year cycle of activity first noticed in 1843. It's related to the motion of super-hot, electrically charged gas inside the Sun – a kind of internal conveyor belt where vast sub-surface rivers of gas take 40 years to circulate from the equator to the poles and back. Somehow, in a way not very well understood, this circulation produces the sunspot cycle in which every 11 years there is a sunspot maximum followed by a minimum. But recently the Sun's internal circulation has been failing. In May 2006 this conveyor belt had slowed to a crawl – a record low. Nasa scientist David Hathaway said: "It's off the bottom of the charts... this has important repercussions for future solar activity." What's more, it's not the only indicator that the Sun is up to something.
Astronomers called it the "Maunder Minimum." It was an astonishing discovery: our Sun can change. Between 1645 and 1715 sunspots were rare. About 50 were observed; there should have been 50,000.
Ever since the sunspot cycle was discovered, researchers have looked for its rhythm superimposed on the Earth's climate. In some cases it's there but usually at low levels. But there was something strange about the time when the sunspots disappeared that left scientists to ponder if the sun's unusual behaviour could have something to do with the fact that the 17th century was also a time when the Earth's northern hemisphere chilled with devastating consequences."
THE SUN'S CHILLY IMPACT ON EARTH
A new NASA computer climate model reinforces the long-standing theory that low solar activity could have changed the atmospheric circulation in the Northern Hemisphere from the 1400s to the 1700s and triggered a "Little Ice Age" in several regions including North America and Europe. Changes in the sun's energy was one of the biggest factors influencing climate change during this period, but have since been superceded by greenhouse gases due to the industrial revolution. (NASA News).
(Thanks to Ken Fletcher and Mike Terry for regular updates). Links to the full articles are on my website. http://www.jameswelsh.org.uk
Thursday, 22 May 2008
June 2008
Propagation Summary
A recurrent coronal hole (CH327) was in an Earth facing position on May 18-19. Another recurrent coronal hole (CH328) rotated into an Earth facing position on May 23-25.
Following a disturbance around 21st May, with the A index at 25, and the K at 5, conditions will have settled down by 23rd May, with the A index at 10 and the K at 3 where it will remain until May 31st with the A rising to 10 and the K index remaining at 3 until 3rd June when the A will drop to 5 and the K to 2.
The Solar Flux, however will drop from 72 to 68 by 25th May until 9th June when it will rise to 70. This is then followed by another rise to 72 by the 12th where it will remain until at least the 16th.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is fair.
(From WWM7D.com, NOAA and www.dxlc.com/solar).
The Ionosphere
Scientists call the ionosphere an extension or a part of the thermosphere. So technically, the ionosphere is not another atmospheric layer, but a region of the atmosphere. The ionosphere represents less than 0.1% of the total mass of the Earth's atmosphere. Even so, it is extremely important!
The upper atmosphere is ionized by solar radiation. Under normal conditions free electrons and ions tend to recombine and a balance is established between electron and ion production and loss.
Ionization processes release energy, which heat up the upper atmosphere. So temperature increases with height in the ionosphere region to the extent that by 150-200km, the Earth's atmosphere is extremely hot compared to surface temperatures.
Different regions of the ionosphere make long distance radio communication possible by reflecting the radio waves back to Earth. It is also home to auroras and the mega-ampere currents that heat the atmosphere at high latitudes during geomagnetically active times. During storms, depletions and enhancements of ionization occur depending on the local time and geographical location.
Aeronomy is a term of recent origin, which is applied to the processes, both physical and chemical, of the ionosphere. From http://www.windows.ucar.edu/ (University Of Michigan)
HF Propagation Predictions For 2008
Here is an interesting website by G4FKH, which has a monthly chart of predicted HF conditions listed by capital cities: http://uk.geocities.com/g4fkh@btinternet.com/
See also: http://www.hfradio.org/propagation.html
The New Shortwave Propagation Handbook (Paperback) - by George Jacobs, Theodore J. Cohen, R. B. Rose. The NEW Shortwave Progagation Handbook may well be the only book you'll need on the subject of ionospheric propagation! It is a "must read" for Radio Amateurs, Shortwave Listeners, and radio communicators of any type who need to make the most productive use of the radio spectrum, regardless of the time of day, the season of the year, or the state of the sunspot cycle. It will become your ever-present companion the operating table as you master the art of shortwave radio progagation. (Available from Amazon.com posted from the USA)
Thanks to KF and MET for regular updates.
A recurrent coronal hole (CH327) was in an Earth facing position on May 18-19. Another recurrent coronal hole (CH328) rotated into an Earth facing position on May 23-25.
Following a disturbance around 21st May, with the A index at 25, and the K at 5, conditions will have settled down by 23rd May, with the A index at 10 and the K at 3 where it will remain until May 31st with the A rising to 10 and the K index remaining at 3 until 3rd June when the A will drop to 5 and the K to 2.
The Solar Flux, however will drop from 72 to 68 by 25th May until 9th June when it will rise to 70. This is then followed by another rise to 72 by the 12th where it will remain until at least the 16th.
Long distance low and medium frequency (below 2 MHz) propagation along paths north of due west over high and upper middle latitudes is poor. Propagation on long distance northeast-southwest paths is fair.
(From WWM7D.com, NOAA and www.dxlc.com/solar).
The Ionosphere
Scientists call the ionosphere an extension or a part of the thermosphere. So technically, the ionosphere is not another atmospheric layer, but a region of the atmosphere. The ionosphere represents less than 0.1% of the total mass of the Earth's atmosphere. Even so, it is extremely important!
The upper atmosphere is ionized by solar radiation. Under normal conditions free electrons and ions tend to recombine and a balance is established between electron and ion production and loss.
Ionization processes release energy, which heat up the upper atmosphere. So temperature increases with height in the ionosphere region to the extent that by 150-200km, the Earth's atmosphere is extremely hot compared to surface temperatures.
Different regions of the ionosphere make long distance radio communication possible by reflecting the radio waves back to Earth. It is also home to auroras and the mega-ampere currents that heat the atmosphere at high latitudes during geomagnetically active times. During storms, depletions and enhancements of ionization occur depending on the local time and geographical location.
Aeronomy is a term of recent origin, which is applied to the processes, both physical and chemical, of the ionosphere. From http://www.windows.ucar.edu/ (University Of Michigan)
HF Propagation Predictions For 2008
Here is an interesting website by G4FKH, which has a monthly chart of predicted HF conditions listed by capital cities: http://uk.geocities.com/g4fkh@btinternet.com/
See also: http://www.hfradio.org/propagation.html
The New Shortwave Propagation Handbook (Paperback) - by George Jacobs, Theodore J. Cohen, R. B. Rose. The NEW Shortwave Progagation Handbook may well be the only book you'll need on the subject of ionospheric propagation! It is a "must read" for Radio Amateurs, Shortwave Listeners, and radio communicators of any type who need to make the most productive use of the radio spectrum, regardless of the time of day, the season of the year, or the state of the sunspot cycle. It will become your ever-present companion the operating table as you master the art of shortwave radio progagation. (Available from Amazon.com posted from the USA)
Thanks to KF and MET for regular updates.
Friday, 2 May 2008
Propagation Report May 2008
Propagation Forecast
The last week in April has been quite stable following a minor disturbance on the 23rd apparently caused by a coronal hole. Details at: http://www.dxlc.com/solar/
From 27th to the 30th, the index has remained at 5 and the K at 2. The first week in May will be quite disturbed. On the 2nd May, the A index will peak at 20 and the K at 5, then by the 8th May, conditions will settle with the A index at 5 and the K index at 2 until May19th when conditions are likely to deteriorate with the A index rising to 10 and the K index to 3. The solar flux has a downward trend remaining at 75 for the last week in April, then dropping to 70 by 2nd May where it will remain till the 19th May when it again rises to 75.
(Via wm7d.net)
Propagation explained:
The Ionosphere: A collection of ionized particles and electrons in the uppermost portion of the earth's atmosphere which is formed by the interaction of the solar wind with the very thin air particles that have escaped the earth's gravity. These ions are responsible for the reflection or bending of radio waves occurring between certain critical frequencies with these critical frequencies varying with the degree of ionization. As a result, radio waves having frequencies higher the lowest usable frequency (LUF) but lower than the maximum usable frequency (MUF) are propagated over large distances.
D-Layer:
The lowest part of the ionosphere, the D-layer appears at an altitude of 50-95km. This layer has a negative effect on radio waves because it only absorbs radio-energy, particularly those frequencies below 7MHz. It develops shortly after sunrise and disappears shortly after sunset. This layer reaches maximum ionization when the sun is at its highest point in the sky and this layer is also responsible the complete absorption of sky waves from the 80m and 160m amateur bands as well as the AM broadcast band during the daytime hours.
E-layer:
This part of the ionosphere is located just above the D-layer at an altitude of 90-150km. This layer can only reflect radio waves having frequencies less than 5MHz. It has a negative effect on frequencies above 5MHz due to the partial absorption of these higher frequency radio waves. The E-layer develops shortly after sunrise and it disappears a few hours after sunset. The maximum ionization of this layer is reached around midday and the ions in this layer are mainly O2+.
F-layer:
Highest part of the ionosphere. The F-layer appears a few hours after sunset, when the F1- and F2-layers merge. The F-layer is located between 250km and 500km in altitude. Even well into the night, this layer may reflect radio waves up to 20 MHZ, and occasionally even up to 25 MHZ. Ions in the lower part of the F-layer are mainly NO+ and are predominantly O+ in the upper part.
Thanks to Mike Terry and Ken Fletcher for regular updates.
The last week in April has been quite stable following a minor disturbance on the 23rd apparently caused by a coronal hole. Details at: http://www.dxlc.com/solar/
From 27th to the 30th, the index has remained at 5 and the K at 2. The first week in May will be quite disturbed. On the 2nd May, the A index will peak at 20 and the K at 5, then by the 8th May, conditions will settle with the A index at 5 and the K index at 2 until May19th when conditions are likely to deteriorate with the A index rising to 10 and the K index to 3. The solar flux has a downward trend remaining at 75 for the last week in April, then dropping to 70 by 2nd May where it will remain till the 19th May when it again rises to 75.
(Via wm7d.net)
Propagation explained:
The Ionosphere: A collection of ionized particles and electrons in the uppermost portion of the earth's atmosphere which is formed by the interaction of the solar wind with the very thin air particles that have escaped the earth's gravity. These ions are responsible for the reflection or bending of radio waves occurring between certain critical frequencies with these critical frequencies varying with the degree of ionization. As a result, radio waves having frequencies higher the lowest usable frequency (LUF) but lower than the maximum usable frequency (MUF) are propagated over large distances.
D-Layer:
The lowest part of the ionosphere, the D-layer appears at an altitude of 50-95km. This layer has a negative effect on radio waves because it only absorbs radio-energy, particularly those frequencies below 7MHz. It develops shortly after sunrise and disappears shortly after sunset. This layer reaches maximum ionization when the sun is at its highest point in the sky and this layer is also responsible the complete absorption of sky waves from the 80m and 160m amateur bands as well as the AM broadcast band during the daytime hours.
E-layer:
This part of the ionosphere is located just above the D-layer at an altitude of 90-150km. This layer can only reflect radio waves having frequencies less than 5MHz. It has a negative effect on frequencies above 5MHz due to the partial absorption of these higher frequency radio waves. The E-layer develops shortly after sunrise and it disappears a few hours after sunset. The maximum ionization of this layer is reached around midday and the ions in this layer are mainly O2+.
F-layer:
Highest part of the ionosphere. The F-layer appears a few hours after sunset, when the F1- and F2-layers merge. The F-layer is located between 250km and 500km in altitude. Even well into the night, this layer may reflect radio waves up to 20 MHZ, and occasionally even up to 25 MHZ. Ions in the lower part of the F-layer are mainly NO+ and are predominantly O+ in the upper part.
Thanks to Mike Terry and Ken Fletcher for regular updates.
Saturday, 22 March 2008
Propagation Report April 2008
Propagation Forecast
The Solar flux has remained at a steady 70 throughout March and this should continue until at least mid-April. However, the A and K Index are a different story. Over the Easter weekend, the A Index has remained at 5 and the K Index at 2. There will have been a serious disturbance of HF reception from 25th to the 29th March with the K Index rising to 5. The worst day of March being the 27th, with the A Index also peaking at 25. This is due to a coronal hole rotating into an earth-facing position, and pointing towards the Council Estate on March 23rd. The next disturbance will be from 4th to 11th April peaking on the 7th, with the A Index at 25, and the K Index at 5. Regularly updated Solar Terrestrial Activity Reports and forecasts, plus regional and frequency specific information can be found at: http://www.dxlc.com/solar/
Coronal Stream Activity
Coronal Streams are responsible for the recent disturbances. They are streams of charged particles originating from the sun's corona. Coronal streams have similar effects as CME's (Coronal Mass Ejections) by increasing the A- and K-indices but usually to a lesser extent. However, a few coronal holes may cause major storm levels at the higher latitudes on earth resulting in total propagation fade-out at these latitudes.
IMO Meteor Shower Calendar 2008.
The International Meteor Organisation has an online Meteor Shower Calendar for 2008, which includes a detailed summary for the year. The web address is:
http:// www.imo.net/calendar/2008
Solar Cycle 24
The Solar flux readings indicate that we are still awaiting some activity for Solar Cycle 24. Daily reports and the latest SOHO (the Solar and Heliospheric Observatory) images can be found at: http://www.solarcycle24.com or you can find out more about SOHO at: http://sohowww.nascom.nasa.gov/ Space weather alerts can also be found at: http://www.swpc.noaa.gov/alerts
This month’s links and more can be found at: http://www.jameswelsh.co.nr
The Solar flux has remained at a steady 70 throughout March and this should continue until at least mid-April. However, the A and K Index are a different story. Over the Easter weekend, the A Index has remained at 5 and the K Index at 2. There will have been a serious disturbance of HF reception from 25th to the 29th March with the K Index rising to 5. The worst day of March being the 27th, with the A Index also peaking at 25. This is due to a coronal hole rotating into an earth-facing position, and pointing towards the Council Estate on March 23rd. The next disturbance will be from 4th to 11th April peaking on the 7th, with the A Index at 25, and the K Index at 5. Regularly updated Solar Terrestrial Activity Reports and forecasts, plus regional and frequency specific information can be found at: http://www.dxlc.com/solar/
Coronal Stream Activity
Coronal Streams are responsible for the recent disturbances. They are streams of charged particles originating from the sun's corona. Coronal streams have similar effects as CME's (Coronal Mass Ejections) by increasing the A- and K-indices but usually to a lesser extent. However, a few coronal holes may cause major storm levels at the higher latitudes on earth resulting in total propagation fade-out at these latitudes.
IMO Meteor Shower Calendar 2008.
The International Meteor Organisation has an online Meteor Shower Calendar for 2008, which includes a detailed summary for the year. The web address is:
http:// www.imo.net/calendar/2008
Solar Cycle 24
The Solar flux readings indicate that we are still awaiting some activity for Solar Cycle 24. Daily reports and the latest SOHO (the Solar and Heliospheric Observatory) images can be found at: http://www.solarcycle24.com or you can find out more about SOHO at: http://sohowww.nascom.nasa.gov/ Space weather alerts can also be found at: http://www.swpc.noaa.gov/alerts
This month’s links and more can be found at: http://www.jameswelsh.co.nr
Saturday, 23 February 2008
Propagation Report March 2008
During the second half of February, the Solar flux has remained at a constant 72, and is likely to remain the same until at least 17th March, which would suggest that we may at last have reached sunspot minimum at the start of Solar Cycle 24.
The A index rose to 12 on February 21st, and dropped back to 5 the next day. The next disturbance will be on Feb 28th, to March 3rd with the index at 15 and the K at 4 followed by another disturbance 8-13th with the A index peaking at 15 on the 8th and 9th. The A index will then rise again to 10 by the 16th for at least 2 days.
In conclusion, the best days for HF reception will be March 4th 5th 14th and 15th with the A index at 5 and the K index at 2, the worst days being the 1st, 8th 9th and 15th.
The National Oceanic and Atmospheric Administration and the US Air Force have predicted the solar flux to remain at 72 from March 1st continuing into April. (From: www.arrl.org)
Maunder Minimum?
It has been suggested that we may be entering another Maunder Minimum, which is the name given to the period roughly from 1645 to 1715, when sunspots became exceedingly rare, as noted by solar observers of the time. It is named after the solar astronomer Edward W. Maunder (1851–1928) who discovered the dearth of sunspots during that period by studying records from those years. During one 30-year period within the Maunder Minimum, for example, astronomers observed only about 50 sunspots, as opposed to a more typical 40,000–50,000 spots. See: http://en.wikipedia.org/wiki/Maunder_minimum
However, Tad Cooke of ARRL, after seeking the opinion of Dr. Kenneth Tapping of the Herzberg Institute of Astrophysics in Penticton, British Columbia recently wrote:
"I think we can relax about any possible upcoming 70-year period of a quiet Sun. We cannot say that it could not happen, but in fact there is nothing unusual about the current Solar Cycle minimum, and really no known method of predicting such a period."
Thanks to Mike Terry and Ken Fletcher for regular updates. Related links can be found at www.jameswelsh.co.nr.
The A index rose to 12 on February 21st, and dropped back to 5 the next day. The next disturbance will be on Feb 28th, to March 3rd with the index at 15 and the K at 4 followed by another disturbance 8-13th with the A index peaking at 15 on the 8th and 9th. The A index will then rise again to 10 by the 16th for at least 2 days.
In conclusion, the best days for HF reception will be March 4th 5th 14th and 15th with the A index at 5 and the K index at 2, the worst days being the 1st, 8th 9th and 15th.
The National Oceanic and Atmospheric Administration and the US Air Force have predicted the solar flux to remain at 72 from March 1st continuing into April. (From: www.arrl.org)
Maunder Minimum?
It has been suggested that we may be entering another Maunder Minimum, which is the name given to the period roughly from 1645 to 1715, when sunspots became exceedingly rare, as noted by solar observers of the time. It is named after the solar astronomer Edward W. Maunder (1851–1928) who discovered the dearth of sunspots during that period by studying records from those years. During one 30-year period within the Maunder Minimum, for example, astronomers observed only about 50 sunspots, as opposed to a more typical 40,000–50,000 spots. See: http://en.wikipedia.org/wiki/Maunder_minimum
However, Tad Cooke of ARRL, after seeking the opinion of Dr. Kenneth Tapping of the Herzberg Institute of Astrophysics in Penticton, British Columbia recently wrote:
"I think we can relax about any possible upcoming 70-year period of a quiet Sun. We cannot say that it could not happen, but in fact there is nothing unusual about the current Solar Cycle minimum, and really no known method of predicting such a period."
Thanks to Mike Terry and Ken Fletcher for regular updates. Related links can be found at www.jameswelsh.co.nr.
Tuesday, 5 February 2008
Propagation February 2008
Propagation Forecast
The second half of January has remained calm with but February will start off disturbed with the A index at 15, and the K at 4. By the 5th Feb, the A will have dropped to 5, and the K to 2, remaining calm until the 9th, when the A index rises to 15 and the K index to 4. By February 14th, conditions will have settled down again, with the A index at 5 and the K at 2, remaining the same until at least the 18th.
The Solar Flux however, is on a downward trend for February, starting off at 80, then dropping to 75 by the 4th and again dropping to 70 by the 14th. In conclusion, HF reception conditions for February should start off disturbed till the 4th, remaining calm till the 8th. The 9th to the 13th will again be disturbed then conditions should remain calm from the 14th. (Based on the 28 day forecast From WM7D.net)
Solar Cycle 23 VS Solar Cycle 24
There is still much debate among the experts about the emergence of Solar Cycle 24. According to this article from ARRL, (http://www.arrl.org/news/stories/2008/01/18/100/) "Old Cycle 23 spots will appear near the Sun's equator. The first spots of Cycle 24 are at a high solar latitude and will have magnetic polarity opposite of the old spots. There was a brief appearance on January 11 by an "almost sunspot" that had disappeared by the following day; it appeared to be a Cycle 24 spot -- with polarity reversed from Cycle 23 spots -- but it was near the equator, which is the wrong place for a new cycle sunspot."
However, looking at the sunspot number chart on http://www.solarcycle24.com/indexdx.htm sunspot numbers have definitely been on a downward trend. April 2006 had the highest sunspot number of 105, compared with April 07 when it was down to 38. It then peaked at 63 in June 07, and has again been on a downward trend remaining at 15 in October and November 07. Then December '07, saw a significant rise to 44.
Propagation Websites.
‘The Basics Of Radio Wave Propagation’ by Edwin C. Jones, MD, PhD (AE4TM) covers the subjects of Aurora, Backscatter and Grey Line propagation and related subjects, plus Maximum User Frequencies etc. The URL is: http://ecjones.org/propag.html. The XE1BEF website has a comprehensive links page of propagation software and specialist websites, although their bulletin is not currently available in English. http://members.fortunecity.com/xe1bef/propagation.htm. Thanks to Mike Terry and Ken Fletcher for links and updates. Links from this article can be found at http://www.jameswelsh.co.nr/
The second half of January has remained calm with but February will start off disturbed with the A index at 15, and the K at 4. By the 5th Feb, the A will have dropped to 5, and the K to 2, remaining calm until the 9th, when the A index rises to 15 and the K index to 4. By February 14th, conditions will have settled down again, with the A index at 5 and the K at 2, remaining the same until at least the 18th.
The Solar Flux however, is on a downward trend for February, starting off at 80, then dropping to 75 by the 4th and again dropping to 70 by the 14th. In conclusion, HF reception conditions for February should start off disturbed till the 4th, remaining calm till the 8th. The 9th to the 13th will again be disturbed then conditions should remain calm from the 14th. (Based on the 28 day forecast From WM7D.net)
Solar Cycle 23 VS Solar Cycle 24
There is still much debate among the experts about the emergence of Solar Cycle 24. According to this article from ARRL, (http://www.arrl.org/news/stories/2008/01/18/100/) "Old Cycle 23 spots will appear near the Sun's equator. The first spots of Cycle 24 are at a high solar latitude and will have magnetic polarity opposite of the old spots. There was a brief appearance on January 11 by an "almost sunspot" that had disappeared by the following day; it appeared to be a Cycle 24 spot -- with polarity reversed from Cycle 23 spots -- but it was near the equator, which is the wrong place for a new cycle sunspot."
However, looking at the sunspot number chart on http://www.solarcycle24.com/indexdx.htm sunspot numbers have definitely been on a downward trend. April 2006 had the highest sunspot number of 105, compared with April 07 when it was down to 38. It then peaked at 63 in June 07, and has again been on a downward trend remaining at 15 in October and November 07. Then December '07, saw a significant rise to 44.
Propagation Websites.
‘The Basics Of Radio Wave Propagation’ by Edwin C. Jones, MD, PhD (AE4TM) covers the subjects of Aurora, Backscatter and Grey Line propagation and related subjects, plus Maximum User Frequencies etc. The URL is: http://ecjones.org/propag.html. The XE1BEF website has a comprehensive links page of propagation software and specialist websites, although their bulletin is not currently available in English. http://members.fortunecity.com/xe1bef/propagation.htm. Thanks to Mike Terry and Ken Fletcher for links and updates. Links from this article can be found at http://www.jameswelsh.co.nr/
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