Re: Topband: Bad 160m Conditions
Fabulous explanation - Thank you Frank! 73 Bob, KQ2M On 2023-01-09 01:27, Frank W3LPL wrote: There's some confusion about the effects of increasing solar activity on 160 meter DX propagation. 160 meter DX propagation is often badly affected by nighttime propagation degradations, especially as Solar Cycle 25 becomes much more active from now through solar maximum in about 2024-2025 and as it slowly declines to current ionization levels through about 2027-2028. Solar flares have no know impact on 160 meter DX propagation. Solar flares produce electromagnetic radiation that travels from sun to Earth at the speed of light - in about 8 minutes. Solar flare electromagnetic radiation (mostly X-rays) affects only the sunlit side of the earth and ionosphere. There are no known physical processes that extend solar flare effects into the night time ionosphere. While solar flares have no relevance to 160 meter DX propagation, solar flares often occur coincident with (but are not caused by) coronal mass ejections that can cause severe post-midnight absorption in the D region on propagation paths that cross the auroral oval (e.g., North America to northern Europe and Asia). CMEs cause the auroral oval to dip to much lower latitudes causing post-midnight increased D region absorption on propagation paths crossing lower latitudes. Unrelated to CMEs, coronal hole high speed stream effects also cause increased D region absorption in the post-midnight auroral oval and occur very frequently compared to geo-effective CMEs (thankfully most CMEs never strike the Earth or its magnetosphere, they usually miss our tiny planet). But what about 160 meter absorption usually present much earlier in the night, from sunset through midnight and later? The E region usually retains enough ionization to degrade 160 meter night time propagation especially during the more active years of the solar cycle. The ionized night time E region causes increased absorption at the bottom of the E region (just above the D region) and blankets propagation that would otherwise pass through the E region to the F region. Blanketing causes many shorter hops that suffer increased loss from multiple lossy passes through the ionized E region. 73 Frank W3LPL _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Bad 160m Conditions
There's some confusion about the effects of increasing solar activity on 160 meter DX propagation. 160 meter DX propagation is often badly affected by nighttime propagation degradations, especially as Solar Cycle 25 becomes much more active from now through solar maximum in about 2024-2025 and as it slowly declines to current ionization levels through about 2027-2028. Solar flares have no know impact on 160 meter DX propagation. Solar flares produce electromagnetic radiation that travels from sun to Earth at the speed of light - in about 8 minutes. Solar flare electromagnetic radiation (mostly X-rays) affects only the sunlit side of the earth and ionosphere. There are no known physical processes that extend solar flare effects into the night time ionosphere. While solar flares have no relevance to 160 meter DX propagation, solar flares often occur coincident with (but are not caused by) coronal mass ejections that can cause severe post-midnight absorption in the D region on propagation paths that cross the auroral oval (e.g., North America to northern Europe and Asia). CMEs cause the auroral oval to dip to much lower latitudes causing post-midnight increased D region absorption on propagation paths crossing lower latitudes. Unrelated to CMEs, coronal hole high speed stream effects also cause increased D region absorption in the post-midnight auroral oval and occur very frequently compared to geo-effective CMEs (thankfully most CMEs never strike the Earth or its magnetosphere, they usually miss our tiny planet). But what about 160 meter absorption usually present much earlier in the night, from sunset through midnight and later? The E region usually retains enough ionization to degrade 160 meter night time propagation especially during the more active years of the solar cycle. The ionized night time E region causes increased absorption at the bottom of the E region (just above the D region) and blankets propagation that would otherwise pass through the E region to the F region. Blanketing causes many shorter hops that suffer increased loss from multiple lossy passes through the ionized E region. 73 Frank W3LPL _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Bad 160m Conditions
Hi guys This kind of propagation is common on 160m for this part of the solar cycle, I'd taking notes about propagation since 2006, and 2012 to 2014, all notes are very bad propagation in January, like we are seeing now. However there was great DX along those years. DX expeditions are coming back and the fun with them. As Frank mentioned, nowadays the E layer blocks most of the signals on 160, but some times the same E layer have holes and create some ducts that can allow DX for long distances with very strong signals. That’s one of many reason 160m is unpredictable and we need to work very hard to get a new one. 73's N4IS JC _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Bad 160m Conditions
Bob and Dave, Solar flares are primarily X-ray events that affect 160 meter propagation only on the sun facing side of the earth. Geo-effective Fast Coronal Mass Ejections (CMEs) are by far the most damaging solar effects on 160 meter propagation. The majority of fast CMEs never impact the earth and its ionosphere. Strong geomagnetic storms are are the best indicators of geo-effective fast CMEs, those are storms that produce K indices of 5 or more. We've had very few of them so far in Cycle 25. But buckle your seat belts because they're coming this year and over at least the next five years I suspect we're experiencing the absorptive and F2 blanketing effects of increased E region ionization that often limits 160 meter propagation during periods when the solar flux index exceeds about 100 73 Frank W3LPL - Original Message - From: "Bob Shohet, KQ2M" To: "Dave Olean" Cc: "topband" Sent: Sunday, January 8, 2023 9:04:17 PM Subject: Re: Topband: Bad 160m Conditions On 2023-01-08 14:37, David Olean wrote: > All the flare action normally happens on the downslope of the cycle. Why do you say that? We had far more flares in 2022 than in 2021 and I expect more flaring in 2023 than 2022. And it is not just the frequency of the flaring that has increased, it is also the intensity of the flaring; 2022 had far more M class flares in 2022 than 2021 and 2022 also had the first X class flare, after many years of not having even one. And now we just had another X class flare only 8 days into 2023. There is almost always more flaring during the upside of the new cycle than during the bottom of the previous cycle and the flaring is almost always more intense. Frequency and intensity of flaring typically follows this order: 1) Downside of the cycle 2) Upside of the new cycle 3) Bottoming phase of the previous cycle Bob, KQ2M > Who knows what will happen then!! > > Roger, I am still trying to fix my 160 rx antennas > > > 73 > > Dave K1WHS > > On 1/8/2023 2:41 PM, STEVE MCDONALD wrote: >> >(in fact I don't even recall the Cycle affecting Top Band very >> much, unlike the higher bands. >> >> Roger, I somewhat agree that things do seem a little different this >> time as even HF is not reflecting what these high flux numbers should >> be doing. I may be wrong but this present run-up of the cycle seems to >> have much more flaring (sometimes 20-30 per day) than previous cycles >> have had and these can really disrupt even HF propagation on the polar >> path. If we can see several days of a quiet undisturbed field things >> might improve for a bit. >> >> Steve 73 >> >> >> WEB - "The VE7SL Radio Notebook": http://qsl.net/ve7sl/ >> >> VE7SL BLOG - "Homebrewing and Operating Adventures From 2200m to >> Nanowaves": >> http://ve7sl.blogspot.ca/ >> _ >> Searchable Archives: http://www.contesting.com/_topband - Topband >> Reflector > _ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Bad 160m Conditions
On 2023-01-08 14:37, David Olean wrote: All the flare action normally happens on the downslope of the cycle. Why do you say that? We had far more flares in 2022 than in 2021 and I expect more flaring in 2023 than 2022. And it is not just the frequency of the flaring that has increased, it is also the intensity of the flaring; 2022 had far more M class flares in 2022 than 2021 and 2022 also had the first X class flare, after many years of not having even one. And now we just had another X class flare only 8 days into 2023. There is almost always more flaring during the upside of the new cycle than during the bottom of the previous cycle and the flaring is almost always more intense. Frequency and intensity of flaring typically follows this order: 1) Downside of the cycle 2) Upside of the new cycle 3) Bottoming phase of the previous cycle Bob, KQ2M Who knows what will happen then!! Roger, I am still trying to fix my 160 rx antennas 73 Dave K1WHS On 1/8/2023 2:41 PM, STEVE MCDONALD wrote: >(in fact I don't even recall the Cycle affecting Top Band very much, unlike the higher bands. Roger, I somewhat agree that things do seem a little different this time as even HF is not reflecting what these high flux numbers should be doing. I may be wrong but this present run-up of the cycle seems to have much more flaring (sometimes 20-30 per day) than previous cycles have had and these can really disrupt even HF propagation on the polar path. If we can see several days of a quiet undisturbed field things might improve for a bit. Steve 73 WEB - "The VE7SL Radio Notebook": http://qsl.net/ve7sl/ VE7SL BLOG - "Homebrewing and Operating Adventures From 2200m to Nanowaves": http://ve7sl.blogspot.ca/ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Bad 160m Conditions
All the flare action normally happens on the downslope of the cycle. Who knows what will happen then!! Roger, I am still trying to fix my 160 rx antennas 73 Dave K1WHS On 1/8/2023 2:41 PM, STEVE MCDONALD wrote: >(in fact I don't even recall the Cycle affecting Top Band very much, unlike the higher bands. Roger, I somewhat agree that things do seem a little different this time as even HF is not reflecting what these high flux numbers should be doing. I may be wrong but this present run-up of the cycle seems to have much more flaring (sometimes 20-30 per day) than previous cycles have had and these can really disrupt even HF propagation on the polar path. If we can see several days of a quiet undisturbed field things might improve for a bit. Steve 73 WEB - "The VE7SL Radio Notebook": http://qsl.net/ve7sl/ VE7SL BLOG - "Homebrewing and Operating Adventures From 2200m to Nanowaves": http://ve7sl.blogspot.ca/ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Bad 160m Conditions
>(in fact I don't even recall the Cycle affecting Top Band very much, unlike >the higher bands. Roger, I somewhat agree that things do seem a little different this time as even HF is not reflecting what these high flux numbers should be doing. I may be wrong but this present run-up of the cycle seems to have much more flaring (sometimes 20-30 per day) than previous cycles have had and these can really disrupt even HF propagation on the polar path. If we can see several days of a quiet undisturbed field things might improve for a bit. Steve 73 WEB - "The VE7SL Radio Notebook": http://qsl.net/ve7sl/ VE7SL BLOG - "Homebrewing and Operating Adventures From 2200m to Nanowaves": http://ve7sl.blogspot.ca/ _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Bad 160m Conditions
Thanks for that Bob (I must confess that I've never really been into understanding all the technical factors that affect propagation) But the thing is that I've been DX-ing on 160m for over 50 years . . . and never known it be so poor for so long, at any point in the Solar Cycle. (in fact I don't even recall the Cycle affecting Top Band very much, unlike the higher bands) Roger G3YRO _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Re: Topband: Bad 160m Conditions
Hi Roger, We currently have a combination of elevated A and K indices, an X class flare within the past 24 hours and we are 2 years into Cycle 25 with higher levels of SFI, SSN and absorption. Disappointing propagation for on 160 sure but none of this should be a surprise since it happens every solar cycle. Here in W1, there was a decent opening to JA on 160 three mornings ago when the K was 0 and A was 4 and there have been good openings on JA on 80 on several mornings as well when the K=0 or K=1. Any morning with K = 2 or greater and 160 is mediocre to poor; very similar with 80. 73 Bob, KQ2M On 2023-01-08 11:01, Roger Kennedy wrote: I wonder why DX propagation continues to be so bad? Certainly across the pond from Europe, signals are still at least 20dB below normal . . I've never known it be so poor for so long Roger G3YRO _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
Topband: Bad 160m Conditions
I wonder why DX propagation continues to be so bad? Certainly across the pond from Europe, signals are still at least 20dB below normal . . I've never known it be so poor for so long Roger G3YRO _ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
