Archive for the ‘hf’ Category
Weekly Propagation Summary – 2016 Sep 05 16:10 UTC
September 5th, 2016 | 
Author: 
Here is this week’s space weather and geophysical report, issued 2016 Sep 05 0405 UTC.
Highlights of Solar and Geomagnetic Activity 29 August – 04 September 2016
Solar activity was at low levels from 29-31 Aug. Regions 2583 (N13, L=025, class/area Dao/130 on 29 Aug) and 2585 (N08, L=222, class/area Ekc/590 on 03 Sep) were responsible for the C-class activity. Activity dropped to very low levels for the remainder of the period. No Earth-directed CMEs were observed.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit was at high levels on 29 Aug and 02-04 Sep due to CH HSS influence.
Geomagnetic field activity was at quiet to unsettled levels on 29-31 Aug with active conditions late on 30 Aug due to CH HSS effects. Mostly active to major storm conditions were observed on 01-03 Sep due to effects from an extension of the northern polar coronal hole. Active to minor storm levels prevailed on 04 Sep due to continued CH HSS effects.
Forecast of Solar and Geomagnetic Activity 05 September – 01 October 2016
Solar activity is expected to be at very low to low levels throughout the forecast period.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high to very high levels on 05-12 Sep due to CH HSS influence. Normal to moderate levels are expected from 13-20 Sep and 26-28 Sep. High levels are expected on 21-25 Sep and 29 Sep-01 Oct due to effects from anticipated recurrent CH HSS events.
Geomagnetic field activity is expected to be at unsettled to active levels on 05-06 Sep with minor storms expected early on 05 Sep as CH HSS effects continue. Quiet to unsettled conditions are expected on 07-08 Sep as effects begin to subside. Mostly quiet conditions are expected from 09-18 Sep with isolated unsettled periods likely on 13, 14 and 17 Sep due to weak recurrent CH HSS events. Quiet to unsettled levels are expected on 19-21 Sep with active periods possible on 19 Sep due to effects from a recurrent, negative polarity CH HSS. Mostly quiet conditions are expected from 22-25 Sep. Quiet to unsettled conditions are expected on 26-27 Sep followed by active to major storm levels from 26 Sep-01 Oct due to effects from the northern polar coronal hole extension.
Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/
Live Aurora mapping is at http://aurora.sunspotwatch.com/
If you are on Twitter, please follow these two users: + https://Twitter.com/NW7US + https://Twitter.com/hfradiospacewx
Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!
Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g
We’re on Facebook: http://NW7US.us/swhfr
Weekly Propagation Summary – 2016 Aug 29 16:10 UTC
Here is this week’s space weather and geophysical report, issued 2016 Aug 29 0520 UTC.
Highlights of Solar and Geomagnetic Activity 22 – 28 August 2016
Solar activity was at very low levels the majority of the period with low levels reached on 28 August due to an isolated C1/Sf flare at 28/2128 UTC from Region 2583 (N13, L=023, class/area Dao/030 on 28 Aug). Regions 2579 (N12, L=034, class/area Dao/090 on 23 Aug) and 2581 (N12, L=337, class/area Cao/110 on 28 Aug) were the largest spot groups on the visible disk, but were in a decay phase as of 24 and 28 August, respectively. No Earth-directed coronal mass ejections were observed during the period.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit was at normal levels on 22 August, moderate levels on 23-24 August, and high levels from 25-28 August. The maximum flux reached 2,334 pfu at 27/1705 UTC.
Geomagnetic field activity ranged from quiet to G1-minor storm levels during the period. The beginning of the period, solar wind conditions were nominal with solar wind speeds between 350 km/s and 420 km/s. The geomagnetic field was at quiet levels on 22 August. By 23 August, total field increased to around 14 nT with the solar wind speed increasing to around 550 km/s as a negative polarity coronal hole high speed stream (CH HSS) moved into geoeffective position. By midday on 24 August, total field had decreased to near 5 nT, however solar wind speeds remained elevated until late on 25 August when they began to decline. The geomagnetic field responded with quiet to G1-minor storm levels on 23-24 August, followed by quiet to unsettled conditions on 25-27 August. Quiet conditions were observed on 28 August under a nominal solar wind environment.
Forecast of Solar and Geomagnetic Activity 29 August – 24 September 2016
Solar activity is expected to be at very low to low levels throughout the period.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at normal to moderate levels with high levels expected on 31 August-12 September and again from 21-24 September due to recurrent CH HSS activity.
Geomagnetic field activity is expected to be at unsettled to active levels on 29 August-08 September, 13-14 September, 17 September, and 19-21 September with G1-minor storm levels likely on 29-30 August due to recurrent CH HSS activity.
Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/
Live Aurora mapping is at http://aurora.sunspotwatch.com/
If you are on Twitter, please follow these two users: + https://Twitter.com/NW7US + https://Twitter.com/hfradiospacewx
Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!
Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g
We’re on Facebook: http://NW7US.us/swhfr
Weekly Propagation Summary – 2016 Aug 22 16:10 UTC
Here is this week’s space weather and geophysical report, issued 2016 Aug 22 0524 UTC.
Highlights of Solar and Geomagnetic Activity 15 – 21 August 2016
Solar activity was at low levels on 15 August due to an isolated C1 flare at 15/0023 UTC from Region 2578 (N09, L=084, class/area Cro/020 on 18 Aug). Very low levels were observed from 16-21 August. Although Regions 2574 (N05, L=173, class/area Dho/290 on 09 Aug), 2576 (S15, L=160, class/area Hsx/140 on 10 Aug), 2577 (N03, L=164, class/area Dso/130 on 12 Aug), and 2578 were on the visible disk during the period, the regions appeared to be in slow decay. No Earth-directed coronal mass ejections were observed.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit was at high levels on 15-16 August, moderate levels on 17 and 19-21 August and normal levels on 18 August. The largest flux of the period was 9,570 pfu observed at 15/1605 UTC.
Geomagnetic field activity was at mostly quiet to unsettled levels with an isolated active period observed on 21 August due to a pair of weak, negative polarity coronal hole high speed streams (CH HSS). Quiet levels were observed on 15 August under a nominal solar wind regime. By early on 17 August, solar wind speed increased to 435 km/s while total field increased to near 9 nT. Quiet to unsettled levels were observed from 16-18 August with quiet levels on 19-20 August. Solar wind speed decreased slowly until midday on 21 August when another CH HSS became geoeffective. The geomagnetic field responded with quiet to active levels on 21 August.
Forecast of Solar and Geomagnetic Activity 22 August – 17 September 2016
Solar activity is expected to be at very low to low levels through the forecast period (22 Aug-17 Sep).
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at normal to moderate levels with high levels likely on 26-28 August and from 31 August-12 September as a result of recurrent CH HSS activity.
Geomagnetic field activity is expected to be at unsettled to active levels from 23-25 August, 29 August-08 September, 13-14 September, and again on 17 September with G1 (Minor) storm levels likely on 30-31 August due to recurrent CH HSS activity.
Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/
Live Aurora mapping is at http://aurora.sunspotwatch.com/
If you are on Twitter, please follow these two users: + https://Twitter.com/NW7US + https://Twitter.com/hfradiospacewx
Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!
Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g
We’re on Facebook: http://NW7US.us/swhfr
Weekly Propagation Summary – 2016 Aug 15 16:10 UTC
Here is this week’s space weather and geophysical report, issued 2016 Aug 15 0115 UTC.
Highlights of Solar and Geomagnetic Activity 08 – 14 August 2016
Solar activity was at very low to low levels with C-class activity observed on 08, 09, 11 and 14 Aug. Region 2574 (N05, L=173, class/area Dho/290 on 09 Aug) was the most active region recording six C-class flares. The largest of these was a C8/Sf observed at 09/0042 UTC. Regions 2571 (N13, L=268, class/area Dac/200 on 08 Aug) and 2572 (N13, L=320, class/area Dao/110 on 07 Aug) each produced weak C-class flares on 08 Aug. The period ended with a C1 flare observed at 14/1936 UTC from an unnumbered region on the NE limb. A few CMEs were observed during the period, but none had an Earth-directed component.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit was at high levels throughout the summary period. A maximum of 12,032 pfu was observed at 13/1745 UTC.
Geomagnetic field activity was at quiet to active levels on 08 Aug through early on 12 Aug due to effects from a positive polarity CH HSS. Quiet levels were observed for the remainder of the period. Solar wind speeds reached a maximum speed of about 675 km/s at 10/0830 UTC. Bt ranged between 3-8 nT while the Bz component varied between +7 to -5 nT early in the period. The phi angle was in a predominately positive sector throughout the period.
Forecast of Solar and Geomagnetic Activity 15 August – 10 September 2016
Solar activity is expected to be very low with a chance for C-class activity through the outlook period.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at high levels on 15, 19-23, 26-28, 31 Aug and 01-10 Sep. Normal to moderate levels are expected for the remainder of the outlook period.
Geomagnetic field activity is expected to be at G1 (Minor) storm levels on 16 and 30-31 Aug due to recurrent CH HSS activity. Unsettled to active levels are expected on 15, 17-19, 24-25 Aug and 01-08 Sep, all due to recurrent CH HSS activity. Mostly quiet conditions are expected for the remainder of the outlook period.
Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/
Live Aurora mapping is at http://aurora.sunspotwatch.com/
If you are on Twitter, please follow these two users: + https://Twitter.com/NW7US + https://Twitter.com/hfradiospacewx
Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!
Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g
We’re on Facebook: http://NW7US.us/swhfr
Remembering The ‘Woodpecker’
Those of you that have been hams for a long time will no doubt recall the Russian 'Woodpecker'. The 'Woodpecker' was a strong, fast repeating signal / racket that often wiped out amateur communications on 20m here in North America ... maybe other parts of the world as well.
Amateurs with yagis eventually determined that the signals (yes there was more than one it seemed) were coming from the USSR. The QRM was persistent and in spite of formal complaints being lodged via diplomatic channels, continued for many years ... from 1978- 1989. Some of the new transceivers built during the time actually had a 'WOODPECKER' position on the noise blanker switch, hopefully offering some relief to the problem.
For you younger folks, here's what Duga usually sounded like:
Several web searches brought up numerous descriptions of the Duga (Russian for 'arc' or 'bow') project, some with conflicting information. From what I can sort out, there were three Duga sites ... one near Chernobyl, another near Chernihiv and a third, much later, in Siberia. The first two (Duga and Duga-1) were in the Soviet Ukrainian SSR (now Ukraine) while the third was located near Komsolmosk-on-Amur in the Russian far east. One source indicates that the second Chernobyl site is often misidentified as the Duga-3 array and should be referred to as Duga-1, with Duga-2 being the Siberian location.
Initial speculation suggested this intrusive signal was some form of 'jammer' ... very common during the Cold War. It wasn't long before the true nature of Duga was thought more likely to be an 'over-the-horizon' (OTH) long-range radar system for detecting the launch of North American missiles aimed at the USSR. The three radar sites gave the Soviets good over-the-pole coverage as well as to the east, where it could also be utilized for tracking domestic rocket launches.
 |
| courtesy: http://www.globalsecurity.org/wmd/world/russia/steel-yard.htm |
The antennas themselves appear to be phased dipole curtain arrays, commonly used in various configurations by shortwave HF broadcasters.
 |
| courtesy: http://www.antenna.be/hr.html |
Each site was paired with a receiving array ... remember, this was a radar system, with two of the three systems having the receiving array located tens of kilometers from the transmitter. The Chernobyl Duga is said to have had the receiving antenna located on site. Sources discussing physical size indicate the dimensions for the receiving array to be larger than those of the transmitting antenna. It seems possible then, that the pictures and videos commonly found are those of the receiving array and not of the transmitting antenna. It might make sense to have more gain on 'receive' than on 'transmit' as echoes from small targets many thousands of miles away would not be easy to detect. No matter what the actual case, I can only imagine the fun of hooking up an HF transceiver to one of these arrays during a DX contest on 20m CW!
The Chernobyl site shows two arrays, side-by-side ... possibly the larger being that used for receiving and the smaller one for transmitting. This antenna has been noted as a 30/10/2 array ... 2 bays, 30 dipoles wide and 10 high, 600 elements in all!
Further research tends to indicate that each dipole is what is called a 'Nadanenko' dipole. The main feature of this style was its cage-styled construction, giving the element a large diameter resulting in a broad bandwidth.
 |
| courtesy: https://shema.info/en/antenna/ |
 |
| courtesy: englishrussia.com |
First, you see that there are two sets of arrays 15 driven elements wide by 10 driven elements high for a total of 600 elements! They are intermeshed and offset from each other by 1/2 wavelength both vertically and horizontally. There is a horizontal wire screen reflector behind the driven elements.
Some of the other things I noticed are ...
... you can see the open-wire feeds and reflector screen. Each set of collinear elements is fed individually with open wire line. There is a support line between each two bays of driven elements.
... that the reflector screen is supported on the sides by the stand-alone free-standing towers at each side of the array. (I had been wondering why they would have those towers next to the array like that. Now I know.)
... that the element supports are steel pipe instead of fiberglass (or something similar). Apparently, the shape of the radiators allows for the pipe supports to enter the element cages at the element low-impedance point which made the supports invisible to the antenna and also allowed for the supports to not radiate themselves.
 |
| courtesy: http://anzee.livejournal.com/65530.html |
The Duga system was operative between 7 and 19MHz, with 40kHz wide pulses, usually lasting for about seven minutes. The most common pulse rate was at ~10Hz but this sometimes varied. Power levels used often mention 10 megawatts but it's not clear if this was RF output, peak pulse power or ERP.
It's somewhat gratifying after all these years, to actually see close-up, where the Woodpecker signal started its journey around the world and to appreciate the superb engineering that went into these impressive structures ... but sad to see the last one in such a rusted state of decay and abandonment. It would be nice to hear it just one more time ... but please, only for a couple of minutes.
Weekly Propagation Summary – 2016 Aug 08 16:10 UTC
Here is this week’s space weather and geophysical report, issued 2016 Aug 08 0119 UTC.
Highlights of Solar and Geomagnetic Activity 01 – 07 August 2016
Solar activity was at very low to moderate levels. Very low levels occurred on 01-04 and 06 Aug with low levels on 05 Aug and low to moderate levels on 07 Aug. Region 2572 (N13, L=320, class/area Dao/110 on 07 Aug) produced a C1/Sf flare observed at 05/1012 UTC. On 07 Aug, activity increased to moderate levels with an impulsive M1 (R1-Minor) x-ray event observed at 07/1444 UTC from an active region just beyond the SW limb. 07 Aug also saw numerous C-class flares. Region 2571 (N12, L=267, class/area Dai/150 on 07 Aug) produced a C5 event at 07/2232 UTC. New Region 2573 (N08, L=177, class/area Dso/060 on 07 Aug) produced a C8/Sf at 07/1509 UTC. No Earth-directed CMES were observed during the summary period.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit was at moderate flux levels on 02-03 Aug and high flux levels on 01 and 04-07 Aug. The highest flux reading was 16, 206 pfu observed at 06/1445 UTC.
Geomagnetic field activity was at quiet to minor storm levels. The period began on 01 Aug at quiet levels under a nominal solar wind regime. Midday on 02 Aug, activity levels increased to unsettled to minor storm (G1-Minor) levels due to shock enhancement from the arrival of the 28 Jul CME coupled with a CIR in advance of a recurrent, positive polarity CH HSS. Solar wind speeds increased from about 310 km/s early on 02 Aug to near 550 km/s by midday on 03 Aug. Unsettled to minor storm levels persisted through 03 Aug.
Wind speeds increased further on 04-05 Aug with a peak speed of near 675 km/s recorded late on 05 Aug. Winds speeds began a slow decay on 06 Aug. Mostly unsettled to active conditions were observed on 04-06 Aug. By 07 Aug, wind speeds decreased to about 500 km/s as effects from the CH HSS waned. Mostly quiet to unsettled levels were observed on 07 Aug.
Forecast of Solar and Geomagnetic Activity 08 August – 03 September 2016
Solar activity is expected to be at low levels with a chance for M-class flares (R1-R2, Minor-Moderate) on 08-20 Aug due to the flare potential from Regions 2573 and 2574. Very low to low levels are expected on 21 Aug – 01 Sep. An increase to low levels with a chance for M-class flares (R1-R2, Minor-Moderate) are expected on 02-03 Sep with the return of Regions 2573 and 2574.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at high flux levels on 08-15, 22-23 and 26-28 Aug and again on 31 Aug-03 Sep due to recurrent CH HSS activity. Normal to moderate levels are expected for the remainder of the outlook period.
Geomagnetic field activity is expected to be at unsettled to G1 (Minor) storm levels on 08 Aug and again on 31 Aug due to recurrent CH HSS activity. Unsettled to active levels are expected on 09-11, 15-16, 18-19, 24-25, 29 and 30-31 Aug along with 01-03 Sep, all due to recurrent CH HSS activity. Mostly quiet conditions are expeced for the remainder of the outlook period.
Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/
Live Aurora mapping is at http://aurora.sunspotwatch.com/
If you are on Twitter, please follow these two users: + https://Twitter.com/NW7US + https://Twitter.com/hfradiospacewx
Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!
Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g
We’re on Facebook: http://NW7US.us/swhfr
Weekly Propagation Summary – 2016 Aug 01 16:10 UTC
Here is this week’s space weather and geophysical report, issued 2016 Aug 01 0511 UTC.
Highlights of Solar and Geomagnetic Activity 25 – 31 July 2016
Solar activity was very low throughout the period with the exception of a single C1 flare at 25/0909 UTC from departed Region 2567 (N05, L=166, class/area Dki/380 on 21 July). Region 2570 (N10E24, Axx/alpha) was the sole numbered sunspot for the majority of the period but was unimpressive and did not contribute any significant flaring. A 25 degree filament, centered near N01E06, was observed lifting off of the visible disk in SDO/AIA imagery beginning at 28/1620 UTC. ENLIL analysis showed an Earth-directed component with CME arrival expected early on 02 August.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit was at moderate levels on 25, 28-29 July and high levels on 26-27 and 30-31 July.
Geomagnetic field activity was at quiet to active levels on 25 July due to residual influence from a weak transient that arrived at Earth on 24 July. This shock enhancement was likely associated with flare activity from 20 July. Geomagnetic field activity was quiet on 26-27 July under a nominal solar wind regime. Quiet to active conditions were observed on 28-29 July after the arrival of a CIR followed by a transition into a negative polarity CH HSS. Wind speeds reached 600 km/s while total field (Bt) measurements were as high as 17 nT. Geomagnetic field activity returned to quiet conditions on 30-31 July.
Forecast of Solar and Geomagnetic Activity 01 August – 27 August 2016
Solar activity is expected to be at very low levels from 01-04 August. Low levels with a chance for M-class (R1-R2, Minor-Moderate) flares are expected from 05-19 August with the return of Regions 2565 and 2567. A return to very low levels is expected on 20-27 August.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at high levels on 08, 5-15, 18-22, 25-27 August due to recurrent CH HSS activity. Normal to moderate levels are expected for the remainder of the forecast period.
Geomagnetic field activity is expected to be at unsettled to active levels on 04-05, 10-11, 15-16, 24-25 August with G1 (Minor) storm levels likely on 03 August due to recurrent CH HSS activity. A CME associated with the eruptive filament from 28 July is likely to arrive early on 02 August causing unsettled to G2 (Moderate) storm levels. Quiet to unsettled conditions are expected for the remainder of the period.
Don’t forget to visit our live space weather and radio propagation web site, at: http://SunSpotWatch.com/
Live Aurora mapping is at http://aurora.sunspotwatch.com/
If you are on Twitter, please follow these two users: + https://Twitter.com/NW7US + https://Twitter.com/hfradiospacewx
Get the space weather and radio propagation self-study course, today. Visit http://nw7us.us/swc for the latest sale and for more information!
Check out the stunning view of our Sun in action, as seen during the last five years with the Solar Dynamics Observatory (SDO): https://www.youtube.com/watch?v=zXN-MdoGM9g
We’re on Facebook: http://NW7US.us/swhfr
