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Radio Propagation : Space Weather : Sunspot Cycle Information

a live reference resource site for solar and geomagnetic data and images
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Gain the on-air edge: This article explains how the ANTENNA is the key! -> Read this introduction to Antenna Modeling



X-ray Conditions (Flares) 5-min.

X-ray plot

X-ray Conditions (Flares) 1-min.

X-ray plot

Geomagnetic Conditions (Kp)

plot of Kp

Satellite Environment Plot:

Satellite Environment Plot

Main Propagation Menu:

+ Aurora Resources

How-To Articles:

- Is HF Propagation Reciprocal?
- De-mystifying HF Radio Propagation and Modeling

Check out the ACE-HF propagation software - the latest is version 2.05. ACE-HF is propagation forecasting and modeling for Amateur Radio as well as for Shortwave radio Listening and general HF operation. This software is even used by the military and other clients around the world. This software is developed and maintained by the same engineers that keep VOACAP up-to-date. As a result, this software is the most accurate user interface integrated with VOACAP. CHECK IT OUT, TODAY. This software is the most accurate modeling software available, and is endorsed by NW7US. Read the details to find out why.

Main Site Menu:

- Main NW7US Page
- About NW7US
- About Amateur Radio
- Feedback - Contact NW7US

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This website is kept alive by Tomas (NW7US), out of "spare change" (which there's not always enough of), and, by the kind, helpful people who visit this website. Would you like to help me keep this site running 24/7? If you are able to help me keep this website up and running, please: help me keep this site running for everyone... click on this donation button:

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Other links of interest:

- PropNET - live propagation studies
- Shortwave Radio Resource Center
- Shortwave Broadcasting Search

Comments? Please use the feedback form. I look forward to hearing your comments.

Web hfradio.org

Warnings/Alerts issued
in the last 24 hours, if any:

(Key: NOAA Scales)

[ live aurora display ]
[ auroral power maps ]

[ d-layer conditions ]

[ latest solar images 1 ]
[ latest solar images 2 ]
[ latest solar images 3 ]

[ active solar regions ]
[ current solar region image ]

[ What is a flare and its class? ]

Recent Space Environment Reports:

+ Reports of Solar & Geophysical Activity
+ Solar & Geophysical Activity Summaries

From the Space Environment Center:

Solar X-ray Flux

+ A 3 day plot of 5-minute solar X-ray flux values measured on the GOES 8 and 10 satellites.
+ A 6-hour 1-min Solar X-ray Flux plot

Satellite Environment Plot

[ Proton Flux ] [Electron Flux ]
[ GEOS Hp ] [ Estimated Kp ]

Additional Resources

+ SpaceW.com Aurora Network
+ D-Layer Absorption Conditions/Predictions
+ 160 Meter Propagation Forecast
+ Solar Physics Department of the Royal Observatory of Belgium, the official keepers of sunspot data.

Solar Activity Forecast
The Forecast of Solar Activity as well as Geomagnetic Activity

Probability of Flares
and Proton Events
0-24 hrs
24-48 hrs
Geomagnetic Activity Probabilities

Middle latitudes
High latitudes

0-24 hrs
24-48 hrs
0-24 hrs
24-48 hrs
Minor Storm
Major-severe Storm

Solar Sunspot Cycle 24 Progress

Solar Cycle 24 Smoothed Sunspot Progress
Solar Cycle 24 10.7-cm Monthly Progress
Solar Cycle 24 Planetary A Index (Ap) Monthly Progress
Do you want the latest solar conditions sent to you as an RSS feed? Click: XML RSS propagation feed

You will need a newsreader for RSS/XML.

(Use http://hfradio.org/propsupport/prop.rss as your RSS channel url)

This page was rendered on 21-Aug-17 0956 UTC.
This page was first created in 1998, by Tomas David Hood (NW7US)

Current Sunspot Cycle 24 Activity and Space Weather

Sun Spots: 44 as of 08/20/2017 :: 10.7-cm Flux: 86 SFU
(SFU=Solar Flux Units)

Space Weather Overview Graphic from SWPC

30 Minutes of Dazzling Sun! Ultra-high Definition 4k View

An Intimate View of the Sun, Every Day of 2015 (Year 6 of SDO) UHD 4k

Watch Five Very Intense X-class X-ray Flares Erupt, Back-to-back!
(From the largest sunspot region in 20+ years...)

Check out the X2.7 X-ray Flare (May 5 2015) - 'Biggest' of 2015, so far

See highlights of the last five years of the Sun, as seen by SDO

The Solar Dynamics Observatory (SDO) Latest Solar Images
Click on an image for full-sized view

SDO - Solar Dynamics Observatory     SDO - Solar Dynamics Observatory

D Region Absorption Predictions (D-RAP) Global Map

Map, Above: Conditions in the D region of the ionosphere have a dramatic effect on high frequency (HF) communications and low frequency (LF) navigation systems. The global D Region Absorption Predictions (D-RAP) depicts the D region at high latitudes where it is driven by particles as well as low latitudes, where photons cause the prompt changes.

Note: At times, images may appear broken or missing, when SDO is working on the AIA/HMI instruments.

Planetary A-index (Ap): 22 | Planetary K-index (Kp): 3
Solar Wind: 588 km/s at 7.0 protons/cm3, Bz is -1.0 nT
(Aug 21, 2017 at 0943 UT)

X-ray Solar Flares:
6h hi [M1.1][0136Z 08/20] 24h hi [M1.1][0136Z 08/20]

Background X-ray Level, Last Six Days

Aug 20 2017 :: B3.3
Aug 19 2017 :: B3.3
Aug 18 2017 :: B1.3
Aug 17 2017 :: A8.3
Aug 16 2017 :: B1.3
Aug 15 2017 :: B1.0

Check out the current Aurora Oval and activity.

Here is a video introduction to shortwave / HF amateur radio -- what is it that we amateur radio oprators listen to? If you have not yet been introduced to this world, this is a very basic introduction.

If you are using software utilities such as Ace-HF, that require a "smoothed" sunspot number
(Referred to as the SSN), or, the smoothed 10.7-cm Radio Flux Index,
use the following predicted values in this following table:

To understand more about the Maximum Usable Frequencies, and related
science, please read the MUF Basics Page.

Global HF Propagation Conditions
Global HF Propagation Conditions for 0900Z on 21 Aug, 2017
High Latitude: Fair-Normal
Middle Latitude: Normal
Low Latitude: Normal

Geomagnetic Latitude Ranges:
High: 60-90 degrees
Middle: 20-60 degrees
Low: 0-20 degrees

At 0805 UTC, on 9 August 2011, a strong magnitude X6.9 X-ray flare -- the strongest yet in this current solar cycle (Cycle 24) -- erupted on the northwestern solar limb. Here is a HD Movie of the event:

Videos of Interest - Space Weather, Solar Dynamics Observatory, STEREO, and more... from the NW7US YouTube Channel. (Click on the small image to launch the video...)

Video: Voyager Finds Magnetic Foam at Solar Systems Edge
Video: Voyager Finds Magnetic Foam at Solar Systems Edge

Video: Zoom View of Prominence Eruption and X-Ray Flare - M2.5 Magnitude - June 7 2011
Video: Zoom View of Prominence Eruption and X-Ray Flare - M2.5 Magnitude - June 7 2011

Video: X-Ray Flare, Coronal Mass Ejection, Proton Storm - M2.5 Magnitude - June 7 2011
Video: X-Ray Flare, Coronal Mass Ejection, Proton Storm - M2.5 Magnitude - June 7 2011 (Close-up of the video, above)

Video: Stunning Close-up View of M3 X-Ray Flare 24 February 2011
Video: Stunning Close-up View of M3 X-Ray Flare 24 February 2011

Video: June 2011 20-meter (14-Mhz) JT65A Coverage Map of NW7US Radio Signal
Video: June 2011 20-meter (14-Mhz) JT65A Coverage Map of NW7US Radio Signal

The NW7US Current Sunspot and Geophysical Activity Report
The observations, prognastications, and comments by NW7US
NW7US is Tomas David Hood, Propagation and Space Weather Columnist
for CQ Communications

More about Background X-rays

The hard X-ray energy present from the wavelengths of 1 to 8 Angstroms provide the most effective ionizing energy throughout all of the ionospheric layers in our atmosphere. The GEOS satellites measure these wavelengths and the resulting measurements are reported as the "background X-ray level" throughout the day. A daily average is reported, as well.

Just like X-ray flares, the background hard X-ray level is measured in watts per square meter (W/m2), reported using the categories, A, B, C, M, and X. These letters are multipliers; each class has a peak flux ten times greater than the preceding one. Within a class there is a linear scale from 1 to 9.

If one records the daily background X-ray levels for the course of a sunspot cycle, one would discover that the background X-ray levels remained at the A class level during the sunspot cycle minumum. During the rise and fall of a solar cycle, the background X-ray energy levels remained mostly in the B range. During peak solar cycle periods, the background energy reached the C and sometimes even M levels.

Armed with this information, can we discover any clues as to the current status of Sunspot Cycle 24? Below is a graph plotting the background hard X-ray energy reported by the GEOS satellites since the end of Sunspot Cycle 22. Clearly, we see a noticeable rise in Cycle 24 activity. We're seeing the energy mostly in the B level more often, supporting the view that Cycle 24 is alive and moving along toward an eventual sunspot cycle peak in several years.

Overall, the monthly average background 'hard' X-ray level is rising (as seen by the following plot), showing a change from deep solar cycle minimum. We are certainly in the rising phase of Sunspot Cycle 24. While it has been a slow up-tick over the last eighteen months, I expect to see a more rapid rise during mid to late 2011.

Background X-ray (1 to 8 Angstrom) Plot

Highlights of Solar and Geomagnetic Activity
Covering the period: 07 - 13 August 2017

Solar activity was very low. Region 2670 (S05, L=119, class/area Cso/160 on 02 Aug) continued it transit across the visible disk during the period as a simple Hsx/alpha spot group with no flaring activity observed. 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 reached high levels from 07-11 Aug with a peak flux of 11,301 pfu observed at 07/1440 UTC. Electron flux values decreased to normal to moderate levels on 12-13 Aug due to the arrival of a negative polarity coronal hole high speed stream (CH HSS).

Geomagnetic field activity ranged from quiet to unsettled levels during the period. Solar wind speed was in decline at the beginning of the period from a waning positive polarity CH HSS. Solar wind speeds declined from near 570 km/s early in the period to nominal levels by late on 08 Aug. Total field ranged from 2-6 nT through 10 Aug. On 11 Aug, total field and solar wind began to increase as a negative polarity CH HSS became geoeffective. Total field increased to a maximum of 12 nT at 12/0135 UTC while solar wind increased to around 650 km/s by 13/1750 UTC. The geomagnetic field responded with quiet levels from 07-10 Aug and quiet to unsettled levels from 11-12 Aug. Geomagnetic activity decreased to quiet levels again on 13 Aug.

Monthly and smoothed sunspot number - The monthly mean sunspot number (blue) and 13-month smoothed monthly sunspot number (red) for the last five cycles. You can see that this current cycle, Cycle 24, is a weak cycle, compared to the last few.

(Click to see actual size)
Monthly and smoothed sunspot number chart

Daily and monthly sunspot number (last 13 years)

Daily sunspot number (yellow), monthly mean sunspot number (blue), smoothed monthly sunspot number (red) for the last 13 years and 12-month ahead predictions of the monthly smoothed sunspot number:

SC (red dots) : prediction method based on an interpolation of Waldmeier's standard curves; It is only based on the sunspot number series.

CM (red dashes) : method (from K. Denkmayr and P. Cugnon) combining a regression technique applied to the sunspot number series with the aa geomagnetic index used as a precursor (improved predictions during the minimum phase between solar cycles).

(Click to see actual size)
Daily and monthly sunspot number (last 13 years)

What is 'Space Weather'? Click on these two information slides to view them in full size:

What is Space Weather? Slide 1 of 2 What is Space Weather? Slide 2 of 2

View of numbered sunspot regions and plages (if any)
Source: http://www.solarmonitor.org/.
(Click for large view)

Active Regions and Plages

Active sunspot regions, and plages, identified by SIDC

SIDC Solar Disc with active regions and plages

Latest GOES 15 Image of the Sun

Latest GOES-15 Image of the Sun

STEREO Behind Image
What is coming
SOHO EIT 195 Image
Current View
STEREO Ahead Image
What was...

Real Time Solor Wind and Aurora:

On 2017 Aug 21 0950Z: Bz: 0.2 nT
Bx: -3.5 nT | By: -0.3 nT | Total: 3.5 nT
Most recent satellite polar pass:
Centered on // : UTC
Aurora Activity Level was at UTC
visit noaa for latest.

This is a video of the simulation from May 27-28, 2011, showing
the Geomagnetic disturbance caused by the solar wind

Space Weather and Propagation Forecast
Prepared by the US Dept. of Commerce, NOAA,
and the Space Weather Prediction Center

Three Day Forecast of Solar and Geomagnetic Activity
(as of 2200Z on 07 Dec 2014)

Solar Forecast:

Solar activity is expected to be low with a chance for M-class flares on days one, two, and three (08 Dec, 09 Dec, 10 Dec).

Geomagnetic Forecast:

The geomagnetic field is expected to be at quiet to minor storm levels on day one (08 Dec), quiet to active levels on day two (09 Dec) and quiet levels on day three (10 Dec).

Forecast of Solar and Geomagnetic Activity
14 August - 09 September 2017

Solar activity is expected to be at very low levels. A chance for C-class flare activity is possible from 14-28 Aug as a new active region rotates across the visible disk.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high levels from 14-16, 18-30 Aug and again from 01-07 Sep due to CH HSS influence. Normal to moderate levels are expected on 17, 31 Aug and again on 08-09 Sep.

Geomagnetic field activity is expected to be reach unsettled to active levels on 14, 16-22, 30-31 Aug and from 01-02 and 08-09 Sep with G1 (Minor) geomagnetic storm levels are likely on 17-18 and 31 Aug due to recurrent CH HSS activity.

Real-time foF2 map from IPS (Ionospheric Prediction Service), Australian Space Weather Agency

foF2 Map from IPS, Australia

Space Weather + Ham Radio Resources

Click on image to
view larger versions

The following images
are from SOHO

C2 LASCO Image
C3 LASCO Image

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Check out this amazing NASA SDO (Solar Dynamics Observatory) video
showing plasma rain on the Sun!

Check out this amazing NASA SDO (Solar Dynamics Observatory) video
showing a prominence the Sun:

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Additional Views of the Sun

Be sure to check the Date shown in each photo - is it today's date?
(click to enlarge)

Current Numbered Sunspots / MDI MagnetogramCatania Solar Disc

H-Alpha View 1H-Alpha View 2

Check out these books on Radio Propagation:

+ 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 a the operating table as you master the art of shortwave radio progagation.

+ How Radio Signals Work (Paperback) - by Jim Sinclair. This book provides a basic understanding of the way radio signals work-without becoming bogged down with the technicalities. It covers all kinds of radio signal types--including mobile communications, short-wave, satellite, and microwave. No detailed knowledge of electronics or mathematics is required. A-Z coverage of radio signals including satellites, mobile communications, and short-wave radio. No math or electronics background necessary.

+ Introduction to RF Propagation (Hardcover) - by John S. Seybold. This book provides readers with a solid understanding of the concepts involved in the propagation of electromagnetic waves and of the commonly used modeling techniques. While many books cover RF propagation, most are geared to cellular telephone systems and, therefore, are limited in scope. This title is comprehensive-it treats the growing number of wireless applications that range well beyond the mobile telecommunications industry, including radar and satellite communications.

Data and images courtesy of IPS Australia, NOAA, NASA, SWPC, SIDC

Layout, analysis, commentary, and certain forecasts and content is
Copyright, 2017, Tomas David Hood (NW7US), all rights reserved.
No part, except for the space weather 'banners', may be copied without express permission.

Last Update: January 04, 2017