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.
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This page was rendered on 26-Apr-24 2038 UTC.
This page was first created as HFRadio.org in the mid 1990s, and morphed here in 1998, by Tomas David Hood (NW7US)
Current Sunspot Cycle 25 Activity ~ Space Weather ~ Shortwave Radio Propagation
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): 3
| Planetary K-index (Kp):
Solar Wind: 321 km/s at 3.0 protons/cm3, Bz is -7.0 nT
(Apr 26, 2024 at 2025 UT)
X-ray Solar Flares:
6h hi [M1.3][1703Z 04/25] 24h hi [M1.3][1703Z 04/25]
What is the difference between the CB and Amateur Radio Services, in the USA? Here are some thoughts on the portrayal of the Amateur Radio Service by the Hit TV Series, NCIS, and a clarification of the difference between CB radio and ham radio.
(Skip to timecode 1:33 to bypass the introductory chat and talk about the headset microphone.)
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:
Predicted SMOOTHED Sunspot Number And Radio Flux Values
With Expected Ranges
YR/MO
Smoothed Sunspot Number
Predicted/High/Low
Smoothed 10.7 cm Radio Flux
Predicted/High/Low
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 0400Z on 05 May, 2021
High Latitude: Normal
Middle Latitude: Normal
Low Latitude: Normal
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: 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 (Close-up of the video, above)
Video: Stunning Close-up View of M3 X-Ray Flare 24 February 2011
Video: On How NCIS TV Show Maligned Amateur Radio Service (Full UHD Version)
What's the difference between CB and amateur (ham) radio?
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.
Highlights of Solar and Geomagnetic Activity
Covering the period: 15 - 21 April 2024
Solar activity reached moderate levels on 15 Apr, 16-19 Apr and 21 Apr and was at low levels on 20 Apr. A large amount of numbered regions were recorded on the visible disk, with 26 in total. Region 3639 (N26, L=222, class/area=Eki/320 on 17 Apr) produced the highest flare of the period, an M4.0/1n (R1-Minor) at 15/1932 UTC. 17 other M-class (R1) flares were observed this period from multiple other regions. An complex area of sunspot groups was observed in the southern hemisphere. Region 3638 (S17, L=226, Cai/beta) was far from the most magnetically complex of the group but was very active in its production of eruptions associated with numerous CMEs over the past week. Most of the ejecta was thought to move south of the ecliptic but some of the activity may have produced CMEs whose periphery may be on the Sun-Earth line.
Other activity included an eruption N of Region 3636 (S21, L=251, Class/area=Cso/100 on 13 Apr) around 15/0557 UTC. A faint CME thought to be associated with the event was observed in SOHO/LASCO C2 imagery beginning after 15/0648 UTC. Modeling of the CME suggested arrival on 18 Apr but the most pronounced portion of the CME was observed passing Earth over 19 Apr.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit ranged from normal background to moderate levels.
Geomagnetic field activity was ranged from quiet to G3 (Strong) geomagnetic storm levels this period. Quiet to unsettled conditions on 15 Apr increased to G1 (Minor) geomagnetic storm levels due to transient influence from a CME activity on the Sun over 12 Apr. Quiet to unsettled conditions on 17 Apr were associated with a weak passing CME that left the Sun on 14 Apr. Quiet conditions were then observed on 18 Apr as solar wind conditions trended towards nominal levels. An increase to G3 (Strong) geomagnetic storm conditions were observed with the passage of CME associated with activity on the Sun over 15 Apr. Total magnetic field strength (Bt) reached a peak of 18 nT at 19/1425 UTC. The Bz component was sustained in a far southward orientation with a maximum deflection of -17 nT observed at 19/1421 UTC. Solar wind speeds steadily increased from the low 300's to ~500 km/s by the end of 19 Apr. Bt returned to near 5 nT on 20 Apr and the geomagnetic field responded with quiet to unsettled conditions. Active conditions were again observed on 21 Apr following additional periods of sustained Bz south.
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)
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)
What is 'Space Weather'? Click on these two information slides to view them in full size:
View of numbered sunspot regions and plages (if any)
Source: http://www.solarmonitor.org/.
(Click for large view)
Active sunspot regions, and plages, identified by SIDC
STEREO IMAGES
What is coming
Current View
What was...
Real Time Solor Wind and Aurora:
On 2024 Apr 26 2033Z: Bz: -7.0 nT
Bx: -1.1 nT | By: 10.4 nT | Total: 12.6 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
Solar Flares: M-class flares expected (probability >=50%) Geo-Disturbance: Minor storm expected (A>=30 or K=5) Solar Proton Event: Warning condition (activity levels expected to increase,
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
22 April - 18 May 2024
Solar activity is expected to be moderate levels (R1-R2/Minor-Moderate), with a chance for X-class flare R3 (Strong), over 22-27 Apr due to a plethora of productive sunspots rotating towards the W limb. As those spots groups rotate off, solar activity is likely to be a low levels with a chance for M-class (R1-R2), through the remainder of the outlook period due to both developing spots in the E hemisphere and the return of productive spot groups on the farside of the Sun.
There is a chance for the greater than 10 MeV proton flux at geosynchronous orbit to reach above the S1 (Minor) levels over 22-27 Apr due to the plethora of sunspots in the W hemisphere.
The greater than 2 MeV electron flux at geosynchronous orbit may reach high levels on 22-25 Apr in response to geomagnetic activity observed on 19 Apr.
Geomagnetic field activity is like to reach active levels over 22-24 Apr and 26-27 Apr in response to multiple coronal hole high speed streams (CH HSSs). There is potential for combined influence of coronal hole activity and multiple weak transients over 22-24 Apr. Unsettled levels are likely on 25 Apr, 01-03 May, and 05-07 May due to the anticipated return of multiple other weak CH HSSs. The remainder of the outlook period is likely to be at mostly quiet levels.
Data and images courtesy of IPS Australia, NOAA, NASA, SWPC, SIDC
Layout, analysis, commentary, and certain forecasts and content is Copyright, 2022, Tomas David Hood (NW7US), all rights reserved.
No part, except for the space weather 'banners', may be copied without express permission.