Sun Images for Past 72 Hours

Images copyrighted by the SDO/NASA and Helioviewer project
๐ Propagation Summary:
HF propagation today is being shaped by moderate solar activity and a low geomagnetic disturbance level. The solar flux is at 89 (recently trending downward), and the sunspot number is at 25, both indicating below-average ionospheric support for higher bands. Expect lower bands (80m, 40m) to provide the most reliable contacts, especially at night, while higher bands (20m and above) will be challenging, with most upper HF bands (15m, 12m, 10m) likely to be closed or poor throughout the day. Operators should focus on lower frequencies for both local and DX work, and take advantage of the relatively quiet geomagnetic field for stable conditions on the available bands.
๐ก Operator Tips
- Prioritize 80m and 40m for both local and regional contacts, particularly during nighttime and early morning.
- Digital modes (FT8, PSK31) will outperform SSB/CW on marginal bands like 20m and above.
- Vertical antennas or low dipoles will help maximize low-angle radiation for DX on lower bands.
- Monitor grayline times for possible short-lived openings on 20m.
- Avoid high bands (17m, 15m, 12m, 10m) for DX; these are mostly closed under current solar conditions.
- For contests or DX hunting, focus your efforts after sunset and before sunrise on 80m/40m.
โฐ Best Operating Times
- 80m & 40m: Best at night and early morning; fair during the day for local NVIS.
- 20m: Fair during midday and early afternoon; check around sunrise/sunset for possible brief openings.
- 17m, 15m, 12m, 10m: Poor or closed all day and night; not recommended.
- Grayline: Try 40m and 20m during sunrise/sunset for enhanced propagation.
๐ DX Opportunities
- Grayline paths on 40m and possibly 20m offer the best chance for DX, especially east-west.
- Northern latitudes may see slightly enhanced auroral absorption, but overall aurora activity is low (Aurora: 1).
- No significant special propagation events expected; focus on traditional night-path DX on lower bands.
- VHF/UHF: No enhanced propagation expected due to low auroral and solar activity.
๐ป Band-by-Band Analysis
| Band | Morning | Day | Evening | Night |
|---|---|---|---|---|
| 80m | ๐ก Good | ๐ Fair | ๐ก Good | ๐ข Excellent |
| 40m | ๐ก Good | ๐ Fair | ๐ก Good | ๐ข Excellent |
| 20m | ๐ Fair | ๐ Fair | ๐ Fair | ๐ Fair |
| 17m | ๐ด Poor | ๐ด Poor | ๐ด Poor | ๐ด Poor |
| 15m | ๐ด Poor | ๐ด Poor | ๐ด Poor | ๐ด Poor |
| 12m | ๐ด Poor | ๐ด Poor | ๐ด Poor | ๐ด Poor |
| 10m | ๐ด Poor | ๐ด Poor | ๐ด Poor | ๐ด Poor |
80m and 40m are the best-performing bands, especially at night, offering excellent conditions for both local and DX contacts. 20m is marginal throughout the day, with only fair conditions and limited DX potential. Higher bands (17m-10m) are poor or effectively closed due to low solar flux and sunspot numbersโskip these unless youโre experimenting or monitoring for rare openings.
๐ Current Solar Activity
Solar Activity Metrics
K-index
Solar Flux (10.7cm)
Sunspot Number
- K-index: 2 (very quiet geomagnetic field) โ expect stable propagation, minimal auroral absorption.
- Solar Flux: 89 (low) โ limits ionization, especially impacting higher HF bands.
- Sunspot Number: 25 (well below average) โ further reduces maximum usable frequency (MUF) and band openings.
- Space Weather Overview: No major flares or disturbances; X-ray flux at B2.8 is low, indicating minimal risk of HF blackouts.
๐ Geomagnetic Conditions
- Recent K-index trend: Stable and low (K=2), with no significant geomagnetic storms in the past 24 hours.
- Impact: Quiet geomagnetic conditions mean less fading and absorption, especially on lower bands. No warnings or alerts for HF or VHF users.
๐ Space Weather Details
Space Weather Dashboard
X-ray Activity
Solar Wind Speed
Aurora Activity
- X-ray Activity: B2.8 level โ very low, so no risk of sudden HF blackouts.
- Solar Wind: 387.6 km/s โ moderate, not enough to trigger geomagnetic storms.
- Particle Environment: Electron flux at 1700 (moderate); proton flux at 18 (quiet) โ no significant impact on HF propagation.
- Aurora Activity: 1 (very low) โ no auroral propagation for VHF/UHF; northern operators will see normal conditions.
- Helium Line: 104.5 โ stable, indicating no significant solar trend changes.
๐ก Propagation Timeline & Technical Details
Propagation Quality Timeline (24 Hours)
- Recent solar flux and sunspot trend: Both have declined steadily over the past 6 months (solar flux from 138 to 105, sunspots from 93 to 60), reflecting a waning solar cycle phase.
- Impact: This downward trend means fewer band openings above 20m and generally lower MUFs, so expect continued reliance on 80m/40m for reliable contacts.
Solar Activity Trends (6 Months)
๐ฎ 3-Day Forecast
3-Day K-index Forecast
- Solar and geomagnetic activity expected to remain low and stable โ no major flares or storms forecast.
- HF conditions: 80m and 40m will continue to be the best bands, especially at night. 20m may offer short, fair openings during midday and grayline. Higher bands will remain poor.
- VHF/UHF: No enhanced propagation expected.
- Recommendations: Focus on lower bands, use digital modes for marginal conditions, and monitor for any sudden solar events. No alerts or warnings at this time.