Amateur Radio Propagation Report

Sun Images for Past 72 Hours

Images copyrighted by the SDO/NASA and Helioviewer project

📋 Propagation Summary: HF propagation today is shaped by a moderate solar flux of 148 and a sunspot number of 135, both supporting fair conditions on most bands. However, a K-index of 4 and elevated A-index (16) indicate unsettled geomagnetic activity, which may cause some signal fading and absorption, especially on higher frequencies. Expect the lower bands (80m/40m) to be less effective during the day, while 20m–15m offer the most reliable paths for both local and DX contacts. Watch for short-lived enhancements around sunrise and sunset, and be alert for possible auroral effects at higher latitudes. Operators should adapt to variable conditions and take advantage of the best band openings as they occur.

💡 Operator Tips

• Focus on 20m, 17m, and 15m during daylight for the most consistent contacts, especially for DX.
• 80m and 40m will be more productive after sunset; daytime performance is poor.
• Use digital modes (FT8, PSK31) to overcome increased noise and fading on marginal bands.
• For DX, target grayline periods (dawn/dusk) for enhanced propagation, especially on 20m and 40m.
• Monitor real-time K-index: If it rises further, expect rapid band changes and possible HF blackouts.
• Portable and low-noise antennas will help mitigate geomagnetic noise, especially for weak-signal work.

⏰ Best Operating Times

• 80m/40m: Best after sunset and through the night; avoid daytime for long-haul contacts.
• 20m/17m/15m: Mid-morning through late afternoon for both local and DX; check for brief evening openings.
• 12m/10m: Mostly fair during the day, but may close early if geomagnetic activity increases.
• Grayline (sunrise/sunset): Enhanced long-path DX on 40m and 20m.

🌍 DX Opportunities

• 20m and 17m: Most reliable for intercontinental DX, especially during grayline.
• 15m: Watch for short, sporadic DX openings in the afternoon.
• 10m/12m: Occasional short-skip and sporadic E possible, especially during local midday.
• Grayline: Enhanced propagation to antipodal regions; check 40m and 20m at your local sunrise/sunset.
• Auroral paths: Possible on VHF/UHF for northern operators due to moderate aurora activity (level 3).

📻 Band-by-Band Analysis

Analysis:
The mid-bands (20m, 17m, 15m) are the most reliable throughout the day and into the evening, offering fair but workable conditions for both local and DX. 80m and 40m are largely poor during the day but improve to fair at night, making them best for late-night and early-morning operation. 12m and 10m may open briefly during the day but are likely to close quickly as geomagnetic activity increases. For the best results, focus on 20m–15m during daylight and 40m–80m after dark.

📊 Current Solar Activity

• K-index: 4 (unsettled) – Indicates increased geomagnetic activity, which can cause signal fading, absorption, and auroral effects, especially on higher bands.
• Solar Flux: 148 – Moderately high; supports fair-to-good propagation on 20m–10m, but not at peak cycle levels.
• Sunspot Number: 135 – Above average; helps maintain the ionization needed for higher band openings.
• Space Weather Overview: X-ray flux at B7.0 (low), no major flares reported, but keep an eye on sudden changes.

📈 Geomagnetic Conditions

• Recent K-index trend: The K-index has risen to 4, indicating a shift from quiet to unsettled geomagnetic conditions over the past 24 hours.
• Impact: Expect increased noise and fading, especially on higher HF bands and polar paths. If the K-index increases further, short-term HF blackouts are possible.
• Aurora: Level 3 – Moderate auroral activity may affect VHF/UHF propagation in high latitudes.

🌟 Space Weather Details

• X-ray Activity: B7.0 (low) – No significant risk of HF radio blackouts from solar flares at this time.
• Solar Wind: 389 km/s – Slightly elevated, contributing to unsettled geomagnetic conditions and potential for minor disturbances.
• Particle Environment: Electron flux at 2150 (elevated) and proton flux at 21 (moderate) – May cause minor absorption and increased noise, especially at higher latitudes.
• Aurora Activity: 3 – Moderate; VHF/UHF operators in northern regions may see auroral propagation, but HF may experience increased absorption.
• Helium Line: 129.8 – Indicates moderate solar activity; watch for trend changes as this can signal upcoming propagation shifts.

📡 Propagation Timeline & Technical Details

• Historical Solar Flux: Over the past 6 months, solar flux has declined from a high of 160 (Dec 2025) to the current 120 (Apr/May 2026), indicating we are past the recent solar peak.
• Sunspot Trend: Sunspot numbers have also decreased from 124 (Dec 2025) to 79 (Apr 2026), matching the solar flux trend.
• Impact: This downward trend means HF band openings, especially on 10m/12m, are less frequent and shorter, while 20m/17m remain the most reliable for DX.

🔮 3-Day Forecast

• Propagation Outlook: Expect continued fair conditions on 20m–15m, with 80m/40m best at night. If geomagnetic activity remains elevated, anticipate further absorption and fading, especially on higher bands.
• Recommendations: Monitor real-time indices for sudden changes. Be ready to switch bands quickly and use digital modes for weak-signal work. Watch for possible short-lived 10m/12m openings during local midday if geomagnetic conditions improve.
• No major alerts or warnings at this time, but stay tuned for updates if K-index rises further.