☀️ Space weather & propagation

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132Solar flux (SFI, 10.7 cm)

87Sunspot number

1,7Kp-Index · ruhig

6A index

415Solar wind km/s

+4Bz (nT) – negative = storms more likely

NOAA-Skalen jetzt: Funkausfall R0 · Strahlungssturm S0 · geomagnetischer Sturm G0 (0 = nichts los, 5 = extrem).

🌍 MUF worldwide – model calculation

Modell, keine Messung: Monatsmittel der höchsten brauchbaren Frequenz MUF(3000) – für eine Funkstrecke von 3000 km mit Reflexionspunkt im jeweiligen Feld. Tagesschwankungen, Ionosphärenstürme und Sporadic-E sind nicht enthalten; typische Abweichung ±15–25 %. Felder von 5° × 10° – genauer ist das Modell nicht.

Standings: 18.10.2026 20:24 UTC · Sonnenaktivität R12 = 88 (Vorhersage für 2026-10)

unter 5
5–10
10–15
15–20
20–25
25–30
30–35
ab 35

Values in MHz

Calculate radio path

Quelle: Modell: CCIR-Koeffizienten (ITU-R P.1239) als Monatsmedian, berechnet mit PyIRI (Forsythe et al. 2023, MIT-Lizenz); Sonnenaktivität: R12-Vorhersage NOAA SWPC (gemeinfrei). R12 wird höchstens einmal am Tag geladen, zuletzt 17.10. 23:01.

Bands – assessment for Central Europe

Bei Mitte Deutschlands ist gerade Night (highlighted).

Band	Day	Night
80 m	medium	good
40 m	good	good
30 m	good	good
20 m	good	medium
17 m	good	poor
15 m	good	poor
12 m	medium	poor
10 m	medium	poor

Rule of thumb from solar flux and Kp index, not a measurement: higher bands (20–10 m) need a lot of solar flux and open mainly by day; 80 and 40 m work best at night. A disturbed geomagnetic field (Kp 5 and above) mainly degrades the higher bands and night-time paths. CB radio (11 m) behaves roughly like 12 and 10 m.

Forecast for the next days

Tag (UTC)	Flux	Kp max.	Radio blackout R1–R2 / R3+	80/40 m at night	20 m by day	15/10 m by day
So 18.10.	95	1,7 ruhig	25 % / 5 %	good	good	medium / poor
Mo 19.10.	100	4,7 aktiv	25 % / 5 %	good	good	medium / poor
Di 20.10.	100	4,7 aktiv	25 % / 5 %	good	good	medium / poor

“Radio blackout” means HF outages on the day side caused by solar flares (probability according to NOAA). They usually last minutes to an hour.

27-day outlook

The sun rotates about once every 27 days, so active regions often return – NOAA uses this for this rough outlook.

Day	Flux	Ap	Kp max.	10 m by day
So 18.10.	95	5	2	poor
Mo 19.10.	100	5	2	poor
Di 20.10.	100	5	2	poor
Mi 21.10.	105	15	3	poor
Do 22.10.	100	20	4	poor
Fr 23.10.	100	15	4	poor
Sa 24.10.	95	10	3	poor
So 25.10.	95	5	2	poor
Mo 26.10.	105	5	2	poor
Di 27.10.	110	5	2	poor
Mi 28.10.	110	5	2	poor
Do 29.10.	110	5	2	poor
Fr 30.10.	110	5	2	poor
Sa 31.10.	105	30	5	poor
So 01.11.	105	25	5	poor
Mo 02.11.	105	10	3	poor
Di 03.11.	100	5	2	poor
Mi 04.11.	105	5	2	poor
Do 05.11.	105	5	2	poor
Fr 06.11.	110	10	3	poor
Sa 07.11.	110	10	3	poor

What do the values mean?

Solar flux (SFI): Radio emission of the sun at 10.7 cm. Below 80: quiet sun, only the lower bands work well. From about 120: 15 and 10 m open by day, often worldwide. From 150: busy upper bands.
Sunspot number: The more spots, the more strongly the ionosphere is charged and the higher the usable frequencies reach.
Kp index (0–9): Disturbance of the geomagnetic field, every three hours. 0–2 quiet, 3–4 unsettled/active, 5 and above geomagnetic storm (G1–G5): HF gets worse, but aurora contacts on 6 and 2 m become possible.
A index: Daily average of the disturbance: below 10 quiet, above 30 disturbed.
Solar wind and Bz: Fast solar wind (over 500 km/s) and a prolonged negative Bz often herald storms.

Stand 18.10.2026 22:24. Daten: NOAA Space Weather Prediction Center (US authority, public domain). The band assessment is our own rule of thumb and does not replace listening on the band.

☀️ Space weather & propagation

Now

🌍 MUF worldwide – model calculation

Calculate radio path

Bands – assessment for Central Europe

Forecast for the next days

27-day outlook

What do the values mean?

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