📡 Propagation conditions

Real-time indicators for radio amateurs

HB9V - Radio Amateurs of Canton Vaud

Welcome to the HB9V propagation dashboard

This page brings together all the key indicators for assessing radio propagation conditions in real time. Whether you are into DX, contests or simply everyday QSOs, you will find all the information you need here to make the most of your communications.

🕐 Last updated:

☀️ Solar and geomagnetic indices

Why these indices matter: solar activity and the Earth's magnetic field have a direct impact on radio wave propagation. The solar flux influences the density of the ionosphere, while the geomagnetic indices show disturbances that can degrade communications.

🌞 Solar flux (SFI)

Current value: see widget below

The 10.7 cm solar flux is an indicator of solar activity. A high value means a denser ionosphere and better conditions on the higher HF bands.

SFI < 70: poor conditions
SFI 70-100: normal conditions
SFI 100-150: good conditions
SFI > 150: excellent conditions

🧲 A index

The A index measures geomagnetic activity over 24 hours. The lower it is, the better the propagation conditions.

A = 0-7: Excellent
A = 8-15: Good
A = 16-29: Fair
A ≥ 30: Poor

⚡ K index

The K index measures variations in the Earth's magnetic field over 3 hours. It is crucial for anticipating aurora and propagation disturbances.

K = 0-1: Excellent
K = 2-3: Good
K = 4-5: Fair
K ≥ 6: Storm

🌟 Sunspot number (SSN)

The sunspot number shows the level of activity in the 11-year solar cycle. The more sunspots there are, the better the HF conditions.

SSN < 20: solar minimum
SSN 20-50: low activity
SSN 50-100: moderate activity
SSN > 100: solar maximum

📊 Real-time solar data (N0NBH)

📈 Detailed solar index charts

📻 Propagation conditions by band

Reading the conditions: propagation conditions vary considerably depending on the frequency band used. The low bands (160m-40m) are generally better at night, while the high bands (20m-10m) work best during the day.

🌍 Worldwide propagation map (VOACAP)

This map shows HF propagation predictions based on the VOACAP model. Click on your QTH and the destination to get detailed predictions.

🎯 HF bands - current status

Conditions by band (HamSCI)

Band	Frequency	Day	Night	Typical range
160m	1.8 MHz	Poor	Excellent (DX possible)	500-2000 km
80m	3.5 MHz	Good (short distance)	Excellent (DX)	500-3000 km
40m	7 MHz	Good	Excellent	1000-5000 km
30m	10 MHz	Very good	Good	2000-8000 km
20m	14 MHz	Excellent (worldwide DX)	Good	3000-15000 km
17m	18 MHz	Excellent	Fair	3000-12000 km
15m	21 MHz	Excellent (high solar flux)	Closed	5000-15000 km
12m	24 MHz	Good (high solar flux)	Closed	4000-12000 km
10m	28 MHz	Variable (sporadic E)	Closed	2000-10000 km
6m	50 MHz	Sporadic E (summer)	Very limited	500-3000 km

📡 VHF/UHF propagation and special modes

🌠 Sporadic E

Sporadic E layer propagation makes spectacular DX contacts possible on the VHF bands (50 MHz, 70 MHz, 144 MHz). The phenomenon is most common from May to August.

Real-time sporadic E map

🛰️ Meteor scatter

Meteor scatter propagation: the ionised trails left by meteors allow short but effective QSOs on 50 and 144 MHz. The best times are during the major meteor showers.

Meteor shower	Period	Intensity
Quadrantids	1-5 January	High (120 ZHR)
Lyrids	16-25 April	Moderate (18 ZHR)
Perseids	17 July - 24 August	Very high (100 ZHR)
Geminids	7-17 December	Very high (120 ZHR)

🌙 EME propagation (Earth-Moon-Earth)

Moonbounce: propagation by reflection off the Moon requires powerful equipment but allows worldwide QSOs on the VHF/UHF bands.

Best time: Moon at perigee
Best bands: 144 MHz, 432 MHz, 1296 MHz
Propagation delay: ~2.5 seconds
Path loss: ~250 dB

🔧 Prediction and analysis tools

📍 The grey line

The grey line is the transition zone between day and night. Propagation along it can be exceptional because the D and E layers disappear while the F layer remains ionised.

🎯 Propagation calculator

Recommended tools:

VOACAP Online - professional HF predictions
KC2G Solar Data - solar data and predictions
DR2W Propagation - detailed analysis by band
Australian Space Weather - official forecasts

📊 PSK Reporter - real-time activity

PSK Reporter shows the actual activity of stations using digital modes. It is an excellent indicator of open bands and current conditions.

🌐 DX cluster and spots

Recommended DX clusters:

DX Summit - worldwide spot aggregator
DX Watch - modern interface
Reverse Beacon Network - automatic CW/RTTY spots

⚠️ Solar alerts and events

🌞 Current solar activity

Images of the Sun (SDO/NASA)

⚠️ Events to watch for:

Solar flares: can cause sudden radio blackouts (SWF)
Coronal mass ejections (CME): cause geomagnetic storms 1-3 days later
Coronal holes: fast solar wind streams affecting the polar regions

📡 NOAA Space Weather

NOAA's Space Weather Prediction Center (SWPC) provides the official alerts and 3-day forecasts.

🔔 Solar storm scale

Scale	Type	Impact on radio
G1	Minor storm	Slight degradation of VHF signals
G2	Moderate storm	Aurora possible, HF disruption
G3	Strong storm	Serious degradation of HF communications
G4-G5	Severe storm	HF blackout possible, damage to satellites

💡 Practical tips to get more out of your QSOs

🌅 Best times

Sunrise/sunset: excellent long-distance propagation on all bands
14:00-18:00 UTC: peak on 20m for Europe-America DX
00:00-06:00 UTC: low bands (80m/40m) for DX
Solar noon: best for 15m and 10m

📈 Choosing your band

SFI < 80: favour 40m and 80m
SFI 80-120: 20m and 30m are best
SFI > 120: try 15m and 10m
K > 4: avoid the high bands

🎯 Recommended modes

Poor conditions: FT8, FT4, WSPR
Average conditions: PSK31, RTTY
Good conditions: CW, SSB
Short-range propagation: FM, AM on VHF

🔍 DX strategies

Watch PSK Reporter to see which bands are active
Use DX clusters for real-time spots
Check the grey line for long-distance paths
Try several bands quickly with FT8

📚 To find out more:

Take a look at the HB9V club's resources on hb9v.ch for detailed tutorials on digital modes, station set-up and advanced DX techniques.

📖 Glossary and references

Terms and acronyms

Term	Definition
SFI	Solar Flux Index - 10.7 cm solar flux index
SSN	SunSpot Number
A-Index	Average planetary geomagnetic index over 24 hours
K-Index	Local geomagnetic index over 3 hours
MUF	Maximum Usable Frequency
LUF	Lowest Usable Frequency
FOT	Frequency of Optimum Traffic (≈85% of the MUF)
SWF	Short Wave Fadeout - HF blackout caused by a solar flare
CME	Coronal Mass Ejection
ZHR	Zenithal Hourly Rate of meteors
Es	Sporadic-E - propagation via the sporadic E layer
EME	Earth-Moon-Earth - propagation by reflection off the Moon

🔗 External resources

HamQSL.com - comprehensive propagation tools
NOAA SWPC - official space weather alerts
SolarHam - solar news and analysis
SpaceWeather.com - daily news
KC2G Propagation - charts and trends
DXMaps - real-time propagation maps