Auroral activity

When a solar wind blow reaches the Earth, it creates additional ionization in the areas around the magnetic poles. The radio propagation paths that cross the poles may be degraded because of increased absorption of the radio signal. The auroral activity index ranges from 1 to 10.

North Pole Aurora South Pole Aurora

Real time k-index

The K index showing the geomagnetic conditions, indicates HF noise primarily below 10 MHz.
(K=1; HF Noise= S1-S2), (K=3; HF Noise= S2-S3), (K=5; HF Noise= S4-S6), (K=7; HF Noise= S9+), (K=9; HF Noise= Black-out)

Solar Wind

The solar wind is a constant outflow of gasses, electrons and particles from the sun. Disturbances to the solar wind from a solar flare or coronal hole, can cause serious disruptions to HF by triggering a geomagnetic storm When BZ component is negative (southward) coupling with earth magnetic field is strongest and geomagnetic activity will increase. Solar wind speed is highly variable ranging from 200 km/s to 1000 km/s, increasing following a major solar flare, generating noise on the HF bands. Dynamic pressure of the solar wind is a function of speed and intensity

Solar Wind Cockpit

Galactic Cosmic Ray

It seems 160 meter ducting varies with Galactic Cosmic Rays. DXing on 160 improves considerably when GCR decreases and is at least 10 to 20 units below zero.

Sunspots (Sunspot number)


Sunspots are cooler areas on the solar surface. These active regions should be carefully watched for possible flare activity. A solar flare releases energy than can affect HF propagation:
  1. Ionizing radiation that arrives at earth immediatly;
  2. A supersonic shockwave riding along the solar wind;
  3. Dense particles behind the shockwave that arrives two to three days after the flare.
Good DX contacts are possible immediately following a solar flare until sundown due to improved reflectivity and the higher MUF opening higher bands. Night time conditions on 80-40 can be excellent. About two days after a solar flare, the shockwave arrives on earth triggering a geomagnetic storm.

Sunspots (Sunspot number)

X-ray flux levels

A solar flare is an explosion on the Sun. There are 3 categories:
  1. X-class flares are big; they are major events that can trigger planet-wide radio blackouts and long-lasting radiation storms.
  2. M-class flares are medium-sized; they can cause brief radio blackouts that affect Earth's polar regions. Minor radiation storms sometimes follow an M-class flare.
  3. C-class flares are small with few noticeable consequences here on Earth.

Short historical graph of WWV numbers

The solar flux, indicating the level of ionization, affects HF propagation above 10 MHz. The solar flux does not affect 7 MHz and below, since the MUF seldom drops below 10 MHz. The higher the inonization the more reflective our ionosphere is to HF signals, and the higher the MUF. Sunspots are cooler areas on the solar surface. These active regions should be carefully watched for possible flare activity. A index, is derived by averaging the K-index. It ranges from 0-20 for quiet conditions, up to 400 for extreme conditions, representing the overall planetary geomagnetic conditions.

WWV Numbers

Cycle 23 / Cycle 24 Prediction

With cycle 24 prediction tells us the expected peak and intensity of the sun spot cycle.

CT1BOH - Josť Carlos Cardoso Nunes -