Spokane DX Association

The colored insert can give you good information on how the bands are in real time. It is updated every three hours. Here are some definitions.

Solar Flux – The 10.7 cm (2800 MHz) radio flux is the amount of solar noise (light) that is emitted by the sun at 10.7 cm wavelengths. The solar flux is measured and reported at approximately 1700 UT daily by the Penticton Radio Observatory in British Columbia, Canada. Values are not corrected for variations resulting from the eccentric orbit of the Earth around the Sun. The solar flux is used as a basic indicator of solar activity. It can vary from values below 50 to values in excess of 300 (representing very low solar activity and high to very high solar activity respectively). Values in excess of 200 occur typical during the peak of the solar cycles.

The solar flux is closely related to the amount of ionization taking place at F2 layer heights (heights sensitive to long-distance radio communication). High solar flux values generally provide good ionization for long-distance communications at higher than normal frequencies. Low solar flux values can restrict the band of frequencies which are usable for long distance communications. The solar flux is measured in “solar flux units” (s.f.u.). One s.f.u. is equivalent to a unit of solar radio emission per unit frequency interval, equal to 10 to the -22 power watt per square meter per hertz at the earth.

K is an index number 0-9 that is related to the maximum fluctuations of the magnetic field observed on a magnetometer relative to a quiet day, during a three-hour interval. For more information on the relationship between the K and the A, go to:

http://www.swpc.noaa.gov/info/Kindex.html

nT is nano-tesla, where tesla (symbol T) is actual unit of measure for the magnetic field or magnetic flux density.

The background X-Ray is in levels, with a letter and number. LT A 1.0 is the absolute lowest. LT = light, A1.0 is lowest, A5.0 would be higher in the lowest catagory, then it goes to C X.XX and M X.XX . Current x-ray flux readings are from the GOES-10 and GOES-12 satellites. The lower the readings, the better HF / shortwave propagation conditions are. Ranges are A1-A9,B1-B9,C1-C9,M1-M9,X1 and up. Low readings, especially in the A range, generally indicate good conditions. Higher readings can indicate poor conditions. Solar flares can cause readings to jump into the M and X range, which can cause radio blackouts for paths in the sunlit area.