Welcome to the home page of Ham Radio Station OP4K    

Primary call ON4JZ
Other callsigns used OO4JZ - OQ4JZ - OR4JZ - OS4JZ - OT4JZ and OT5A (contest team Lier M/M) 

Ex callsigns ON1BZJ - ON4AJZ





WW locator JO21FF
GPS coordinates
5112'35.28"N    425'47.45"E

Member of (click on each icon for more information)

Province: Antwerp (AN)
Section: Antwerp Contest Club (ACC)






What are K and A indexes?
The K-index indicates the size of the irregular changes in the magnetic field of the earth over a period of 3 hours. This index is calculated on the basis of values ​​measured by an observation station, wherein the location (relative to the magnetic pole) of the station is taken into account. These observations are made ​​by many observatories.

The scale of the index K is quasi-logarithmic scale, and the number increases with the size (from 0 to 9) of the disturbance of the magnetic field.

The A-indices may vary in value from 0 to 400, and are derived by means of the K-indices a table of equivalence as follows:

K 0 1 2 3 4 5 6 7 8 9
A 0-2 3-5 6-10 11-20 21-35 36-61 62-102 103-166 167-268 >269

There is also a conversion of these indices by "name":

A-index K-index Name
0-7 0-1 Quiet
8-15 2-3 Unsettled
16-29 4 Active
30-49 5 Minor Storm
50-99 6 Major Storm
100-400 7-9 Severe Storm


Ziegelshiffer Joe OP4K 2021 - Last update July 22, 2022