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



2023 is almost gone
2024 is already upon us...
A new year with new dreams... and challenges !
Everything gets a new color
Good luck and peace
Lots of love for each other
Attention to one's neighbor
It's going to be a wonderful year

Merry Christmas
Happy New Year 2024


Enjoy the Holidays

חג חנוכה שמח



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 November 29, 2023