Since this report was written over a two year period, not all procedures and results are valid anymore. Some new reduction software has been written like a new source extraction program. This program is written in IDL by R. Rengelink. The reason why we changed from AIPS to IDL was that over the years new features were needed in SAD that were not available in the original AIPS program. At a certain point it became allmost impossible to change the software (partly because AIPS software is very hard to rewrite, partly because the whole structure of SAD had to be changed because of our new requirements). Late 1993 a decision was made that a new SAD program had to be made, completely rewritten from scratch. Since IDL was allready heavily used for other tasks the decision was made also to program the new SAD routine in IDL. Since R. Rengelink wrote this program details are not mentioned here. A desciption of the algorithms used will be published in the first article about the technical details of the WENSS survey (to be published in 1994/1995).