Contemporary military and civilian systems become increasingly dependent on electronic devices. This is in particular pertinent to the development of the NBF (Network based defence). One powerful weapon against such a system is HPM-weapon. One component often utilised in the pulsed power system of a HPM-weapon is the spark gap. This report outlines how one may simulate this radiation from a spark gap that is included in a pulsed-power conditioning system. Models of spark gaps incorporated in circuit simulation software are powerful in the simulation of the current passing through the spark gap when the spark gap forms a part of a pulsed power conditioning system. When this current is found, it can be used in radiation calculations.