De or het radiopeiling?

The correct Dutch article is:

de radiopeiling

Rule Words ending in -ing: almost always de. See the rule

How to use radiopeiling

the radiopeilingde radiopeiling
this radiopeilingdeze radiopeiling
that radiopeilingdie radiopeiling
our radiopeilingonze radiopeiling
your radiopeilingjouw radiopeiling
every radiopeilingelke radiopeiling
which radiopeiling?welke radiopeiling?
a big radiopeiling / the big radiopeilingeen grote radiopeiling, de grote radiopeiling