Complex sentence: The first "scheduled" (announced in the press) radio broadcast is said to be made by Nederlandsche Radio Industrie station PCGG at The Hague, which began broadcasting concerts and found it had a large audience outside the Netherlands, mostly in the UK.
Split into simpler sentences: The first "scheduled" (announced in the press) radio broadcast is said to have been made by Nederlandsche Radio Industrie station PCGG at The Hague, which began broadcasting concerts. It found it had a large audience outside the Netherlands, mostly in the UK.