A very unique air-raid siren recording....

Function check of an old air-raid siren as a special double-tone version: with high-tone & low-tone in action at same time. This siren was constructed in the year 1934 by HELIN. It was in use in war times of the WW2. Now the low-tone unit was reactivated by an accurate restoration of the whole siren. It was out of function since 1 1/2 years, because it wa so difficult to find a way to restore this siren in an original state as it was in the year 1934.
Every 3rd saturday in a month is a regurlarly check of this rare & unique kind of siren. Her location is on area of the voluntary fire department (Schiffdorf/Niedersachsen/Northsea/Germany).
Remember the recording exactly 3 years ago: https://youtu.be/L76AK0HFhfY

Some more detailed informations about this siren will come later!!