Morning jingle where?

Hi,
Back in 2017 I was staying in Anbo in Yakushima island. Every morning at 6 I was woken by a kind of morning jingle playing loudly around the town area.

I learned this is some kind of way testing the equipment everyday, which makes sense. And it was a good alarm clock for me as the minshuku offered me breakfast by 7.

I have also heard this kind of tune in Tokyo, not the same tune but it was playing in the early morning. I did not expect that in such a big city though. I have never heard it before while staying in Tokyo.

How common is it to find this kind of morning jingle in Japan? I mean, does it play everyday, everywhere? Or just certain times of the year?

It's difficult to determine without a sample audio.
Did it sound like this?: https://youtu.be/b4SH_lap4ag
Then it's a morning calisthenics that is common in schools, some work places, and some parks.
But 06:00 is probably too early for schools and work places.

In Japan as a whole there are few areas to be broadcast in the morning.
There are still many towns in the country that are broadcasting to urge children
at 17:00 in the evening to back home. (also in some urban cities, but it is very rare)
https://youtu.be/8yz23xrR5QE

In Yakushima it seems to call "village broadcasting(集落放送 shuuraku housou)",
https://youtu.be/fjQNB93IT_U
but in Japan as a whole it is called "town broadcasting(町内放送 chounai housou)"
or "disaster prevention radio broadcasting(防災無線放送 bousai musen housou)" usual.
http://www.soumu.go.jp/soutsu/kyushu/ru/prevention.html
In coastal area, also "test broadcasting(試験放送 shiken housou)" is conducted once a week
to confirm the operation of the "tsunami" warning system.

It is also functioning as a substitute for watch in areas where agriculture is popular
as "scheduled broadcasting(定時放送 teiji housou)" or "time signal(時報 jihou)",
12:00 for lunch time break and 15:00 for tea break mainly.
In areas where mountains are close to,
broadcasting is done with contents like attention to "monkeys" and "bears".
At the fishing port, it is sometimes used as a signal of the fishing start time.

In the southern areas such as Yakushima, the "typhoon" often hits directly,
so it is also used for the purpose of disaster prevention,
and on remote islands it may be broadcast whether the ferry is operated or not in the morning.

In recent years, test broadcasting of "J-Alert" and warning of "bank transfer fraud" are increasing.
https://en.wikipedia.org/wiki/J-Alert
https://en.wikipedia.org/wiki/Phone_fraud
https://www.photolibrary.jp/mhd7/img591/450-20180423110053181017.jpg

In holiday morning extraordinary broadcast,
it is mostly whether or not to hold a local event (traditional fes and sports day).
Also to signal whether to hold a festival or not especially sports day(運動会 undou kai),
some fireworks(花火 hanabi) are launched at 6:00 or 7:00 rather than broadcasting also usual.
https://youtu.be/ljl7KaqmhW4
https://youtu.be/ZF1XYnz0Fxw

Here's the one I heard in the mring in Yakushima.

https://www.youtube.com/watch?v=C3ejoc4Pe7A


I think it was the same kind of sound but with Für Elise playing in Tokyo. I made a slight recording of it but havn't been able to find the recording yet among my tapes.

The Yakushima one is actually the song Edelweiss from Sound of Music. I would not be surprised to find out the other tune you remember is Fur Elise.

https://www.youtube.com/watch?v=4g84dejrJXI

Minato-ku plays one through the wards street sound system every evening at 5pm.