From some time my time capsule (new one) almost everyday for 5 sec i lost connection. And i think it started since the last version update. Is there a setting for that or is probably my provider or is my TC fault?
So what you are saying is that you applied the new 7.7.3 firmware and now it has issues? I am not aware of any issues with the new firmware, but I am not denying their possibility in your configuration.
If using a Mac, open AirPort Utility and select your Base Station. Where you see the version (e.g. 7.7.3) hold option and click it. A small drop down menu will appear and allow you to select the older 7.7.2 firmware.