Often the connection to the Internet (router) is lost how to fix it?

[allsorts]

When connection is lost to internet, can you still access the detector web and ping 8.8.8.8?

malyan has just answered that "no". That indicates to me that it is the LAN that has stopped working as the computer being used can't see the detector or the internet. As it does work sometimes I don't think that can be a routing configuration problem. Which really only leaves a problem with the LAN switch or router.

Upgrade software to 8.3b2, this version is the most stable.

https://forum.blitzortung.org/showthread.php?tid=1623

malyan says the link is not available. I'm afraid that "it works for me" both the link above which takes you to the forum topic and the link in the first post to the firmware. I've been running 8.3b2 from not long after it was released, no problems and I have turned off the deafult daily reboot. My controller uptime currently 11 days, it's been up to 40 ish days before a power cut  forced a reboot.

Voltage maybe too low, I think that voltage should be 4.75v - 5.25v or 5v +/- 5%.

Looks on the low side to me as well. 4.75 to 5.25 V is the official USB specification but the cotroller isn't a true USB device. The measured voltage is not the complete story with power. Some 5 V power supplies have a lot of noise on thier output and this can cause the controller to do strange things. If malyan has access to an osciloscope that would show up the noise. Without a 'scope try several power supplies to see if there are any differences to the performance of the controller. One might be found that is nearer 5 V as well.