I would not worry about negative power levels as they are measured on a logarithmic decibel scale relative to 1mV, so power levels lower than 1mV voltage will have a negative decibel value.
The network logs maybe useful.
As you are experiencing poor speeds all the time, it maybe worth starting a broadband quality monitor here. You will need to enable Respond to ICMP Echo Requests in the advanced section of the Hub's GUI first if you have a SH 1/2
It has never been this high for weeks so i really do not know what is going on and before anyone suggests it is high utilization at peak hours i would have to disagree due to the fact run tests each night at various times and this is the highest for this time it has ever been.
My speeds actually hit 205 mbs two nights ago but were down to 160 this afternoon and as i type this im down to 90 mbs which is still better than 1 or 10 mbs which i have been getting but i would like to know why there is such a huge difference in speeds.
This is my speed test results over the last month where you can see the differences in speeds.
The 2 links you provided will only work for you, we cannot view them... take screenshots and post images.
Welcome to the high utilisation club, a member of the forum team will apologise in 7 days or so and supply you with a fault code you cannot look up and a review date that means nothing as its not a repair date.