Connection only apparently good / signal fluctuates greatly in reality

The quality of the radio signal is very volatile at in this WLAN adapter and breaks often for very short periods sometimes completely. It seems as if the signal processing with the two antennas do not work cleanly.

My 6 year old HP laptop with an internal 54Mbit Intel WLAN Card provides the same location from a much clean signal image.
See also added customer images in the gallery mode.

In short, the product is not recommended, moreover, has TP-Link still not managed to provide a Windows 8 drivers, although the adapter came on the market only after Windows 8.

The signal was measured using the inSSIDer program and recorded.