I have a computer which is plugged directly in the net via the ADSL modem provided by the ISP.
Sometimes there is need to connect other computers on the net. Then I add a TP-LINK wireless router to the sytem, so that the wireless router is plugged into the ADSL modem and the mentioned computer is plugged with a cable into one of the ports of the wireless router and other computers connect wirelessly.
The problem is when the wireless router is connected then the net is much slower. When the computer is plugged into the ADSL modem directly then it has 2 MBps download speed, but if it is plugged into the wireless router then the download speed is only 0.7 MBps.
Why is that? It's not the problem of the wireless connection, because the main computer is plugged directly into a port of the wireless router, so it has direct cable connection (computer - wireless router - adsl modem). I'd understand it if it were a wireless connection, but it is a cable connection, so there couldn't be a collision in the radio frequency. BTW, the net is slow even if only the main computer is connected to the wireless router, so it's not about the other computers connected wirelessly taking up extra bandwidth.