My D7000 appeared to be working OK until I bought a new laptop. The laptop would connect to the router OK, but once it did all other devices on wifi, and the laptop, ran very very slowly (less than 2Mbps instead of 30 plus Mbps). I thought it was the ISP, but it wasn't. This happened regardless if I connected on a 2.4 or 5GHZ channel and to all devices whether they were on 2.4 or 5GHZ. Ethernet connected devices appeared to be OK. Disconnect the laptop and everything fine again. I plugged in a usb wifi dongle and used that rather than the inbuilt wifi adapter on the new laptop, but same result - i.e everything on wifi running very slowly. However, if I connected to the wifi via my tethered mobile (which was connected to the router via wifi), everything was fine with normal speeds. So something about the laptop's wifi, when connected directly to the router, makes the wifi bandwidth go right down.
So far everything pointed at the laptop having the problem. However, I swapped routers to one the isp had provided and everything now works fine.
I used metageek's Insider to look at the signals coming from the D7000 and noticed something odd, which might be related to the fault. On the 2.4GHZ channel showing the Mac address of the router there was also another stronger signal on the same channel with a different Mac address. This was also coming from the D7000 even when nothing connected to it and with the new problem laptop not connected. Every time I changed channel this signal changed with it. Switch off the 2.4GHZ channel and the signal goes too. Looking at my network map there is nothing with the rogue signals Mac address and it does not seem to be part of the router, but clearly is.
I checked the wifi adapter settings of the laptop causing the problem with another latop that did not slow down the wifi when connected, and they appear to be the same as the new laptop's except the old laptop's it is only 802.11a/g and the new laptop is 802.11n. However, my phone has wifi 6 and that connects to the router without slowing the bandwidth.
The new laptop has a problem, but clearly the fault is with the router. Something with the new laptop triggers the problem with the router. I am at a complete loss to understand what is causing it. Any ideas?
