Inconsistent Home Network - Looking For Advice

[Smiley Fishy]

First of all, I will post all of the recommended specifications for my setup:

ISP: Wightman Telecom 20 Mbps Fibre to the Home, Seen Here

Router: Linksys Q87-EA4500
90% of the time only my PC is connected to it, with occasional laptops and mobile devices

Modem: Installed by Wightmans, has no markings on it, and when hooked up directly to any device (PC or Laptop) it keeps the constant 20mbps all the time

My PC (Always connected by wireless):

• 
  Motherboard: GIGABYTE GA-B85M-D3H LGA 1150 Intel B85 HDMI SATA 6Gb/s USB 3.0 Micro ATX Intel Motherboard
  
  Power Supply: Thermaltake TR2 600W Power Supply (TR-600)
  
  Wireless Adapter: D-Link DWA-552 Extreme-N Wireless PCI Adapter
  
  Operating System: Windows 10

Lastly, Speedtest.net Results

As you can see from the results, my internet speeds are very inconsistent all the time (earliest results are from March, and test speeds are as low as 100kb/s). I have tested my speeds while hooked directly up to my modem with multiple devices and they are always right at the 20mbps like they should be, but my speeds are always different while on my wireless connection (I have tested mobile devices, laptops, and my PC). I am also 100% sure that when my speeds are low, it isn't because other people are using the network. I am also pretty sure the low speeds aren't a result of my router being too far away from my devices, as I used to get the constant 20mbps since at least fall of 2015 with the exact same setup.

I was wondering if anything can be done to make my speeds more consistent while on my wireless network, as a wired network just isn't an option for me at the moment. If I need to I will buy a new router or possibly even a wireless adapter if they seem to be the problem, but I don't know for myself.

I hope someone can offer some advice, because I'm starting to go insane from these internet speeds, and it bothers my that I can't even reach the full speeds that I am paying for from my ISP. I have talked to my ISP several times and everything is always fine on their end, and the problem is somewhere in my hardware (they always tell me to rent their routers).

 

[kanewolf]

Have you tried powerline networking? It will be more consistent than WIFI. Won't be as good as wired ethernet but better that WIFI usually.

 

[azaran]

At first blush, I'm going to go with your routers wireless has some hardware fault in it or there enough interference between you and the router that you're getting such inconsistent speeds.

If you connect a laptop wirelessly to the router, and put it right next to the router do you get the same problems?

Wifi is very easily blocked (metal walls, walls with water pipes, people, trees, etc) so I'd try testing it with something mobile that you can step away from the router in increments and see whats causing your connection problem. If you're connected right next to the router and you're getting those low and inconsistent speeds, then its time for a new router.

As for getting the signal to your PC (assuming its a tower), you could try alternative means of connecting. MoCA and Ethernet over Powerline could be a good solution to bypass any wireless issues.

 

[Charitzo]

Following what Azaran said, I'd personally go wired if you can. However if that's not an option, maybe you should consider the possibility of wireless interference. Great break down of the most common ones here:

http://packetworks.net/blog/common-causes-of-wifi-interference