Wi-Fi loosing connection every few seconds on my macbook pro and its not my router's fault (running yoseomite)

Question

Basically I bought my new Macbook Pro retina display in September 2014. My wifi was working perfectly well for about a month or two until Yosemite was brought out. I'm not sure if it was immediately after I downloaded Yosemite or not, but not long afterwards I noticed I was having trouble with my wifi (and not just mine but my schools as well). Every time my computer tries to join the wifi network it will work for a while (5 seconds) and it will say that I have a wifi connection but then it will just stop working and it will say I'm not connected to wifi. A few seconds later and it will then reconnect and say I have wifi. I am fairly certain this is not my wireless router ( a BT home hub) as I have other devices such as my iPhone and a computer which does not suffer these problems. After a while of it loosing connection and then gaining connection it will finally stop and the wifi icon at the top will suggest I have a wifi connection but when I hover over it, I see it says "Wi-Fi:looking for networks..." and then 2 seconds later it will say "Wi-Fi: On" and it will repeat like this for however long I am on the network. When the icon appears to suggest I have a connection I am able to load a webpage but it is slow and watching Netflix can be tiresome. I've scoured these forums for information that will solve my issue however all I have found is outdated information from 2010 or 2012 or too technical information that I can't understand. Does anyone else have this problem, has anyone else found a solution, it would be much appreciated if any one could help me solve t.

Answer 1

Please test after taking each of the following steps that you haven't already tried. Stop when the problem is resolved. Back up all data before making any changes.
Step 1
Take the applicable steps in this support article. The Wireless Diagnostics program generates a large file of information about your system, which would be used by Apple Engineering in case of a support incident. Don't post the contents here.
Be sure to test on more than one Wi-Fi network, if at all possible. A desktop computer can be tested with a mobile hotspot, such as the hotspot created by a cell phone. If the problem only exists on one network, then the access point of that network should be the focus of your attention, not the computer.
Step 2
Disconnect all USB 3 devices. If you don't know which are USB 3, disconnect all USB devices except keyboard and mouse.
Step 3
If you're not using a wireless keyboard or trackpad, disable Bluetooth by selecting Turn Bluetooth Off from the menu with the Bluetooth icon. If you don't have that menu, open the Bluetooth preference pane in System Preferences and check the box marked Show Bluetooth in menu bar. Test. If you find that Wi-Fi works better with Bluetooth disabled, you should use the 5 GHz Wi-Fi band. Your router may not support it; in that case, you need a new router.
Step 4
Open the Energy Saver pane in System Preferences and unlock the settings, if necessary. Select the Power Adapter  tab, if there is one. Uncheck the box marked
          Wake for Wi-Fi network access
if it's checked.
Step 5
Open the Network pane in System Preferences and make a note of your settings in the Wi-Fi service. It may be helpful to take screenshots of the various tabs in the preference pane. If the preference pane is locked, unlock it by clicking the padlock icon and entering your administrator password. Delete Wi-Fi from the service list on the left by selecting it and clicking the minus-sign button at the bottom. Then recreate the service by clicking the plus-sign button and following the prompts.
Step 6
In the Wi-Fi settings, select
          Advanced... ▹ TCP/IP ▹ Configure IPv6: Link-local
Click OK and then Apply.
Step 7
Reset the System Management Controller.
Step 8
Reset the PRAM.
Step 9
Launch the Keychain Access application. Search for and delete all AirPort network password items that refer to the network. Make a note of the password first. Turn Wi-Fi off and then back on. You'll be prompted for the password when you reconnect. Save it in the keychain.
Step 10
Make a "Genius" appointment at an Apple Store, or go to another authorized service center.