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I watched a DX-Engineering video today on YouTube, meant for Ham (Amateur) Radio operators.  Overall it was very good, and in the main DXE is an excellent place to find information on RFI, and such topics as coaxial cable and RF connectors.

Interestingly, one of the common maladies that both Hams and Wi-Fi networks face is Radio Frequency Interference (RFI).   

It is often the case that RFI in Ham stations can be cured, or at least reduced, by the proper addition of Ferrite cores on interconnecting cables.  That is, provided that they are of the proper "mix" i.e. chemical composition, and other installation consideration.    Sometimes, a slightly less than optimal Ferrite core can even help, if "enough" of them are used. 

In the DXE video, a table is presented that shows mix # 61 as being effective up to 2 GHz.    This is nonsense, and I can tell you from extensive personal experience that Mix-61 might be helpful, under a few extremely limited and properly shielded conditions, but  in 99.999% of cases, neither Mix-61 nor any other ferrite cores, will provide effective shielding against 2.4 GHz  or higher frequencies.

Mix -61 just cannot help with GHz RFI mitigation in a WLAN environment, in the same way that a single or string of Ferrite cores can help with HF through VHF frequencies.    If you need better shielding at Wi-Fi frequencies, look to extremely well shielded Faraday cages and double shielded coax cables. 

Even double copper screened and  professionally installed Screen rooms can leak enough WLAN signal to disturb RF measurements made within them.  I have even seen $250k  full metal and ferrite-tile shielded rooms leak when careless (or clueless) technicians have left cable access holes, under  their raised floors, partially open.  Compliance engineers, are not necessarily radio engineers.

In reality, Mix 61 is only useful up to approximately 600 MHz, and that is probably stretching things.   If you inspect just about any Impedance plot for a ferrite, you'll see a peak at the higher frequencies, that gradually drops off again.  This is the self-resonant frequency of the ferrite and is the point where the ferrite should not be expected to add any further reduction in RFI.

I am a fanatic about using Ferrites cores.  I love them, but trust me as a Ham and WLAN professional, don't expect currently available Ferrites to help you with Wi-Fi  interference.    I'm still hoping for this to change some day, but I'm not holding my breath.