Will my powerline deliver lesser speeds if connected to extension cord?

[GambinoGod]

Now I am no electrician or an networking specialist type of guy, but I am purchasing a powerline adapter (this one >

that has no built in sockets (powerline with sockets >

Since I have two sockets and one is being used by my PC and the other for the extension cord, I have no others choice but to connect it to extension cord.
Will it deliver lesser speeds when connected to extension cord rather than an wall socket?

 

[why_wolf]

They recommend against using an extension cord. Using one may make the powerline adapter not work at all.

 

[Alabalcho]

Why not just plug your PC into the power socked already on the plug?

 

[USAFRet]

You've shown powerline devices for two different locations..
US and Europe.

Where are you?

And connecting the powerline through a power strip may not work.

 

[GambinoGod]

I am from Europe, and I am not connecting my PC to some cheap extension cord, hell no.
I guess I am buying a powerline with built in sockets which concludes this thread.
Thanks for you responses.