WiFi issue

Hello, I would like to thank you in advance for taking time to read this message.

My MacBook Pro retina is connected to AirPort Time Capsule 5Ghz, now and then the connection seems lost. The WiFi icon on the Mac doesn't appear grey but if I check the bandwith by holding option key I see 14mbps...

In fact I'm in the very same room as Time Capsule is. My bandwith is always 450mbps. But for whatever reason the bandwith drops to 14mbps now and then and comes back to 450mbps within 10 seconds.

When it happens the files I was downloading, uploading or the web pages I was browsing stop. Like if my WiFi was turned off. And within 10 seconds everything works fine again.

The 5Ghz network is all set to automatic. I never had issues before... It happened a week ago...