My Wi-Fi link-speed is only on 11mbps

Hold down the Option key while you click on the Wi-Fi Icon one the menuBar. You get a display like this older one:

use its info to answer these questions:

> what do you get for PHY Mode and Channel?

> what do you get for RSSi or Signal or signal-to-Noise, and

> at what estimated distance from the Router?

> What do you get for tx or transmit rate?

> How many Networks are shown?

That information you posted is not self-consistent. You cannot use 802.11 ac on the 2.4GHz band. I will presume you meant to say it is currently using 802.11n.

You have a signal (RSSI ) level of -64dB. With a typical noise level of -85, that give you about -19dB of signal-to-noise, which is good.

A transmit rate of 145 on this channel says you are using two antennas, and the data are being sent as the difference between the two to double the transmit rate.

You are using the very crowded and interference-prone 2.4GHz band, where there are only three clear channels, and most of your neighbors are likely fighting with you over those channels. If your Router is set to "automatic" channel selection, it will "sniff" the airwaves when it power sup, and move to the least-used channel.

If your Router were capable of operating in the 5GHz band, I would expect it to be using the 5GHz band and to be giving you better transmit rates, although it may not as you are near the edge of good transmit rates using the 2.4GHz band, and 5GHz signals are little harder to pick up.

If your Router has 5GHz band, you can Force it to connect on that band by giving the two bands different names, and selectively logging in to the 5GHz network.

¿are you, in fact, using 802.11n and not 802.11ac?

¿Is your Router currently set for "Automatic" channel selection? or did you choose Channel 6 manually?

¿Is you Router capable of 5GHz channel operation?

-- If unknown, please post the Make&Model and readers can try to look it up.