WiFi is very weak on module

I have recently bought Jetson TX1 module and flashed Jetpack 3.3 L4T r28.2.0
I can see that I have a wifi card and ifconfig actually shows wlan0. But the problem is that my wifi is very weak and I am not able to connect to my wifi. I can see that my wifi exists but with only 1 bar.

How can I fix it?

abyl.ikhsanov,

Do you have an antenna connected to the system?

No I do not but will it change the signal drastically? I thought I can use WiFi without antennas due to design limitations of my application.

Can I use other antennas which are smaller?

In my experience, with a VERY strong wifi signal in my office I could not connect without an antenna even though I could see the access point.

I would expect that an alternate antenna would work but I’m far from an RF expert! The antenna provided in the dev kit works well.

I did some research and ordered these antennas: