Hi
I have a wifi router on ground floor of my home. The devices on ground floor are having good wifi signals. The problem is that that my PC is having only 1 signal in my room which is on 1st floor. How can I increase signals in my room?
Regards

How far is your computer from the router?
Is your computer a laptop with a built in wireless adapter or a desktop etc.
What type of building structure is between your computer and the router?

Distance and what is in between you and the router have a big affect on signal strength. I assume you are using a basic home 2.4 GHz router. Are there any other devices nearby that are also 2.4 GHz? 2.4 GHz Cordless phones have a lot more power and will interfere with a WIFI signal.

The more obstacles between you and the router, then the weaker your signal will be. Is your PC stuck under a table, next to a large pipe?

First you should find the existing signal strength. Coz if the signal is extremely weak, then it may be unfeasible to fix it. I can connect to wifi here with signal strength of -79dBm. So how does yours compare?

Given that your wifi network interface is wlan0, tryOr alternatively, a wireless scanner like iwScanner can measure signal strength too.

A lot depends on the equipment you already have. Does your router have an internal antenna? If so, then your options are limited. If your router has an external antenna, then is it removable? If so, then buy a larger antenna, and boost the signal that way.

Is your router's antenna a dipole type? If so, then there are cheap DIY projects to make a shield that fits behind the antenna to boost the signal. Look here and here.

And the same with your PC too. Is the antenna removable etc. Microwave ovens can affect wifi too.

Happy with ur solution... then tick "yes" and mark as Solved!

First, you cannot beat wired. Second, if you have neighbors they likely have Wi-Fi and their interference is much greater on 1st floor (that's the way radio communications work, too lazy to go into details). If this is the case, try using a different channel. There are only three channels that are not overlapping. First, sixth, eleventh. If your device is not mobile go wired.

Thanks all of you for your responses. Let me answer all the questions one by one:

Its a laptop with bultin wifi (I said 'PC', my mistake)
The distance of the laptop from wifi router is not more than 25-30 feet.

Type of structure!! Hmm... walls made of bricks and cement also the router is exactly in room beneth to my room.

Yes, I am using 2.4 GHz router. I don't think that there is any other device using 2.4 GHz as I don't have Cordless (i use mobile phone if it is not on same frequency...). My laptop detects another wifi which is somewhere in neighbour and on same frequency but its signals are very weak here.

There is no other obstace except walls but actually these walls should not be obstacle because I can walk between my laptop and router with any door or any other closed area.

When I take my laptop one step out my room (and still remain on first floor) the signals are now 'full' but when I take the laptop inside my room (even 2-3 steps in) then the signals drop to 1.

Also there is no device physically in between PC and router, refrigrator and microwave oven are away in other rooms.

I tried channel 1, 6 and 11 but the result is same.