Default [Q] Is there a way to controll wifi strength in tethering?

Hello. There are many people who are more intelligent than me and I hope they may answer my question. It's only slightly related to N7 and I guess it may be removed. Nevertheless, I'll have a go!
So, the problem is that I purchased a 2012 wifi N7 and I have a free 3g internet available. I want to use an old LG GT540 as a modem, The problem is that wifi tethering drains my battery really fast. Is there a way (an app, a frameowork, a setting) to reduce the wifi strenght? I always carry my N7 around LG and I don't want it to produce a very strong wifi signal.
Thanks in advance for any possible solutions.