Anyone know something about modifying USB wireless card, and is it clever to put de-solder antenna and put connector for connecting antenna cable and putting outdoor antenna or maybe better indoor antenna ?

I know something:) ...just kidding - I dunno anything about that bro.. maybe someone here would know more...

Yes, and you probably should not do that. Modifying your wireless card IS LIKELY to give you many problems. One of the first problems you are going to run into will probably be impedence mismatches from your solder joints and definately mismatches if you change the antenna. Placing your antenna outdoors will not necessarily be any better than having it indoors. The only reason to have an outdoor wireless antenna, in my opinion, would be to service an are that is not within a normal wireless range. (From your living room to bedroom for example.) Sounds like you might need an industrial wireless solution.

Check out www.cirronet.com for an idea of what I am talking about.

Good luck!

I realised this thread is about 2 years old. Anyway since it is bumped, I shall contribute.

You can modify your own wireless cards or even your wireless router to whatever you want it to be. However by modifying, all warranties will be void immediately. Also, you have a very high chance of getting a non-working product as a result unless you are very sure of what you are doing and a professional in it. If you know how to modify it, you can even tune it into FM radios or detect walkie-talkie signals at far ranges.