I need to move the tv to another side of the room, but the cable is too short. I will have to move it again in the future (long story, trust me) and do not want to hassle with cable guys coming over.

While Samsung has the allshare box for 2500 Baht, that is only to wirelessly stream the screen from gadget to tv.

I need to plug the cable to a box. Then another box (?) to the tv in order to get cable to it. Possible? Move it around and still get cable? Wet dream?

Buy a Cable TV wireless extender.

Something like this?

http://www.allaboutadapters.com/witvtuavsere.html

Assuming the cable box is HDMI-out:

http://www.amazon.com/dp/B0043BPZWA

Not that cheap, but then again you have the freedom to move the TV as and when you feel like it.

No box. Just a coax coming out of the wall. The tv has an hdmi plug, also.

Will look into the other items posted.

Oh, you mean "terrestrial television"?

Can't remember, it's been a long time.

When you said "cable" I assumed you meant "Cable" not "a cable".

You are out of luck if there is no set-top box as such.

You need a wire..

Wired connection is the simplest. Why not just get matching cable (impedance must be same) and use a cable connector to join that to the existing cable->TV connection.