In the case of an attic installation your tv antenna will be sheltered from the environment so there s no need to ground it for that reason.
How to ground attic antenna.
Run a length of 6 jacketed stranded ground wire from whichever you installed there directly to your bussbar.
There are very specific requirements for grounding an antenna both via mast ground and a shield ground.
Install a polyphaser or at the very least a ground cable with ring connector inline between your antenna pigtail and the coax run.
Neither apply to an antenna in the attic.
From your description it sounds as if you may create a ground loop which may cause problems throughout the house.
There is no requirement to ground an indoor or attic antenna.
However the connection of your antenna coax to various ac operated equipment in this case your converter box or tv introduces the potential of electric shock.
If you need to bend the ground wire make the bends as gradual and as smooth as possible.
If you find the attic install unsatisfactory and you move the antenna outside then you definitely do need it.
I have no idea how to ground it though.
Securely fasten the grounding wire to the side of your house using staples or other zip screw type wire clamp suitable for the job.
I want to cut the cord and put a antenna in my attic.
Stick to the building code.
I have read many mixed opinions on grounding in the attic so i have decided to ground just to be safe side.
It doesn t support what you want to do.
So there isn t any ground from the tv either to bleed off any voltage that might pass through the antenna.