If you have no access it s hard for me to tell you to go to extremes to find a way.
Do you need to ground antenna in attic.
But if you have access to a ground connection that can serve the attic splitter it makes sense to use it.
Agreeing with adtech i don t see the nec requiring you to ground an indoor antenna system.
Some attics are dark unwelcoming places used only for extra storage and in those cases nearly any antenna will get the job done.
Typically the house wiring and gutters represent a much lower impedance path to ground for lightning than the floating attic antenna.
There is no requirement to ground an indoor or attic antenna.
If you look at the image below you ll want to use a 6 awg ground wire for all of your grounding runs and suitable ground clamps.
Keep your grounding parts however.
If you ve taken the time to insulate lay flooring or even decorate your attic however you may want something that s a little less of an eyesore.
Below is an image taken form the nec code book that shows how to properly ground a tv antenna.
For all practical purposes an attic antenna is considered and indoor antenna and does not require any special grounding.
The nec requires that the antenna mast be grounded directly.
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.