Where to put the ground block
Can we put a ground block anywhere on our coax lines? Theoretically yes if it is properly grounded, but in reality, no.
Theoretically, if you were to lay out two new, equal 10 meter copper wires in parallel and on one put a ground block half way through it but on the other put a ground block near the end you would have a very difficult time detecting any difference in how quickly or efficiently an electrical charge applied to the beginning of the wires would be drained off to ground.
In reality, the final word is that the appropriate Electrical Code requirements for grounding your home must be followed and definitely not messed up or thrown out-of-Code by your OTA grounding solution. As discussed many times in this thread, we always try to keep any excess electrical charges from entering the building. If this is not possible, we always try to establish the most direct route of grounding to the power panel's ground point.
So, putting it plainly, make sure that your home is grounded according to Code, then ground your incoming OTA/Dish/CATV/Telecom connections to it so that your home remains within Code afterwards.