Grounding of an antenna system is always a roll the dice as to how many people will give you the same number of answers +1.
Using the guidelines from both NEC and the cellular market practices, it takes an overall larger view of what is going on. The first thing to keep in mind is that you don't really want multiple ground rods in the system unless they are all connected together. The point on this statement is that you want all devices in the antenna system to have a common ground and not a bunch of different ground rods all trying to do their part. This just allows a difference of potential that can develop between the different grounded items during a strike.
The whole intent is to have everything go up and down at the same potential at the same time. This prevents any flow of current between the different points of the antenna system and equipment. It's the current flow that kills equipment.
Using the water pipe as your ground is just drawing the high voltage into the house and allowing the high voltage to snap over to other metallic things that it can reach. This is what your trying to limit. I would not listen to much any cable tech has to say. The majority of the are lucky the know which end of a screwdriver they should be using. Once on a while you actually find one that knows his electronics, but that is not the norm.
I have had a number of them try to tell me that the coax cable between their cable box and the TV is what was causing lip sync problems on a number of the channels. My first question to them is how long have you been doing this type of work.
Bottom line on grounding is that it is a science and takes a while to understand what is going on and why you don't do certain things when grounding equipment. You will read on here that some people will tell you that there is no way a radio tower can have the radio equipment survive a direct strike to the tower. Having worked in the cellular field for over 20 years, I can say personally that a tower has been struck and the equipment stayed running. I was at a 500 foot tower when it took the hit. It was steaming in the rain after the strike. Went inside the shelter and everything was just playing away fine.
I will say that there is surge protection on the antenna cables, the power line, telco lines and internal data connections. You don't normally find all this done at a personal home. I will say that when you read about grounding, you will see the words of "grounding systems" used frequently. Just remember that it takes more than a single ground rod to make a good ground. It also takes tying everything together so there is no high resistance connection between anything metal in the system.
