Per the national electrical code (NEC) and most likely state and local codes, the new ground rod must also be bonded into the current ground system for the house.
You can't have two independent grounds, the Exede equipment is required to use the house ground. If the two grounds are separated you can have ground currents causing other issues.
A different section of the NEC code also requires a protective grounding of the satellite antenna and coax. So you can't simply disconnect the ground and run the Exede equipment without it - this is for your protection.
Thanks for the info... any idea what's causing the interference from the Exede dish when connected to the house ground? All TV's, dimmers & other electronics worked fine prior to the install & the problem is solved when I disconnect the ground wire from the Exede dish to the house. I had HughesNet & DirecTV for over 15 years with no dish grounding problem like this one. Your explaination makes perfect sense & the installer should have brought that up, but instead, he offered to isolate the dish grounding from the house... & said that (even though this is a new install) I had to pay for the service call & materials to do it.
I have my Exede modem installed in an entertainment cabinet right next to my surround receiver, DVD player, Wi, wireless router, ethernet switch, and entertainment PC (and sometimes my AT&T Microcell too).
Not a trace of hum or other artifacts when we use any of the above.
You could try isolating the Exede modem itself from the AV equipment and power it from a different AC circuit that uses a different breaker. If that doesn't help, try physically moving the modem some distance away from the equipment that is having the problem.
What is the the purpose of using a grounding rod if the ground is going to be connected to the house ground?
The purpose of tying the two grounds together is to keep ground current off the coaxial cable and to (hopefully) lower the overal resistance to ground.
As Greg said, there are two parts to the grounding process. Grounding of the antenna, and installation of a ground block on the coaxial cable prior to building entry.
The length of these ground connections must not exceed 20 ft. If that is not possible, the code provides this text: "Exception: In one- and two-family dwellings where it is not practicable to achieve an overall maximum bonding conductor or grounding electrode conductor length of 6.0 m (20 ft), a separate grounding electrode as specified in 250.52(A)(5), (A)(6), or (A)(7) shall be used, the grounding electrode conductor shall be connected to the separate grounding electrode in accordance with 250.70, and the separate grounding electrode shall be connected to the power grounding electrode system in accordance with 820.100(D)."
The referenced sections talk about bonding the supplemental grounding electrode to the building structure's ground system.
The modem itself is not separately grounded. It gets its ground over the coaxial cable and through the connection from the DC power supply, which in turn is grounded through the internal house wiring.