Exhibit 3.6

                            CERTIFICATE OF FORMATION
                                       OF
                                  COAXIAL LLC

     This Certificate of Formation of Coaxial LLC (the "Company"), dated as of
July 24, 1998, is being duly executed and filed to form a limited liability
company under the Delaware Limited Liability Company Act.

     FIRST.  The name of the limited liability company formed hereby is Coaxial
LLC.

     SECOND.  The address of the registered office of the Company in the State
of Delaware is 1209 Orange Street, Wilmington, New Castle County, Delaware
19801.

     THIRD.  The name and address of the registered agent for service of process
on the Company in the State of Delaware are The Corporation Trust Company, 1209
Orange Street, Wilmington, New Castle County, Delaware  19801.

     FOURTH.  The name and address of the authorized person are Sarah J. Welch,
c/o Dow, Lohnes and Albertson, PLLC, 1200 New Hampshire Avenue, N.W.,
Washington, D.C. 20036.

     FIFTH.  Any manager of the Company shall have only that authority
specifically delegated to the manager in the limited liability company agreement
of the Company or in a management agreement entered into pursuant to the limited
liability company agreement of the Company and executed on behalf of the Company
by all members of the Company.

     IN WITNESS WHEREOF, the undersigned has executed this Certificate of
Formation as of the date first above written.



                                        /s/ Sarah J. Welch
                                        -------------------
                                        Sarah J. Welch
                                        Authorized Person