C-Band Antennas in the Continental U.S.

Under the C-Band Alliance proposal to clear mid-band spectrum for 5G use, thousands of relevant C-band earth stations will have to be equipped with filters to protect incumbent customers from potential interference as 5G wireless signals are introduced to the cleared portion of the band.

The CBA has been working with its member companies, their customers and the FCC earth station database to compile the necessary information that will allow us to plan for the distribution of filters and other field services in order to clear the spectrum and preserve customers’ services.

A number of data sources inform the CBA’s view on the number of C-band “receive antennas” in the Continental United States.

The core source of data is the FCC’s International Bureau Electronic Filing System (IBFS). This database, which recently saw an influx of new registrations in response to an FCC public notice, indicates there are approximately 13,500 registered or pending valid earth stations in the continental U.S.

Under the FCC’s rules, each earth station site registered can include multiple antennas, so long as they are within 1 arc second of the initial antenna. In some cases, in comparing registrations to available images, it appears that some multi-antenna sites have not reflected all the antennas at a site in its registration.

Thus, to determine the total number of antennas, the CBA triangulated the FCC data with multiple sources of satellite imagery. Based upon this analysis, which has been conducted by our team over the last 8 months, we estimate the total number of antennas in the continental U.S. at approximately 35,000. This estimate could vary, but given it is quite likely that a number of registered sites under-report the number of antennas, we believe this to be a realistic number.

In order to plan for an interference-free environment, every antenna in the United States will need to have a filter installed at least once. Most antennas will need at least two filters, given the use of two polarizations. Furthermore, the CBA’s proposed two tranches of clearing will require filters to be installed twice, in a sizable number of antennas, because the filters in the first phase address a smaller spectrum than that in the second phase. Therefore, the CBA estimates the total number of filters that will need to be installed in the continental U.S. is likely 90,000 or more.

One of the advantages of the CBA’s approach is that the CBA will coordinate this significant effort to ensure filters are installed in a timely and efficient fashion, helping the U.S. quickly and safely get the mid-band spectrum needed to unlock the economic benefits of 5G.