ASM-1 at Green Bank Observatory

ESM Initiatives

What We're Doing

The spectrum is a finite resource, and NRAO is working to make sure that this finite resource is preserved as much as possible for use by passive services like radio astronomy. A passive service is one that does not intentionally transmit radio waves, but only receives them. Spectrum Management at NRAO encompasses five major areas of effort: National Radio Dynamic Zone (NRDZ), National Radio Quiet Zone (NRQZ), Puerto Rico Coordination Zone (PRCZ), Radio Frequency Interference (RFI) Monitoring & Mitigation, and National and International Spectrum Policy. A little more detail about each of these efforts is given below.

National Radio Dynamic Zone

A NRDZ is an idea first proposed less than 10 years ago. It will be a geographical area within our national boundaries that will be a test bed for new technologies and new ways to use spectrum. The hope is that within the boundaries of an eventual NRDZ, innovators will be able to more quickly test new ideas, and that it will enhance the cooperation between active and passive services. The National Spectrum Strategy (NSS), published in Fall 2023 specifically calls for the establishment of an NRDZ. NRAO is working to develop technologies and algorithms that will enable radio astronomers to better understand their local Radio Frequency Interference (RFI) environment, and to more easily coexist with the large and growing number of radio transmitters on the ground and in the sky.

National Radio Quiet Zone

The NRQZ is a geographical region in the Eastern US set aside by the federal government to provide a fixed location to protect sensitive instrumentation from Radio Frequency Interference (RFI). The NRQZ was established by the Federal Communications Commission (FCC) in 1958 to minimize possible harmful interference at both the National Radio Astronomy Observatory (NRAO) in Green Bank, WV and the radio receiving facilities for the United States Navy in Sugar Grove, WV (now Sugar Grove Research Station). The NRQZ encloses a land area of approximately 13,000 square miles near the state border between Virginia and West Virginia, and all fixed radio transmitters in this region are required to coordinate their location, direction and power with the NRAO Zone Regulatory Services office.

Puerto Rico Coordination Zone

The PRCZ consists of islands of Puerto Rico, Desecheo, Mona, Vieques, and Culebra within the Commonwealth of Puerto Rico (the Puerto Rican Islands). Any applicants for fixed or base stations below 15 GHz within this area must correspond directly with the PRCZ Administrator in the NRAO Zone Regulatory Services Office for coordination. This coordination insures that the location of the former Arecibo Observatory remains available for radio astronomical observations.

RFI Monitoring and Mitigation

All Associated Universities, Inc. (AUI) radio astronomy sites (Green Bank Observatory, Jansky Very Large Array and The Atacama Large Millimeter Array) carry out some sort of regular RFI site monitoring, and careful RFI testing of devices to be deployed at any of the sites. RFI is generally a bigger issue at lower frequencies, as many devices emit low frequency electromagnetic radiation, and also because lower frequencies travel (propagate) farther more easily. NRAO has many staff involved in the regular monitoring and archiving of RFI at each site. The current RFI monitoring practices at each site are explained in more detail here. Historical and more current reporting on RFI studies can be found in the NRAO RFI Memo Series. NRAO also holds a monthly RFI Journal club for scientists, engineers, and data analysts.

Sample spectra from 1-5 GHz taken with the ASM-1 device at CDL (orange) and GBO (blue). While the RFI environment is clearly better at the GBO, the National Radio Quiet Zone (NRQZ) is not completely quiet. Signals near 2.4 GHz are from WIFI networks.

ESM Policy

The Federal Communications Commission (FCC) administers the spectrum for commercial uses in the US, and is largely responsible for setting national policy on spectrum issues. The FCC also plays a large role in organizing the US national delegation to the International Telecommunications Union (ITU). It is to the FCC that astronomers must generally respond on issues affecting the health of their discipline. ITU-R, the radio bureau of the International Telecommunications Union (a UN agency in Geneva) sets radio telecommunications policy worldwide. Every 3-4 years, a World Radiocommunication Conference (WRC) crafts new treaty language to which member states subsequently adhere by national adoption (with some leeway). For more details on the organizations and agencies that impact spectrum policy nationally and internationally, see here.

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