RFI Mitigation on Site

The Green Bank Observatory is a unique resource for Radio Astronomy. We are located in the National Radio Quiet Zone (NRQZ) which provides protection from permanent, fixed, licensed transmitter services. Our location, surrounded by National Forest and the mountainous terrain of West Virginia, also serves to protect observations. Additionally, the West Virginia Radio Astronomy Zoning Act allows us to prohibit the use of any electrical equipment within a ten mile radius that causes interference to Radio Astronomical Observations.

On the Green Bank Site our protection policy differentiates two zones, one for the laboratory, housing, and visitor facilities (Zone 2), and one for the Radio Astronomical Instruments themselves (Zone 1) as illustrated on the following map:

In Zone 1 a preventative, proactive approach is used. Interference potential is assessed through testing, and equipment is shielded, filtered, etc. as necessary before installation or use. By policy, we do not install equipment first and then mitigate it if it happens to cause interference. We additionally protect this zone by limiting motorized traffic to approved diesel vehicles, and all persons in Zone 1 should leave their electronic devices behind, whether they are entering by foot, bus, vehicle, bike, or any other means.

So, for Zone 1:. So, for Zone 1:

All digital cameras, cell phones, fitness trackers or similar devices should be left at home or have transmissions turned off and be left in your office, or in your vehicle the Jansky Lab, or in your car or residence. (How do I turn off my device?).
If your work involves any equipment that will be left behind after you leave, whether it is installed or just overnight our out of work hours, that equipment must be tested and approved or given a waiver before being brought into Zone 1.
Temporary equipment which is known, or likely, to cause interference must be given a waiver in advance of entering Zone 1.
Only approved diesel vehicles are allowed in Zone 1.

Remember – the GBT is not the only instrument on site. We have many project sharing out facility. As a result, coordinating with the GBT schedule is not sufficient.

Zone 2 includes the laboratory, housing, and visitor facilities. Here we differentiate between intentional and unintentional radiators. An intentional radiator is any device that intentionally, or is known, to transmit radio waves. All intentional, and known, radiators are prohibited unless a waiver for their use has been granted. Prohibited devices include cordless telephones, Bluetooth headsets and other devices, most raspberry pi and similar small computing boards, cell phone which do not have all transmissions completely off, microwave ovens, etc. A good rule of thumb is, if it uses radio frequency energy to communicate, it is likely prohibited. Waivered devices include site radios when used exclusively for the safety of staff and visitors (43 MHz radios), 2.4 GHz WiFi (in Zone 2b only), and Bluetooth devices which are necessary for the safety of staff (e.g. heart and blood sugar monitors).

Following these simple guidelines goes a long way toward preserving the relatively RFI quiet environment at Green Bank Observatory. Your cooperation is vital to protecting the research that we do.

If you would like to request an RFI waiver, please go to: https://forms.gle/T71Cbo6FztXbW73V7.

If you have any questions, feel free to reach out to the Green Bank IPG (ude.o1760093069arn@g1760093069pibg1760093069 or ude.o1760093069arn@d1760093069ael-g1760093069pibg1760093069).