All Quiet On The West Virginia Border: The National Radio Quiet Zone

Ask a hundred people why they like to escape to the forest and you’ll probably get a hundred reasons, but chances are good that more than a few will say they seek the peace and quiet of the woods. And while the woods can be a raucous place between the wildlife and the human visitors, it is indeed a world apart from a busy city street, at least in the audio frequencies. But on the EM spectrum, most forests are nearly as noisy as your average cube farm, and that turns out to be a huge problem if you happen to run exquisitely sensitive radio receivers.  That’s the reason for the National Radio Quiet Zone, a 13,000 square mile electromagnetic safe-zone in the woods west of Washington DC. Who’s listening to what and why are a fascinating part of this story, as are the steps that are taken to keep this area as electromagnetically quiet as possible.

Great Big Thing

NRQZ_map_colorLike so many aspects of our contemporary technological life, the NRQZ can trace its roots all the way back to the Cold War era. When the Soviet Union launched Sputnik and started the Space Race, the US was far behind and knew it. Playing catch-up involved building all the infrastructure needed to support a space-faring culture, and radio astronomy was a big part of those early efforts. Finding a convenient place to build that infrastructure that was not subject to a lot of interference was an imperative.

Established in 1958 by the FCC, the NRQZ is a rough rectangle of land about 110 miles by 120 miles, straddling the border between Virginia and West Virginia and just barely touching the western tip of Maryland. Nestled in the Allegheny Mountains, the area was selected for a national radio astronomy program first for its proximity to Washington, but also for the possibility of using terrain shielding to protect the yet-to-be-built antennas from stray RF interference. The area was also sufficiently rural and difficult to reach that it was expected to not suddenly share in the post-war boom in development; even in the 1950s, the suburbs could be noisy RF environments.

The “Great Big Thing”. Source: NRAO

The National Radio Astronomy Observatory (NRAO) Green Bank site, located in the western third of the Zone, has been the home of a number of telescopes over the years. The original main dish served from 1962 until it collapsed in 1988. The current dish, officially the Robert C. Byrd Green Bank Telescope, was built in 2000.

The list of superlatives of this piece of technology is almost as massive as the thing itself, which is currently the world’s largest fully-steerable radio telescope and consequently the largest moving land-based object in the world. Its 2-acre main reflector has over 2000 panels that are individually repositionable with an accuracy of 0.003 inches, which helps it adjust for the distortions introduced by gravity. Abbreviated “GBT”, it’s no wonder they just call it the “Great Big Thing.”

Lowering the Noise Floor

But an ultra-sensitive set of ears is no good with a high noise floor, so the NRQZ sets strict limits on emissions in the frequencies that are important to radio astronomy. That mainly means the microwave frequencies, and since the GBT’s active surface allows it to work efficiently up to 116 GHz, there’s a huge chunk of spectrum that’s off limits. And it just so happens to correspond to the wavelengths that are most important to our current wireless world. The Zone is administered by the FCC, so the rules mainly concern licensed transmitters, and license applications are strictly reviewed with preference given to public safety systems.

Portable Emissions Measurement Setup (PEMS) used by the NRAO Interference Protection Group. Source: NRAO

But it’s the huge increase in unlicensed transmitters in the Zone that cause the astronomers the most grief. Bluetooth, WiFi, wireless landline phones, alarm systems, and even microwave ovens – the GBT cafeteria microwave is in a Faraday cage, by the way – can ruin a telescope observation session. Even broadband RFI from spurious sources can wreak havoc, including a ratty old electric blanket that was arcing, or the RF from the ignition systems of gasoline engines.

The latter is mitigated by limiting vehicles within a mile of the antenna to diesel engines without ECUs. Tracking down and correcting the former is a job for the NRAO’s Interference Protection Group. Armed with spectrum analyzers and directional antennas, the team searches for point sources of RFI and works with the telescope’s neighbors to remediate the problem. For the dodgy electric blanket, which was used to comfort an elderly couple’s old dog, the solution was as simple and humane as buying them a new blanket. Things get a little harder when the source is telemetry tags for flying squirrels being studied by the Fish and Wildlife Service, but somehow the IPG manages to keep the Zone quiet enough to do important science.

Spooks in the Zone?

But is science the only thing going on in the Zone? Not by a long shot. The eastern third of the Zone is home to Sugar Grove, West Virginia, the decidedly landlocked former home of Naval Information Operations Command Sugar Grove. Decommissioned in 2015, NIOC Sugar Grove started life in the Zone as another radio telescope installation, with what was to be a 600-foot parabolic dish to gather signals intelligence by capturing stray Soviet radio signals bouncing off the moon. Construction was halted in 1962, and through the lobbying efforts of Senator Byrd, and because of the good listening conditions in the Zone, Sugar Grove became a naval listening station.

“Fred-10” arrays at Sugar Grove. Source

The mission of Sugar Grove was unclear. The Navy maintained that the two AN/FRD-10 circularly disposed array antennas (CDAA) were used primarily for research and maritime search and rescue efforts. But the “Fred-10” arrays were gigantic circular antennas with a 3200 nautical mile range that could be electronically steered and were used in other Navy installations around the world to monitor and triangulate on high-frequency transmissions from Soviet submarines. Whatever the real reason behind its construction, Sugar Grove’s Fred-10 arrays were rendered obsolete by the end of the Cold War.

The Navy wasn’t the only outfit whose spooks took advantage of the radio silence in the Zone. Sugar Grove was, and perhaps still is, home to one of the National Security Agency’s ECHELON listening posts. Named by Edward Snowden in his leaked NSA documents as a site code-named “Timberline”, Sugar Grove was part of a network that intercepted signals to and from communications satellites in orbit above the Atlantic. As more and more communications has shifted to lower-latency undersea cables over the years, snooping on communications satellites has become less profitable to the spooks, so chances are that Timberline is no longer active. But the NRQZ is a priceless asset for electronic intelligence, and it’s doubtful that it’ll go to waste.

Staying in the Zone

Sadly, the “Great Big Thing” is falling on hard times. Despite the outstanding location, the superior technology, and the ability to keep 13,000 square miles in near-radio silence, the NRAO’s $10 million yearly budget is under scrutiny and could be defunded at any time. Here’s hoping that the observatory can partner with universities so it doesn’t fall like Sugar Grove, and that the Quiet Zone stays quiet and enables great science for a good long time to come.

42 thoughts on “All Quiet On The West Virginia Border: The National Radio Quiet Zone

      1. I remember watching an episode of “Nova” on the topic of string theory. One of the three Ivy League scientists’ sent to lobby Congress for a $1 billion research grant admitted using the line “we could make laser guns, like in ‘Star Wars'” at a meeting with the Defense Dept.

        They got the funding!

      2. I remember watching an episode of “Nova” on the topic of string theory. One of the three Ivy League scientists’ sent to lobby Congress for a $3 billion research grant admitted using the line “we could make laser guns, like in ‘Star Wars'” at a meeting with the Defense Dept.

        They got the funding!

    1. Yup. God bless the man because NOBODY in government wants to help out WV financially. The state wouldn’t have survived without the questionable dog ears on all of his bills.

    2. Yeah, it’s kinda sleazy, but pork is what keeps congress running. “You want your military appropriations bill? Well, I’ve got an astronomy project and a glitchy “Nay” button. Make my day.”

      1. And making life miserable. I’ve heard stories of people objecting to halogen lights because they think they’re harmful! And people walking around town with wifi transmitters, just to irritate the “electrosensitives”

        1. You don’t need to carry an actual wifi transmitter, just something that looks like one. Since the idiots can’t ACTUALLY detect EM radiation.

          Someone double-blind the fuckers, quick, before the magic crystal healers and the audiophiles get together to sell them the ultimate Little Box of Bullshit.

    1. My one friend’s mother installed a ‘cellphone blocker’ in their house. Supposedly to block the ‘harmful’ RF signals from ‘entering’ the house. If only she knew that she was infact injecting _more_ RF energy, not reducing it…

  1. The NRQZ is not all *that* quiet at RF. There are at least half a dozen major colleges in that big rectangle, plus the I-81 corridor (a major East Coast trucking artery)… and that’s just on the Virginia side. Whatever noise floor advantage the telescope may once have enjoyed is long gone, outside of maybe a 5 or 10-mile radius around the site.

  2. I visited Green Bank as a young boy and was thrilled with the public presentation, demonstration and tour. Later in life, in 2000, I was lucky enough to get a behind the scenes tour of the new Robert C Byrd telescope. I actually got to stand in the dish just a few weeks before it went “live”. Fascinating stuff. I would have loved to go to work there (and they were looking for an electrical engineer at the time) but my wife preferred a little more convenience (like grocery stores less than an hour away).

    1. If you’re still interested, the NRAO location in Charlottesville is a more family friendly place to live. I believe they’re hiring for a few positions at the moment too.

  3. I live in Charleston, WV. I have been to the NRAO 20 times, and 2 times with my youngest daughter. I would hate to see the site close down due to funding. I had a few friends who helped make a 10 meter, half inch aperture, steerable antenna. Basically…a suspended wire antenna in a pipe that had a 1/2 inch slit all the way down and shielded. It worked. It wasn’t until I saw the Jansky antenna that someone beat me to what I thought was a radiotelescope breakthrough.
    On a side note, my daughter always reminded me to shut off my radio and cell phone once we left US-19. :) I truly would hate to see this helium cooled, low signal amplified, monster of an array close down. Hey Bill Nye, Neil Degrasse Tyson, Bill Gates and least I forget Stephen Hawking…keep the dreams of space viewing alive. Same goes for the young hacker out there, like I was…looking up the stars like Jack Horkheimer always said at the end of his show Star Hustler. 73, KC8KVA

    1. ” Hey Bill Nye, Neil Degrasse Tyson, Bill Gates and least I forget Stephen Hawking…keep the dreams of space viewing alive.” Yea, at $10 million a year Bill Gates could keep the place going until the heat death of the universe. But if you want real radio silence you should put a satellite in orbit around the “dark” side of the moon.

      1. The moon’s gravity is too lumpy to invest big money in a long-term satellite. It would take too much propellant to keep it up there. Just build on the surface instead. It’s not like there is a significant atmosphere to try to ‘see’ through.

    2. We just need to make the world look like a Death Star…a REALLY, REALLY BIG ARRAY. :) Look at the old HARP project, Mt. Aracebo and the likes. SETI doesn’t have the funds, heck…they used PC’s and Playstations to help process data. *sigh* I just hate to see such a great build go for not. Cheers and 73, KC8KVA

  4. I don’t know if this will turn into a double post, if so, my apology in advance.

    I recall seeing years ago, some sort of “radio quiet zone” on a map of the mountains above Boulder, Colorado, USA. I suspect it was related to the NIST Laboratory in Boulder.

  5. Years ago I was looking at a map of the Boulder, Colorado, USA area.
    Up in the mountains was an area marked as a “radio quiet zone” (or something), I think it was used by the NIST Laboratory in Boulder. I looked at Google Maps a few hours ago, but didn’t see it.

  6. “currently the world’s largest fully-steerable radio telescope and consequently the largest moving land-based object in the world”

    Woa… Wait a minute… “land based”! Is anybody else thinking what I am thinking? How about a sea based telescope?

    Let the water support the weight. Maybe you can build bigger that way. Also you could get away from populations and interference easily. There would be no more drawing of imaginary lines on the land and telling the people that live there they can’t have modern wireless conveniences. Also, you wouldn’t even need giant motors to turn the thing, you could do it with ballast tanks!

    Would waves make it move too much? Large things like cruise ships and aircraft carriers don’t rock in the waves.

    Actually… there is an idea.. cruise ships. Maybe 3 old cruise ships coudl be welded into a big triangle with the dish built and suspended in the middle. Then the support structure would double as living quarters for the crew! It would be a spook and radio astronomer’s island!

    1. I’d guess that even slight rocking of a ship would bugger up a telescope. You’re not gonna get the .003 inch stability this gigantic thing has. Cruise ships have active stabilisers, but that’s to avoid making the passengers sick, orders of magnitude away from this.

      Still, nice idea. Just need some other reason to justify living at sea. That said, I’d just take a few friends, prob better to live on land and just be sneaky about any unjust laws. Plus y’know, I can’t swim.

    2. Hmm….

      “An earlier stabilization technology was gyroscopic stabilization. The World War I transport USS Henderson, completed in 1917, was the first large ship with gyro stabilizers (right). It had two 25 ton, 9 ft diameter flywheels mounted near the center of the ship, spun at 1100 RPM by 75 HP AC motors.”


      1917, 2x 25 ton gyroscopes! It measured roll using a small sensor gyroscope, then tilted these the opposite way to counter it. In 1917! Seems like the Navy was a good place to be a geek back then.

      Wouldn’t work for a telescope but it’s a pretty mad idea.

      1. I’m guessing that when it comes to waves, sometimes it is better “to go with the flow” than to fight them. A hull that rolls with a huge wave will (I’m guessing) will experience less stress than one forced to maintain perpendicularity.
        (Hmmm, I thought I made up that last word, but Spell Check let it by…)

  7. Back when, the Army Security Agency was in charge of tactical (battlefield) radio intercepts. The Navy Security Group was in charge of strategic radio intercepts. That is, the location and strength of entire fleets or armies. The easiest way to locate a fleet is through triangulation. Hence the FRD-10 s.

  8. Back when Sugar Grove was first being built, my father worked as an engineer on the design of the radio telescope there, for the National Observatory if I remember correctly. He later told me when they finally got it working right, it located unknown quasars so far out into space that it pushed the known edge of the universe millions of light years outward. It seemed worth knowing, even if it did make us an even smaller piece of it all.

    I also remember when the federal officers came and tracked down his old electric razor that apparently had a short in it and was causing some ‘noise’, similar to the old dog blanket mentioned in an earlier post. They went out and got dad a better new one in trade. Nice guys, and we had no more problems like that.

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