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NSA Gives Cool Secret Site to Astronomers

By kipster in Technology
Fri Jan 05, 2001 at 12:42:21 PM EST
Tags: Science (all tags)
Science

The Baltimore Sun has a cool story about a bunch of radio astronomers who got to keep an old NSA listening fascility. It's down in North Carolina. The story describes some of the cool technology and X-Files grade security gizmos.


The weirdest detail is the carpets. They're welded down with little bits of metal. This is apparently done to cut down on static, but maybe there are some weird aliens that need to be grounded when they walk along?

There's also strange and cryptic graffiti. Were the spooks just bored, or maybe there's something more. Does anyone live near there?

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NSA Gives Cool Secret Site to Astronomers | 20 comments (14 topical, 6 editorial, 0 hidden)
Welded carpets (4.00 / 3) (#2)
by Cironian on Fri Jan 05, 2001 at 10:07:14 AM EST

Could the metal fibers (the article doesnt mention real welding as we know it) be there to absorb some EM emissions? I think I remember that radar stealth surfaces used (among other things) a similiar surface structure to reduce signals to something more like random noise.

(Probably wrong, but I'd be happy if someone could refresh my memories on this)

Metal fibres (3.80 / 5) (#3)
by FeersumAsura on Fri Jan 05, 2001 at 10:29:22 AM EST

We use grounded carpets as well. We have metal wires running trough every 15cm. These are then grounded to earth. The best solution is not to have carpets though and force everyone to ground themselves regularly. We even have to ground all the doors (metal) and have anti-static storage areas where all the shelves are earthed.

I'm so pre-emptive I'd nuke America to save time.
Technical mistakes (4.66 / 3) (#4)
by tftp on Fri Jan 05, 2001 at 10:36:14 AM EST

First half of the linked article is full of most clueless technical mistakes. Conductive (metal) mesh is used as a shielding - those guys must have heard about Tempest :-) However light bulbs don't need any shielding at all, they don't radiate anything except light (and heat); their "sleek metal grids" most likely are to keep the broken glass inside and foreign objects outside in case of nuclear strike (judging by presence of autonomous life support system at the site).

flourescent lightbulbs (4.00 / 1) (#8)
by rebelcool on Fri Jan 05, 2001 at 12:34:01 PM EST

often emit interference. Everytime I turn this desklamp on my speakers crackle. With the sensitivity of the equipment around there, i imagine even a small crackle would be amplified millions of times.

COG. Build your own community. Free, easy, powerful. Demo site
[ Parent ]

Fluorescent lamps (4.00 / 1) (#9)
by tftp on Fri Jan 05, 2001 at 12:47:58 PM EST

Fluorescent light sources are absolutely, unconditionally banned from any self-respecting RF facility. They are incredibly noisy in very wide range of frequencies. That's why I discounted that possibility. If those guys went into trouble of building a center far away from RF-polluting cities I'd assume they know what lamps to use.

Furthermore, a grill won't shield the lamp well. No, I take that back. A grill won't shield the lamp at all. Slots in the grill are short wave guides, and waves of some length can't go through. But the wave guide must be fairly long to be effective, that's why shield in your microwave is several millimeters thick; geometry of holes is chosen so that the RF can't go through the shield but you can look inside.

[ Parent ]

hmm... (4.00 / 1) (#14)
by rebelcool on Fri Jan 05, 2001 at 02:30:52 PM EST

See I thought flourescent because government buildings tend to be full of the harshest, cheapest light :)

then perhaps if a light bulb burned out. A spark jump as the bulb burns out would throw out a wide range of interference.. I recall reading about the noises the first radio telescope received on the first night they used it. But it was eventually traced to some guy's bad ignition switch on his car several miles away...

COG. Build your own community. Free, easy, powerful. Demo site
[ Parent ]

'Tempest' Shielding... (4.00 / 1) (#10)
by Parity on Fri Jan 05, 2001 at 01:00:08 PM EST

The light bulbs certainly do need tempest shielding... otherwise, there's a risk that an unshielded signal would be received by the light bulb and transmitted along the power lines! (Of course, with the power-plant internal to the facility, an enemy agent getting access to the wires seems unlikely, so maybe you're right after all... but not necessarilly.)

Parity Odd

[ Parent ]
Linearity issues (4.00 / 1) (#11)
by tftp on Fri Jan 05, 2001 at 01:08:29 PM EST

Thanks, that's yet another argument against fluorescent lights. The plasma inside fluorescent lamps is a non-linear component, meaning that it can alter the spectrum of input signal so that it can get intercepted via unexpected frequencies.

Regular light bulbs, however, are pretty linear and there is no reason to shield them any differently than the power line itself.

[ Parent ]

Say what? (none / 0) (#16)
by ScottW on Sat Jan 06, 2001 at 02:22:23 PM EST

I don't know who told you that, but that is BS.

Fluorescents work by energizing the gas in the tubes. This generates plasma, which produces UV light, which excites the phosper coating inside the tube, producing light. The frequancies in the visable light part of the EM spectrum are a lot higher than microwave frequancies. A lot higher, as in far above 300 GHz. The only thing that the non-linear plasma inside fluorescent lamps can interfere with are some IR devices.

The ballests, on the other hand, can put out interferance if they're miswired, the fixture has a bad or nonexistant ground, or the tube/ballest is failing. If you're picking up interferance from a working fluorescent light, your equiptment is sensitive enough that you need to install EMI/RFI filters anyway.

BTW, "regular" (didn't you mean "incondesent") light bulbs aren't that linear, eigher. In fact, the filamets in incondesent bulbs act like large inductors, which act like very effective antennas.

[ Parent ]

Physics of fluorescent lamps (5.00 / 1) (#19)
by tftp on Sat Jan 06, 2001 at 05:43:47 PM EST

I don't know who told you that, but that is BS.

People can draw their own conclusions, postulate and prove theorems. It is not necessary to be "told" something.

Fluorescents work by energizing the gas in the tubes. This generates plasma

This is a random process (see here). All sorts of oscillations are produced. You can test that with any portable receiver. Keep in mind that the light from fluorescent lamps flickers, this means that the gas discharge starts and stops 120 times per second. Any non-linearity in this process guarantees that you get harmonics. It is pretty obvious that the discharge starts "all at once" - you can not feed 12V into the lamp and get it dimmer (at 10% of its normal output), this proves that the fluorescent lamp is a non-linear device. Any EE engineer should be familiar with characteristics of plasma-based devices.

The ballests, on the other hand, can put out interferance

The ballast inductor is a linear device. It can not put out anything beyond what is fed into it; however the lamp current goes through it, and all noise of that current will be emitted (poorly) via magnetic field. Ballasts usually have magnetic shields around them, but they won't be radiating much on RF bands. The bulk of microwave emissions comes from the plasma inside the lamp.

In fact, the filamets in incondesent bulbs act like large inductors, which act like very effective antennas.

The inductance of the filament is less than 0.001H, I fail to see how it can be called "large". Also, since when inductors became "very effective" antennas?

The only non-linear part of incandescent light bulb is that its impedance depends on the temperature of the filament. If the temperature stays more or less constant the lamp is as linear as it gets. They are commonly used as dummy loads to test transmitters.

[ Parent ]

OK, I'll bite... (1.00 / 1) (#20)
by ScottW on Sun Jan 07, 2001 at 10:54:28 PM EST

People can draw their own conclusions, postulate and prove theorems. It is not necessary to be "told" something.

Excuse me for living, jackass, but your origanal post sounded like something thrown together from somethings you may have heard previously.

All sorts of oscillations are produced. You can test that with any portable receiver.

I tried that, it tures out that I had to get the antenna really close (1-2") to the fixture to pick up anything definate.

Keep in mind that the light from fluorescent lamps flickers, this means that the gas discharge starts and stops 120 times per second. Any non-linearity in this process guarantees that you get harmonics.

Incondessent lapms flicker too, when feed from AC. This is because the AC votlage fluctuates form 0 to full+ to 0 to full- and back to 0 agian at a certian frequancy. Weather the lamp is fluorescent or incondesent makes no diffrence, in fact, it is possable to power fluorescent lamps from DC. Also, you can get dimmable fluorescent lights and kits that convert regulur fluorescent lights to dimmable lights at any hardware store.

The ballast inductor is a linear device. It can not put out anything beyond what is fed into it;
Neigher can anything else, sherlock, there's no such thing as a mechine that's 100% efficent. Also, not all lamps use magnetic ballasts, the newer ones use electronic ballasts, which are basicly switching power supplies.
however the lamp current goes through it, and all noise of that current will be emitted (poorly) via magnetic field. Ballasts usually have magnetic shields around them, but they won't be radiating much on RF bands.
Your forgetting about the wiring inside the fixture, and the power wiring going to it. Also, RF emissions are electromagnetic emissions, they have both electrical and magnetic componets.
The bulk of microwave emissions comes from the plasma inside the lamp.

And what strengh and frequancy range are those emissions? Some factaul data please...

The inductance of the filament is less than 0.001H, I fail to see how it can be called "large". Also, since when inductors became "very effective" antennas?

Well then, I guess the 1/4 wave fully loaded antenna on my 2M HT is really just useless decoration, despite the fact I successfuly contacted a station 50 miles away with it. Also, I guess that its only a rumor that some ham operators have been able to communicate with stations as far as halfway around the world with nothing more that a simple light bulb and antenna tuner for an antenna despite the fact that hams who use light bulbs as low-profile antennas log contacts from around the world.

The only non-linear part of incandescent light bulb is that its impedance depends on the temperature of the filament. If the temperature stays more or less constant the lamp is as linear as it gets. They are commonly used as dummy loads to test transmitters.

Actully, resistors are used as dummy loads, not inductors. You don't want to use inductors as dummy loads, you want to make sure that nothing from the transmiter you're testing makes it out into the air. In fact, you don't want to use metal film resistors in dummy loads because the spiral construction of the metal film can act as an inductor at certain frequancies. So can the filament (which is nothing more than a coil of wire) in a light bulb...

[ Parent ]

Trust No One -- especially the U.S. Forest Service (1.00 / 1) (#15)
by turtleshadow on Sat Jan 06, 2001 at 12:52:45 AM EST

While everyone is going gaga over the gee whiz stuff of the NSA I hear no complaints against the complete and utter disaster that the U.S. Forest Service is getting away with.

The USDA Forest Service has once again shown it is unable to adequately protect and steward the property of America.

No other Department could "throw away" by 5 years disuse such valuable facilites yet still continue to lobby hard to legislate that those who enjoy the outdoors have to pay exhorbitant trail fees for access to American wilderness that used to be free.
Per the Pari site's own presentation, the facility is 100,000 square feet (temperature controlled == air conditioned) with 30,000 square feet of computer raised floor. Most .coms would kill for this square footage -- the ultimate co-location! According to the FAS, downlink at the "former" Rosman Research Center was being looked at, cool NSA site intel.
FYI The presentation on the site has many nice pictures of this once secret facility!

This was obviously a multi-multi million dollar development that took years to complete, it was allowed develop unspoiled land, and sunk a chunk of change for National Security, none of this is being paid back to the public.

The fact remains this impressive facility was turned over by the NSA to an obviously outclassed Department. The USDA Forest Service Department traded it for a piece of wilderness, what was the price? I couldn't find details in their plan, no mention in most sites that should list it.

Most Government installations must be decommissioned if not for safety by law. The citizens must get their fair share back from the salvage!

Im not wholely against this. I want to ensure a fair deal. Even the old nuke silos are being salvaged in a positive manner and are at least sold to the highest bidder.
If it wasn't for any other reason it went to science I'd be writting my Congressman asking for a GAO audit. Hell I still may, against the NSA's waste of money.... I ain't afraid of no NSA man.

Turtleshadow
Well maybe a little afraid


I think that you're being a little overly harsh (3.75 / 4) (#18)
by handle on Sat Jan 06, 2001 at 02:52:40 PM EST

If you read the article you'll see that the Forest Service tried unsuccessfully for several years to engineer a trade and that there were very few interested parties. I wondered why they just didn't sell it, but I imagine that there is some sort of regulatory restriction about the FS from profitting on real estate transactions. A land trade would be a nice way to get around that. As to trading it for a piece of wilderness, isn't that what the FS is supposed to do?

[ Parent ]
I disagree the Forest Service is sloppy (none / 0) (#21)
by turtleshadow on Thu Jan 11, 2001 at 11:42:42 PM EST

The difficulty of "sale" for the US forest service should not be at issue. Indeed the land could have had severe problems with facility liablity and remoteness issues.
Im not wholely against the PARI project. I want to ensure a fair deal and my threshold has not been met in this case. Show me the land swap price, show me the link to the environmental studies, show me meeting minutes when the multi-million dollar facilities and public land were being swapped in a public forum or under public review. I still just have a fishy smell in my nose. Without taxpayers money "changing" hands I doubt even the auditors got a look at the T&C's of the deal. Facilities like this really never get decommissioned just transfered to an unwitting shill partner for safekeeping.

Regards,
Turtleshadow

[ Parent ]
NSA Gives Cool Secret Site to Astronomers | 20 comments (14 topical, 6 editorial, 0 hidden)
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