For several years in the 1990s, the best internet resource for anyone interested in learning more about outdoor RCS ranges was "Radar Ranges of the Mojave Desert" on the Bluefire web site, created by Tom Mahood. Tom is no longer maintaining those pages, but has graciously allowed The Howland Company to re-post them. So, here they are, merged into a single page (image links will open in new windows):

Radar Ranges of the Mojave Desert

• What is an RCS facility?
• Northrop RCS facility at Tejon
• McDonnell Douglas Gray Butte RCS facility
• Lockheed Martin Helendale RCS facility
• Junction Ranch RCS facility at China Lake

No, I'm not talking about microwave ovens in the desert. What I'm referring to are also known as radar cross section (RCS) facilities. Why should these things be of any interest? Well, a segment of the UFO community has firmly latched on to the idea that these installations are simply covers for "underground bases." The stories go on to describe multiple levels (with the requisite genetic engineering labs) and discs zipping in and out through surface openings. And we don't want to overlook the underground tunnel systems that connect the facilities with Edwards AFB and even Area 51 (Ah, at last a connection!).

It would be pretty cool if it were true. But is it?

Personally, the first time I saw one of these weird things (the McDonnell Douglas installation at Gray Butte) while exploring in the desert, my reaction was "What the hell is this place??!" I have a pretty good mechanical aptitude, but I couldn't make much sense of the sharply angled pylons (some kind of odd antenna??) the massive microwave dishes and the strange, tall building without two sides.

This is the result of my research into these facilities. It includes a number of lurking visits to the facilities, an aerial overflight, combing of public records, a lot of digging into technical journals, books and capabilities brochures, and even a perusal of some of their construction plans. Some of the personnel at the facilities are even willing to talk with you if you don't appear to be a nut (Apparently I fooled them). While I found nothing to support the underground base premise (although at one facility there are some very impressive underground structures), it did become obvious how some of the stories may have arisen, given that the storytellers seem to have done little research. All of the info I collected is available to anyone willing to spend the time to ferret it out.

The wild stories are a bit unfortunate as some of the facilities are interesting in their own right. That said, there are some stories and oddities involving one of the facilities that I can't explain and do find a bit unusual. Those will be discussed as well. Since a picture is worth 1k words, you'll find lots of photos of various details of the installations.

There are four of these thingamabobs in the Mojave, in relatively close proximity. There is Northrop's facility in the western part of Antelope Valley. Moving east, there is the McDonnell Douglas facility at Gray Butte. Moving further east and north, there is Lockheed's supremo-high tech installation just north of Helendale. Finally there is a little known RCS facility run by the Navy at China Lake called the Junction Ranch RCS facility.

What is an RCS Facility? - RCS 101

The following is a really brief introduction to how RCS ranges work. It's intended to be a summary, so I've left out a lot of nasty details. Also, I'm tremendously far from being an expert on radar, so all you radar gurus out there.....unless I'm saying something totally stupid, cut me some slack!

Pretty much everyone knows how radar works. A radar beam (a high frequency radio wave) is sent off toward an incoming object. Some of the beam bounces back off the object and is picked up by a sensitive receiver. The distance to the object can then be figured by comparing the difference in time from when the beam first went out to when a bit of it got bounced back.

The key here is "bounced back". Picture a Greyhound bus flying through the air (now there's an image!). Its big flat metallic sides will bounce a lot of signal back to the radar receiver making for an extremely strong signal. It will also make the radar operator say "What the hell is that??!" Now picture a Volkswagen flying through the air. Its smaller size and curved surfaces will reflect a lot less radar signal back, so its "blip" on the screen will be a lot weaker. To produce the same intensity of blip as the bus, the Volkswagen would have to be much closer to the radar unit. That is because the Volkswagen has a smaller radar cross section (RCS) than the bus.

The RCS of an object is usually expressed in square meters and is defined as:

The projected area of a metal sphere which would return the same echo signal as the target if the sphere is substituted for the target.

First, when a radar pulse is directed toward an object, it hits the object with a certain amount of radar energy. The amount that hits the object is equal to the cross sectional (or projected) area of the object. So an object with a cross section of, say 10 square meters, will absorb the same amount of energy be it a sphere, flat plate, cube, or whatever. It's the object's cross section that matters as to how much energy is absorbed.

The second part of the explanation is where it gets interesting. After absorbing a radar pulse, the object immediately re-radiates the energy as an echo. This energy is primarily radiated at right angles to the object's surface. In the case of a sphere, it radiates the echo equally in all directions. But in the case of a flat plate, it all radiates off the front and back flat surfaces. If one of those surfaces happens to be facing the radar transmitter, a huge signal will be radiated (or "bounced", if you prefer) back, tremendously larger than a sphere of the same cross sectional area. Depending on the frequency of the radar in use, the return from a flat plate can be 1000 times larger than that of a sphere of the same cross section, and thus seems much "larger" to the radar receiver. To make things more complicated, the RCS values will change depending what frequency they are being measured at. But you can easily see the tremendous value of angling surfaces so that the radar beam is directed away from its source.

Just for chuckles, here are some typical RCS values for different objects from the "Radar Engineer's Sourcebook" by Morchin:

To interpret the table, let's use the bicycle as an example. Based upon our definition, the bicycle has a radar return the same as that of a sphere with a cross section of 2 square meters. To spare you the math, that would be a sphere about 1.6 meters in diameter.

The very essence of stealth technology is to shape the object is such a manner that incoming radar beams are radiated every which way but back toward the radar receiver. It's an amazingly simple concept, but the trick is its implementation.

Every object, even stealth aircraft, can be picked up on radar. The important thing is how close the object has to be before the signal it's reflecting toward the radar receiver is strong enough to register. Our bus would likely be spotted a hundred miles out, leading to early deployment of anti-bus missiles. But a stealth fighter might only start registering a mile away, leaving the radar operator only enough time to put down his coffee cup before his facility is destroyed.

So, the goal is to minimize the RCS of our aircraft to ensure their survivability. That's where RCS facilities get into the act.

The most reliable way to find out how much radar signal a new aircraft design will reflect is to simply try it and find out. And there's no need to use an actual aircraft, a smaller size model will work just fine. Reduced to basics, what RCS facilities do is to put a model on a pole a few thousand feet away, and bounce radar pulses off it to see how much comes back.

Of course there's much more to it than just that. The pole, properly known as the pylon, must itself not bounce any signal back. If it did, it might be confused with the signal from the model. To prevent this, the pylons have beveled faces that radiate the radar pulses away from the receiver. Also, the pylons lean toward the radar receiver, the more lean the better (The amount of forward tilt is usually limited by the pylon's structural considerations). In effect, the pylons are stealth shapes, the very earliest implementation of the concept.

The model also needs to be able to rotate on the pylon. Getting back to our flying Greyhound, the amount of radar reflected from the bus when it's pointed head on toward the radar unit will be less than if the bus is sideways. There's simply less area to reflect the signal. By rotating a model on the pylon, the radar reflectivity can be measured from all angles, thus identifying any problem areas that might require reshaping.

An RCS facility must allow for testing of models at different frequencies. Sometimes these frequencies are also referred to as lettered bands. Long range search radars operate at lower frequencies and targeting radars operate at higher frequencies. This is because higher frequency radar establishes the position of the object with much greater accuracy. The drawback to higher frequencies is that the atmosphere tends to absorb them more, so their range is not nearly as great as lower frequency radar. RCS facilities usually have a broad range of testing frequencies available. It's possible to get an idea of what types of frequencies are in use simply by looking at the radar dishes. The high frequency targeting radar dishes will be small, while the long range, low frequency radar require much larger dishes.

The ground between the radar transmitter and the model is a concern too. As the radar pulse leaves the antenna and shoots downrange toward the target, a portion of the beam bounces off the horizontal surface of the range and also strikes the target. This is called the "ground plane effect" and can create problems in some instances. Designers of radar ranges either try to eliminate this ground plane bounce, or incorporate it into the overall operation of the facility.

In most cases, designers simply pave the area with asphalt. This will also prevent the growth of vegetation, a big no-no. The paving gives an RCS range the appearance of a very strange landing strip. But a landing strip it is most definitely not.. The paving is typically only a few inches thick, too thin to support anything heavier than a very small light plane. Then there are the pylons sticking up in the middle of the range, providing quite a surprise for an incoming pilot.

Security considerations at RCS facilities are a major concern. State of the art stealth shapes must be kept from prying eyes on the ground, as well as spy satellites. This can be accomplished in a number of ways. It's possible to simply inflate a large opaque plastic dome over the model while it's on the pylon. The plastic is generally transparent to the radar beam, and what little signal is returned from the plastic bubble can be factored out. Some RCS facilities have large buildings (also known as target shelters) on tracks with roll-up sides. These can quickly scoot over the pylon and hide the model if necessary. These buildings also have the added benefit of internal hoists to place the model on the pylon. Finally, the most high-tech of the RCS facilities have sophisticated mechanisms that retract the pylon and model into the ground. The model comes to rest in an underground room where it can be worked on and maintained.

The ultimate in security is provided by indoor ranges, where the entire facility is enclosed in a very large building. However this type of facility can be quite a challenge to make perform well, and is usually quite smaller than the outdoor ranges. For most purposes, outdoor ranges are preferred.

For further exploration into the field of RCS, I can suggest a few books. They're a bit esoteric to be found at the local library, but many college or university libraries may carry them. The first is "Radar Cross Section - Its Prediction, Measurement and Reduction", by Knott, Shaeffer and Tully, 1985. This book specifically describes some of the facilities in the Mojave, and their capabilities. Another very good book is "Radar Cross Section Measurements", by Eugene Knott, 1993. Knott is one of the experts in the RCS field. This second book again talks about some of the Mojave RCS facilities and also has a good chapter on security concerns and black projects. A little light reading for those boring evenings!

There is also an excellent (and even understandable) explanation on the mechanics of stealth and radar on the web. It was taken from a Lockheed publication, authored by Alan Brown, who retired as Director of Engineering at Lockheed Corporate headquarters in Calabasas, California. Having worked on the F-117 program, this guy should know what he's talking about. The piece is called "Fundamentals of Stealth Design" (THC: the link is to an archived copy, without the images; but the text is worth reading.)

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Tejon RCS Facility - Northrop Grumman

Location

The facility is located at the northwest end of the Antelope Valley, on the slopes of the Tehachapi Mountains, at the mouth of Little Oak Canyon. It is 18 miles due west of the town of Rosamond.

Its remote location on unnamed dirt roads makes discerning a site address difficult, but two have been found. A notice on the access gate refers to "8900 Waynes Road" and a Northrop filing with the FCC refers to 7000 230th Street West.

History and Property Ownership

According to published reports, the range was constructed "in the early 1980s".

Attempts to track down official records on the facility have proven a most curious affair. The facility is located primarily on Sections 25 and 36, of T10 N., R16 W., SBM. This puts it within the County of Kern, the county seat being Bakersfield.

A visit to the Assessor's office in Bakersfield revealed the property in question is owned by the Tejon Ranch, a massive property owner in the Tehachapi Mountains. The records also show that the surrounding land to the south and east consist of a multitude of smaller parcels, all in a large number of different hands. Strangely, the Assessor's records show that there are no improvements on the parcels upon which the RCS facility sits. Further, they show the use to be an agricultural preserve, and taxed at a very low rate.

Confused by this, I ended up speaking with several of the Assessor's staff. It turns out they are aware of the facility , but stated, "we not allowed to set foot on it." One of the staff told me he attempted to visit the site a number of years ago, but was turned away by armed guards. The Assessor's staff told me it is "a secret government installation." When I replied it was my understanding it was owned by Northrop, they suggested that Northrop was perhaps the operator, but that the improvements were in reality owned by the government. I asked what paperwork they might have identifying the improvements as government owned (they referred to what they called a "government exclusion"), thus authorizing them not to carry the facility on their tax rolls. They told me verbally that they did not know of any.

After submitting a written request for clarification to the Assessor's office, it turns out the improvements are indeed listed, but as "unsecured property" on a different set of tax rolls. The owner is listed as Northrop Grumman, with an assessed valuation of approximately $7 million. It therefore appears the facility is not owned by the government.

I also paid a visit to the Kern County Fire Station in Rosamond. They have jurisdiction for doing fire inspection for all commercial and industrial development in that part of Kern County. They told me that it was a secret facility and were not allowed on the property. They said any inspection was done by the government.

Facility Description

The facility has a total of four ranges, the two largest of the four being from the original installation and the remaining two being somewhat newer (photo, 72k jpg).

The two older ranges are asphalt ground plane ranges radiating directly from the main antenna array at the operations complex (photo, 47k jpg). One range is 1,500' long and the other is 3,000'. The 3,000' foot range has target positions at the 3,000' position and also at 1,500', thus providing for three target positions between the two ranges.

The target positions are the light colored "diamonds" in the middle of the asphalt range (photo, 29k jpg). These diamonds are, in actuality, large concrete slabs surrounding the pylon locations and are typical of outdoor RCS ranges. They perform two functions.

First, and most important, they provide a foundation for the pylon itself. The pylons are bolted to these massive reinforced concrete slabs, (some may even have piles below) which act as counterbalances to the large bending forces generated by heavy models placed on the forward leaning pylons. The pads must also be large enough to spread the vertical loads over a sufficient area.

They serve another purpose in the mounting of the models. Since there appear to be no sophisticated mechanisms at this facility to retract the pylons for model mounting, the models (as well as the pylons themselves) must be put in place with cranes. Since the thin asphalt surface is relatively fragile, the concrete pads provide a firm foundation for crane operation. The reason for the pads' diamond shape is to minimize any radar returns from the asphalt/concrete interface.

Curiously, most of the pylons at this site are a sinister black, instead of the usual white color. Why this might be is not known, but it is obviously an indication the forces of darkness are at work.

Just uprange of each of the target positions are visible small mounting locations for calibration shapes.

The large "X" painted on the longer of the ranges (as well as being found at other RCS facilities) is an indication to pilots that they should not attempt to land there, that it is not a useable runway. Beyond the problems of a thin surface and pylons poking up in the middle of it, the range slopes rather steeply as it runs downrange.

The two smaller ranges are newer additions (photo, 55k jpg). Unfortunately, little is known about them, so what follows is speculation based upon observation from both the air and ground.

At the uprange end of both ranges, the antenna arrays are plainly visible. From the very small size of the dishes, as well as the short length of the ranges, it suggests that very high frequencies are being utilized for these two ranges.

The larger of the two ranges is particularly intriguing. Midway down the range are two barriers, one large and one smaller, set across the range and tilted back vertically. These are known as "radar fences". They are used to prevent radar beams reflected off the surface of the range from hitting the target. Since this ground plane reflection, as it is called, often becomes troublesome at very high microwave frequencies, the presence of the radar fences tend to reinforce the idea that this is indeed a very high microwave frequency range.

At the end of this range is a trailer next to a horizontal device on a large mount (photo, 25k jpg). During visits by myself and others to the site, this device has been observed apparently rotating. In some ways, it suggests a search radar, but that would seem to conflict with its placement at the target end of the range. It may be that it is simply some sort of target holder, perhaps for an inverse synthetic aperture radar, in which the radar transmitter is held steady and the target is moved or rotated. Another possibility is that it is a holder for radar receiving antennas and is used to measure the sensitivity and response of antennas in various angular positions.

Range Capabilities

A published account in 1985 stated that the range has the ability to test at frequencies from 2 GHz to 18 GHz.

Range Security

No remarkable security arrangements exist. The initial gate into the area is unmanned and unlocked, and posted against trespassing (It provides access to other property owners in addition to Northrop). Another gate, apparently manned, is reached a mile up the road. The facility itself is fenced off with some rather dilapidated barbed wire cattle fencing. The surrounding land is private and vacant, some posted with No Trespassing signs.

Other Information

Of all the RCS facilities in the Mojave, this one is the most visible. It sits high on the sides of the valley, and can be seen from twenty miles away. Further, there appears no clever mechanisms to quickly hide secret test items. Yet the lack of a paper trail for this facility suggest some strangeness.

In spite of the high visibility of this installation, or perhaps because of it, there have been a number of odd "glowing orb" sightings near the facility. While other RCS facilities have generated a few such reports (most easily dismissible), there seems to be a disproportionate amount at the Northrop site. Again, a great many of these might be dismissed based upon the credibility of the witnesses. However, I am aware of some reports from apparently substantial observers, that for my part, I find difficult to ignore. While I'm not ready to accept the idea of flying discs regularly visiting the site, I am inclined to think there may be ongoing testing of something very interesting, something that from a distance appears as a glowing orb. What this "something" might be, I don't know.

After examination of the site from both the air and the ground (and review of photo enlargements), there were absolutely no indications of any type of "underground facilities". This would include access points, ventilation fixtures or utility feeds. The operation is apparently just what it appears; a rather mundane, somewhat low-tech RCS range. But those glowing orb reports are intriguing...

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Gray Butte RCS Facility - McDonnell Douglas

(THC: Since 2001, the Grey Butte facility has been used for RDT&E of General Atomics Aeronautical Systems' Predator UAVs.)

Location

McDonnell Douglas's Gray Butte RCS facility is located approximately 25 miles due east of Palmdale, on the Los Angeles-San Bernardino county line. It is at the site of an old World War II auxiliary airfield and has utilized the old runways as its ranges. The site address is 25500 East Avenue R-8, Palmdale.

History and Property Ownership

This facility is the oldest of the RCS ranges in the Mojave, dating back to the 1960s.

This sprawling 4.5 square mile facility is owned and operated by a McDonnell Douglas subsidiary called McDonnell Douglas Technologies. I have heard the facility has been recently sold off to another corporation since Boeing's acquisition of McDonnell Douglas, but I have no hard ownership data at the moment.

According to the LA County Assessor's office, most, but not all, of the facility's land is owned outright by McDonnell Douglas. There are a number of small parcels showing other ownership, so it is a reasonable assumption there are long term lease arrangements in place. This part of the desert is a patchwork of various sized private parcels, and McDonnell Douglas seems to have in place an acquisition program for properties to the north and south.

The 1995 assessed value of the facility was $12,896,000 for land, $6,429,000 for improvements and $7,446,000 for "personal property", for a total value of $26,771,000.

Facility Description

As mentioned, the facility is laid out on the site of an old airfield (photo looking SE, 59k jpg) (photo looking W, 46k jpg). Here's a 67k jpg SPIN-2 satellite photo taken of the facility in 1989, with the remnants of the old airfield obvious. From the antenna array at the operations center (photo, 50k jpg), located at the west edge of the facility, three asphalt ranges radiate to the east in a "V" pattern. The central range, which appears to be the main range, has a fixed pylon and mobile target shelter at the east end.

The mobile target shelter (photo, 17k jpg) is a very tall, large metal sided building on rails. Walls on two sides roll up, thus allowing large RCS models to be brought into the structure. The upper part of the building contains a hoist for lifting the models. Once a model is in the building and raised, the entire self-powered structure moves forward several hundred yards to the west on rails to a point directly over the pylon (photo, 29k jpg). The model is then lowered onto the pylon and attached. The building then moves back and the testing begins. While the model is housed in the mobile target shelter, it is protected from both the weather and unauthorized observation. This arrangement is not unique to this facility; Boeing has a very similar layout at an RCS range they own in northern Oregon.

In front of the pylon on the center range may be seen a raised berm, in the shape of a chevron, (photo, 32k jpg) constructed of concrete. This chevron is presumed to be an attempt to reduce the ground plane reflections toward the model. By careful placement, a chevron can deflect the radar beams that run parallel to the main beam, but bounce off the surface of the range, and keep them from illuminating the target. These type of reflections can cause a lot of headaches, particularly when measuring in the upper frequency ranges.

The other two ranges on each side of the center range appear to be rather ordinary ranges with fixed pylons. Lacking their own target shelters, models would be placed on these ranges via the use of cranes.

It appears the northerly range was at one time extended to some distance in excess of 5,000'. However this extension seems abandoned and in disrepair, and is cut through by a flood control channel. The northerly most range also shows some evidence of abandoned and removed structures at its east end.

Range Capabilities

Literature put out by McDonnell Douglas describes three different independent ground plane ranges, varying in length from 1260' to 3750'. They can test over a continuous frequency range of 145 MHz to 18 GHz, and also spot frequencies of 24 and 35 GHz.

Targets weighing up to 25,000 pounds can be accommodated by the facility.

Range Security

Target security on the main range is provided by the movable target shelter. Should adversarial satellites pass overhead, or other unauthorized observers be in the vicinity, the target shelter may simply be moved over the target and pylon, blocking the model from view.

The facility itself is surrounded by a typical barbed wire cattle range fence with the usual No Trespassing signs (photo, 17k jpg).

An unusual security feature worth noting is the presence of video cameras (photo, 16k jpg) along the east perimeter of the facility. The remotely movable cameras are mounted on masts about every quarter mile. Each camera head appears to consist of two side by side units (photo, 19k jpg), so it's a reasonable assumption one is a standard daylight camera, and the other a low or no light unit. Since these cameras exist only on the east, or downrange side, it may be that their purpose is primarily one of safety, to ensure that no persons are in the strong beam path during tests. In a number of visits to the site, I have never noted the cameras as being active, and they appear to take no interest in visitors.

Other Information

At the end of 1975, Lockheed, not having a range of their own at the time, tested a 10' wooden model of the F-117A prototype (the "Hopeless Diamond") at this facility.

A close inspection of the facility from both the air and ground showed no evidence whatsoever of any kind of subsurface structures, other than normal building and mast foundations. There were no signs of access points, ventilation ducts or utility feeds.

However that wasn't necessarily always the case. On my first visit to the site in 1993, there was an interesting structure at the far northeast corner of the property, where a dirt road, adjacent to powerlines, accesses the site. It was a small, slightly depressed concrete structure, that from a distance looked like either a guard station or an electrical vault. Since it was right at the property line, I assumed it to be a guard station and gave it a wide berth. A visit to the same spot a few years later surprisingly found the structure gone, with essentially no trace.

I have since seen photos of this structure, and it looks like some sort of utility vault. There was also another small bunker-like structure about a hundred yards to the southeast. Both of these structures had ventilation turbines on them, perhaps the genesis of the "underground facility" rumors. Close examination of the 1989 satellite photo show them to be there then, but not today. The best guess is they were some part of a program that involved the northerly-most test range, and were removed when the program was completed. Unnecessary structures or objects on an RCS test range can cause complications, so their removal may not be too strange.

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Helendale Avionics Facility - Lockheed Martin

Location

This facility is located on approximately 9 square miles (over 5,700 acres) of land, about 5 miles north of Helendale and just west of the Mojave River. It has a site address of 17452 Wheeler Road, Helendale CA 92342.

History and Property Ownership

This fairly new range, and most mechanically sophisticated of the ranges, was constructed as an initial phase in 1983 and expanded in 1985. Its official name is the Helendale Avionics Facility and is owned and operated by the Lockheed Martin Skunk Works.

At this time, Lockheed actually owns outright only one square mile, Section 33 of T9N, R4W, the parcel the majority of the range is on. Lockheed leases the remainder.

Lockheed first took control of Section 33 August 11, 1979, by means of a lease, with option to buy, from the previous owners, the Seino family. Officially however, the lease was not to Lockheed, but rather an attorney, J. Gregg Evans of Los Angeles. Evans apparently was a front for Lockheed in the transaction, and the previous owners may not have known who they were really dealing with. On July 20, 1981 the lease was recorded, omitting specific details. It wasn't until December 7, 1989 that Lockheed officially took title to the parcel by exercising their option to buy clause in the lease

The remaining 8 square miles making up the facility are owned by a division of Southern Pacific Land Company (The railroad people) called Catellus Development Corporation, located in San Francisco. The property came into Southern Pacific's hands on July 7, 1981, when it was granted ownership, by way of a patent, directly from the US government. Presumably, they immediately turned around and entered into a long term lease with Lockheed for these parcels.

There were two phases to the development of Lockheed's facility at Helendale, the first beginning in 1982, at a cost of $15-20 million. This first phase, becoming operational in October of 1983, was a relatively modest installation with target locations downrange 2,500' and 5,000' from the operations complex and antenna array. The overall length at the time was 5,500'.

The expansion of the Helendale facility to what it is today, or "HELEX, Phase 2," as it was known, began in early 1985 and was completed by the end of that year. The project was also known as the Area 20 range extension. This expansion lengthened the range to 8,200', added a new target position and built the massive concrete structure at the end of the range known as the "Upper Chamber." The plans were prepared in late 1984 by the H.K. Ferguson Company of San Francisco, a subsidiary of Morrison-Knudsen.

Facility Description

The orientation of this 8,200' long facility is north-south, with the centerline only a few hundred feet east of the east edge of the old Helendale airport (photo looking S, 65k jpg) (photo looking N, 40k jpg). One of the three paved runways (4/22, 4,600' long) of the old airstrip is still maintained and operational, and has lighting for night operations.

At first glance, that fact that it is only a single range with just three target positions, might make one think this is a relatively simple installation. Quite the contrary is true. This is truly a remarkable facility with superbly clever engineering. We'll start our "tour" of the facility at the south end with the operations center, and proceed downrange (northward) from there.

The Operations Complex (photo, 53k jpg) is the large cluster of buildings at the very south border of the property. Located here are the office and administrative areas, control rooms, data measurement facilities, hangars for model storage and maintenance (totaling 75,000 square feet), and a 150,000 gallon emergency water reservoir.

On the north side of the Operations Complex is the Antenna Array. This 70' high tower holds a number of different radar antennas, covering a wide range of frequencies. Hydraulic elevators on the tower move the antennas up or down, to place them in optimum positions for any given test. According to the most recently released public information, the antennas are fed by a 1 kilowatt System Planning Corporation (SPC) MK III radar unit. However the SPC MK III is no longer a "state of the art" unit, now superceded by the SPC MK IV, which is currently the most widely used radar cross section measurement radar in the country. It's reasonable to assume the Helendale facility has upgraded to a MK IV unit by now. (The MK V radar unit, which will use a Windows (!) control system, is about to enter prototype stage.)

Extending north from the Antenna Array is the range itself. It is a 300' wide asphalt surface 3" thick, extending for the next 7,500' The surface is absolutely flat, with even the curvature of the earth removed. At least initially after construction, the surface was dusted with sand so that pilots wouldn't mistake it for a landing strip, and also to reduce radio wave distortion from heat shimmers.

Rather than trying to defeat the ground plane effect inherent in ground plane type radar ranges, this range has been designed to take advantage of the multipath bounce of the radar beam off the asphalted surface. This increases sensitivity by about 12 db.

Moving 1,400' downrange from the Antenna Array, we come to Antenna Pit 1. At this location, test objects can be placed upon four different mounts. The support may be either a 14' long metal or composite pylon, a foam column, or an inflated air column. The targets mounted at Pit 1 may be up to 14' in length and weigh up to 1,600 pounds. The targets here are placed upon the mount using either a crane or forklift.

Immediately uprange of Pit 1, visible on the surface of the range, is a long white metal cover. Under this cover is a hinged calibration pylon. Prior to testing a model at Pit 1, the calibration pylon is extended with a known, measured shape mounted on it. The technicians at the operations complex can then adjust and calibrate their equipment on the basis of a known shape. The calibration pylon is then retracted and an actual model measured.

Moving next to a point 5,000' from the antenna array, we come to Pit 2 (photo, 35k jpg). This 80' deep pit is covered by hinged white doors on the surface and contains a pylon extended by means of a hydraulic ram. Just beneath these doors, and above the retracted pylon is a small workroom in which models up to 50' in length and weighing up to 6,000 pounds may be mounted to the pylon. Immediately adjacent and uprange to Pit 2 is a much smaller pit containing a calibration shape mounted on a hinged pylon. It functions in the same manner as the calibration pit for Pit 1.

This is pretty much the limit of the first phase of the facility at Helendale. But then in 1985, work began to extend the range and the major bells and whistles were put in.

A large 60' diameter mobile antenna on a crawler-type transporter was added 5,300' from the main antenna array. When not in use, the transporter moves the large dish antenna laterally, off to the west side of the range. This massive antenna required a specially constructed roadbed and bridge over a flood control channel. The antenna, known as MOBATS, is used for low frequency, high power RF measurements. This mobile crawler antenna seems to be a replacement for an antenna pit planned at the 5,400' point, but never implemented.

At the 7,300' mark, we come to a very long white metal cover in the surface of the range. Beneath it is another calibration pit (Area 50), the largest of the range at 130' long. As with the other calibration pylons, a simple methodology is used to raise it. The pylon is merely hinged at one end, and after the cover doors are opened, it is elevated from its horizontal resting position within a well to a near vertical position. Again in this case, its purpose is to place an object of known shape and size into the radar beam to calibrate the receiving equipment prior to actual model testing.

The jewel of the facility is found at the 7,500' point. This curious structure, in the depression at the far end of the range, is known as the "Upper Chamber" (or Area 30 during construction). Although it appears to be built of solid concrete, it is actually composed of concrete blocks. On the side of the structure with the vertical face, there is a large, side-sliding hangar door in the 40' high face of the structure. It is through this door that models are brought into the Upper Chamber.

Careful inspection of the Upper Chamber's roof reveals what appears to be a square cover, 80' on a side, with a split along a diagonal. This cover retracts on two sides, separating along the diagonal, exposing an 80' square opening into the Upper Chamber below. When closed, an air bag arrangement seals the diagonal seam.

Surprisingly, the useable area within the Upper Chamber is less than it appears when viewed from outside. Actual level floor space is only about 130' by 110', about 14,000 square feet. Most of the area apparently covered in concrete surrounding the Upper Chamber is actually covered slope. At the time of construction this area was not utilized and left as covered, but bare slope.

The area within the Upper Chamber is primarily a workroom and staging area (photo, 36k jpg). There is a large overhead traveling bridge hoist for the movement and manipulation of RCS models. There is also a diesel generator, a control room, restrooms and a small winch room off to one end. There are no office areas. The right rear portion of the Upper Chamber is dominated by the Silo and its cover.

Cutaway view of Upper Chamber and Silo, 109k jpg

The Silo, also known as Area 35, is located directly beneath the floor of the Upper Chamber and takes up much of the useable floor space. It is a massive circular shaft with an inside diameter of 33', reaching a depth of 210' below the floor of the Upper Chamber. It is constructed of reinforced concrete with a minimum wall thickness of 3-1/2'. The upper walls of the Silo are a bit thicker. Construction of the Silo structure alone required in excess of 3,000 cubic yards of concrete to construct. That's the contents of about 300 fully loaded cement trucks, hence the local residents' tales of "cement trucks lined up for miles" during the facility's construction. The depth of the Silo puts it well below the water table of the adjacent Mojave River, and ensuring seepage water is constantly pumped out is a concern. There are some stories that the design of the Silo was based upon that of an underground Titan missile silo. If true, there was undoubtedly intense interest in the site from Soviet spy satellites during construction!

Residing within the Silo is the retractable pylon upon which models are placed for raising into the radar beams for measurement. The pylon rests upon a counterbalanced hoist structure just beneath it, which is raised by a dual cable winch mechanism. In addition to a ladder, access is provided to various levels of the Silo by means of a small, Swedish made personnel elevator.

For testing, models (or even full sized aircraft) are brought into the Upper Chamber through the side sliding doors, raised by the bridge hoist, and placed over the tip of the pylon. After any necessary calibration, the roof of the Upper Chamber is opened and the pylon begins to rise. The pylon, which was upgraded in May, 1996 with a new, stealthier design (called a "Squareback Superskirt" by Lockheed), has the capability to move the model fore and aft 7' or rotate it 360 degrees, to help clear the opening in the roof of the Upper Chamber. The movement capabilities of the pylon are also used in the testing program.

When the pylon reaches full extension (photo, 37k jpg), hydraulic cylinders tilt the pylon forward to an angle of 55 degrees from horizontal and the roof may close beneath it. When fully raised in its normal tilted position, it can place a model or actual aircraft (weighing up to 30,000 pounds with dimensions up to 105' by 73') about 100' above the roof of the Upper Chamber.

The silvery stretched pumpkin seed shape on the end of the main pylon, (and the shape on the pylon at Pit 2), is a "polecap". The "Star", a company newspaper published by the Lockheed Martin Skunkworks, in the June 21, 1996 issue, ran a photo of the new pylon and polecap on its front page. The polecap is used during calibration of the main pylon. The shape of the pylon is so stealthy, that only the very tip of the pylon ends up being a significant source of signal return. To minimize this, a precisely shaped polecap is placed on the tip of the pylon to eliminate any radar returns from this spot. Then, once the very small return from the pylon is accurately determined and the system calibrated, the polecap is removed and a model put in its place. Perhaps surprisingly, the polecap was fabricated for Lockheed by a boat-building firm, Goetz Boats in Bristol, Rhode Island. It consists of aluminum honeycomb and carbon fiber, and the band along the outside edge is made of Kevlar, and the whole thing coated with RAM. After fabrication, it was shipped across country on a flatbed truck, looking to the world like the hull of a racing yacht.

There are a few other facilities of note, located behind the Upper Chamber (or downrange) in relationship to the antenna array, on the original grade. The first of these is a fire pump house, also called Area 10. It's a small cement block structure near the edge of the depressed area. It contains a pump for emergency fire situations. Adjacent to the pump house is a small parking area with space for 20 cars. The small, dark colored rectangular area on the northeast side of the pump house is an emergency water reservoir (covered by a flexible membrane to keep out animals and dirt) for utilization by the pump house. Further downrange from that is a tower containing various instruments, the weather station mast.

Range Capabilities

The facility has the capability to test the complete frequency range from 120 MHz to 18 GHz, and a spot frequency of 35 GHz with four different signal polarizations.

Range Security

Test security is primarily provided by the unique ability to quickly remove models from sight by retracting the pylons underground. The facility itself is surrounded by a low fence, posted with "No Trespassing" signs. Lockheed security occasionally patrols the boundaries. Much of the land to the north and east is public, and development is occurring to the south, thus making discrete testing more difficult. This is alleviated somewhat by the ability to move models quickly out of sight.

Other Information

To construct their own facility, Lockheed used the knowledge gained from their construction of the RAMS facility they built for the Air Force at White Sands in New Mexico. This facility uses virtually the same design as RAMS and seems to have been built concurrently. Here is a photo of the RAMS site in New Mexico for comparison to the Helendale facility

A couple comments on the idea of this being an "underground base" or "Continuity of Government" facility: The aerial photos of this site were taken on June 15, 1996. Coincidentally, that day Lockheed Martin was having an Open House or Family Day (That was the reason I was able to obtain such interesting photos). A large number of people, including children, were observed on tours of the entire complex. They were shown within the Upper Chamber and the pylon raised and put through its paces. It's hardly likely that the facility would be thrown open for family tours were there anything truly secret or sinister there.

Furthermore, I had the opportunity to review the construction plans for the facility and other than the unique engineering work for the facility itself, nothing was out of the ordinary. Certainly there are subsurface structures, but there is nothing that could even be remotely construed as a "base". The only deep underground components are the pylon wells, and they are filled with the pylons. The Upper Chamber, basically a covered excavation, is much more modest a facility than it appears to outside observers. This is an absolutely fascinating facility, but in its own right, not because of some idea that it is an "underground base".

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Junction Ranch RCS Range

Location

Although the other three RCS ranges in the Mojave are somewhat well known, the Junction Ranch RCS Range is not. It is located in an isolated valley on the west side of the Argus Mountain range, about 2 miles southwest of Maturango Peak in the far northeastern portion of the China Lake Naval Weapons Center.

History and Property Ownership

The newest of the Mojave RCS facilities, it was constructed in 1988.

It is owned and operated by the US Navy as part of the Naval Air Warfare Center Weapons Division at China Lake.

Junction Ranch RCS - Horizontal Range

Facility Description

The Junction Ranch RCS Range is actually comprised of two ranges, located adjacent to each other. One is a typical horizontal range, but the other is a "look-down" range with a water filled pond. This look-down range, also known as the "Wet Site", simulates a sea surface environment for RCS testing.

The horizontal RCS facility has two pylon locations, one 700' downrange, and one 4,000' downrange. This provides for target positioning for both low and high frequency radars. The pylon is of a low RCS design, 40' in height, and capable of supporting 6,000 pounds. Surprisingly, the surface of the range is compacted soil, rather than the more typical asphalt. The range managers have found this economical design to work quite well, requiring only occasional grading and treatment with soil sterilants.

The Wet Site is centered around a shallow salt water pond 78' wide and 100' long. It contains a 30' diameter hydraulic turntable that may be raised or lowered to provide lookdown angles from 5 to 30 degrees. The radar is located at a slant distance of 17,000 feet. It seems as if this facility, at least in an initial phase, was used in the model testing of the Skunk Works "Sea Shadow" stealth ship.

Wet Site viewed from transmitters (Photo from China Lake Exhibit Center)

Range Capabilities

Junction Ranch can perform extremely rapid measurements in UHF, L, S, C, X, Ku and Ka frequency bands. The facility also has the capability for bistatic RCS measurement. Because of the very low levels of RF interference at the location, HF capability (40-60 MHz) has recently been http://www.sysplan.com/added. The radar measurement equipment was manufactured by the System Planning Corporation in Arlington, Virginia. This image of some of the Junction Ranch equipment was taken from SPC's web site.

Range Security

Test security is provided by its remote location within an already secure military reservation. The facility is essentially hidden from public view. Only a portion of the lookdown facility is visible from the hills south of Darwin, while the horizontal range remains completely out of sight. In keeping with its no-frills, high efficiency mode of operation, when adversarial surveillance satellites pass within range, models are simply taken off the pylons or covered. No exotic retractable pylons here.

Other Information

Although a spokesman for Junction Ranch was unwilling to specifically name any of the facility's clients, he indicated they serve a wide range of customers, covering both the government and private sector. They also provide a way to check data and measurements submitted by contractors utilizing their own RCS facilities.

The remote location ensures very low levels of radio frequency interference that could compromise measurements. While it appears a modest facility, built without the bells and whistles of some of the other ranges, it offers state of the art measurement and data processing, while maintaining low operating costs.

Funding for this facility comes from the MRTFB program. MRTFB is an acronym for Major Range and Test Facility Base. The MRTFB is a set of test installations, facilities, and ranges which are regarded as "national assets." These assets are sized, operated, and maintained primarily for DoD test and evaluation missions. However, the MRTFB facilities and ranges are also available to commercial and other users on a reimbursable basis.

Junction Ranch has additional information available on the web at:

Pacific Ranges page (THC: Link is to a 1997 archived copy; the Navy no longer updates this page.)

A nice three page overview (THC: Link is to a 1997 archived copy; the Navy no longer updates this page.)

A very good technical paper about EM testing at Junction Ranch (7 meg PDF file)

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