Tejon Ranch Radar Cross Section Facility: Is it history?

This is the Northop RCS facility west of Edwards AFB.

Check out coordinates N34 55 39.12 W118 31 56.93 on Google Earth.
The radar dishes and support equipment are missing in the 5/24/2013 imagery. They are easily seen in the 7/15/2011 imagery. The place looks deserted>I suppose it could be a weekend photograph. The photograph in theory would have been taken on a Friday, but you can't always trust the date on Google Earth imagery.

At n34 54 58.62 w118 31 22.54, they have removed the pylon for the test article and even scraped the pavement from the area.

At n34 54 56.21 w118 31 40.67, buildings have been removed.

reply to post by gariac


I don't have GPS number ability. All I have is west...so far 5 large antennas with a shack..is that what you are looking for?
I will give you if there is not a town or noted landmark...it can not be saved or starred. Hmmm. I've got to the ground resolution from all over the Mojave death valley..
You always pick them out if I can get close enough..just 2 days ago I found the X-33 launch complex. East of base on mars..mercury Blvd.......OK now my marker is gone.., so yeaaa.. there is that.....

The building west has five white trucks and one silver suv of a sort...tall radio tower... on a single road into a loop off of rosamond Blvd.. close? This is of 4 other antenna sites I see.

5 shacks. 1 antenna each...don't mock me its late


And I'm outside..coco running low...lol


I'll screen capture..eventually I'll figure a way to upload all of these...

reply to post by gariac


The Northrop Grumman Tejon Test Complex was forced to close in 2011 due to nearby construction of solar power arrays and wind turbine towers that interfered with radar and antenna testing at the site.

Northrop Grumman appealed a September 15, 2010, approval by the Los Angeles County Regional Planning Commission of a 230-megawatt facility known as AV Solar Ranch One, which was proposed to be built on 790 acres at 170th Street West and Avenue D, approximately five miles from the Tejon Test Complex, on the basis that it would disrupt radar measurements.The Los Angeles County Board of Supervisors denied the appeal two months later. At the very least, Northrop wanted to delay construction of the plant to see if it could work with First Solar, Inc., to find a way to build AV Solar Ranch One that wouldn't harm the test facility. According to news reports from 2010, Northrop reached such an agreement with a wind farm in the area. Personally, I would have thought that the forest of extremely tall wind turbines that has been built just two miles east of the test site would cause greater interference than the solar farm.

Another proposal, from Sempra Generation, for a 960-acre solar farm to be built between 150th and 135th streets west and Holiday and Kingbird avenues also worried Northrop Grumman officials. A similar challenge filed with the Kern County Board of Supervisors was denied after the Department of Defense verified the Sempra project would have no impact on the military mission in that area.

In its appeals Northrop Grumman contended that the solar plants could interfere with testing by reflecting or emitting radio waves, increasing the background electromagnetic "clutter" and making its tests less accurate. Leonard Figueroa, Northrop Grumman director of engineering, claimed that several secret programs aimed at creating "the next generation of stealth aircraft" could be adversely affected by interference with work at Tejon. He said the projects at risk were secret and could not be publicly discussed.

The Tejon Test Complex was built in the early 1980s when Northrop Corporation (before its merger with Grumman) was developing stealth technology for use in the proposed Advanced Technology Bomber, which ultimately became the B-2. The site location, a 1,400-acre parcel within the boundaries of the privately owned Tejon Ranch on the southeaster slopes of the Tehachapi Mountains, was chosen for its relative remoteness and sparse population. The land was initially leased from the ranch but later purchased outright by the company.

The test complex is comprised of two radar cross-section (RCS) measurement ranges, two antenna ranges (nicknamed the "Ant Hill" according to Northrop documents and personnel), and one indoor RCS range. The outdoor RCS ranges were capable of handling models or full-scale aircraft up to 8,000 pounds on 14-foot or 26-foot support pylons at several fixed locations up to 3,000 feet from the transmitter array.A 50-foot pylon was available for targets weighing up to 10,000 pounds. RCS test frequencies ranged from 145 MHz to 18 GHz in vertcal and horizontal polarizations, with imaging capability available at all bands. The Antenna ranges were used for testing electromagnetic interference and for developing state-of-the-art antenna and radome configurations at frequencies from 100 MHz to 40 GHz. One of the two antenna ranges had unobstructed 360-degree capability and could handle weights up to 75,000 pounds. The RCS Compact Range, completed in 2000, is a 20 by 20 by 40 foot chamber capable of accommodating targets up to 500 pounds and providing measurements at frequencies ranging from 2 GHz to 18 GHz.

The facility included a machine shop and fabrication area for target assembly and modification, six segregated secure model storage/work areas totaling approximately 30,000 square feet, a 1,200-square-foot paint booth, radar controland data acquisition buildings, security office, pump house, emergency generator, two 10,000-gallon tanks for potable water, a 300,000-gallon water tank for fire suppression, propane and diesel storage, hazardous materials storage, and other equipment. According to a company brochure the test site also offered materials and test analysis, a low-speed wind tunnel, analytical chemistry, fatigue and static mechanical testing, environmental exposure testing, heat treatment, composite testing, and thermal analysis.

Loss of the site's capabilities must have been a severe blow to Northrop Grumman after making such a large investment over the years. I have not heard of any plans for a replacement facility.

reply to post by Shadowhawk


Well you earned a star from me. ;-) No replacement seems unlikely in the long run.

The solar plant is probably using DC/DC converters and/or an inverter. These make some RF hash.

Windmills just reflect the radar. It is possible using timing that you can gate out the reflections and just get the first bounce, which would be from the test structure. I never thought much about how they measure the returns at a RCS, but if they used a CW (continuous wave), they would eventually get clutter no matter how empty the surrounding area. Helendale could probably count the cars on the highway if they wanted too.

I found this paper regarding a wind farm near the Tejon RCS and how to mitigate the effect of the windmill. It has a fair amount of abbreviations in it, but I know enough of the theory that can I explain the basics.

Windmills and RCS

If you have a single frequency (or more correctly test with a single frequency at a time), it can be transmitted as CW (continuous wave) or in burst mode (small packets of sinewaves carefully gated so they turn on and off at the zero crossings.]

On page three, they have diagrams to show the basic problem. PRF is the pulse repetition rate. At this point, the authors have given up on painting the target with CW. This is because if they put out a continuous wave, it would reflect off the windmills, AKA clutter. So they send a series of pulses, and record the earlier pulses, which come right off the target, then ignore the pulses from the windmill.

Now they mention phase coding. At this point, the bursts will not be of sine wave but phase modulated in some manner not shown. The deal with modulating the signal is the radar system has full knowledge of the modulation, i.e. "a priori" knowledge. Because you know exactly how the signal was modulated, you can use a companion demodulator that is highly sensitive to the modulation, while rejecting signals that don't match. I think this is their attempt to get around the Doppler reflected signal, which will be phase shifted a bit.

Page 6 shows the Doppler effect on the reflected signal. [QinetiQ is pronounced Kinetic. This is the company that did the study.]

On page 11, they introduce PN. This stands for Pseudorandom Noise. If the phase modulation was a boring 10101010, it would be hard for your demodulator to discriminate between desired signal and clutter. You get lost in the repetition. Using random coding, you can make your modulation look more unique. [Yes, that is poor grammar. If something is unique, you can't make it more unique. But hopefully you get the idea.] The more random the coding, the more likely that the demodulation can determine the initial reflection from the clutter.

Page 14 shows the Tejon facility and an artists deception of the wind farm. But at this point, Northrop threw in the towel.

What a shame and what a waste of the Tejon facility.

Was quite the place!

Northrop RCS job

Well they are still analyzing RCS data.

a reply to: weavty1

Theres......some sort of activity eminating from right around there. Too strange to go into detail about. Whatever they are fly from tejon ranch /tahachapi area south towards neenach. Something is still going on there abouts.

a reply to: BASSPLYR

Well, they don't actually fly anything out of the Tejon Test Site. There are no runways, just asphalt strips for the radar and antenna ranges. These strips are badly fractured and the RCS ranges have various square pits for mounting model support pylons.

Over the last several years since the site was closed there has been no noticeable activity, though I understand that there are occasional visits by a caretaker. The outdoor ranges are no longer useable due to the interference from solar and wind farms but, theoretically, the indoor range should still be available if it hasn't been dismantled.

a reply to: Shadowhawk

Yeah thats what they say. These may be eminating out from tahachapi maybe or real close to tejon rcs. They dont appear to need runways. I think they are taking metrics on these things and other data. Trying to minimize their signature maybe.

Not really OT but I found this website, kinda cool but here is a timelapse link to the rcs facility
rcs timelapse