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by Tom Mahood

 

Radar Ranges of the Mojave Desert

 

Junction Ranch RCS Range, Naval Air Weapons Station China Lake

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 (Figure 24).

Figure 24. NAWCWD China Lake Etcheron Valley Junction Ranch RCS Range, Horizontal
Range Site. (US Navy Photo.)  Click for a larger version

Figure 24. NAWCWD China Lake Etcheron Valley
Junction Ranch RCS Range, Horizontal Range Site.
(US Navy Photo; click image for a larger version.)

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 (Figure 25). 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.

Figure 25. NAWCWD China Lake Etcheron Valley
Junction Ranch RCS Range, Wet Site Viewed from the Parrot Peak Antenna Array Site. (US Navy Photo.)

Figure 25. NAWCWD China Lake Etcheron Valley
Junction Ranch RCS Range, "Wet Site" Viewed from the
Parrot Peak Antenna Array Site. (US Navy Photo.)

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. To take advantage of the very low levels of RF interference at the location, HF capability (40-60 MHz) has recently been 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.

Figure 26. NAWCWD China Lake Etcheron Valley 
                Junction Ranch RCS Range, Mobile Radar Measurement System. (SPC Photo.)

Figure 26. NAWCWD China Lake Etcheron Valley
Junction Ranch RCS Range, Mobile Radar
Measurement System. (SPC Photo.)

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:

External Link  Pacific Ranges page (THC: Link is to a 1998 archived copy; the Navy no longer updates this page.)

External Link  A nice three page overview (THC: Link is to a 2004 archived copy; the Navy no longer updates this page.)

External Link  "EM Field and Instrumentation Diagnostics in Support of the LFT&E HPM Methodology Testing"--1997 technical paper on instrumentation for High-Power Microwave (HPM) testing at Junction Ranch (7 meg PDF file)

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