Atlantic Research Corp. of Alexandria, a high-tech defense company, will stake a claim to new territory this fall when it opens two "Tempest" testing laboratories in Sunnyvale, Calif.

Tempest, a classified government engineering program, is intended to control emissions from electronic equipment such as computers. Such emissions, if intercepted and analyzed, could reveal classified information.

ARC doesn't produce computers. Rather, it tests and modifies equipment produced by other companies to make it conform to the government's Tempest data-security standards.

ARC's Tempest laboratories may find a ready market in California, where government contractors and even rival computer firms are eager to safeguard their secrets. The company's business is already thriving in the Washington area, where Tempest sales rose 21 percent in 1986 over 1985.

By moving to California, ARC is moving beyond the government market to government contractors. "We are using the new labs as a base to build up Tempest on the West Coast," said Steve Hines, director of marketing for the Tempest division of ARC.

The division is only about six months old. It was formed in January when ARC's Tempest design and testing team merged with ARC's wholly owned subsidiary, Systematics General Corp.

The division markets products that complement most large computer manufacturers in the country. For example, Tempest Mac is a Tempest-certified version of the Apple Macintosh, and the T-5151 is a Tempest system based on the IBM-compatible personal computer from Wyse Technology.

The division is new, but ARC has been involved in Tempest research and marketing for the past 20 years. The company is one of the largest Tempest testing organizations in the world, with 48 testing labs at its Northern Virginia facilities.

ARC will add four testing laboratories in Sunnyvale by the first quarter of 1988. The first two labs will be 5,000 square feet and should be completed by September. Hines estimates that the project will cost between $700,000 and $800,000.

The company plans to hire most of the staff locally. James Dickinson, formerly based in Alexandria, is the new manager of western operations. He and another engineer from the Alexandria will supervise the new facility.

ARC's new Tempest offices in the west are just one area in which the company has expanded recently. It bought Systems and Applied Sciences Corp., a professional services company providing data and logistics management, systems engineering, and technical support services, in October 1986. In April 1987, the company acquired ORI Group Inc. of Rockville to fend off efforts by Clabir Corp. to take over Atlantic Research. In doing so, ARC's staff jumped from 2,800 to 5,000. The company then consolidated its operations into two groups: the ORI Group, headed by Harvey Kushner, and the ARC Group, headed by William H. Borten. The Tempest division is part of the ARC Group.

Now that the reorganization is complete and ARC's independence is saved, it is moving west with the hope of finding new territories with new customers.

Porsche Cars of North America has contracted Telenet Communications Corp., a US Sprint company based in Reston, to provide data communications services to Porsche Cars of North America, the U.S.-based distributor of the European auto manufacturer. The Telenet computer network will connect the company's 324 automobile dealerships nationwide to Porsche's headquarters in Reno, Nev.

The system can locate vehicles, set pricing, report on deliveries, enter parts orders and retrieve warranty information. Telenet has developed and installed nearly 100 private data networks for corporations and government agencies.

Resources Consultants Inc. has been awarded a three-year, $6.5 million contract by the Naval Sea Systems Command. The company will provide technical, data management and material support services for NAVSEA Auxiliary and Special Mission Ship Acquisition Program.

The United States Postal Service awarded a $4.7 million contract to Strategic Financial Planning Systems of Alexandria for the design, development and testing of an automated postal teller. The project aims to design self-service machines that can weigh packages, select the desired mail class, and let customers use cash or debit cards for postage. The Post Service hopes to offer 24-hour service to the public with the machines.

The Institute of Scrap Iron and Steel Inc. and the National Association of Recycling Industries Inc. merged into one scrap industry trade association representing 1,800 member companies. The new association will be known as ISIS/NARI Inc. until a new name is selected. Sandy Shapiro and Howard Meyers, copresidents of the new association, said the need for a strong, unified voice for the processors and consumers of scrap commodities led to the merger. They noted that in the past five years, scrap markets have been weak and the industry has become vulnerable. They said the merger was an important part of the associations' survival.

Hadron Inc. received a $2 million contract from Martin Marietta Energy Systems Inc. to provide information and logistical services to the U.S. Navy. Hadron is a high-technology company that provides technical and consulting services in engineering, computer science and telecommunications systems. The two-year contract calls for program management support services for the Navy's electronic warfare programs. According to L. Kenneth Johnson, president of Hadron Inc., Hadron has supported the development of these electronic warfare acquisition programs over the past eight years. The contract involves developing data bases to assist Martin Marietta in building automated decision support systems and training users on the system.