Keep your guard up
Changes in the RF test shielding industry have narrowed the competitive field, but they haven’t diluted the product pool.
When riot police advance on an unruly crowd, they link their shields together to form a seamless barrier against the mob. With the wall of protection successfully established, the police prove there really is “safety in numbers.”
Whether the company had this maxim in mind at the time or not, ESCO Technologies, St. Louis, applied a similar line of thinking to its business strategy in 2000 by expanding its stable of RF test-shielding subsidiaries to include Lindgren RF Enclosures, Chicago, and Holaday Industries, Eden Prairie, MN.
The players The two new acquisitions will join ESCO’s subsidiary EMC Test Systems (ETS). Formed in 1995, the company began with the merging of EMCO, an ESCO subsidiary and manufacturer of EMC test equipment, and the anechoic absorber and chamber business unit of another subsidiary, Rantec Microwave and Electronics. In the same year, Ray Proof North America, a manufacturer of RF shielding, was added to ETS.
With the first of two acquisitions executed this year, ESCO brought Lindgren, a company established in 1951, into the fold by integrating its test and measurement operations into ETS. The new entity will be known as ETS-Lindgren. The two companies will employ about 450 people at offices located in the United States, England, Finland and Singapore.
The second acquisition took place when ESCO announced that Holaday Industries’ operations would be integrated with ETS.
The products ETS produces RF enclosures for a variety of uses. Beginning on the small end, the company offers the 5200 Series of benchtop test cells. The benchtop cells are designed for applications where an RF-isolated environment is required for making immunity or emission measurements that include design qualifications, post-production sampling, QC/QA, incoming material qualification and repair bays. The cells offer from 60dB to 120dB of shielding, and they are absorber/ferrite-lined.
On the other end of the spectrum, the company also produces walk-in enclosures for larger needs. The Ray Proof Series 81 shielding systems are constructed with modular panels that enable as many as 30 enclosure configurations. The 3/4-inch-thick, dimensionally stable cores are laminated on both sides with 26-gauge sheet steel that meets ANSI A208.1 specifications. The panels are joined together with a 1/8-inch “hat and flat” clamping system. The enclosures can be dismantled, moved and rebuilt as needed.
Lindgren brings a selection of enclosures to the table as well. The company’s double electrically isolated (DEI) enclosures use two separate conductive electromagnetic barriers that are electrically isolated and attached by a single-point ground connection. The DEI enclosures are available in screen and solid models.
Bronze and copper screen enclosures are used where absence of a sense of confinement or casual observation from the outside is desirable.
Enclosures with solid-wall construction are designed in various combinations of steel and copper, and they can be built with supplementary sound-deadening material between the inner and outer shields or attached to the exposed wall surfaces.
The ETS family of companies are not the only players in the RF test shielding game, however. Ramsey Electronics, Victor, NY, manufactures several benchtop test enclosures as well. For applications that require several devices for sequential tuning and repair operations, Ramsey’s STE-3000 includes three BNC or TNC feed-through connectors and a filtered DB-9 feed-through connector. The box offers access holes complete with ultra-fine shielded mesh gloves. The work area has built-in illumination via four low-voltage incandescent lamps powered by an RF-filtered ac supply. Suppression is -50dB at 1GHz, and it drops off to -30dB at 3GHz.
Building on the concept of its STE-3000 RF-shielded test enclosure, Ramsey introduced the STE-2000 portable RF test box. Heavy-duty, rugged 0.090 and 0.125 aluminum is used throughout, and double-woven monel flexible gaskets are used at all joint locations. Access holes in the top cover offer access for non-metallic alignment tools for closed-cover alignment. The box provides as much as 70dB of RF isolation in a 4″ 3 7″ 3 9.5″ footprint.
Although the recent mergers and acquisitions in RF test shielding have narrowed the field, the players still in the game are continuing to provide dealers and manufacturers with the one thing they need – just a little protection.