The prime task of a screened room in this application is to ensure that a noisy ambient does not interfere with testing. Higher performance screened rooms can achieve 60 to 90 dB attenuation, which is enough to achieve this result. Safety is a major concern for Start Spellman, because personnel have to conduct tests with high voltage within a sealed room. To overcome that concern, the end wall of the room has a 300 x 300 mm screened window, which is RF shielded to maintain the room's original specification. Regular visual checks take place to ensure personnel working in the room are safe.
Doors are clearly important for both RF performance and everyday use with low maintenance.
The room has a lightweight steel slam-shut door. The door uses a single row of fingerstock gaskets, which maintain the necessary conductive contact between the opening leaf of the door and the frame of the screened room. A screened room provides an RF clean environment that is ideal for accurate conducted emission testing, but Start Spellman's engineers had concerns about reflections from the room walls during emission testing. To meet their concerns, they use an emission reference source that enables them to quantify the reflection levels and to double check on the test set-up in the room. Now that Start Spellman can measure emissions, immunity, and ESD with accuracy and repeatability, the company is able to carry out all their development testing in house.