RADIO-FREQUENCY SHIELDING PROVIDED BY BOLTED SEAMS CONNECTING ARMORED-PLYWOOD PANELS
Technical rept. Aug 1965-Aug 1966
NAVAL CIVIL ENGINEERING LAB PORT HUENEME CA
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Rooms shielded against radio-frequency RF signals are essential to the Navys research and development and operational use of equipment sensitive to RF interference. A series of shielding-effectiveness measurements of armor-clad plywood sections representative of those used in the construction of radio-frequency shielded rooms has been conducted. Five sections and their bolted seams were subjected to wet cycles of 70 F, 100 RH and to dry cycles of 200 F, 10 RH. The precent moisture content, thickness variability, DC resistance, and surface currents at 12.8 kHz were observed during the wet-dry cycles. DC surface resistance of the seams increased monotonically throughout the test period. Standard deviation of the surface current measurements reached a peak at approximately 12 days. Another series of tests indicated that seams caulked with silver-loaded compounds had distribution of surface currents similar to those of solid armored sheets.
- Electrical and Electronic Equipment