By Brian Bauer, Raychem Corporation
The drop has long been considered the weak link in the CATV system. As future systems require greater shielding due to CLI restrictions and higher bandwidth, the drop will receive increasing demands for sustained performance. At the root of many drop problems is corrosion at the F-interface.
As part of project, an conducted into a CableLabs funded investigation was the destructive dynamics of corrosion as it pertains specifically to the F-interface. The electrical performance profile of Fsplice samples exposed to Copper-Accelerated Acetic Acid Salt Spray (CASS) was determined. These samples have been dissected, and much of the mystery behind the discontinuous nature of shielding degradation is explained through the use of Scanning Electron Microscopy and X-ray Spectroscopy. Relative corrosion rates of often used metals within a CATV drop interface, including port, connector, and cable materials are examined. The weakest material link in this connection, found to be the aluminum braid, is studied with regard to relative galvanic coupling to key materials. Corrosion data is offered that is pertinent to the design of future connectors/ cables/ ports.