By Jody Shields, United Artists Cablesystems Corporation
Due to the increasing concern for RF shielding, UACC Engineering sought some means of shielding evaluation of the products used in the field. Devices are available to make these measurements in a lab environment on aluminum and drop cables, such as the Belden SEED, but similar devices to test other CATV system components including amplifiers, subscriber taps, system passives, and drop passives are not commercially available at a reasonable price.
Therefore, UACC Engineering designed and built a device very similar to but much larger than the Belden SEED to measure the RF shielding of CATV components other than cable. The original purpose of the chamber was to determine relative values of RF shielding from product to product. However, it has also revealed great differences in RF shielding between various models of CATV components allowing UACC to set minimum RF shielding specifications for approved products. Additional research has been done to determine correlation factors of RF shielding measurement to signal leakage levels measured in actual operating conditions.