[JT118]

Generally the cheaper sensors (particularly FO sensors) cut costs at every point of their manufacture, one of which is the cable, which is the thinnest cheapest cable they could use, increasing cable gauge and quality and screening is one way of extending cable run and maintaining signal quality.
See link here.

http://www.geosense.co.uk/technical/sensor-outputs

http://stores.ebay.co.uk/Brimal-Componen...34.c0.m322