Why a shielded two-wire line?
The main reason for the fact is the fact that each open two-wire line is very sensitive to enviromental influences. Open two-wire lines may not be shifted being because of metallic articles, parallel to cables, directly at the mast, in the supplying pit or on the soil. During a shielded two-wire line (shielded pair) the kind of the transfer does not play a role. Due to the screen it has a high fail-safe characteristic and can be everywhere shifted. The characteristic to co-ordinate antennas for multiple reel enterprise remains. The disadvantages of the shielded two-wire line are somewhat higher losses and a velocity factor smaller 1. The losses are negligible in the high-frequency. The velocity factor depends on the used type of coaxial cable. Structure and computation of a shielded two-wire line even built: Shielded two-wire lines are made of two parallel led coaxial cables and represent a symmetrical antenna inlet. The two cable lengths must be equal long exactly. The cables bound in
