LOADING FOR TELEPHONE CIRCULfS 



237 



TABLE VII 



First Standard Loading Coils for Phantom Working 



Note. The resistance data apply to circuits of a complete phantom group; i.e., 

 the side circuit data include effects of the phantom coils, and phantom circuit data 

 include effects of the side circuit coils. Effective resistance values correspond to line 

 current of 0.002 ampere. 



designed for open wire lines and for 10-A.w.g. cable had 65-permeabil- 

 ity wire cores and stranded copper windings. The coils designed for 

 13-A.w.g. cables had 65-permeability wire cores and non-stranded 

 copper windings. The other coils had 95-permeability wire cores. 



Potting Features. The general practise for cable loading is to 

 pot side circuit and phantom loading coils in the same case as phan- 

 tom groups, since this has important installation and transmission 

 advantages. The phantom coils, being considerably larger than the 

 side circuit coils, are mounted in separate spindle compartments. 

 The cross-connections between the side circuit and phantom coils 

 are made within the case, in order to reduce the amount of splicing 

 required in the field. Thus, the stub cable contains only the con- 

 ductors to be spliced to the "east" and "west" conductors in the line 

 cable. Quadded construction is used in the stub cable of all loading 

 coil cases for phantom loading in order to avoid serious capacitance 

 unbalances. 



