LOADIKG FOR TELllPI lONIi CIRCilTS 1^1 



Cable Loadiii'i lustallatioii Fealtires. Cost considerations make il 

 desirable to use aerial cable in tiie long toll cable installations, so 

 this type of construction is generally used in the open countrx". In 

 the vicinity of large population centers, underground cable is used. 



Typical aerial cable loading installations are illustrated in Figs. 12 

 and' 18. On the main trunk cables two-pole // fixtures capable of 

 supporting four to six large coil cases are usually required. I'ig. 12 



Fig. 12— Installation of aerial toll calile loading on -4-case "H" fixture 



illustrates a fixture of this type designed for supporting four cases, 

 three of which are already in place. On the smaller branch cables a 

 single pole fixture such as illustrated in Fig. 13 is commonly used. 



At the time a toll cable is installed, provision is made in the cable 

 splices for the ultimate requirements as well as for the initial loadmg 

 installation. Ordinary splices are made for the coils which are in- 

 stalled at the time the cable is placed, and "balloon" splices which 

 provide the slack wire required for splicing are^ arranged for sub-_ 

 sequent installations. 



III. Loading for Incidental Cables in Open Wire Lines 



In the loading applications discussed in the preceding sections, the 

 primary purpose of the loading is to reduce line attenuation losses and 

 frequency distortion eftects. In the case of incidental pieces of cable 

 in open wire lines, however, the [primary function of the loading is to 

 give the inserted cable approximately the same impedance character- 

 istics as the open wire line, in order to minimize reflection effects 



