Look at this monster core I pulled out of the 111C!
Over a pound of barn roof cold rolled steel.
Insertion loss is only 0.5 db. This line transformer is ten times bigger than most output transformers.
The first layer is cloth:
http://vacuumbrain.com/The_Lab/TA/Western_Electric/WeCo_Repeater/111c_core8.jpg
Then the first winding. It is bare copper wire covered in cloth (served), spaced for minimum leakage, about 350 turns...
Next is a shield. Why is it interupted with the cloth?
5 pts to the first correct answer.
http://vacuumbrain.com/The_Lab/TA/Western_Electric/WeCo_Repeater/111c_wind27.jpg
These folks were seroius about their shielding. Look how tight they keep it around those leads. That huge Ni core attracts stray Webers like a magnet:
Three laps of buss wire soldered to the foil in two places. Lots of work went into this thing. Why is the buss wire not a shorted turn?
10 pts.
http://vacuumbrain.com/The_Lab/TA/Western_Electric/WeCo_Repeater/111c_wind33.jpg
http://vacuumbrain.com/The_Lab/TA/Western_Electric/WeCo_Repeater/111c_wind34.jpg
The shield is covered with a layer of cloth...
http://vacuumbrain.com/The_Lab/TA/Western_Electric/WeCo_Repeater/111c_wind39.jpg
Then the twisted pair winding. Spaced like the first winding. 10 twists per foot. This is the line winding. About 700 turns. You can see that it is actually two wires if you look close. Served enamel. About 73 ohms/1000 ft.
http://vacuumbrain.com/The_Lab/TA/Western_Electric/WeCo_Repeater/111c_wind46.jpg
Another look at the line winding..
http://vacuumbrain.com/The_Lab/TA/Western_Electric/WeCo_Repeater/111c_wind48.jpg
And then another e-shield, and a winding like you saw earlier spliced into the inner winding to form the drop.
The core is 1 1/8 slit Ni alloy, 0.0145 thick, 2 inch ID, 3 inch OD, taped at bothe ends.
Total turns ratio: 1408 Line, 1420 on the Drop. Extra turns probably to make up for insertion loss and a mile of wire back to the transmitter.
cj