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So, as some of you know, I am now part of our student radio station. Our transmitter is in the midst of being replaced and I met the station's engineer last week. We transmit our signal over dry pairs from the studio to the transmitter site. I did some looking around, and apparently they use a Western Electric 111C repeating coil on each side of the line. Can someone explain exactly what this does?
Thanks,
Jeff
Jeff Moss
Moss Communications
Computer Repair-Networking-Cabling
MBSWWYPBX, JGAE
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Moderator-Vertical, Vodavi, 1A2, Outside Wire
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Moderator-Vertical, Vodavi, 1A2, Outside Wire
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It's basically a 1:1 transformer that isolates the dry pairs electrically at each end from the audio equipment in an effort to eliminate hum. If I recall correctly, there is also a series of capacitors on the line side to absorb AC hum and shunt it to ground. I haven't seen one of those things in years, so I can't speak with with complete accuracy.
Ed Vaughn, MBSWWYPBX
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Moderator-1A2, Cabling
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Moderator-1A2, Cabling
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"Where are we going and why are we in this hand basket?"
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Joined: Dec 2002
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The way I understand it is, there is a coil on each side, left and right. On the coil itself they mounted a 42A block. The dry pairs connect to one set of terminals, and the audio pairs connect to another.
Sam, thanks for the link.
Jeff Moss
Moss Communications
Computer Repair-Networking-Cabling
MBSWWYPBX, JGAE
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Joined: Dec 2005
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RIP Moderator-Mitel, Panasonic
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RIP Moderator-Mitel, Panasonic
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Never mind the answer, what a great pair of web sites! Thanks, SAM  John C.
When I was young, I was Liberal. As I aged and wised up, I became Conservative. Now that I'm old, I have settled on Curmudgeon.
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Basically a nice high quality high-level audio transformer.. can be strapped for 150 or 600 ohms on each side. I've got a couple 111C's stashed out in the garage someplace..
I took a 111C, and built it into a hammond box with binding posts and XLR on both sides, with switches for impedance and ground lift on both sides for use on remote broadcasts.
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Joined: Dec 2005
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RIP Moderator-Mitel, Panasonic
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RIP Moderator-Mitel, Panasonic
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And I just saw some pairs of 111's on e-bay, for anyone interested. John C.
When I was young, I was Liberal. As I aged and wised up, I became Conservative. Now that I'm old, I have settled on Curmudgeon.
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