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km987654
Joined: 25 Jul 2007
Posts: 2874
Location: Australia
TV/Projector: Barco BG809s
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| Posted: Sun Jun 05, 2011 10:29 am Post subject: Coax in my PJ |
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Just did some damage to a small piece of coax on the base of my PJ frame. I have re attached the broken coax and currently hoping for the best. This has caused me to ask Why. What is the point of the coax as it would appear that only the centre section is used which amount to a single wire so why not just use wire as the little 2cm piece of coax connects a wire from a socket to another wire on another socket.
Its a BG808s frame.
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Sparky015
Joined: 12 May 2009
Posts: 1185
Location: Cleveland / Akron, OH
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| Posted: Sun Jun 05, 2011 12:28 pm Post subject: |
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generally coax is used as low noise cable and to maintain impedance. The outer braid, the thickness of the insulator between the braid and center conductor, and the radius of the center conductor all are designed for that purpose. Is the outer braid not connected to ground?
_________________
~Paul
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Spanky Ham
Joined: 22 Mar 2006
Posts: 5643
Location: Comedy Central
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| Posted: Sun Jun 05, 2011 5:06 pm Post subject: |
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Not sure what you are asking. Are you asking why you can't use just a bare wire or a wire with a thin piece of plastic over it like speaker wire? I seem to remember tse testing coat hangers and finding that they worked well. Having said that, what Sparky said.
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km987654
Joined: 25 Jul 2007
Posts: 2874
Location: Australia
TV/Projector: Barco BG809s
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| Posted: Sun Jun 05, 2011 10:02 pm Post subject: |
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| Sparky015 wrote: | | generally coax is used as low noise cable and to maintain impedance. The outer braid, the thickness of the insulator between the braid and center conductor, and the radius of the center conductor all are designed for that purpose. Is the outer braid not connected to ground? |
There is no outer braid there is only the centre section of a coax cable the white inner insulation and a single wire inside that. All of the other parts you would normally see in coax are not there. The wiring diagram labels it as coax. Why use just the centre section of coax instead of just wire the only thing I could think of was impedance.
Last edited by km987654 on Sun Jun 05, 2011 10:09 pm; edited 1 time in total
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km987654
Joined: 25 Jul 2007
Posts: 2874
Location: Australia
TV/Projector: Barco BG809s
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| Posted: Sun Jun 05, 2011 10:08 pm Post subject: |
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| Spanky Ham wrote: | | Not sure what you are asking. Are you asking why you can't use just a bare wire or a wire with a thin piece of plastic over it like speaker wire? I seem to remember tse testing coat hangers and finding that they worked well. Having said that, what Sparky said. |
I am asking because when re-fitting the frame to the chassis I broke one end of one of these cables (can't believe I did that) and had to re attach it. I thought I might use plain wire since only the centre section of the coax was used but I repaired the problem with the same coax because I thought that Barco could have used plain wire also but did not and I really want to know if there is some reason for this or perhaps Barco had too much coax and wanted to use it. 
The silly thing for me is the coax joins two copper sections of the circuit.
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