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The table of the twist in the tail cable

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SpatialKing
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re: The table of the twist in the tail cable
SpatialKing   12/15/2010 5:51:04 PM
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I suspect the video world uses coax since in the early TV days, say post WW2, the video world was TV and it revolved around single ended tubes and single ended systems for which coax was well suited.

David Ashton
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re: The table of the twist in the tail cable
David Ashton   12/2/2010 12:24:39 AM
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Considering that flat cable is intended for Audio telephone use only, the impedance issues at anything above a few hundred KHz are anyone's guess. I will never again use flat cable for anything other than plain old telephones!

sharps_eng
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re: The table of the twist in the tail cable
sharps_eng   11/30/2010 11:14:49 PM
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It always amazed me how well 5-6MHz baseband video travelled, measurably unharmed, across loops of hookup wire and rambling PCB traces, despite all the trouble taken with it when in its 75R co-ax form. It also puzzled me as an audio person, why the video world didn't use differential signals on twisted pair, since co-ax had so many problems. Now look at them; 1.45-3Gbps over co-ax for HD-SDI, relentlessly spending money on interfaces that only work over short ranges, and cost a ton of money and power. I suspect it all done so that the video guys can tell which are their cables, and which belong to the audio or IT guys...:-)

David Ashton
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re: The table of the twist in the tail cable
David Ashton   11/30/2010 1:11:18 AM
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Doesn't work for me either. There are two parts so far published: Part one: http://www.eetimes.com/design/communications-design/4009566/Transmitting-video-over-CAT5-cable Part two: http://www.eetimes.com/design/communications-design/4009568/Transmitting-video-over-CAT5-cable--Part-2 There is a part 3 still to come. If you are Mike Wong from Intersil, there you are (and my compliments on a great article).

SpatialKing
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re: The table of the twist in the tail cable
SpatialKing   11/29/2010 7:13:38 PM
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The link to the original article is not working - I get a server not found error. I wonder if this is the same article of the same name I wrote and had published?

BYOV
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re: The table of the twist in the tail cable
BYOV   11/29/2010 6:39:52 PM
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This reminds me of a time when I had to be educated about something I should have known I occasionally barrow a 4-12 ft CAT5 & CAT6 network cable from our IT manager, I always wrap the cord up into a very neat, small & tight coil before returning it, he finally asked me to stop wrapping the cords as I am screwing up the twist & spacing of the conductors inside of the cable, therefore running its high speed data capabilities. It turned out that it was another one of those Homer Simpson Doh! moments.

David Ashton
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re: The table of the twist in the tail cable
David Ashton   11/21/2010 7:58:42 AM
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Aside from the reference to the "Tranmsitting Video over Cat5 Cable" article above, there is another excellent article that deals with all the parameters involved, in a more general fashion here: http://www.eetimes.com/design/industrial-control/4013761/Getting-the-most-out-of-your-twisted-pair-cable

David Ashton
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re: The table of the twist in the tail cable
David Ashton   11/18/2010 4:45:34 AM
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Would've been a nice ending if the customer's shotgun had blasted the antenna cable open at the antenna. But, as I have pointed out before, I have a bit of a mischievous sense of humour.....

zeeglen
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re: The table of the twist in the tail cable
zeeglen   11/18/2010 1:20:13 AM
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The vertical hold story is a classic! Then the story of the TV repairman walking up to to the house and seeing several birds perched on the rooftop TV antenna. He joked to the customer that the birds were ruining the signal. He pulled the TV out from the wall and saw the antenna cable had a wire loose. He reconnected the wire, good picture again. Suddenly he heard a BLAM! The customer came back in with a smoking shotgun and saw that the problem was solved. The TV tech got such a laugh he did not even charge for the service call.

David Ashton
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re: The table of the twist in the tail cable
David Ashton   11/18/2010 12:16:53 AM
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Thanks Glen...chain...weakest link...etc Back to TVs. I heard a lovely story about the valve TV days. Repairman gets called to an upmarket home to sort out the TV...a nice model but showing its age. Lady says "I want it good as new, money no object." He changes some valves, gets all the adjustments spot on and gets a nice picture. Calls owner in and asks, "How's that?". Owner says, "Yes, it's ok but not as good as when it was new". Back to work....replaces some caps, checks antenna alignment, changes another couple of valves, and amazes even himself with the quality of picture. Calls owner back. "Yes, it's very good, but still not as good as new." So he reaches behind the set and knocks out the vertical hold adjustment. As the frames slowly roll, he says to the customer, "OK, when you see a picture that you like, tell me and I'll lock that one in." Good thinking......

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