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I just stripped my rack in preperation for flooring the HT, and I was horrified at the rats nest I created behind the rack.


The BNC jumpers I've been using are all 3m Extron RGBS units I picked up with my secong PJ.

I'd like to replace the 3m cables with either made to order cables or 1m discreet cables. Are there any caveats to selecting BNC cables I should be aware of? Are there low cost sites to recommend?


Perhaps I should confert that ribbon I've got to custom length units...



Any thoughts?
 

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Stay away from BNC's that have a nylon/plastic liner inside the female housing, these are 50ohm.

Your Extron BNC's will not have the liner, so that's what a 75ohm BNC looks like


I make my own and get most of it at Markertek (Carnare, Belden, Trompeter)


Or contact member Gn2 (Paul) He can custom make what you want


David
 

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Quote:
Originally Posted by AVWERKS
Stay away from BNC's that have a nylon/plastic liner inside the female housing, these are 50ohm.

David
David,

I used to think the same way as you do until yesterday when I read this from Extron's website:
http://www.extron.com/technology/arc...tifyingcables1


Scroll down and see the section ...

"BNC Connectors -

Is There a Difference? "


But in the end, you are the best judge :)


-Rajiv
 

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Rajiv - thanks for the link. Very interesting reading, including the bit about VGA connectors. :)
 

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I have always made my own 75 ohm cables, using a very good grade of Belden RG-6 cable and either Trompeter or Amp silver-plated 50 ohm BNC connectors.


Why 50 ohm BNCs and not 75 ohm BNCs? Because I can find no measurable difference in performance between 50 and 75 ohm BNC connectors at the signal frequencies we use with CRT projectors.


The care with which you trim and dress the cable end before soldering has more effect than the BNC type itself.


Of the total cable length, the very small portion of the path that is the connector introduces an insignificant amount of VSWR (Voltage Standing Wave Ratio) due to the impedance mismatch, when compared to the HUGE effect on VSWR that the much longer cable run itself has.


So use a very good RG-6 equivalent, double shielded or even better, Beldfoil 100% shielding is best. And do yourself a favor, use 50 ohm connectors and save a buck, since I can't see any difference on my network analyzer between the two types of BNCs at the frequencies we use. They are just not high enough to matter.
 

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Quote:
Originally Posted by rajdude
David,

I used to think the same way as you do until yesterday when I read this from Extron's website:
http://www.extron.com/technology/arc...tifyingcables1
I've posted a link to that a couple of times in the past. For the most part it was ignored. I think it's because most people want cables, connectors, power conditioners, etc. to be a performance enhancers, to be high tech and sexy. They do not want or appreciate these type of things being demystified. ;)
 

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I've seen Extron's site before and don't disagree about the result's obtained. I use the lowly HD15 plug because I have too and can see no difference visually, even though it's worse than a 50ohm bnc :)


But if I have a left bin with 50ohm's next to a right bin with 75ohm's bnc's...,.


I'll take the right bin since it's closer to perfection :D


David
 
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