CurtPalme.com Home Theater Forum

[zaphod]

there are so many ways that i've been stupid here i beg that noone starts pointing them out ...

the situation is that the RGBHV extron cable running from the scaler up the wall through the ceiling to the PJ is unterminated at the end by the scaler. i had planned for curt to slap on some BNC, but it turns out that his crimps won't work on this cable, so i'm going to terminate the cable with BNC connectors mounted on a wall plate. simple enough except that the cable will then be is 6 inches too short. i believe the word i'm looking for is "sh*t".

the questions:

why didn't i get the right length? well i had a line on a longer cable, but even though i paid for it, i never got it.
why didn't i run conduit to allow me to replace this cable in case i needed to (such as it turned out to be too short)? good question. before i put up the ceiling drywall, it was suggested to me, but at the time i just wanted to get the damn drywall up and couldn't be bothered to put up some piping. stupid stupid stupid.

can i extend the cable?

well there is the guts of the matter. i have a 12" length of the same cable, and i'd like to just attach the two peices. the cable is made up of 5 coax cables, centers and sheild both stranded.i have attached a picture.

i can, and am stubborn enough to strip the wire, and for each of the 5, attach center to center, sheild to sheild, heat shrink on new casing and be done with it. i even have additional foil to use to join the outer foils on the two pieces. the cable part is E101876 if you are that way inclined.

my question is this - am i guarenteed to introduce issues in the cable? i'm pretty good with a soldering tool - build my own cables - but is having a soldered join going to create a noisy cable?

the alternative would be to put BNC female on the end of the "in wall" and BNC male on the 12" length and just have a BNC join in the wall instead of a soldered one.

replacing the length is not really an option as the ceiling is new and i didn't run conduit (stupid, stupid, stupid).

thanks. you may begin laughing ...

[paw]

I'm not a cable expert by any means. However, I'd go for the BNC to BNC connection. It's a known entity. Soldering???

[Joust]

I have done a lot of RF work in the past. As an RF "expert" i have to say, BNC connectors are CRAP! They are convenient due to the 1/4 turn feature. but have terrible electrical characteristics. Almost as bad as those RCA connectors.
I have no real experience using BNC with low frequencies but I will say this. Any well spliced cable connection will be better than any BNC connection. Obviously this relies on the skill of the tech. It sounds to me like you do have the skills to do it right. The noise will be due to impedance missmatches. if you can maintain the dielectric as much as possible (exposing as little of the center as you are able), isolate sheilds if the original cable has them isolated. Use proper grounding procedures. You will be gold.
The fewer connectors in series with yoru signal the better off you will be.
if you still would prefer to use connectors, there are better alternatives than BNC. SMA comes to mind. just make sure they are the 75ohm variety. Most of these types of things are 50ohms for radio use.

try the splice. If you don't like the result. put a connector. Costs you nothing but some time.

my 2¢

[zaphod]