Baluns with 18/2?

[bpzle 0]

I've got a client that has existing siamese in some iffy conduit underground going to a single camera. The goal is to add another camera.

There's no pull string there (who does that?!?) and a snake would probably be too difficult...There's some bends in the conduit and don't want to risk using the old wire as a pull string in fear of breaking the cable.

 

There's a 120v power at the target area so I was thinking we could power the cameras locally and utilize that 18/2 pair somehow...

 

Anyone ever have luck using 18/2 with baluns? Seems risky but it would be a real cheap and easy solution if it worked... The distance is between 100 and 150 feet.

[hardwired 0]

That's one of those "why not try it" kind of things. The cable probably does not have any twist, so noise/interference could be an issue.... But if it can be tested easily enough, why not... Let us know if it works!

 

***********EDIT**********

 

You could use a set of these http://www.fmsystems-inc.com/cw/Details.cfm?ProdID=95&category=4 ,Pretty expensive, though. I have used them, and they do work.

[bpzle 0]

That's one of those "why not try it" kind of things.

 

Your right, but he's a DIYer and don't want to ship him things that may or may not work...

 

 

You could use a set of these http://www.fmsystems-inc.com/cw/Details.cfm?ProdID=95&category=4 ,Pretty expensive, though. I have used them, and they do work.

 

I vaguely remembered a thread with someone running multiple analog cams on one coax with something like that... but couldn't find it.

 

That thing is way too expensive for sure! Anything like it but more down to earth? Point to point and a megapixel cam would be cheaper than that!!

[bpzle 0]

I've got plenty of baluns... if only I had some 18/2 laying around....

[Soundy 1]

I've done baluns over 18/2, works just fine. I've used them over station-Z wire (four 22ga conductors, non-twisted) without a problem. I've even run video *and* power over station-Z in a pinch (situation similar to yours - cameras on a gas station's pump canopy, where all the conduits have been sealed).

 

Realize that the "balanced line" concept really doesn't rely on the pairs being twisted - that helps with EMI rejection, but it's really not crucial in most instances. Consider that the concept is the same (though there are slight technical differences) to that used for balanced audio lines in pro audio, and that typically uses shielded, non-twisted 18/2 or 20/2.

 

All that said, if you'd prefer to delete the Siamese and start clean, instead of using the Siamese to pull new wire... use it to fish through a proper pull string, then use THAT to fish your new run.

[bpzle 0]

Sweet! Nice to hear. Thanks!

[tomcctv 190]

Sweet! Nice to hear. Thanks!

 

cheapest way when we have had to add extra camera in your situation is both images down 1 coax. the balun way works but bad picture loss.

 

two cameras /power/data down 1 coax. we have used these many times. here is a full list of products.

http://biwave89.myweb.hinet.net/product/product01.htm will save you time and money.

[survtech 0]

Realize that the "balanced line" concept really doesn't rely on the pairs being twisted - that helps with EMI rejection, but it's really not crucial in most instances. Consider that the concept is the same (though there are slight technical differences) to that used for balanced audio lines in pro audio, and that typically uses shielded, non-twisted 18/2 or 20/2.

However, the impedance would be wrong. CAT3, CAT5, twisted-pair etc. are 100 ohms nominal. 18/2 would probably be different.

 

The twists are quite necessary for noise rejection. Without them, one wire in a pair might pick up more interference signal than the other. Twisted pair relies on the noise getting cancelled out by subtracting the signal on one wire from the other. If the noise signals aren't equal, they won't be totally cancelled out.

[Guest]

I've got a client that has existing siamese in some iffy conduit underground going to a single camera. The goal is to add another camera.

There's no pull string there (who does that?!?) and a snake would probably be too difficult...There's some bends in the conduit and don't want to risk using the old wire as a pull string in fear of breaking the cable.

 

There's a 120v power at the target area so I was thinking we could power the cameras locally and utilize that 18/2 pair somehow...

 

Anyone ever have luck using 18/2 with baluns? Seems risky but it would be a real cheap and easy solution if it worked... The distance is between 100 and 150 feet.

 

I would suggest treat it as a RF system and modulate/demod multiple cameras on one coax

 

Ilkie

[Soundy 1]

the balun way works but bad picture loss.

Why would you say that? There's no technical reason for any loss of quality using baluns over non-twisted wire of any kind - if you've experienced it, there's probably some other reason.

[bpzle 0]

It works! Looks pretty good too... Client is happy. I never would have thunk it...

 

Thanks!

[Soundy 1]

It works! Looks pretty good too... Client is happy. I never would have thunk it...

 

Thanks!

 

(Arnold voice) YOU HEAR ME NOW, BELIEVE ME LATER!

[bpzle 0]

YA! in your face nay sayers!

[Soundy 1]

Next thing you know, you'll be using twist-on connectors on steel-core, aluminum-shielded RG6 to connect up your HDcctv cameras to your eBay DVRs!

[bpzle 0]

Don't make fun of my country! That's all I can get!