UTP Baluns

My customer has intercom gate entry to their home with a small analog camera built into the pillar. The coax (underground in conduit) run is approximately 350-450' to a standard analog DVR in the home. He lost video feed and after testing, it appears the issue is with the coax. There is no handhole between the home to the gate pillar and unfortunately I cannot remove the pillar top.

I'm trying to find an inexpensive alternative to get this camera back up and thought maybe to use the unused pairs from the intercom with baluns. I've honestly never used baluns before and while it seems simple enough, I'm wondering in this particular application if I will run into issues with the intercom (between the voltage there and my picture quality).

Has anyone done this, been successful, or have any other suggestions? Thank you,


There are lots of intercoms that shoot video and intercom traffic down the same cable, so you're probably okay. However, it's hard to guarantee you 'no issues'.

I've used really cheap UTP baluns that worked well, and <gulp> troubleshot applications where two cameras used the same run on UTP with four baluns. No, it isn't the best choice for video quality (ie: color distortion, rolling bars through the image) but for a video intercom you're likely just fine, especially since repulling new cable is the next step and will be significantly more expensive.

For the cost it is definitely worth a try. As others have stated you can have problems sometimes depending what else is traveling on that cable but in my experience most of the time it works just fine. Have sent multiple feeds on a single Cat5, shared power and video over a single Cat5 (DC power though) etc. I think you'll solve this problem with this solution.


Best,

As David says, should have no issue using baluns on a spare pair - I've used them over Cat5e, Cat3, station-Z, even old abandoned 18/2 speaker runs. I've run power and video for two cameras over a single Cat5e, as well as four cameras on a single cable.

The rolling and image issues Brian mentions are typically a result of a ground loop rather than the type of cable or interference with other signals, and IME is mostly caused when using multiple cheap cameras that use a shared video/12V ground; with a single camera, it shouldn't be an issue.

One important note: use only a single pair with the intercom (a twisted pair, ideally). I've seen installations using a separate twisted pair for each balun terminal (eg. blue/white pair for one terminal, orange/white pair for the other), and while it works, you don't get a proper balanced pair and you lose the noise rejection provided by a twisted pair. Also, make sure you observe polarity at both end.

Great, thanks guys. Appreciate the input.