Re: CCTV using Baluns

["Bob La Londe" <none@xxxxxxxxxx>]

"Jim" <alarminex@xxxxxxx> wrote in message
news:14421fd7-ee17-455d-b8e4-183c8bc068e7@xxxxxxxxxxxxxxxxxxx
> On Wednesday, January 2, 2013 10:51:20 PM UTC-5, G. Morgan wrote:
>> Jim Wrote: >I'm starting a CCTV job tomorrow in a small (30K
>> sqft)warehouse using analog cameras over cat5. Up till now I've used
>> siamese coax and 12vdc. I typically do more residential work than
>> commercial so I usualy don't have to worry about voltage drop. > >On this
>> system I'm installing 10 inside cameras all with IR LED's. Each camera
>> draws 700ma with IR LED's on. I've got 5 cameras that will be in the rear
>> of the warehouse where there are no power outlets so the cameras will be
>> aprox 100 to 150 feet from the 24vac power source. I bought Balun's with
>> screw connections (rather than an RJ45 connector) for the Cat5 so that I
>> could use six of the conductors for the power, giving me aprox a 19 guage
>> wire. I figure that should give me a voltage drop of about 2 volts which
>> is less than 10% of 24volts required by the cameras. I didn't do any
>> research on what affect the distance of 150 feet over a 24 guage wire
>> would have on the video signal. I don't think it'll be a problem but I
>> can always switch one of the voltage wires over to the video terminals. >
>>  >I'm just looking for some comments, suggestions and possible problems
>> that I might not have thought of when using Baluns and Cat5 Any comments
>> about longer distances using Cat5 would be appreciated also. I've got a
>> couple more larger warehouse jobs coming up so voltage drop is going to
>> be a bigger issue I don't think you'll have any problems within 150'. I
>> switched to CAT5 exclusively for new installs a few years back. It saves
>> money on cable, and it "future proofs" the install in case they want IP
>> cams later. I always use a different color cable than what their network
>> is using to avoid any confusion. If the Ethernet network is using blue,
>> I'll go with yellow or something completely different so their network
>> tech's don't get confused.
>
> Not necessary in this case but good idea to keep in mind
> Thanks

I have used a few baluns, and for the most part have had good luck on the
video side.  I tend to be cautious though and stay at a max of about 75% of
the balun's rated max distance.  For powered and amplified twisted pair
baluns/hubs over longer distances distance is more critical as if you go too
much higher on distance rating you get an over voltage or over driving
signal on the video which can cause issues.  (Never actually checked the
precise why, but it isn't good.)

Now going old school.  I had some old b/w composite cameras going a couple
thousand (that right thousand) feet over RG6 copper cable.  (special order)
I had issue with voltage drop on the supply side so I went with higher
voltage transformers as needed.  It was marginal, but it worked, and I was
the only one who could make it work.   I didn't need any video amplifiers
either.  Waaaaaay out of spec, but the video was adequate to drive the
multiplexor and recorded adequately on the VCR.

You do know that RG-59 copper and 18/2 is used all the time up to 750'
right?  At one time one of my vendors was selling it in 750' spools instead
of the more common 500' or 1000' spools.

One of the nicest thing about going with baluns is that Seco-Larm has a nice
ground loop isolator that is pretty inexpensive compared to some of the
others, and it doesn't grey out the video as bad as the coax one from Pelco.