Re: CCTV with Cat5 and what I've learned.

[G. Morgan <sealteam6@xxxxxxxxxxxxxxxxx>]

Jim Wrote:

>A few weeks ago I mentioned that I was doing my first CCTV install using Cat5 and Baluns. I think it was here (but maybe in other groups too) that it was touted as being less expensive to use Cat5 and Baluns compared to Coax Siamese etc.
>
>This is what I learned:
>12 cameras in a warehouse. Cameras draw 800ma max. Contrary to what the Balun people say their products will do ..... doing the calculations myself,(wire size, number of conductors, voltage drop, etc)theycouldn't/wouldn't
>"guarantee" that the cameras would work at the distances their advertising said they would. Their estimates of video distance was not my concern but they had no idea that the Baluns could not carry camera "power" over the same distance. Since there are no outlets in the back of the warehouse (where most of the cameras are located) I had to use 24VAC supply with 1- amp output each channel because there was more than a 10% voltage drop at the furthest camera if I used 12VDC. $200.00 for power supply. Max safest distance to keep cameras at less than 10% voltage drop is somewhere around 150 to 200 feet. In order to do this, I had to inquire with the Balun mfgs/suppliers, how many of the Cat5 pairs were  used to carry power. No one that I talked to knew. They "assumed" two pair were used for video and two pair for power. Two pair for power would not stay within voltage drop spec at 168feet. (my furthest run) So, I located Baluns with screw terminal connections, so I could use three Cat 5
>pairs for power and one pair for video. So that elimiated using Baluns with RJ45 connectors and required more time to untwist, strip, twist pairs and connect wires to termials, then it would take to crimp an RJ45 connector for plugging into a RJ45 Balun. 12 Baluns @ $16.00 each plus shipping.
>I also had to locate Baluns that had the power and video in/outputs on flying leads, because the Baluns with the BNC connectors attached would not all fit on the back of a 16 channel DVR if they had to be plugged directly into the connectors on the back of the DVR. But THEN .... even though you have flying leads, you also cannot have 12 Baluns hanging off of the back of a DVR by 6 inch leads. They have to be mounted elsewhere, out of sight. (I didn't think of this until later) When using Siamese coax, you just have to strip the power wires back and re-route them to the power supply and connect them directly to the terminals in the power supply and then continue the coax runs to the DVR and and crimp BNC's on them. When using the Baluns the Cat5 has to be run to where the Baluns are going to be located and untwisted, stripped, twisted in pairs and attached to the screw termials on the Baluns. Then, using the hard wire adapter power plugs, it's necessary to run additional wires from
>the Baluns back to the power supply. But now, since the Baluns are located "away" from the back of the DVR, it is necessary to manufacture BNC jumper cables from the video output of the Baluns to run between the location of the Baluns to the back of the DVR.
>
>Behind the desk, mounted to the wall is a 12 x 12 x 4 inch plastic "juction" box containing the Baluns $15.00. Out of this box runs a group of power cables from the power supply (mounted next to the plastic junction box.) a group of Cat5 cables from the cameras and a group of BNC jumper cables going to the back of the DVR. BNC connectors 12X2 @ .59each $15.00
>
>I don't know if I'm missing something (?) I don't know if I've gone overboard (?) but from what I see, with the additional parts and labor there's no F....ing way it's cheaper to do a Cat5 with Baluns CCTV job compared to a siamese wire job.
>
>Comments please?

In a warehouse environment with the large lengths of cable I can see why
you might be saying that it's not cost effective.  If it were a 12 cam
job with drop tile in a retail store (or home) it's definitely faster
and cheaper with baluns.  Think about this, you can use a flex bit to
corner mount a camera just like a motion because the cable is so thin.
All your wire running tricks from security come back into play with CAT5
video.  Try using a 3/8" flex bit to run siamese cable!

As others have said, in the warehouse some guys will place the power
supplies mid-run (wherever an outlet is convenient).  You can strip back
the outer jacket and inject power before it goes out to no-man's land.
Makes it a pain to troubleshoot if you don't document where the power
supplies are though.  Since *you* are likely the one to service it, you
may not need that level of documentation a big company has where a
different tech may go out each time.

I think you'll find baluns cheaper than $16/pair will do the job just
fine.  ADI sells them in a bag with two for half that.  Also, if you
plan for always using CAT5 in the future you may want to change the cams
you buy.  Some have built-in baluns.  You can pre-build the head-end box
at the shop to make the on site part go faster.  I have not found the
perfect way to mount baluns in the box yet, but with some trial & error
and all the clips and stand-offs available I'm sure you can make a
system that works for you.  MCM Electronics has TONS of stuff like that.
The catalog is 2" thick.  And it's full of goodies for our trade -
including audio.

Anyway, how was the video quality?  Any noticeable difference?

<aside>   I bought a Raspberry Pi mini-computer for $35 from MCM.  It
runs Debian Linux on a SD card.  It has 15 I/O's and the possibilities
are endless.  Comes with 512M RAM and a HDMI & composite out, plus audio
and network. If you like to tinker, get one!

<aside 2> Someone asked where to get LCD screens about 6 months ago, MCM
has them in all sizes.


http://www.mcmelectronics.com/