Hi Everyone,
I have recently taken on a CCTV job and i was wondering if using RG6 Quad Shielded 18AWG cable is the best to use. Is there any disadvantages to using such a high quality cable. I was told RG59/U is the way to go, but i've also heard that it has losses over a 20 metre run. Anybody's help will be much appreciated.

Hi there Brite-Spark!.
It really depends what's around the area where you are installing the coax and the length of the run.
Personally I think that standard RG-6/U coax would be more than adequate for this application.
That's all I've used in the past and never had any problems.

Given that you're dealing with baseband video with a bandwidth of 50Hz to about 5MHz, the losses of RG59 are very low in comparison to it's usual use at VHF and UHF. Even for VHF, a 20m run of RG59 does not cause concern.
One of the instruments I work with is a video signal test rack where by means of a swtiching unit and pattern generator, baseband video can be fed through a number of different things to observe the effects. Such things include attenuators, filters, equalisers, and relevant to this topic, a 300m roll of military grade RG59 which would be about 25 years old.
Compared to a straight through connection, there is a slight loss of contrast (ie. there's less than 1Vp-p of video at the end of the coax) when the 300m length of coax is placed in the signal path. Otherwise there doesn't appear to be any degradation. Winding up the contrast slightly on the monitor and you wouldn't even know.
RG6 has lower loss than RG59 and is rapidly taking over with cable, satellite, and digital TV. The cost difference isn't as high as it once was, but beware of some really cheap nasty cable out there.
To answer the question, it would be much more than 20m before worrying about the loss of RG59. There is certainly no disadvantage in using RG6.

Aussie240, u said to beware of cheap and nasty cable out there. What should i be looking for to check if its a bad quality cable?

So, if i use RG6 Quad shield i should be almost certain that i will not get any problems, such as noise and losses.

Brite-Spark,
The better quality co-axial cables have the foil sheilding bonded to the dielectric insulation over the centre conductor.
Also, the shielding braid should be tinned copper and should be as thick as possible.
I'd also go with a coax that has either a foam or an air-spaced dielectric covering on the centre conductor.
I'd avoid any cables that have a stranded centre conductor, I've had nothing but problems with this sort of cable, especially when using it with F-type connectors.
I have to agree with Aussie though, there are some really dodgy cables out there, worst place you can buy it from here in NZ is a DIY store.

I've got several 100 metre long RG59 cctv cables installed here, and they are all fine. For baseband video there is no problem with loss so long as you avoid the air-spaced cables. Moisture can get into any cable, but it's worst with the air-spaced types.

Do try to keep the terminations in the dry, as the cheaper nickel plated bnc connectors corrode to a high resistance or even a diode effect. This can be cured with silver plated bncs, as silver oxide is the only conductive oxide, but they are a good bit pricier than nickel plated.

Just as an after-thought, could you get all of that braiding (that a Quad-shielded coax has)
into a BNC connector?.

Yeh your are probably right Trumpy, you wouldn't fit a bnc Connector on Quad shield. I'll just use RG59, tinned copper cable and it'll be more than enough. Thanks guys for all your help.

Good on ya mate.
Don't get me wrong, I have nothing against RG-59 cable at all, or Quad-shield for that matter.
Up until a couple of years ago, I was using an entire system of RG-59 here at home and pumping UHF signals down it (Highest frequency 800MHz) with no noticeable picture degradation.
I had pretty shortish runs though.
Best of luck with your install B/Spark, let us know how it went.

Other options include cat-5..
you can get baluns for cat5, and run camera power over the spare pairs.

I'd concur with the comments so far: RG59 will be fine for baseband video over runs as short as those you're thinking about.

You can start getting problems with group delay over long distances, but you'd need a very much longer run of cable before that would start to become a problem.

Thanks for your responses. I'm also using 24 strand, 0.20mm (0.75mm2) figure 8. My runs will be about 40metres long and there will be five of them. Will i get voltage drop as the transformer will be that far away from the cameras? anybodys help would be much aprreciated.

Voltage drop won't be a problem...assuming a 24V supply. CCD cameras have low current requirements compared to their tube predecessors, so voltage drop is minimised to begin with. While I haven't actually checked it, the camera electronics presumably work on 12V so there's a lot of voltage drop you can get away with before regulation is lost.

I was going to use a 12V Supply, because the CCD Cameras are 12V. But if i use a 24V supply will i have overvoltage problems? What are your suggestions to use as a main supply 12V or 24V?

Britespark.
we do a hell of olot of CCTV installation work and we personally only use RG59 on shortish runs, and all cameras are on 12VDC.

the power supply units are fully rectified and regulated DC and are positioned as close to the camera as possible, but some installs we place the PSU by the main equipment and feed the camera via two core 1mm flex (under 100m) with no trouble or loss of picture quality.

all cameras are usually 480TVL and are fitted with Direct Drive lenses.

as to using Cat % or even Cat 6 this is not a problem, all you have to do is use a BalUn (Ballanced to Unballanced) connection unit to each camera and back art the Multiplex and or DVR (Digital Video Recorder.

the company we use is COP, details can be viewed on www.cop-eu.com

htey are very helpfull and have an excellent technical department, (and they are cheap, but very good quality equipment because they make it them selves!!)

if you need any advice just ask.

Britspark

thanks Britspark, your help is much appreciated. I so if put the Power supply near the main equipment and feed the cameras with 0.75mm2 Figure 8 i should have no problems. My runs will be less than 40 metres. Does this sound alright Britspark?

Britespark,
placing the PSU as close to the camera is recommended,

but it will not be a problem feeding the cameras from a central PSU with 0.75 2 core cable, just remember dont run it near 240/440v ac,

i have seen a few systems installed this way and the picture quality is a little funny!!

i have just quoted for a system, against the client supplying the kit and us fitting it, yes its a bit more expensive for us to supply and fit, but the client realises that you cant beat good quality cameras and good quality installation.

it all comes down to the old thing of `selection nand erection` of equipment.

oh and another thing, if you dont have one get one, a service monitor, a small colour lcd battery powered monitor. they are a godsend!! but they are not cheap, you should be able to pick one up from a dedicated security wholesaler, or use COP.

as before if you need any advice just ask.

Britspark

Britspark,
I've decided to buy the cameras and the DVR through COP Security. I'm gonna use RG6 standard for my coax runs, is there a problem running the RG6 near 240V AC?

What is the recommended distance away from 240V AC Power for the RG6 Coax?

Also what is the recommended distance away from 240V AC power for the 0.75 2 core flex?

Britespark.

if you are in the UK the regulation state that cat 1 and 2 cabling should not be run adjacent to cat 3 cabling anless there is continuous seperation.

the way we do it is either to put the coax in one conduit or trunking run and the power (12v) in another conduit

if the cameras are for external use you can ( obviously ) run the cabling adjacenmt to the existing 240v ac

basicaly if you run your coax and you 12vdc tgether in trunking you should be within the regulations.

try to keep all data (coax and 12v) away from any high loads IE motor / air con etc if you do run them near the above you will have a few ficture problems.

what DVR are you going for?

i have just ordered a 16 channel with LAN PTZ and CD/RW for a public house CCTV job.

going out tomorow to install a nice little 4 cameras ( colour day/night ) set up on a dry berthing site in town.
i am so looking forward to that job!!

Britspark

The mid-range day/night cameras that have infra red led illumination built into them pull quite a bit of current at 12 volts and are sensitive to volts drop. Their other problem is that the leds light up spiders building webs across the front of the camera!

Traditional style high end cameras still rule.

I'm using a 16 channel CD-Rw with Lan functions.

So if i run the coax and the 12vDC next to each other up the wall cavity to the cameras. I shouldn't have any problems, aslong as i keep at least a 30cm away from 240V AC power. Or do you reccomend run a conduit down the wall cavity as insulation?

No part of the cables will be exposed to weather conditions.

Brite Spark.

PS; Hope the install goes well. Let us no how is goes.

Britespark,
just got back to the office, me and my crew just finished that little CCTV project and i am proud to say it went very well!!

lots ofcable trunking (aka raceway) all over the place, (very tidy i might add).

the client decided on 8 cameras outside and eight cameras inside, all well within the reach of the system,

one monitor to the front door of the club, one monitor to the bar area, and the main one, a rather large 21" monitor in the main office together with the DVR and main power supplies.

all pictures are perfect, with a little adustment by yours truly, to what the client wanted to see.

the DVR i used was the COP one order no: 15 - VT16 - cd/rw.

what a good bit of kit!!!

we will be using a few more of these in the future, my IT man came in and set up the Router and LAN coonection.

and the best of all the client gave me the cheque!!!

a little thing if you are going to be doing a lot of CCTV get yourself a test monitor, they are a life saver, (and time saver as well).

COP order no; 15 - MC035K £148.90 PLUS VAT

bye for now. i am going home now, as i am a little bit tired.!!!

Britspark

Britespark,
You could tape the 12VDC wires to the coax and have no worries at all.
As far as 240VAC goes, as long as your wires cross the Mains wires at 90 degrees there shouldn't be a problem.
Induced voltage really only occurs where Mains and lower voltage cables run alongside each other for an appreciable distance.

As far as bend radii goes, RG-59 wins though.
And don't forget to Heatshrink your connectors, moisture is a killer.

[This message has been edited by Trumpy (edited 11-04-2005).]

Hey there, sorry i havent posted for a while i've been on holidays.

Good to see the install went well Britspark.

Since i'm a little experienced now with CCTV i'm going to do an install at my house. I'm using a 16 channel DVR - Top of the range, 15-DVR16SA CR-RW.

These are the cams i'm using:

3 x 15-CD351 - 12V DC ±10% 3.8W(Max) @ 119ma / 320ma(IR on)

1 x 15-CD47CAI - 12V DC ±10% 8W(Max) @ 200ma / 670ma(IR on)

2 x 15-CM35VAI - DC12V @ 100mA(IR off) / 160mA(IR on)

All the cams are IR, apparently they draw quite a bit of current.

How do you reccommend i power the cams?
Through a central PSU or individual PSU's?

Runs again will not be more than 30 metres for both coax and 0.75 2 core flex.

Brite Spark.

BriteSpark,
Would Line-powering be feasible?.
As in sending 12VDC down the Coax, via a Capacitive link?.
Some of the KingRay gear here will allow you to insert a Maximum of 1.2A of voltages up to 17.5VDC.

Britespark
i would reccommend feeding each camera/ir set up from one power supply unit per camera, the loading is quite high so this is the best way to do it.

Britspark

Also to avoid the cameras interfering with each other, use separate non-grounded supplies for each camera.