Help, I have to run coaxial cable very close to interference

[CharlesStaal 0]

Hey guys, I'm installing an 8 camera system for a local liquor store and I've come across a big problem. A year ago I was fixing their CCTV system and found that the reasons they were having trouble was because the coaxial cable was pretty much laying on multiple 8-light fluorescent fixtures and upgraded their cables to quad shield RG-6 but there is still interference. So I wasn't able to get the job done. Now they called me up and want me to try again. Is there any way I can avoid interference from multiple fl. fixtures? It's in a drop ceiling so I have no way of keeping the cables farther than a foot or a foot and a half... any help is appreciated.

[the toss 0]

I have posted many times trying to convince people about the hazards of using RG6 cable for CCTV and yours is a perfect example. I don't know what your technical background is but read up on the shielding capabilities of RG6 vs RG59. Everyone thinks that RG6 is the bees knees because it has quad shield & is a modern innovation. For digital TV there is no argument that its performance is superior to RG59. This is the first clue. It is designed to stop interference at RF as it's prime purpose is to transport RF signal from your anntena to your TV. Look at the specs and you will see that its shielding capabilities are very poor below about 50Mhz. What is the baseband frequency of CCTV, it is around 5.5Mhz.This is where RG59 comes into use. RG59 shields best at frequencies below about 50Mhz. RG59 was designed for a time when there was nothing that could utilise frequencies of hundreds of Mhz and it did the job well and has years of refinement.

In a low noise environment RG6 can (and does) work ok but you need to understand the dangers (as you have discovered). I would like to know what prompted you to use RG6 thinking it would solve your problem.

[CharlesStaal 0]

Well their original cable was rg59 and was corroded, split open, pretty much beat to the end of its life so since I was running very long spans I decided to go with RG6quad shield since it was a high interference environment. I did not know that it is not good at low frequencies. The longest span is still good but the rest of the cameras are shot, they were dead before I changed the wiring. What would be your suggestion for very long runs, say 100 meters and in very close proximity to fluorescent fixtures?

[the toss 0]

100m is not a very long run. You get both HF & LF interference from Fluoro lights. You get short term HF interference from the striking of the starter & ionisation of the tube. This interference can affect devices at quite some distance but is only short term. The other is LF interference from mains voltage in the ballast transformer & light cabling. This is proportional to current which is quite low in Fluoros so its range is not great but it is long term , being present while ever the light is on. You shouldn't need to do anything more than space your coax as far as possible ( at least 12") and not run parallel with any mains cabling

[shropna 0]

Change cables to twisted pair, and use baluns Symetric line has more higher interference immunity, than coaxial cable.

Immunity to interference, if you use coax, will have cable with lowest shield DC impendance (less than 1Ohm/100 meters).

Mostly, RG6 cables are designed for high frequences, and has high DC impendance, and should not be used for analog CCTV cameras.

Another problem can be , when cameras and DVR are grounded/powered from different locations. This also can cause high interference problems.

[the toss 0]

As with RG6 , twisted pair is not the best to use, It can be extremely convinient to use & give good results but again it is not designed for this purpose. Its characteristic impedance is 100^ (120^) and requires impedance matching devices to operate (baluns) . The use of each balun will result in an insertion loss of up to 1.5db. This may offset any advantage over long runs.

 

I guess it boils down to - TV guys will always want to use RG6

Comms/IT guys will always want to use Cat5/6

Electricians probably want a way to use 2/E

CCTV guys will always want to do it right & use RG59

 

Do farmers want to use barbed wire?

[shropna 0]

As with RG6 , twisted pair is not the best to use, It can be extremely convinient to use & give good results but again it is not designed for this purpose. Its characteristic impedance is 100^ (120^) and requires impedance matching devices to operate (baluns) . The use of each balun will result in an insertion loss of up to 1.5db. This may offset any advantage over long runs.

Some cameras has twisted pair output in camera. Its camera "design problem", not a cable

Yep. If you want extend distance from analog camera, you will use twisted pair or fiber optic, but not coax Say also, that fiber is designed for day light transmission from Austrlia to night Europe, but not for CCTV

[the toss 0]

As with RG6 , twisted pair is not the best to use, It can be extremely convinient to use & give good results but again it is not designed for this purpose. Its characteristic impedance is 100^ (120^) and requires impedance matching devices to operate (baluns) . The use of each balun will result in an insertion loss of up to 1.5db. This may offset any advantage over long runs.

Some cameras has twisted pair output in camera. Its camera "design problem", not a cable

Yep. If you want extend distance from analog camera, you will use twisted pair or fiber optic, but not coax Say also, that fiber is designed for day light transmission from Austrlia to night Europe, but not for CCTV

 

 

???????

[Kawboy12R 0]

 

Do farmers want to use barbed wire?

 

Use enough barbed wire and you don't need cameras...

[Q2U 0]

Hang enough rustlers and you don't need no barbed wire.

[shropna 0]

As with RG6 , twisted pair is not the best to use, It can be extremely convinient to use & give good results but again it is not designed for this purpose. Its characteristic impedance is 100^ (120^) and requires impedance matching devices to operate (baluns) . The use of each balun will result in an insertion loss of up to 1.5db. This may offset any advantage over long runs.

Some cameras has twisted pair output in camera. Its camera "design problem", not a cable

Yep. If you want extend distance from analog camera, you will use twisted pair or fiber optic, but not coax Say also, that fiber is designed for day light transmission from Austrlia to night Europe, but not for CCTV

 

 

???????

I mean, glass is designed for light transmission.

But fiber optic use cctv, cable television, computer networks, etc.etc.

So, say, that RG59 is designet for cctv, RG6 for catv, and cat5 for networks - is not correct.

First computer networks also use coax cable, but now twisted pair

[Islands7 0]

Problems with 8' 2-tube fluorescent hung from ceiling interfering with HDTV cable signal, cable runs along floor parallel (no other route possible) 14' then cants away 6' then perpendicular 14' then up the wall to TV.

Original cable thought to be the problem, once RG58 then RG59, then most channels resolved after omitting some interim connectors, then replaced entire route with

Coaxial Cable (50 Feet) with F-Male Connectors - Ultra Series by Mediabridge - Tri-Shielded UL CL2 In-Wall Rated RG6 Digital Audio / Video - Includes Removable EZ Grip Caps (Part# CJ50-6BF-N1 )

 

Today discovered a channel that only works when fluorescent is turned off, same problem as prior.

 

The Tri-Shielded was rated by many as better than quad.

 

NOW I am shopping for external cable or ballast shields to employ and ... kitchen aluminum foil is NOT it (doesn't work)

[Islands7 0]

Problems with 8' 2-tube fluorescent hung from ceiling interfering with HDTV cable signal, cable runs along floor parallel (no other route possible) 14' then cants away 6' then perpendicular 14' then up the wall to TV.

Original cable thought to be the problem, once RG58 then RG59, then most channels resolved after omitting some interim connectors, then replaced entire route with

Coaxial Cable (50 Feet) with F-Male Connectors - Ultra Series by Mediabridge - Tri-Shielded UL CL2 In-Wall Rated RG6 Digital Audio / Video - Includes Removable EZ Grip Caps (Part# CJ50-6BF-N1 )

 

Today discovered a channel that only works when fluorescent is turned off, same problem as prior.

 

The Tri-Shielded was rated by many as better than quad.

 

NOW I am shopping for external cable or ballast shields to employ and ... kitchen aluminum foil is NOT it (doesn't work)

 

How about this

http://www.amazon.com/AUCH-20Pcs-Ferrite-Suppressor-Diameter/dp/B016XE2BS0/ref=cm_cr_arp_d_product_top?ie=UTF8

 

or this?

http://www.amazon.com/RadioShack-RF-Interference-Filter-1500025/dp/B00LMGM23E/ref=sr_1_2?ie=UTF8&qid=1463922207&sr=8-2&keywords=rf+noise+filter