I am running cctv cameras over rg6 and rg59. I have compression f connectors on both ends with screw on bnc adapters. I have a fluke microscanner pro that I am using to verify the cables. SO here is the problem. I have 12 runs from 82' to 220' I am getting a 3 and 6 popping up on the screen telling me I have a fault on every cable. The funny thing is that when I short a know good cable the 3 and the 6 have a line on the screen running between the two numbers showing a short. My tests just show a 3 and a 6. Not one of my cameras is coming up and I have reterminated with mutliple types of connectors. I have done hundreds of f connectors in the past and never had a problem. Does anyone know if emi or improper grounding is leading to this issue? All comments welcome. And thank you for your help in advance.
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Coax issues 1
- Thread starter ddobb
- Start date
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1
- #2
daronwilson
Vendor
Hmm, never used that tester for coax. I'd start with a quick multimeter check and see if you have a short between the center conductor and the shield (with the cable not connected to anything). You should have an infinite resistance (i.e. no connection) between the center and shield.
Next I would short the center pin to the shield on one end of the cable, and go to the other end and make sure you DO have continuity between the center and shield, showing a complete circuit for the length of the wire.
Were it me, I would crimp on BNC's to start with since I hate the adapters, but your method should work. Do the above checks with the BNC connectors on there, it is possible the 'stinger' on your "F" fitting connection is not making contact inside the BNC adapter. If you fail to get a complete circuit with the 'shorting one end' test above, remove the BNC adapters and try it just on the coax with the "F" fittings to see where the problem is.
You might share with us what type of cameras, and what you are doing to power them. The distances you indicate should be no problem for RG59, and I really don't see the problem being EMI or grounding related if you are getting no signal at all.
Good Luck, let us know!
It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
Next I would short the center pin to the shield on one end of the cable, and go to the other end and make sure you DO have continuity between the center and shield, showing a complete circuit for the length of the wire.
Were it me, I would crimp on BNC's to start with since I hate the adapters, but your method should work. Do the above checks with the BNC connectors on there, it is possible the 'stinger' on your "F" fitting connection is not making contact inside the BNC adapter. If you fail to get a complete circuit with the 'shorting one end' test above, remove the BNC adapters and try it just on the coax with the "F" fittings to see where the problem is.
You might share with us what type of cameras, and what you are doing to power them. The distances you indicate should be no problem for RG59, and I really don't see the problem being EMI or grounding related if you are getting no signal at all.
Good Luck, let us know!
It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
- Thread starter
- #3
AvayaNovice
Vendor
My first step would be to use a premade RG-6 jumper that you know is good, and bring a camera right to your equipment, hook it up, and see if it works. Sounds like you may have problems not relating to your cabling...
- Thread starter
- #5
I was able to get 2 cameras up momentarily. They were stable one minute and gone the next. Sorry Daron for the misspelling (Darren) crazy day yesterday. I believe the issue may be related to power injection at the head end. What is the best known methond to distribute power to small inexpensive b/w cameras that run on 12v?
daronwilson
Vendor
Oh wait, are you carrying the power over coax? That definately could be an issue for you. If you are powering them over coax, you should be using copper braid coax, not the aluminum foil shield and very light braid.
I rarely run power over the coax for these installations, usually we use a siamese 2 conductor 18 gauge wire for power. It can work to power over the coax, but you need good quality coax that the braid can use to carry power.
Please explain a bit more.
It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
I rarely run power over the coax for these installations, usually we use a siamese 2 conductor 18 gauge wire for power. It can work to power over the coax, but you need good quality coax that the braid can use to carry power.
Please explain a bit more.
It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
"If you are powering them over coax, you should be using copper braid coax, not the aluminum foil shield and very light braid."
DSS LNBs are powered over foil and braid at currents up to .5 amps. I would think that would be sufficient to power most cameras. The 220' distance is a bit long but testing with a voltmeter at the camera end should show if there is enough voltage to power the camera. If there isn't then you will need to increase the voltage at the injector end, run new wire or power the cameras with a power supply near the camera (not so good from a surge standpoint).
I agree with AvayaNovice. Try this out in the shop before you wear your legs out wandering all over the building. Get it working with a short jumper then try a long one.
DSS LNBs are powered over foil and braid at currents up to .5 amps. I would think that would be sufficient to power most cameras. The 220' distance is a bit long but testing with a voltmeter at the camera end should show if there is enough voltage to power the camera. If there isn't then you will need to increase the voltage at the injector end, run new wire or power the cameras with a power supply near the camera (not so good from a surge standpoint).
I agree with AvayaNovice. Try this out in the shop before you wear your legs out wandering all over the building. Get it working with a short jumper then try a long one.
daronwilson
Vendor
I think you will find that CCTV coax is generally copper braid, for the reasons I suggested. I've done several TV installations for health care facilities where there is a bed side TV, and they power it with 24 volts on the coax, and they flat out won't run right if you don't have enough current. We had to completely rewire the first one because they failed to spec the copper shield coax and the aluminum wouldn't run it.
It almost sounds like a power issue to me, but standard troubleshooting should apply. Start with a pile of parts you know work (cameras, factory cable, powersupply, monitor) and make it work on the bench. Then add your custom components in there and see where it breaks.
Good Luck!
It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
It almost sounds like a power issue to me, but standard troubleshooting should apply. Start with a pile of parts you know work (cameras, factory cable, powersupply, monitor) and make it work on the bench. Then add your custom components in there and see where it breaks.
Good Luck!
It is only my opinion, based on my experience and education...I am always willing to learn, educate me!
Daron J. Wilson, RCDD
daron.wilson@lhmorris.com
AvayaNovice
Vendor
You'll also notice that most CCTV cable does not have a foil shield.
I was under the impression that DSS systems carried current over the center conductor? I could be wrong... but considering that the fitting itself has continuity to the shield, it would be very easy for that power to jump to ground... I could be wrong.
We carry AC power over the center conductor in CATV systems.
I was under the impression that DSS systems carried current over the center conductor? I could be wrong... but considering that the fitting itself has continuity to the shield, it would be very easy for that power to jump to ground... I could be wrong.
We carry AC power over the center conductor in CATV systems.
AvayaNovice
Vendor
Right, and I was under the impression that the voltage ran over the center conductor, and the shield acted as ground.
- Thread starter
- #12
Sorry I've been working out of the office. I see a minor miscommunication grew into a debate. Reminds me of my girlfiend. Anyway let's clear the air. I am powering the cameras (trying) with distributed 12vdc over cat5 using leviton's residential type distribution block
The only thing going over the coax is the signal
This is our camera package we have six of the bullets and 6 of the mini domes.
I had tried doing the signal and power over the same cat5e cable with baluns on bolth sides but it didn't work so I resorted to just power over UTP.
Thanks for all the help. When it comes to data and voice no problem but throw some Ohm's law in there and I'm screwed.
The only thing going over the coax is the signal
This is our camera package we have six of the bullets and 6 of the mini domes.
I had tried doing the signal and power over the same cat5e cable with baluns on bolth sides but it didn't work so I resorted to just power over UTP.
Thanks for all the help. When it comes to data and voice no problem but throw some Ohm's law in there and I'm screwed.
franklin97355
Technical User
Have you tried applying power directly to the camera locally to eliminate the possibility of too low power over cat5?
If you are trying to to power 12 cameras (most likley around 120ma each) with a 1500ma power supply you are going to have problems. Unhook 6 of the cameras and see if they work.
Leviton's spec sheet says: "Provides 13V DC power for up to 6 devices 1500mA"
Leviton's spec sheet says: "Provides 13V DC power for up to 6 devices 1500mA"
SparksLondon
Technical User
Just a thought from an elctrician. If you have pulled the cable within conduit and it stretched its characteristics would change dramatically as the dielectric would narrow. I guess this would show up on the Fluke though.
Good luck
John Burger
Good luck
John Burger
AvayaNovice
Vendor
Stretching of coax is fairly common, unless you change the actual circular nature to the dielectric, it won't do much (try it out with a signal meter, you can actually enhance the signal level by doing that... it's kind of strange). It's more common in RG-59, as the lack of a dual shield inhibits more strain.
Let me put it this way... I've used RG-6 as a rope before when I lost a couple of steps on a pole... and it was still golden, and I'm 6' 8" about 245 pounds...
Let me put it this way... I've used RG-6 as a rope before when I lost a couple of steps on a pole... and it was still golden, and I'm 6' 8" about 245 pounds...
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