Ground Loop challenges

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Hey Guys!!

I have a camera install that is plagued with Ground Loop issues.

I have been installing individual BNC Ground Loop Insulators on  
individual cameras that are the worst which cleans up the video for that  
camera.

However, over time another camera gets bad, and then another, etc.

As I understand the problem is due to an imbalance in voltage at 60  
cycles or ground reference between phases from the power company. And  
that the video is very sensitive to the imbalance and causes the video  
bars, bla bla bla.

My questions are as follows.

Is there a something device thingie that can be installed at the breaker  
panel across the phases that can blend or sync the cycles, etc.??

Is there a something device thingie that has more than one individual  
port that can be mounted at the head end (like a 8 or 16 port) that can  
isolate the ground loop with out using all the dongles??

Thanks for any insight!!

Les

Re: Ground Loop challenges
On 01/20/2018 01:14 PM, ABLE1 wrote:
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  General rule of thumb.  Only one power source.  Only one ground point.
A IR drop is created between 2 grounds.  If between buildings, where  
power could well be out of phase with the power a of another building.  
The safe bet is either RF or fiber.

john

Re: Ground Loop challenges

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I do remember about 7-8 years ago using a device from ConnectorsPlus out of
 Miami for a large camera job. It was a 16-port ground-loop unit for the dv
r end, where all the camera wirings went into it. It did come with individu
al cables that went into the dvr. Then, at each camera there was an individ
ual unit. That was when we still used coax, now only shielded cat5. Hope th
at helps you.  



Re: Ground Loop challenges

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Is this coax or cat 5 using baluns?
Are the cameras 12vdc or 24vac?
Are you using a single power source or individual power sources for each  
camera?

Doug  



Re: Ground Loop challenges
On 1/21/2018 4:36 AM, doug wrote:
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Sorry, I forgot to mention that important info, brain was not totally
activated.

There is a single power source 120vac for everything with two 16 channel  
24vac power supplies for the cameras.

A few cameras are 24vac but most are 12vdc with a step down inverter at
those cameras.

Cabling is Siamese Coax RG59 w/18-2.

As I said above my understanding was the problem is due to an imbalance  
in voltage at 60 cycles or ground reference between phases from the  
power company.

But then of course I have to question that since I am on a single power
outlet or only one phase of the incoming AC.

Thanks for any input.

Les




Re: Ground Loop challenges
On 1/21/2018 6:36 AM, ABLE1 wrote:
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I thought an inverter turned DC into AC.  I had bad luck with those
AC/DC converters on cameras a while back, and never used one again.  I  
have used several cameras that were AC DC auto switching internally that  
seemed to work just fine, so maybe I just had cheap converters.

I did try a fairly expensive multi tap ground loop isolator at the DVR  
once a long time ago.  It worked but all the camera feeds were grey and  
dim.  Loop termination on and loop termination off at the dvr.  Both  
were the same.  I went to cheap single line ground loop isolators at the  
cameras after that and they seem to work just fine.





Re: Ground Loop challenges
On 1/26/2018 1:58 PM, Bob La Londe wrote:
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Hi Bob,

I guess maybe the term "inverter" could be the wrong term for this  
device and you are most likely correct that an inverter is changing
DC voltage to AC voltage.

Maybe the correct term that should have used would be "converter" where
the voltage is being converted from 24VAC to 12VDC.

In some respects it may just be which side of the Continental Divide you  
are standing on.  :-)

As things always seem to go nuts at the worst possible time, I am  
presently having a problem with one camera that seems to be blowing
the "converter" at the camera.  It is either the camera is pulling to  
many amps when the IR kicks or something like that.  It is a new camera
and still under warrantee.  I just ordered another and before I install
I will be taking some volt/amp readings so I can compare values.  Also
ordered some new "converters" since I am out of stock.

Have a good weekend.

Les






Re: Ground Loop challenges
On Saturday, January 20, 2018 at 4:14:47 PM UTC-5, ABLE1 wrote:
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I don't know much about this subject but I was under the impression that a "line conditioner" would isolate all those kinds of problems out of an AC power source. NO ?

Re: Ground Loop challenges
On 1/21/2018 5:54 PM, Jim Davis wrote:
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Hi Jim,

I have been researching this most of the day.  What I have found out the  
only real choice is the single BNC Ground Loop Isolators, which is what  
I have been using.  It seems that mfg's don't think it is worth the  
effort to put them in a full patch bay of 16 channels.  I have given up
on my quest for this thingie.

Have a good week.

Les


Re: Ground Loop challenges
This might provide you with some useful information. You may want to call them also for their expertise. Toll Free: 877.843.3921

http://www.wecusurveillance.com/groundloopisolators

Re: Ground Loop challenges
On 1/24/2018 1:24 AM, E D wrote:
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E D,

Thanks for the link!!  Very informative!!

Based upon what I assumed and now I am more convinced that
the cheap 16 channel power supplies that came with this
"donated" system to a "non-profit" may be the biggest part of the  problem.

I need to do some math to determine which is more cost effective.
Replace the (2ea) 24vac power supplies or load up more Ground Loop
Isolators on the system.
Very quickly I am thinking the Isolators will win.

Thanks again!!

Have a great rest of your week.

Les



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