Please consider registering
Guest

Search

— Forum Scope —




— Match —





— Forum Options —





Minimum search word length is 3 characters - maximum search word length is 84 characters

Register Lost password?
sp_Feed sp_TopicIcon
ghosting or ground loop at night in IR mode
icecoldtexan
Member
Members
Forum Posts: 10
Member Since:
May 18, 2013
sp_UserOfflineSmall Offline
1
September 9, 2013 - 1:50 pm
sp_Permalink sp_Print

I have a question about image quality during night in IR mode. This is on the 8 Channel Ultimate Series H.264 D1 Realtime Security DVR using 700TVL Indoor/Outdoor Vandal Resistant Dome Security Camera . The cameras are connected to the DVR with cat5e cable and Single Channel Passive Video Balun with Video and Power . The images during the day are great. The images during night in IR mode are great except for some horizontal lines that rise from bottom to top. Three of the four cameras have the lines , one does not. They are powered by 8 Channel Output Switching Power Supply . This is on a residential home.

Thank You,

 

Perry Walters

Matt Stetson
West Palm Beach, FL
Member
Members
Forum Posts: 17
Member Since:
November 21, 2012
sp_UserOfflineSmall Offline
2
September 9, 2013 - 3:30 pm
sp_Permalink sp_Print

How long are your wire runs?  What kind of baluns are you using?  I'd be willing to bet your cameras are starting to starve for power.

icecoldtexan
Member
Members
Forum Posts: 10
Member Since:
May 18, 2013
sp_UserOfflineSmall Offline
3
September 10, 2013 - 9:26 am
sp_Permalink sp_Print

The wire runs are about 60 - 70 ft. the baluns are single channel passive with video and power they use the plug on the end of cat5 cable. Here is the link to the baluns. http://www.securitycameraking......-prd1.html

Ryan Newkirk
Moderator
Moderators

Members
Forum Posts: 62
Member Since:
November 21, 2012
sp_UserOfflineSmall Offline
4
September 10, 2013 - 9:53 am
sp_Permalink sp_Print

On the 3 cables that you are experiencing the horizontal lines at night, are they ran over any higher voltage cables?  Because with Cat5 cable, it is an unshielded cable, which will pick up interference faster than a shielded cable.  Also, have you tried disconnecting a camera or 2 to see if it goes away on the other cameras?  If it is happening on only some of the cameras and not all, then we need to isolate potential causes.  Have you tried taking the camera/s down making a new cable and tried to see if you can duplicate the problem? You can always try one of these to help clean the image http://www.securitycameraking......-prd1.html .  We have a balun version, but I figure since you already have the RJ45 ends on the cable this is the easiest solution to try.  These get put on the end at the DVR to isolate noise from the video feed. 

icecoldtexan
Member
Members
Forum Posts: 10
Member Since:
May 18, 2013
sp_UserOfflineSmall Offline
5
September 15, 2013 - 5:07 pm
sp_Permalink sp_Print

Thanks for the suggestions.

I ended up purchasing a power supply for each camera and that solved the problem.

Would you suggest in the future to have a separate power supply for each camera ? The power supply with multiple

ends on it sure is convenient but if it causes the ground loop interference then it's not good to use.

Matt Stetson
West Palm Beach, FL
Member
Members
Forum Posts: 17
Member Since:
November 21, 2012
sp_UserOfflineSmall Offline
6
September 16, 2013 - 4:04 pm
sp_Permalink sp_Print

It just depends on the scenario.  It sounds like in this case you may have had an Ohms load issue with other devices on the circuit.  Power conditioners are always recommended, but they're pricey.  Honestly, every scenario is different and Murphy's Law states that the moment I tell you independent power supplies are the way to go, you'll start running into the situation where they cause problems.   ;)

SRE
Member
Members
Forum Posts: 20
Member Since:
March 16, 2014
sp_UserOfflineSmall Offline
7
March 16, 2014 - 6:45 pm
sp_Permalink sp_Print

Once I was able to solve this by grounding the negative of the multi-camera power supply to the DVR chassis. Another time I had to switch to one supply per camera (1A supplies are a dime a dozen, eh?). The problem is the camera connects signal ground to power ground, and your baluns do not block DC. It's always a ground loop. Always!! Just sometimes you get away with it. So since the signals are connected at the DVR, the power supplies must float or you must have DC-isolating baluns (good luck with that). My system stumped several professional installers who claimed never to have seen the problem, but I think it's actually quite common. My "video hum" was worst at dusk and dawn as the IRs were powering up and down... probably by switching at different duty cycles.

Forum Timezone: America/New_York

Most Users Ever Online: 41

Currently Online:
10 Guest(s)

Currently Browsing this Page:
1 Guest(s)

Top Posters:

shockwave199: 178

Gilberto: 150

tubac: 131

MrDeepFreeze: 131

Jer7of9: 105

Night Hawk: 88

ShawnInFL: 61

smokey44: 40

Craig: 34

West Coast Jones: 30

Newest Members:

ddarden

Eric_1

samram

iTech Services

modesto

phonebookonline

benH

Saego

akashsharma

lbw5ncd

Forum Stats:

Groups: 5

Forums: 27

Topics: 747

Posts: 3735

 

Member Stats:

Guest Posters: 4

Members: 960

Moderators: 8

Admins: 5

Administrators: Security Camera King, Damon Delcoro, Brad Besner, Dro Simoes, Ian Bailes

Moderators: Dan Maresca, Ryan Newkirk, Jesus Ragusa, Zeke Richey, Jose Malave, Heath Phillips, javajeff, mrkuchuk