Jump to content
Security Installer Community

Video Balun Problems Please Help


mitsifto123

Recommended Posts

Hi, upto now i have used RG59 for my installs, on this paticular install client wanted audio on every channel so i went with CAT5e utp cable with passive video baluns (see attached pics). I am sending power to the cameras using the same cat 5 cable, the power is being suppied by a 16 way PSU (individually fused)

I am having poor picture quality like distortion, lines across the screen, wired thing is when i move the bnc on the video balun on the dvr end the picture gets better???

Anyone come accross anything like this??? any suggestions? please help i am stumped on this.

Thanks in advance

post-18143-1219642077.jpg

post-18143-1219642422.jpg

Link to comment
Share on other sites

could be interference that you are grounding when you touch the bnc. I've had this a lot with NVT, which have an earthing point. If you leave the ground off you often get travelling lines across the screen. I never run power with signal anymore, too risky. Clearview hum eliminators will clear your pictures up but theyre not cheap.

Link to comment
Share on other sites

decent baluns should have isolation.

What sort of lengths you got, what voltage is at the cams, and have you confirmed you have no crossed wires.

Id bet its related to the el-cheapo baluns. Never ever had a problem with NVT

securitywarehouse Security Supplies from Security Warehouse

Trade Members please contact us for your TSI vetted trade discount.

Link to comment
Share on other sites

Have you checked to see if you have a full 12V at the camera end ? Personally I dont trust rj45 with any real of current.

If your cameras have ir lamps, try disconnecting them.

I have sen those bluns on ebay for a couple of quid a pair, and have tried a couple for video distribution over the customers network cabling without any problems. but I'd be wary of cheapo stuff like that, if its a multi camera install.

Link to comment
Share on other sites

Hi, upto now i have used RG59 for my installs, on this paticular install client wanted audio on every channel so i went with CAT5e utp cable with passive video baluns (see attached pics). I am sending power to the cameras using the same cat 5 cable, the power is being suppied by a 16 way PSU (individually fused)

I am having poor picture quality like distortion, lines across the screen, wired thing is when i move the bnc on the video balun on the dvr end the picture gets better???

Anyone come accross anything like this??? any suggestions? please help i am stumped on this.

Thanks in advance

1st check the balun straight on the monitor input. If this is ok you could have a distance issue when connecting to the DVR as these will need a stronger signal.

It would not supprise me if you have a faulty BNC conector within the DVR.

Power will always be a problem over cat5 unless runs are VERY short.

Link to comment
Share on other sites

1st check the balun straight on the monitor input. If this is ok you could have a distance issue when connecting to the DVR as these will need a stronger signal.

It would not supprise me if you have a faulty BNC conector within the DVR.

Power will always be a problem over cat5 unless runs are VERY short.

hi guys,

thanks for all your replys, the longest cable run is about 50 meters, I think its a grounding / power issue as i have just connect one of the cameras via a seperate adapter and the picture is allot clearer and even if you move the bnc end of the balun now it does not seem to affect the picture? where can you get a humbug from them please

Link to comment
Share on other sites

hi guys,

thanks for all your replys, the longest cable run is about 50 meters, I think its a grounding / power issue as i have just connect one of the cameras via a seperate adapter and the picture is allot clearer and even if you move the bnc end of the balun now it does not seem to affect the picture? where can you get a humbug from them please

Might to some extent depend on the camera, but to power a camera, over one pair of a cat5, 50 metres is a hell of a long way.

I think you'd be better off buying decent baluns, which should isolate anyway, such as NVT rather than adding a humbug, probably a cheaper option as well.

Link to comment
Share on other sites

I visited a recent install where 5 cameras from a 4amp 12vdc PSU, 4 had atrocious interference. The 5th camera was cabled in 'shotgun' and seemed immune to the interference. I brought in further PSU's to swap the initial one out, and fitted humbugs and found that very little helped. In the end, I found by percerverence that when I fitted 5 x Computar 12vdc 1amp PSU's, one dedicted to each camera, then the interference vanished.

ACE.gif
Link to comment
Share on other sites

I visited a recent install where 5 cameras from a 4amp 12vdc PSU, 4 had atrocious interference. The 5th camera was cabled in 'shotgun' and seemed immune to the interference. I brought in further PSU's to swap the initial one out, and fitted humbugs and found that very little helped. In the end, I found by percerverence that when I fitted 5 x Computar 12vdc 1amp PSU's, one dedicted to each camera, then the interference vanished.

Used to see crosstalk a lot with early board cameras used in PIRs etc that had inadequate decuopling, if you shared a PSU, But Later ones dont seem to have the problem so much. But yes, if theyre cheapo cameras, or old ones, its a possibility.

you could prove it by powering them up one at a time, see if theres crosstalk with 2 powered up - you could probably actually see both images - which will get worse as you add more cameras.

Link to comment
Share on other sites

Might to some extent depend on the camera, but to power a camera, over one pair of a cat5, 50 metres is a hell of a long way.

I think you'd be better off buying decent baluns, which should isolate anyway, such as NVT rather than adding a humbug, probably a cheaper option as well.

hi,

can u please point me in the right direction for the NVT baluns, you can message if you want to avoid giving out company names.

thanks in advance

Link to comment
Share on other sites

you could prove it by powering them up one at a time, see if theres crosstalk with 2 powered up - you could probably actually see both images - which will get worse as you add more cameras.

Yeah. We did that. as a second cam was added, black rolling bars appeared. (the benefits of walkie talkies lol). We tried different combinations of these 4 cameras and the PSU's and still the same. All cameras were 12vdc antivandal fixed domes. 2 old, 1 not so old, and 1 brand new. All 4 cams were of different type. Place has been open for a good 5 years and the sub said those 4 had always been bad pictures. The odd thing is that these types of cameras are also in use elsewhere on site and operate fine on their respective 4amp 12vdc PSU.

ACE.gif
Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.