Geovision gv-650 night vision problems

[cctvlad 0]

Hi folks

I have a geovision gv-650 12cam with 8cam dsp card have a problems with the video. one is that when i switch on the dsp card at night a multicoloured spots/noise overlay the video what causes this?? cant get rid of it.. its annoyin like!

 

the other thing is thin white rolling bands on all cameras not noticeable during the day but at night time its pretty bad and suspect bad powersupply, i have a 9 port box powersupply any way of improving it with it with this or should i ask for a replacement??

 

would appriecate any help guys.

[cctvlad 0]

Anyone not want to give thier expert view on my problems??

[Neutech 0]

Whats pictures like from DSP in daytime when its on?

 

I'd guess your DSP card is knackered

 

also get the PSU changed as thats where your lines are coming from

[Soundy 1]

I suspect the problem is more with your cameras than with the card or the PSU.

 

The first issue is more common with software-compression systems, but not uncommon with hardware DSP either - your cameras switch to B&W at night, but the card is still processing the picture as a color signal; the colored spots are the compression artifacts of that processing. The more noise there is in the signal, the worse they get.

 

The lines COULD be poorly-filtered power, especially since cheaper cameras won't have any kind of power filtering of their own, but they could also be caused by ground loops.

 

Without more information, it's hard to pinpoint the issue - what make and model are the cameras? How are they connected?

[cctvlad 0]

hey guys thanks for the reply wasnt expecting any!

will take it from the top

ive got my cameras and psu from cctvdirect uk

they are the twilight IR model and psu is a 9 way 10amp model

firstly the set up is at a midpoint where power is short from for the cameras and with rg59 to the cameras not all power wires are connected up yet as not all cameras are finished yet and i have connected 3 IR cameras to date. one camera is at 25 ft away and the other 2 is like about max 7 ft away and power is supplied at the same distance.

HOWEVER the mid point serves as a junction to the computer 60 ft away using brand new baluns and cat5e.

now to the cards the DSP card itself crashes out the system a lot and it prevents video i have disabled the dsp card for now and its working fine but the lines still are strongly appearing but having tried another powersupply invidually theres no lines. the other thing is i want to reduce noise through that. i will order a replacement but still worry about the coloured spots if i get a new machine through realtime dsp. the cards are 5 years old right enough.and recording is leaving a trail in movement as well. the other thing is when sun goes past the cameras theres a polished shine on the lens....never seen this before. these cameras come highly rated at its price of 70 quid each.

 

wiring is all bundled together in trunking power and video and cat5e 60ft is bundled together in another piping without power feeds.

any help greatly appriecated.

p.s what would cause ground loops ive nothing connected to metal??

 

cctvlad.

[Soundy 1]

they are the twilight IR model and psu is a 9 way 10amp model

I take it these are all 12VDC power, and the cameras are NOT dual-voltage type?

 

HOWEVER the mid point serves as a junction to the computer 60 ft away using brand new baluns and cat5e.

...

having tried another powersupply invidually theres no lines.

...

what would cause ground loops ive nothing connected to metal??

When you say "individual" do you mean separate transformers for each camera?

 

With cheap 12V cameras, the video and power share a common ground internally. What can happen, especially when using baluns and a central power supply, is that you get multiple, different-length ground paths for each camera - for example, camera 1 will not only have its ground straight to the DVR, but will also find a path via its power ground, up the power ground of camera 2, and back to the DVR via the video ground for camera 2. As you add more cameras, the problem gets worse.

 

It's worse with passive baluns because basic balun design puts a matching transformer inline with the signal (on a schematic, each transformer winding looks like a choke), which effectively adds dozens or hundreds of feet to the length of that run, as well as several ohms of DC resistance.

 

If the problem clears up with only one camera connected, and gets worse as you add more cameras, that's proof of a ground loop. If you're trying separate transformers for each camera, and the problem clears up... well, that's another proof of the problem, and also one work-around to clear it up. Another "fix" is to use at least one active balun on each camera. The best solution is to use quality cameras with internal power regulation (usually seen in dual-voltage cameras).

 

the other thing is when sun goes past the cameras theres a polished shine on the lens....never seen this before. these cameras come highly rated at its price of 70 quid each.

I wouldn't consider a 70p (about $150) camera "highly rated". Maybe sort of mid-grade. With a few exceptions, "highly rated" starts at about twice that price.

[cctvlad 0]

Hi soundy thanks for the reply,

yeah the cameras are what you say mid range 12v with common ground.the psu is 9 way 10amp.

when i try one camera per powersupply no lines exist. so do you reckon that the psu is at fault or its not right for that kind of design. active baluns are expensive so im not going down that road unless theres some in my price range say 15 pounds

 

so my options would be

individual psu for each camera?

active baluns

keep away from cameras with shared common ground.

 

 

the other thing i worry about is the coloured spots(dsp noise) presumedly would be fixed with active baluns

 

what do ye know about ground loop isolators?

 

I am wanting to get future cctv installs with better quality output.

 

thanks for the sound advice

 

cctvlad

[rory 0]

Couple things to try ...

Test the video at each camera, forget the DVR for now.

Remove cameras from the power supply 1 by 1 until lines go away.

[cctvlad 0]

heh i like the blue flashing light fella!

 

yes i was thinking of trying that using a tv from the dvr end. see what happens.

say removing one by one works and one camera is off what i do then?

does this mean individual transformers must be applied?

 

cctvlad

[rory 0]

thats the quickest way to fix it. Just for that particular camera.

With 24VAC cameras you can get an Multi output Isolated Power Supply from Altronix, for example.

but you have another issue, the junction with the baluns and cat5.

You should also test each camera there from the RG59.

[Soundy 1]

Hi soundy thanks for the reply,

yeah the cameras are what you say mid range 12v with common ground.the psu is 9 way 10amp.

when i try one camera per powersupply no lines exist. so do you reckon that the psu is at fault or its not right for that kind of design.

Nothing is "faulty" as such, other than the basic camera design of having a shared power and video ground. If the camera has an internal regulator (which would apply to dual-voltage 12VDC/24VAC designs), then power and video ground are separated, and you eliminate the source of the problem. Obviously, straight 24VAC cameras won't share power and video grounds either, so the problem is avoided.

 

the other thing i worry about is the coloured spots(dsp noise) presumedly would be fixed with active baluns

Don't think so. Hard to say for certain without a screenshot, but again, I believe this is the result of compression artifacts, from a color-based codec processing greyscale video.

 

what do ye know about ground loop isolators?

I've used them in car and studio audio... never in CCTV video, although I know they exist, and others say they've worked for eliminating at least some ground-loop issues. Worth a try, I suppose - the idea, at least in audio designs, is to use a transformer to physically break the signal connection and thus delete the extra ground path.

 

I am wanting to get future cctv installs with better quality output.

Start with better cameras... again, the design of the camera itself is the root of your problem here.

[cctvlad 0]

ta for the info soundy!

right Ive some answers had a tv at dvr end and at the junction.

Results are

rg59 junction end with shared PSU no lines with expected picture quality (how to improve it I don't know might be the limitation of the camera itself).

DVR end has lines this is baluned with cat5e

 

Night vision is good at both ends without any coloured spots at such soundy I think your right about the compression issues. so the dsp card wont do any good to me? what kind of compression do I need to look for to sort that.

 

so my problem seems to be at junction to dvr end but I would need to test day time also to confirm if so would individual powersupplies still be a fix? and rory would i need still need to remove one by one to isolate the problem camera even though I get a good picture on all at junction rg59?

 

Ive experienced high end shared common ground cameras are at good quality as well.(around £150 plus.)

but I do understand that cameras with regulated power is the best option for quality and will aim for that with future customers.

im glad Ive found some answers to this and cheers to you fellas

cctvlad

[cctvlad 0]

forgot to ask where do i go from here??

cctvlad

[rory 0]

if its good at the junction then its an issue with the baluns.

[Soundy 1]

While the baluns are the root of the problem, they aren't THE problem.

 

Part of the issue is also the fact that the common power supply connects all the power grounds together, which means each camera not only grounds its signal to the DVR through its own ground wire, but through each other camera's ground wire as well. All-coax setups get away with it because the additional differences aren't substantial. When you introduce baluns, though, you add significant length to each ground, as well as significant DC resistance.

 

When you use separate power adapters for each camera, the camera's power grounds are no longer connected together, so one camera doesn't find a video ground path via the other cameras.

 

Just connecting a TV even at the end of the baluns won't show a problem, because you'll only be connecting one camera at a time. The problem arises as you connect multiple cameras. If you put the DVR at the junction point, you should find the images clear as well.

 

Regulated power itself is not the fix: when a camera has a built-in regulator, it means the power and signal DO NOT share a common ground; the power ground is isolated from the signal ground by the regulator itself.

 

For future jobs, spec cameras that support 24VAC or dual-voltage... and if possible, use 24VAC power (less loss over distance, power supplies are cheaper).

[cctvlad 0]

thanks lad makes a lot of sense to me will try separate power supplies. so these 12v shared powersupplies are only good for cameras with regulated power in them??

yes at the junction dvr would be perfect but still need that 60ft run. the other way i could do is put the dvr at the junction and network the pc to the router at the end of the cctv run so i can pick it up at the router for IP access.

something too moot. yeah learnin a bit here.

great stuff thanks dudes did u come across this when in your first installs say first 10 ish.

[Soundy 1]

thanks lad makes a lot of sense to me will try separate power supplies. so these 12v shared powersupplies are only good for cameras with regulated power in them??

No, they work fine if you're not using baluns.

 

yes at the junction dvr would be perfect but still need that 60ft run.

I understand that; the point is, if you put the DVR at the junction point *as a troubleshooting step*, you should not see the interference.

 

the other way i could do is put the dvr at the junction and network the pc to the router at the end of the cctv run so i can pick it up at the router for IP access.

That may be an option as well - you already have the Cat5 in place

 

great stuff thanks dudes did u come across this when in your first installs say first 10 ish.

I was installing for a couple years before we first used baluns, and they were hella expensive then, so they were used pretty rarely. It was another 2-3 years before I first ran into this issue and it took me forever to figure out a work-around... even longer to finally realize what was actually happening to cause the problem.

[cctvlad 0]

hows it goin had a long day did a SAN install (Servers) had a damn long day yes on a easter monday!

 

read the posts this morning soundy yeah I did a right few cctv installs with baluns with good results. thing is this is the first one with a shared powersupply with baluns and previous were shorter runs with coax so guaranteed a success first time round. but 24vac would be great for long runs im starting to do farms andthey need quite long runs never liked wireless as the price is too high and you cant transmit all 4 channels down down one transmitter and receiver IP based servers do well on that though.

 

so im gonna spec up some power regulated cameras for long runs shorter runs I wouldn't need to worry too much as long the camera is mid range are you familiar with HQ1 chipset on cameras? thats the ones i have its supposed to supersede the sony HAD.

 

remember i said about piping down the cameras from the dvr to the router 60 ft run well a good to fair transmission is about 100ft but no idea what is the maximum length per run is for coax.

 

 

well at the end of it all Im going to use the shared PSU for another job with shorter run.

and get some regulated powersupplies only need 2 more at the moment.

 

about the coloured spots need to be sure to aim to avoid that in a new dvr or future installs would like some idea what compression is more susceptible to it. or what camera spec is vulnerable to it.

 

catch you later from sunny NI

[Soundy 1]

but 24vac would be great for long runs im starting to do farms andthey need quite long runs never liked wireless as the price is too high and you cant transmit all 4 channels down down one transmitter and receiver IP based servers do well on that though.

 

so im gonna spec up some power regulated cameras for long runs shorter runs I wouldn't need to worry too much as long the camera is mid range are you familiar with HQ1 chipset on cameras? thats the ones i have its supposed to supersede the sony HAD.

 

Frankly, I prefer to just go 24VAC even for smaller jobs - the power supplies are cheaper, and there's just less trouble overall. We use mainly CNB VCM-24VF cameras, which are dual-voltage, so there's no problem using 24VAC, no problem with balun-related ground loops, and no concern with voltage loss over longer runs. Cat5 is cheaper and easier to work with than coax as well, so it's just more convenient all-around to go that way.

 

remember i said about piping down the cameras from the dvr to the router 60 ft run well a good to fair transmission is about 100ft but no idea what is the maximum length per run is for coax.

Depends a bit on the type of coax. I believe 500' is about the max for RG59, 800'-1000' for RG6 (lower impedance). That will depend a bit on the quality of coax as well, and the quality of the camera to push a signal into a given load, and the DVR's ability to reject noise.

 

well at the end of it all Im going to use the shared PSU for another job with shorter run.

and get some regulated powersupplies only need 2 more at the moment.

Well again, with baluns, it's not the length of the run - the wire in the balun windings increases the total length by several times, so the run itself is largely irrelevant.

 

You don't gain anything with a regulated power supply, either - it's having a regulator IN the camera that avoids the problem.

 

about the coloured spots need to be sure to aim to avoid that in a new dvr or future installs would like some idea what compression is more susceptible to it. or what camera spec is vulnerable to it.

Well, sticking with a color-only camera will help... from my experience, H.264 seems to handle this particular artifact problem better than MJPEG.

[rory 0]

Depends a bit on the type of coax. I believe 500' is about the max for RG59, 800'-1000' for RG6 (lower impedance).

 

About 1200' for color and 1500' for BW

[rory 0]

about the coloured spots need to be sure to aim to avoid that in a new dvr or future installs would like some idea what compression is more susceptible to it. or what camera spec is vulnerable to it.

Possibly the cameras are Color IR and not TDN and are staying in color but becoming noisy in low light .. hence the colored spots.