Flickering problem

[FredB 0]

Have a setup w/ 26 cameras, 2 16 channel Hunt DVR's and 1 multiplexor.

3 monitors. 1 screen per device. Channel 1-9 on the 2 dvrs driving 2 of he monitors. Channel 10-13,14 on the dvr's looped out from the dvr's in to the multiplexor's channel 1-9 to be viewded on the third monitor. The point of the setup is to only use 2 16 channel dvr's and see 9 cameras each on 3 monitors.

 

The cameras that are linked to the multiplexor shows up fine, put when I switch the dvr views to 16 channels I get flickering on those cameras that are linked. The interesting thing is that when the signal continous to the multiplexor it shows up fine. If I dissconnect the loop-through cable to the multiplexor the signal at the "dvr monitor" shows up fine.

 

Any thoughts?

 

Was thinking a couple of things:

1. Get an cable amplifier like this on http://www2.cop-usa.com/ebproductdetail.asp?id=546

 

2. get some kind of isolator or something.

 

Tried to run the cables first to the multiplexor and then to the DVR. No difference.

It is not happening to all the cameras that run to the multiplexor, but I can see a slight picture deration on all of them.

 

Any thoughts would be very welcome!

[FredB 0]

Anyone...

[rory 0]

Hmmm, what brand of multiplexer, and does it have auto termination, or if not did you terminate it manually? Also, are these cheap OEM cameras?

[FredB 0]

Tried with 75 Ohm terminators. No Difference. All high end cameras, and also different ones. (GE, Samsung SDN -520,)

It almost got to be either a "weak" signal. or some sort of ground problem since he cameras look fine when I run them directly to the DVR.

 

The Multiplexor is some of brand, but they do show up fine on the multiplex monitor.

 

What else could it be?

[rory 0]

all color cams, or some BW also? Ive seen on some DVRs where color and BW cams dont mix well, and have to turn down the sat and hue to get rid of the problem, on the BW cams.

 

Sounds like a ground problem also . ..

 

24VAC or 12VDC cams, and which brand multi output power supply?

Are they all in the same socket?

 

Maybe its the mux, what brand is it?

[FredB 0]

All 24 V color cameras, with a Altronic $225 16 channel power supply, individually regulated channels, top of the line power supply.

 

Some odd ball brand mux. Might be the problem. Might take it out and put something else in instead. I think i will call Altronix tomorrow and ask them. Really knowledgeable people there. Linking like that has never been a problem before.

 

Is there a meter of some sort to check for ground problems/ signal streight?

[MetzLyov 0]

Fred,

 

Since you installed 26 high end cameras and a good power supply and 2 DVRs, can you explain why you are using a mux?? Is it for "call up" purposes??

 

If I am reading your components correctly and all the cameras are 24vac, then chances are very good that your mux could be the problem...

 

You also stated that you changed some cables around, what type of cables are you using? Is it a coax or CAT5E?? I have seen a similar problem with one of our installations, where set of 8 cameras were giving us a problems, even after we changed the cables.. What turned up was that a set of cables were run very close to main electrical power distribution of the store, thus introduced the 60HZ into the cable. The simple fix was to move these cables few feet away and the problem went away... Double check your cable runs to insure that they are not very near to electrical panels or tie wrapt to electrical conduits...

 

Levon

[FredB 0]

Fred,

 

Since you installed 26 high end cameras and a good power supply and 2 DVRs, can you explain why you are using a mux?? Is it for "call up" purposes??

 

If I am reading your components correctly and all the cameras are 24vac, then chances are very good that your mux could be the problem...

 

You also stated that you changed some cables around, what type of cables are you using? Is it a coax or CAT5E?? I have seen a similar problem with one of our installations, where set of 8 cameras were giving us a problems, even after we changed the cables.. What turned up was that a set of cables were run very close to main electrical power distribution of the store, thus introduced the 60HZ into the cable. The simple fix was to move these cables few feet away and the problem went away... Double check your cable runs to insure that they are not very near to electrical panels or tie wrapt to electrical conduits...

 

Levon

 

They wanted to have 3 monitors with 9 cameras on each, and I diden't want to spend the extra money on a 3:rd DVR. All cabeling is done with siemese cable (contractors wire and cable brand) I have a 4 channel dvr that I am going to swap out the mux for, just to try it. Since the signal is fine if it just goes to the DVR, the mux might just be the problem. What do you think

[FredB 0]

Fred,

 

If I am reading your components correctly and all the cameras are 24vac, then chances are very good that your mux could be the problem...

 

 

Levon

 

Please eloborate.

[rory 0]

probably just the mux.

 

I have 1 client with 2 muxes and a 1 channel DVR for all 16 cams. The main mux is the GE 16 channel Mux, and then 8 cameras loop to a Provideo 9 channel Mux. Im using 1 monitor in my case, but 2 inputs, 1 for outdoor cams that are always showing and also go out to the RF modulator, and the other 8 are hidden cameras and microphones to that monitor inputs audio side. Basically I have none of the issues you are having .. so I imagine its probably just the mux ... im using a GE DSR-1000e from the GE mux to record all 16 cameras and its great. Was upgraded from 4 years ago where it was originally just the 1 GE mux with 8 cameras for local viewing only, they just didnt want to upgrade the GE mux and DSR yet to the all in one ... too much $$ for something they hardly use, as they live there only a couple months a year ..

 

Seeing as the GE Mux is $1000+ more than the OEM muxes, there must be a reason behind that, besides the extra pricing, and the name brand.

 

anwyay, try what you said and see what happens ..

 

Rory

[qman 0]

I'm with LEV on this one. Somewhere along the way, the wire has to be too close to an electrical line. Flourecent lights are horrible for cameras, and I've also seen that installing the Power Box (altronix in your case) too close to the main power in for the building will also cause interferience.

[Cooperman 0]

Interesting problem FredB,

 

The fact that the picture is o.k. on the multiplexor monitor, suggests to me that the mux video connections are terminated correctly, but the DVR loop throughs, may still be terminated, when quite obviously they shouldn't be.

 

I don't know the DVR you are using, but what method does it employ for terminating the 'loop through' sockets?

 

If you were concerned about possible signal loss on cables, and you wanted to eliminate that as a possibility, you could always fit 'in line' attenuators to reduce the signal still further (which should make the problem appear worse, if that was indeed the cause. If you don't have any attenuators, you could always slap a 100 metre drum of RG 59 in to drop the signal a few dB on one camera, and see if that has any effect.

 

Personally I'm not convinced it's either signal loss, induced hum or earth loop hum, but of course you will need to isolate and test for each to be sure.

 

I'm still leaning towards a termination problem on the DVR's, so it will be interesting to see what it is, when you eventually get it sorted.

[cctv_down_under 0]

I would check a few things..

 

1/ Is there a termination switch on the back of the monitor.

 

2/ Can I also clarify if it is a flicker problem or a rolling picture? the fact that your mux is stable suggests that the problem occurs with syncronisation of the signal, the easiest way to test this is to find the camera that flickers/rolls and then find its power, reverse the polarity and see if the problem still occurs.. of curse that would only be if it was more a roll/than a flicker.

 

3/ Fluero light hum can cause flicker and some cameras have a flicker switch that can be enabled.

 

4/ look I know I work for Bosch but an XF cam allows you to remotely adjust Sync, add distribution amplification and check for flicker so try one out if nothing else works.

 

My gut feeling is some kind of interference between the devices or a bad cable or a power supply that is overloaded so that a weaker signal is picked up by the mux but not switched out correctly as that may be more fussy.

[FredB 0]

Thanks guys for all the help!

I am going over there at the end of the week to try some of the ideas.

Couple of things:

1. If I plug in a cable at the loop out from the DVR and let it hang loose, I get a very whited out picture, and if I then unplug it from the loop out, the picture goes back to normal. That would I asume mean that when nothing is plugged in to the loop out, the auto termination works, and as soon as I plug something in the termination turns of.

Right track or?

 

2. Since the cameras work great if I plug them all in to the DVR's and skip the multiplexor, could it really be a power supply/wire issue. Problem is that we only replaced the cameras so re running wires would be a real head ache.

 

The DVR is from HUNT

http://huntcctv.com/HVR-16S.htm

 

I'll try changing the multiplexor first.

Chepo multiplexor ($300) and great DVR's ($2000).

[rory 0]

Yes thats termination, when it turns whitish.

 

Like i said, probably a mux issue. Maybe get a loaner from someone to try it first to make sure thats what it is.

 

Take a look at the GE Kalatel CBR-16CS, its simplex, you dont need Triplex or Duplex ($400+ more) as you are only using it for the monitor view, not recording.

 

Or even the Provideo RMX-9CD 9 channel Color Mux, ive used this for display like i said in a post above, not as good as the Ge though.

 

Rory

[cctv_down_under 0]

DVR needs 1.1 volt peak to peak, analougue monitor only 1v peak to peak, so doubt its power, sounds like bad termination, was it flickering or rolling though?

 

PS what cable did you use?

[foresight 0]

Terminate the loop out from Mutiplec loop out with 75ohm Resistance.