Interference on cams over CAT5

[danster_uk 0]

Hello peeps,

 

Just wanting some advice regards a couple of cams i've just thrown up. Basically 2 x cheapo ebay cams from our friends in Hong Kong. I've wired them to CAT5 running about 15 metres or so. Each cam being powered from a seperate 12v adaptor. As you can see from attached pic, there's intereference on both cams that scrolls from left to right on one camera, and vice versa on the other. When I unplug one of the power supplies, the interference disappears on the other cam and picture quality improves, and vice versa. Any ideas on how to eliminate this interference will be much appreciated.

 

Thanks guys!

[tomcctv 190]

Hello peeps,

 

Just wanting some advice regards a couple of cams i've just thrown up. Basically 2 x cheapo ebay cams from our friends in Hong Kong. I've wired them to CAT5 running about 15 metres or so. Each cam being powered from a seperate 12v adaptor. As you can see from attached pic, there's intereference on both cams that scrolls from left to right on one camera, and vice versa on the other. When I unplug one of the power supplies, the interference disappears on the other cam and picture quality improves, and vice versa. Any ideas on how to eliminate this interference will be much appreciated.

 

Thanks guys!

 

 

 

hi danster. you have not said if you have used baluns on your install . and did you get them from the same place.

[bongofury 0]

in addition to balun, is it a separate run to each camera?

also is there a ground pin on the 12V adaptors? perhaps remove it.

[Soundy 1]

That picture looks like crosstalk, as if the signal is bleeding between cameras...

[danster_uk 0]

Hi guys,

 

Thanks for your prompt replies. tomcctv - I've not used baluns for one simple reason - I have no idea what they are! CCTV is not my area of expertise as you've probably gathered. I've put my years of graphic design experience into good use, and attached a detailed, accurate wiring diagram Both cameras are running through one CAT 5 cable (the diagram is deceiving).

 

The cameras were bought from the same place, I have several others yet to install and I guess this is going to become a big nightmare, so if you have any suggestions as to how to eliminate it, you would save me a big headache.

 

Thanks,

 

Danster

[ptzguy 0]

Yes you need to use balun transceivers when using twisted pair technology(Cat5 cable).

I have never not used baluns with Cat5 so couldn't tell you what the result would be by omitting them. Also, what connections do you have at the camera end? BNC/Phono connector and a DC plug/socket??

[tomcctv 190]

Hi guys,

 

Thanks for your prompt replies. tomcctv - I've not used baluns for one simple reason - I have no idea what they are! CCTV is not my area of expertise as you've probably gathered. I've put my years of graphic design experience into good use, and attached a detailed, accurate wiring diagram Both cameras are running through one CAT 5 cable (the diagram is deceiving).

 

The cameras were bought from the same place, I have several others yet to install and I guess this is going to become a big nightmare, so if you have any suggestions as to how to eliminate it, you would save me a big headache.

 

Thanks,

 

Danster

 

 

hi danster. no baluns will be your problem. so you have two options either buy 8 baluns (i each end of your cat5 ) you only use 1 paire. or replace your cable with rg59 (coax) and use the existing cat5 to power your cameras. if you let me know what area you are in i will post your closest balun supplier.

 

have you cut the bnc off each camera ???? how did you do the connections.

 

 

 

[danster_uk 0]

Hello guys,

 

Again, thanks for the responses.

 

Looks like i'll be needing some baluns then.

 

The cameras originally came with a female phono for video and 3.5mm female for the power supply (I said they were cheap!). I cut both off and hard wired to the cat5 pairs. I hard wired the power supplies at the other end, and soldered on some male phono sockets which then go into a Phono>BNC converter for the DVI card.

 

The DVI card takes BNC so no problem here, I can simply remove the phonos & converter & insert baluns, but at the camera end, I would have to cut the BNC connector off the baluns, and again solder direct to camera. I assume this wouldn't cause a problem?

 

I've priced them up at Maplin, £14.99 for a pair!!! Do you know any other (cheaper) suppliers?

 

Oh, do I need baluns for the power pairs, or just the video? I have 3 pairs coming back from the 2 cameras... 2 x video, 2 x 12v+ and 2 x GND. On which do I need to add baluns (if not all)?

 

Many thanks

[danster_uk 0]

Sorry, forgot to mention based in Manchester, UK.

[tomcctv 190]

Sorry, forgot to mention based in Manchester, UK.

 

 

pm sent ......... much cheaper than maplins and only up the road from you

[ptzguy 0]

Can I just point out Danster(and I have done it before myself!), that if you do have to modify a camera or its cabling in future, test that it's working first.

If the cameras sent were faulty and you had altered the leads and/or cut them completely you would struggle to get reimbursed or replacements returned to you from the supplier.

Just one more tip for you, don't go and buy cheap baluns just to save a couple of quid, I have had many a headache and seen them melt before my eyes before now! Tom will point you in the right direction.

G'luck.

[danster_uk 0]

I'd like to thank you all for your advice. Much appreciated. I will post results once i've fitted baluns.

[Soundy 1]

The DVI card takes BNC so no problem here, I can simply remove the phonos & converter & insert baluns, but at the camera end, I would have to cut the BNC connector off the baluns, and again solder direct to camera. I assume this wouldn't cause a problem?

I wouldn't recommend it - if you ever need to swap the cameras, you'll be hacking-and-splicing again. I'd re-terminate the camera wires properly (BNCs, or RCAs with RCA/BNC adapters).

 

Oh, do I need baluns for the power pairs, or just the video? I have 3 pairs coming back from the 2 cameras... 2 x video, 2 x 12v+ and 2 x GND. On which do I need to add baluns (if not all)?

Baluns are used only for the video pairs. You DON'T want to share the video and power grounds.

 

Your drawing isn't really clear - are you running two cameras over one Cat5? If so, you'll probably want to use one pair for each camera's video, and another for each camera's power. If you have a separate Cat5 for each camera, I'd suggest one pair for video, and two pairs for power. In my installs, I use the blue/white-blue pair for video, orange/white-orange for power positive, green/white-green for power ground, and leave the brown as a spare.

[ayoubtt 0]

Hi everyone, my googling got me to this page. Im a complete newbie to cctv but have some networking experience using cat 5.

 

In a recent installation I decided to use cat6 cable. Everything hooked up and started working but I got the same crosstalk interference as mentioned in this thread. I ran two coax+2 cables to two cameras and they are working fine.

 

- I used orange/white pair + brown/white pair for positive and negative power. And the green/white + blue/white pairs for video.

 

- I used BNC Male connectors on both ends

Like this one - http://www.made-in-china.com/showroom/supercontact/product-detailFbeJvQIzbopg/China-BNC-Plug-BNC-Adaptor.html

 

-And power connectors male and female on both ends like the following: http://www.ebay.co.uk/itm/Female-DC-Power-Adapter-for-Cat-5-CCTV-Brand-New-/111046402988?pt=UK_CCTV&hash=item19dae1a3ac

 

- Power was from two power adapters each split 4 ways

 

-8 channel avtech dvr

 

- sony effio 700tvl day night colour dome cameras. ( All outside round the perimeter)

 

Cant seem to understand where I went wrong.. is there any difference between baluns and the connectors which I used ?

 

 

Any help will be much appreciated

[Horizon 0]

Hi ayoubtt.

I'm prety sure that those aren't baluns. They're for connecting to coax cable. The baluns are a bit larger, like the ones in tomcctv's post above.

[ayoubtt 0]

Yes I can definitely see the visual difference but i there difference in operation too? I mean if baluns are just meant for termination then the adapters are doing the same thing.

 

Will have to look into that.. any other suggestions anyone ?

 

UPDATE:

Just did some reading into baluns and I think that they might be the reason. I will order some and test them and post the results to you guys as it might help someone else in a similar problem.

[coyoteknee 0]

Did you ever get rid of the interference by trying the baluns mentioned in this thread? I'm curious to see if this solution resolved your issue.