Can Cat5 Passive Baluns Be Used With Active?

[martinnitram]

Can cat5 baluns be mixed with active baluns?

( Im not a cctv engineer, Just a sparky!)

The reason im asking is because ive got an installation running cat5 with the following problem.

The system consists of 2 x speed domes on 8M towers, so there's 8M RG59 running to Active Balun senders in tower base, down a 240M run of cat5 to active recievers and then into DVR. (there is a run of cat5 for each cam, 1 pair for video 1 pair for telemetry)

The system was installed 18 months ago and has worked fine, although the adjustable pots on the recievers were set to minimum on gain and brightness to give decent picture.

But one of the recievers is playing up and giving a over gained picture, the colours are over bright and the picture is very sharp ( jagged outlines to objects) and when camera is tilted up to maximum the picture pulls horizontally a little at the top eighth of picture, although if you put screwdriver in the gain pot and wriggle and push, the picture briefly comes back .

Ive replaced the Reciever with like for like (system Q) but this one has dip switches and on the minimum setting gives about the same picture as the knackered one,

so i am considering putting a passive balun at the camera end and an active one at the DVR end, would this work and which balun set would anyone recommend,

Thanks Martin.

[Gopher]

I can't see why active was used at all since it's less than 300m as you can do passive to passive at that distance and even get co-ax to work at that distance just about.

So in answer to you question yes. I can't see any reason as to why it's active at all.

[martinnitram]

I can't see why active was used at all since it's less than 300m as you can do passive to passive at that distance and even get co-ax to work at that distance just about.

So in answer to you question yes. I can't see any reason as to why it's active at all.

I started off with the passive ones and didnt get very good results, when i put the active ones in i got a good picture.

so does your answer mean yes i could use a passive with an active?

thanks M

[SUBS]

I'm not familiar with systemQ stuff, but why use active transmitter AND receiver ? is that normal practice with their stuff ?

I would have expected it at one end only, preferably the transmitter - amplified receiver will amplify any hum or noise as well as the signal.

As has been said, I would have expected a reasonable picture with passive baluns both ends, are you sure that the active ones are not masking another problem ?

[dmitry]

Ussualy passive one for the dist - 0 - 0.5 km, and active 0 - 1,5 km.

you method of passive transmiter and active receiver is good and all must be ok. but for your situation passive also must be ok.

may be you use someone - The best from the China?

[ian.cant]

Im not familiar with System Q baluns but i would have thought they are much the same as everyone elses kit. I stand to be corrected but i think you got this the wrong way round, you should have passive at the camera end and active at the receiver end.

Ive just had a quick look at System Q's catalogue and they show 500mtrs with passives.

Maybe giving System Q tech a call will help but without the model numbers i couldnt be certain what should be where.

I also wonder whether you have another problem besides the baluns issues.

[dmitry]

Im not familiar with System Q baluns but i would have thought they are much the same as everyone elses kit. I stand to be corrected but i think you got this the wrong way round, you should have passive at the camera end and active at the receiver end.

Ive just had a quick look at System Q's catalogue and they show 500mtrs with passives.

Maybe giving System Q tech a call will help but without the model numbers i couldnt be certain what should be where.

I also wonder whether you have another problem besides the baluns issues.

very correct answer

[breff]

very correct answer

Dmitry, how come your location says 'UK' when I strongly suspect it isn't my old china, say no more, nudge nudge.

[SUBS]

Im not familiar with System Q baluns but i would have thought they are much the same as everyone elses kit. I stand to be corrected but i think you got this the wrong way round, you should have passive at the camera end and active at the receiver end. Ive just had a quick look at System Q's catalogue and they show 500mtrs with passives.

Maybe giving System Q tech a call will help but without the model numbers i couldnt be certain what should be where.

I also wonder whether you have another problem besides the baluns issues.

Yeah, thats how NVT make em !

But I still stand by my comment that it makes more sense to amplify (launch) the signal from the TX end. Think about it.....Start out with 1V p-p, add 100mV noise, if it gets get attenuated say 50% in the cable, then you amp it back up tp 1V, you still got 10% noise, moe in practice.

But start out with say 2V p-p, add 100mV noise - attenuated same ammount in cable = only 5% noise. so if I was Martin and had the choice............

Chinese baluns ( from ebay ) work ok and cheap, but not the best.......I like to use quality kit rather than take the risk of spending time sorting out problems for the sake of a couple of quids.

[james.wilson]

i beleive its passive (tx end) to active if over 250m.

only need active both ends if going for big distance.

also if you have an active at the tx end and a passive at the rx end how will you equilise the signal?