Can I use a Y to split video signal before DVR ?

[bentech 1]

Hi ,

 

I want to split one channel (DVR & on an external monitor).

 

Do I really need a spliter amp box or I can use only a Y .

 

Will it affect the signal or impedance ? Do I need 75 ohm load ?

 

 

Thanks !

[ak357 0]

Hi ,

 

I want to split one channel (DVR & on an external monitor).

 

Do I really need a spliter amp box or I can use only a Y .

 

Will it affect the signal or impedance ? Do I need 75 ohm load ?

 

Thanks !

 

Practically you can

Theoretically it is wrong

[jeromephone 6]

if you try it and it does not work you would need a 1 in 2 out powered splitter probably around 25.00

[Numb-nuts 1]

if you try it and it does not work you would need a 1 in 2 out powered splitter probably around 25.00

I have very often gotten away with using BNC T's to pass the signal onto a matrix or yet another DVR. It works on most DVRs but not sure about when that would degrade the signal. I haven't viewed it on a scope but I do see a very acceptable image on both DVR output and the matrix output. There are no gaurantees when you try something unconventional,

 

the thing is unless you are one of these techno-bores and have to understand every detail to demonstrate your technical prowess (in short a show-off)

 

SIMPLY SUCK IT AND SEE

[ak357 0]

I have very often gotten away with using BNC T's to pass the signal onto a matrix or yet another DVR. It works on most DVRs but not sure about when that would degrade the signal.

 

the thing is unless you are one of these techno-bores and have to understand every detail to demonstrate your technical prowess (in short a show-off)

 

SIMPLY SUCK IT AND SEE

 

Do you understand why u should not T's video signal ?

just curios

[SunnyKim 2]

Bentech,

Yes you can use a splitter. But the voltage of each signal drops by a half. If not long distance, the video image is not affected. You may not notice any degradation.

Please note the most of video decoders (signal receiver) are carrying a good range of amplifier for feeding the signal into the digital sampler(ADC), next to it. The ADC(analog to digital converter) expects the fixed range of the signal voltage level. The amplifier works from 0.3V to 2.5V input range. The ADC mostly operates expecting 1 Volt peak to peak signal input.

[the toss 0]

I think Numb Nuts may be talking about me. So being both a TECHNO-BORE and an instructor bore here we go. Like so many things in life you can do whatever you want until something goes wrong. Like Sunny said if you parallel two devices I/ps you will halve the I/P voltage to each. Actually the I/P voltage will be less than half due to the impedance mismatch as well as a standing wave reducing the source power. This in itself is not usually a problem as most modern DVRs , monitors etc are designed to cater for a wide dynamic source I/P. Phasing interference can also cause problems if the split signal paths are of a reasonable distance.

So if the devices are of good design and the signal paths are short then you can probably get away with it.

[Numb-nuts 1]

I have very often gotten away with using BNC T's to pass the signal onto a matrix or yet another DVR. It works on most DVRs but not sure about when that would degrade the signal.

 

the thing is unless you are one of these techno-bores and have to understand every detail to demonstrate your technical prowess (in short a show-off)

 

SIMPLY SUCK IT AND SEE

 

Do you understand why u should not T's video signal ?

just curios

Not absolutely sure no, (well I am honest about it) but at a guess it reduces the signal? I know that the signal needs to be terminated somewhere but I would like to know the definitive answer...

[Numb-nuts 1]

I think Numb Nuts may be talking about me. So being both a TECHNO-BORE and an instructor bore here we go. Like so many things in life you can do whatever you want until something goes wrong. Like Sunny said if you parallel two devices I/ps you will halve the I/P voltage to each. Actually the I/P voltage will be less than half due to the impedance mismatch as well as a standing wave reducing the source power. This in itself is not usually a problem as most modern DVRs , monitors etc are designed to cater for a wide dynamic source I/P. Phasing interference can also cause problems if the split signal paths are of a reasonable distance.

So if the devices are of good design and the signal paths are short then you can probably get away with it.

 

 

NO I wasn't talking about you specifically, I thought I'd made my point ages ago and left it at that... I also decided to try and become more restrainedin my comments as I know I am not perfect either, and don't wish to upset anyone

however, if you think the cap fits you, then perhaps you can learn something from that.....

 

This Forum has it's fair share of Techno Bores and also it's fair share of TECHNO TWITS too. I am not saying which category I fall into

 

So what you are saying is that the CORRECT way to do this would be a powered splitter for each channel. (EXPENSIVE)

I thought as much However I sometimes allow the client to sit at the main display and view the image and say "left a bit right a bit elevate. lower" etc etc. Obviously a Walkie-Talkie comes in handy too I use a T at the camera then just so I can also view the image, but the T goes with me after I have finished. I had no idea that I was affecting the signal that much though. Thank heavens I

never leave them in permanently.

 

One thing about me I am NOT afraid to admit when I don't know something, otherwise I would never progress

and I am always willing to learn more.

 

By the way what do you mean by I/P ?

[the toss 0]

The cap probably does fit me & I dont mind wearing it. *** disclaimer - non of the following is directed at anyone in particular.

 

I've come across numerous people who ask a question on this forum & want only a yes or no answer. They become offended when you provide an little bit of explanation as well. I think this reflects on their personal insecurities. If all they want is a fix with no understanding then they should pay a professional and leave it at that. I simply cannot understand why,if they want to do something themselves, they dont want to understand what it is they are doing.

I was never like this when I was younger , but as I've grown older have developed a lust for knowledge. I dont think you should ever be ashamed of not knowing something - there are plenty of people willing to help & explain, all you have to do is ask.

While all my tertiary education is in electronics & telecommunications my current passion is automotive engineering. This is a self learning process & I'm helped along the way by a couple of really knowledgable people I've met online. One is a suspension geometery engineer at Nissan helping me grapple with the complexities of Ackerman Angles.

So if I go over the top in any replies just tell me to shut my trap - in a nice way.

 

Back on topic - I/P = input

You don't need a "powered splitter" unless the cable lengths are such that signal amplitude becomes an issue. In theory the closest termination to the source should be in a bridge mode (ie high impedance ) to reduce signal loss & impedance mismatch. The furthest termination should be terminated in a "matched" impedance (75^ for video). Many monitors (not tvs) are designed with a switch to enable the input (I/P) to be terminated in either 75^ or

Hi Z (high impedance bridging)

Leaving the T's in wont cause a problem if there is only one side terminated. All the cameras I use have an inbuilt High impedance monitoring point to plug into.

[SunnyKim 2]

You are very correct, Toss. Your understanding could be the same as mine.

Actually we made and using 4~5 Ts or Y's, impromptu, whatever you call, in order to emulate 8~16 Cameras inputs with using actually only 4~5 cameras, when we design the DVR boards and its chipsets.

My understanding on electric signal is just a wave. My understanding on Impedance is just a brick wall and impedance mis-match bounces off incoming signal, destroying incoming signal in some sense. On the input side of DVR board, there is also a resistance of 75 ohm in parallel to a incoming camera signal through a cable. On the board there is also a capacitance that removes DC (direct current component) and DC's mismatching artifacts. We also put a DC offset controller logic inside the chip. So actually mismatching does not play a lot, in real field, as long as the cable claims 75 Ohm impedance.

[Numb-nuts 1]

[ilk 0]

if you try it and it does not work you would need a 1 in 2 out powered splitter probably around 25.00

I have very often gotten away with using BNC T's to pass the signal onto a matrix or yet another DVR. It works on most DVRs but not sure about when that would degrade the signal. I haven't viewed it on a scope but I do see a very acceptable image on both DVR output and the matrix output. There are no gaurantees when you try something unconventional,

 

the thing is unless you are one of these techno-bores and have to understand every detail to demonstrate your technical prowess (in short a show-off)

 

SIMPLY SUCK IT AND SEE

 

If the centre piece of equipment can be switched to loop-through or Hi-z then the use of the 'T' piece will be OK. The end kit (only) needs to be terminated at 75ohm.

 

If the kit cannot be switched in this way the video signal will be significantly degraded. Specifically the sync pulse will be reduced possibly causing the video from the camera not being seen by the DVR or monitor (likelihood will increase with age) and the fine details in the image will be reduced.

 

Ilkie

[bentech 1]

Is a 50 ohms T ok instead of a 75 ?

[the toss 0]

No

[jeromephone 6]

a look at PI MFG website lists multiple powered splitters that will allow you to split your camera signal to the DVR and Monitor 2nd monitor can be several feet from the dvr 100+ feet if necessary. prices start around 25.00

[the toss 0]

Good post Jerome. $25 isn't much to ensure all the other money you have spent is not wasted