50 Ohm Y Adaptor

[Ish]

Hi

Is this 50 ohm adaptor ok to use with cctv?

http://www.maplin.co.uk/module.aspx?Module...584&doy=5m7

Thanks

[Guest Dave the alarm man]

if you spilt in ampfly it

[Ish]

any links to amps so I can what type of thing to get?

Thanks.

[ispy]

Hi

Is this 50 ohm adaptor ok to use with cctv?

http://www.maplin.co.uk/module.aspx?Module...584&doy=5m7

Thanks

CCTV needs 75ohm for impedance matching, Try again!

[arfur mo]

CCTV needs 75ohm for impedance matching, Try again!

darn, you beat me to it,

for the o/p

you can either run daisy chained from 1st monitor (set to Hz) and then to the second monitor set to 75 ohms. if the 1st monitor only has a single socket use a 'T' piece, but you will need to dump the 75 ohm resistor which mught meen openning the box with all the risks.

or, get a unity gain video amp (not an aerial amp ) with 2 outputs from henry's radio, maybe maplins? (or RS if you flush).

regs

alan

[ilkie]

Hi

Is this 50 ohm adaptor ok to use with cctv?

http://www.maplin.co.uk/module.aspx?Module...584&doy=5m7

Thanks

T pieces should be banned from use in CCTV.

When ever I have seen a T piece in a system it indicates poor engineering.

Ilkie

[arfur mo]

T pieces should be banned from use in CCTV.

When ever I have seen a T piece in a system it indicates poor engineering.

Ilkie

hi Ilkie

i wonder why do you say that, is it a 'pet' hate?

it's mechanically perfectly sound method and conforms to the design parameters of the this kind of circuit. monitors with the through connection are nothing more than a 'T' piece with a (usually a very poor) switch to disconnect the 75 ohm loading resistor.

many budget DVRs and monitors do not have a through connection, it's a perfectly viable way of connecting a 2nd, 3rd or even 4th monitor (and a hell of a lot better than terminal block) especially if it's not convenient to run a second cable through a building, and use a composite video splitter amp.

regs

alan

[ilkie]

hi Ilkie

i wonder why do you say that, is it a 'pet' hate?

it's mechanically perfectly sound method and conforms to the design parameters of the this kind of circuit. monitors with the through connection are nothing more than a 'T' piece with a (usually a very poor) switch to disconnect the 75 ohm loading resistor.

many budget DVRs and monitors do not have a through connection, it's a perfectly viable way of connecting a 2nd, 3rd or even 4th monitor (and a hell of a lot better than terminal block) especially if it's not convenient to run a second cable through a building, and use a composite video splitter amp.

regs

alan

Dear Alan,

We work on major systems and as soon as you see a t piece you know you will have a termination problem at some point.

Some of our video paths will go through several devices with the end on line terminating (of course).

As we work side by side with other companies engineers on the same systems, the issue with the t piece is what is at the end of line and it is terminated, and when that kit is taken out of service is that the terminating device?.

Also, Up until recently we would not come up against any device that did not have an option to terminate or unterminate a ciruit, but the advent of analytic systems (as well as ANPR, face recognition, etc) requires us to link to PCs with cards some which terminate and some which do not (***! IT industry).

The answer is to ban the T piece and only use a decent video distribution amplifier and then terminate everything.

This also removes the need to loop through multiple devices.

Ilkie

[arfur mo]

Dear Alan,

We work on major systems and as soon as you see a t piece you know you will have a termination problem at some point.

Some of our video paths will go through several devices with the end on line terminating (of course).

As we work side by side with other companies engineers on the same systems, the issue with the t piece is what is at the end of line and it is terminated, and when that kit is taken out of service is that the terminating device?.

Also, Up until recently we would not come up against any device that did not have an option to terminate or unterminate a ciruit, but the advent of analytic systems (as well as ANPR, face recognition, etc) requires us to link to PCs with cards some which terminate and some which do not (***! IT industry).

The answer is to ban the T piece and only use a decent video distribution amplifier and then terminate everything.

This also removes the need to loop through multiple devices.

Ilkie

thanks Ilkie, it's good to compare others views.

for pro or high end installs imo you have good policies, but i think for general purpose/budget nothings really wrong with them. video amp is always best as it removes a layer of failure, but tbh there is unlikely to be more tha 2or 3 devices in most bread and butter installs.

the last device will not have a 'T' so should be easy to 'see' the terminating device, and a meter will soon tell you if the absence of an ongoing away cable is not enough to trip the thought in the engineer

if i were that concerned i'd stipulate the use of those eol resistor bnc's, old coax computer networks thrived on BNC 'T' and terminators . mind you, 400 watt boots attached to my CB Radio a few years back used to cause them grief

regs

alan

[amateurandy]

old coax computer networks thrived on BNC 'T' and terminators .

Well, sort of, but the distance off to the side of the T was minimal, and they were only really an updated version of the original ethernet "vampire" clamps with the spike into the cable.....

And if you didn't put the terminators on properly you were in trouble.