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compact HD distribution amplifier


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#1 Ramon Engle

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Posted 22 April 2012 - 07:35 AM

Kramer makes a small dual output version thats around $360. It's a bit chunky. Does anyone know of a more compact model?


Ramon
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#2 Brant S. Fagan SOC

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Posted 22 April 2012 - 07:46 AM

I've got the Blackmagic model and it's great. Not as inexpensive as the Kramer but it is a 1 in by 6 out unit. Since that purchase last Fall, I have added another coax cable running the post and use that for Alexa/Codex setups to feed my Boxx TX unit upstairs.
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#3 Jens Piotrowski SOC

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Posted 22 April 2012 - 10:57 AM

http://www.bhphotovi..._Amplifier.html
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#4 William Demeritt

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Posted 22 April 2012 - 02:12 PM

http://www.bhphotovi..._Amplifier.html


I've got this one, and built a 5v cable for it. Works great, very simple and low power draw (0.4a at 5v).
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#5 Lawrence Karman

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Posted 22 April 2012 - 06:25 PM

I've been using this one: http://www.markertek.com/Routers-Switchers-DA's/HD-SDI-Distribution-Amplifiers/LEN-Limited/HDS01.xhtml?LEN-HDS01

cheap, lightweight and it seems to work fine on the rig
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#6 Nicholas Davidoff

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Posted 22 April 2012 - 11:20 PM

Dumb question here. Is a distro amp necessary if you have SDI loop throughs? I'll wire a signal to my HD monitor, then output from the monitor to a Camwave transmitter. I can also loop out of the Camwave to another monitor or whatever. So is this distro amp only necessary if you don't have loop throughs? Or does it somehow "amplify" your main video signal. Will you get a stronger picture through the transmitter or something?
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#7 William Demeritt

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Posted 22 April 2012 - 11:59 PM

Nick,

Amplifier maybe not so much, but a re-clocking distribution amplifier can be very useful with some cameras that output excessive HD-SDI jitter, like the Red MX. In my research, I found that most devices that have an active loop-through do not amplify or change the signal (reclock, etc) but simply "turn on" the output port. Analog signals benefit from an amplifier in that the strength of the signal was "increased" to allow for longer runs, but with digital, the signal can attenuate or also deteriorate in quality, or be less than quality to begin with (again, the RED MX).

As is my understanding, a reclocking amplifier will take the HD-SDI signal and "recondition" it to be within SMPTE specifications, as well as amplify the signal (if only in so much as amplifying it from multiple outputs, each with 75ohm resistance instead of splitting out several BNC ports). I had considered the passive single channel splitter Lawrence was using, but it doesn't reclock or actively amplify the signal. I believe it is "passive" in so much that it draws no power to enhance the signal; without further research, I suppose it does something akin to a 75ohm T-barrel without the loss in resistance over the 2 output BNC's.

Again deferring to anyone with greater engineering skill than my own, but to answer the question of "Is a distro amp necessary if you have SDI loop throughs?", if you have no problems with your current setup, I'm inclined to say no. As far as I have researched, loop throughs do not amplify your signal, but SDI signals should run a long run before attenuating or deteriorating to the point of loss.
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#8 Nicholas Davidoff

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Posted 23 April 2012 - 08:20 PM

Nick,

Amplifier maybe not so much, but a re-clocking distribution amplifier can be very useful with some cameras that output excessive HD-SDI jitter, like the Red MX. In my research, I found that most devices that have an active loop-through do not amplify or change the signal (reclock, etc) but simply "turn on" the output port. Analog signals benefit from an amplifier in that the strength of the signal was "increased" to allow for longer runs, but with digital, the signal can attenuate or also deteriorate in quality, or be less than quality to begin with (again, the RED MX).

As is my understanding, a reclocking amplifier will take the HD-SDI signal and "recondition" it to be within SMPTE specifications, as well as amplify the signal (if only in so much as amplifying it from multiple outputs, each with 75ohm resistance instead of splitting out several BNC ports). I had considered the passive single channel splitter Lawrence was using, but it doesn't reclock or actively amplify the signal. I believe it is "passive" in so much that it draws no power to enhance the signal; without further research, I suppose it does something akin to a 75ohm T-barrel without the loss in resistance over the 2 output BNC's.

Again deferring to anyone with greater engineering skill than my own, but to answer the question of "Is a distro amp necessary if you have SDI loop throughs?", if you have no problems with your current setup, I'm inclined to say no. As far as I have researched, loop throughs do not amplify your signal, but SDI signals should run a long run before attenuating or deteriorating to the point of loss.


Thanks Will, good info. It's as I thought.
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#9 Ramon Engle

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Posted 26 April 2012 - 09:31 PM

Thanks so much guys. I've been dealing with an Epic with ONE video out and a Boxx Meridian with no loop through video. These HD splitters make all the difference.

Muchisimas Gracias.




Nick,

Amplifier maybe not so much, but a re-clocking distribution amplifier can be very useful with some cameras that output excessive HD-SDI jitter, like the Red MX. In my research, I found that most devices that have an active loop-through do not amplify or change the signal (reclock, etc) but simply "turn on" the output port. Analog signals benefit from an amplifier in that the strength of the signal was "increased" to allow for longer runs, but with digital, the signal can attenuate or also deteriorate in quality, or be less than quality to begin with (again, the RED MX).

As is my understanding, a reclocking amplifier will take the HD-SDI signal and "recondition" it to be within SMPTE specifications, as well as amplify the signal (if only in so much as amplifying it from multiple outputs, each with 75ohm resistance instead of splitting out several BNC ports). I had considered the passive single channel splitter Lawrence was using, but it doesn't reclock or actively amplify the signal. I believe it is "passive" in so much that it draws no power to enhance the signal; without further research, I suppose it does something akin to a 75ohm T-barrel without the loss in resistance over the 2 output BNC's.

Again deferring to anyone with greater engineering skill than my own, but to answer the question of "Is a distro amp necessary if you have SDI loop throughs?", if you have no problems with your current setup, I'm inclined to say no. As far as I have researched, loop throughs do not amplify your signal, but SDI signals should run a long run before attenuating or deteriorating to the point of loss.


Thanks Will, good info. It's as I thought.


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