# Video via mic cable



## Stoldal (Jun 6, 2008)

I was asked to help with a dance performance and they want a back stage video monitor. 

The video source is about 400-500' way from the monitor. So my audio guy says that we can use a RCA to XLR and use 4-5 100' run of XLR mic cable. 

First can that be done?

Second question, what is going to be better RG6 or mic cable, yes that may sound like a silly question.

I just don't want to tell him no thats not going to work, he want to know why it does not work.


___________________________________________________
Part 2

What i plan to do is have one 400' or 500' run of RG6 cable, the signal is going to be coming from a RF modulator. Do i need amplifier.


Thanks!!

Matt Stoldal


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## PadawanGeek (Jun 6, 2008)

I was wondering about that so I did a simple test adapting the video from my Playstation for XLR and then back again and it worked. However, it is not a good idea. The video signal coming thought looked a bit weird and sometimes when gray. Bottom line: Only do this if you can afford for the monitor to sometimes stop working and the video signal not to be its best quality. Only use this in a big big pinch.


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## derekleffew (Jun 6, 2008)

As Pad said, it's *possible*, but not *recommended*. Try the 500' mic run, (preferably without actually running the cable), and if you don't like the results, use the RG-6. See this post.


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## ruinexplorer (Jun 7, 2008)

I recommend ignoring the XLR, too much chance for signal problems. RG6 isn't that expensive and you will likely use it again. Yes, if you have one available, I would use an amplifier on that length of run for better quality.


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## mbenonis (Jun 7, 2008)

I recommend the RG6 as well, but DON'T use an RF modulator! You'll get MUCH better results if you just send the composite signal straight down the cable (using a composite video amplifier if necessary). Composite video is 0-6 MHz and Ch 3/4 is at 60-72 MHz - you'll get less attenuation per 100' at 0-6 MHz.

To connect it up, just get F to RCA adaptors - a few bucks at your local ShadioRack.


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## propmonkey (Jun 7, 2008)

could always go wireless. we have one for $50.

RadioShack.com - Home Entertainment: Accessories: Audio accessories: Wireless signal senders: 2.4GHz Wireless Audio/Video Sender for #15-126


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## Stoldal (Jun 7, 2008)

propmonkey said:


> could always go wireless. we have one for $50.
> 
> RadioShack.com - Home Entertainment: Accessories: Audio accessories: Wireless signal senders: 2.4GHz Wireless Audio/Video Sender for #15-126



The problem with wireless is i will not have LOS. 

i have about 1200' total of RG6 so that is no problem, I think that he just want to try it to see if it worked.


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## incstlouis (Jun 7, 2008)

F to RCA Adapters $1.22/ea.

RG6 by The Foot, 500ft. or 1000ft.


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## mbenonis (Jun 8, 2008)

incstlouis said:


> F to RCA Adapters $1.22/ea.
> 
> RG6 by The Foot, 500ft. or 1000ft.



Those RG6 prices seem about right. The best terminations to get are the Thomas and Betts Snap n' Seal connectors for RG6 Quad Shield (purple insert). Tri State Electronics sells them, among other places. They're a bit expensive but also not likely to fail. You'll need a tool to put them on as well as a coax stripper (believe me, for the $3-5 for the stripper you'll thank me down the road!)


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## Stoldal (Jun 9, 2008)

ok, so i just found out that the video feed is going to be recorded, the video mixer is going to be at the end of the cable run, so i am going to get an amp, now the question is what one would work, btw the camera is a DVX100. 

I have the Cable is just the standard RG6/U. Not the best but not the worst.

will something like Kramer Electronics USA PT-102VN 1:2 Composite Video Distribution Amplifier

or 

VetcoElectronics.com

work, or do i need to ask to borrow one from my dad.

(side note: my dad run the one of the local news stations, KLAS channel 8, one of the first to go Full HD.)


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## FMEng (Jun 9, 2008)

You don't need an amp for that length of run. It'll accomplish nothing, so save your money.


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## SHARYNF (Jun 9, 2008)

I agree, I run that length all the time BUT I do find that many times I need to use a video hum eliminator transformer to get rid of some ac that might get picked up. Allen Avionics makes the ones I use 

video hum eliminator, A V Accessories Cables, Consumer Electronics items on eBay.com 
is an example it is NOT the same as the audio hum eliminators that tend to get shown on the similar pages

Sharyn


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## LDTom (Jun 10, 2008)

For many years I was the house LD at a club here in CA. Every time that Berlin came through the club they had video content that they wanted on the video screens which were around the club. We tried the first couple of times that they came throught to go RCA-To the XLR stage split and then out of the FOH snake to a RCA adapter and this didn't always work and picked up line noise and had a potential for looking like a scrambled TV channel. The way that worked the best was running RG-6 with RCA adapters on each end of it. We also used a 250 foot run of expensive RCA cables which worked but was expensive.

Also make sure to have everything grounded on the same ground to avoid any extra hum, but you should always carry video and audio hum eliminators. If the video in anyway is going through a mixer to the sound board there might be the need for a Ground lift, but each room is different.

The room that I used to work in had ground loops up the yin yang.


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## Andy_Leviss (Jun 10, 2008)

You can run video over mic cable (although it's cleaner over digital-grade cable), but you need a special transformer device known as a baluns. This converts it to a balanced signal that can happily run over mic cable, CAT-5, etc. 

"They" do make BNC to XLR adapters, but they're not really meant for that. And it's not worth the headache. I learned firsthand when the first tour I was out on used those to send our PSM's four video shots over audio mults. When it worked well, it was great, but when it acted up, nothing I could do could fix it, since it was inherent in the physics of it, and you don't want to be the one explaining to the PSM why his/her video can't be fixed because of physics :-D


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## kwotipka (Jun 12, 2008)

From a broadcast perspective, 1200' is forever and a day for composite video right out of a camera. Yes you will get a signal out of the other end but it will in no way be the best it can be. It may not be enough for your switcher to derive sync reference from. Just doing the math in my head, I come up with around 6dB of attenuation. The biggest issue you will have is equalization which will effect the details in the image. The short of it is with poor eq, the image is not as sharp. You can get equalizing DA's from companies like Tektronics but this will require a scope or someone who knows how to do it with a multimeter to do it correctly.

A D/A or 2 in line wouldn't hurt but you will most likely have to power it from the same place as the switcher to avoid ground loops. Also, keep it away from the lighting cable as well. You only have a 1Vp-p signal there so you want to keep it as happy as possible.

Now, in the spirit of low budget projects, I would recommend that you roll tape in the camcorder so that it could replace what is recorded at the switcher later if that is possible.

I have run video down the audio snake on occasion with mixed results. Usually you need a humbucker and the best distance I got was about 200'. After that, the impedance and eq are shot and the signal goes south fast. I would never recommend recording the signal using this method. Monitoring only.

Your other option would be a fiber run. Then you would have a great signal at the console.

Either way, power up the camera and switcher and put the 1200' inline before the day of the shoot to ensure that the whole mess will work.

Let us know how it turns out.

kw


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## Stoldal (Jun 12, 2008)

kwotipka said:


> From a broadcast perspective, 1200' is forever and a day for composite video right out of a camera. Yes you will get a signal out of the other end but it will in no way be the best it can be. It may not be enough for your switcher to derive sync reference from. Just doing the math in my head, I come up with around 6dB of attenuation. The biggest issue you will have is equalization which will effect the details in the image. The short of it is with poor eq, the image is not as sharp. You can get equalizing DA's from companies like Tektronics but this will require a scope or someone who knows how to do it with a multimeter to do it correctly.
> 
> A D/A or 2 in line wouldn't hurt but you will most likely have to power it from the same place as the switcher to avoid ground loops. Also, keep it away from the lighting cable as well. You only have a 1Vp-p signal there so you want to keep it as happy as possible.
> 
> ...




The longest run is 500', it is a three camera shot and in total we will be using
about 765' feet, one is back stage, about 15' away from the mixer, one is at the FoH (aka: the 500' run) and then the last one is about 250' away from the mixer.


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## kwotipka (Jun 12, 2008)

Stoldal said:


> The longest run is 500', it is a three camera shot and in total we will be using
> about 765' feet, one is back stage, about 15' away from the mixer, one is at the FoH (aka: the 500' run) and then the last one is about 250' away from the mixer.



Where did I get 1200'? Time to get some sleep.

kw


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## Stoldal (Jun 18, 2008)

So i just finished up with the show, it went good.

The longest run turned out to be about 450'. We worked it so the video mixer would be next to the camera that is the feed for the backstage video moniter. 

The second camera was only about 75'.


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## headcrab (Apr 6, 2009)

I wanted to do a similar thing at my school. We have a camera with composite output and we wanted to send it back stage for a video monitor. We put in a CAT5E cable and put the signal over one pair. It works reasonably well. coax with an amp would probably be better, but we can't afford that.


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## pacman (Apr 7, 2009)

You might check out UTP Distribution Category- Analog the MultiView products from Magenta Research. You can send any flavor of AV up to 1920x1200 and control signals over CAT5 up to 2000 feet. I'm using some of their gear and quality is really good. Unless you are at the extremes in resolution and distance, standard Cat 5/5e is adequate; they do recommend skew-free cable if you are pushing distance and resolution. You can run lower resolutions well beyond 2000 feet.


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## mnfreelancer (Apr 7, 2009)

I'm surprised the idea of running video over CAT5 wasn't mentioned before the immediately above post. We did a lot of that back in highschool, since my building was new enough that every room had many CAT5 jacks. It wasn't bad quality wise considering some of the insane runs we did, mostly for monitoring purposes.

Sometimes we'd have to run video all the way from the gym or theatre up to the television studio on the other end of the building on the 3rd floor. The CAT5 link was decent for monitoring but nowhere near broadcast quality, so we often employed a Scientific Atlanta broadband cable modulator designed for "iNet" use (institutional network) that used to throw modulated video on a specially designed cable-company loop from school building to school building, sometimes distances of over 2 miles. With some o'scope and waveform monitor tweaking it drove a 750' run of RG-6 quad shield very nicely with broadcast quality results at the other end (broadcast quality relative to 7 years ago). We used an agile demodulator from Blonder Tongue at the other end to bring it back to a composite signal that was then run into a time base corrector to sync it to the outbound system.

Regarding running video signals on other lengths of cable not designed for it, been there, done that with very limited success. The box boom positions in my highschool theatre made excellent interest-angle camera positions but had absolutely no installed cable other than a/c and 4 wire speakon even close to them - like the ONE room in the school with no CAT5. In my experimenting days I decided to try and run y/c over the speakon figuring it had 4 poles and would be of decent quality considering the gauge of the speaker wire...nada - they only connected 2 out of the 4 poles...hmm 2 poles, sounds suitable for composite video...nope, couldn't even sync, not even with a gen lock return. FAIL. So I ended up pulling RG6 quad through a spare conduit run back to the booth and throwing compression BNC connectors on the end of it...and the camera position lived happily ever after!


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## pacman (Apr 7, 2009)

Just a heads-up for those who might consider using an existing CAT5 data network structure within their building. If you have access to your data racks, I would suggest you patch your video devices directly; that is, unpatch from the data network hub or switch so that your video travels from wall jack to wall jack. I'd guess your IT people wouldn't like you running other signals over their data network; it probably wouldn't work anyway & would likely screw up video and data. If you need to route to multiple locations, all the companies like Magenta make CAT5 hubs designed specifically to amplify and split an AV feed from their CAT5 transmitters.


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## mnfreelancer (Apr 7, 2009)

pacman said:


> Just a heads-up for those who might consider using an existing CAT5 data network structure within their building. If you have access to your data racks, I would suggest you patch your video devices directly; that is, unpatch from the data network hub or switch so that your video travels from wall jack to wall jack. I'd guess your IT people wouldn't like you running other signals over their data network; it probably wouldn't work anyway & would likely screw up video and data. If you need to route to multiple locations, all the companies like Magenta make CAT5 hubs designed specifically to amplify and split an AV feed from their CAT5 transmitters.



Yes, video running over CAT5 WILL NOT pass through data switching equipment. You need a direct electrical connection. Streaming, packet switched video is an entirely separate, much more expensive topic...

Also +1 for Magenta products with skew correction, they work very nicely.


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## museav (Apr 7, 2009)

It does not work over a network as video (or audio or control or...) over UTP is not network data or streaming media, it is simply using the twisted pair CAT cabling as the physical cable path and it will not pass through routers or switches. It is also not subject to the 100m distance limitation common to data networks, sometimes a real problem with IT people involved or IT people pulling cable as they often try to tell you it won't work or will modify the cable routing to go through MDF/IDF/data closet locations to keep any run under 100m (but instead just making the actual run much longer than required and potentially causing problems).

When addressing longer runs or critical video, consider active interfaces that have gain and/or EQ adjustment rather than simple passive baluns. This allows you to compensate for overall (gain) and high frequency (EQ) signal loss over long runs.

When dealing with long runs of component video or RGBHV/VGA, also consider interfaces with skew compensation or using skew free cable. In CAT cable the pairs are twisted, but not necessarily with the same twist rate. Over long runs, this looser or tighter twisting for different pairs can actually result in the physical cabling path being different between pairs. The difference in the arrival of the signals due to this path length difference is skew and enough skew can affect the image quality. Exactly the opposite of what one might expect, CAT6 is the least preferred for this type of application as it has the greatest differences in twist rates between pairs while CAT5 is typically a much better choice with lower skew. "Skew free" UTP cable is made just for this application and uses the same twist rate for all pairs, however it is not EIA CAT5/5e/6 compliant.


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## mnfreelancer (Apr 8, 2009)

Has anyone experimented / theorized about using STP instead of UTP and what difference it would make in terms of baseband video quality?


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## waynehoskins (Apr 8, 2009)

mnfreelancer said:


> Has anyone experimented / theorized about using STP instead of UTP and what difference it would make in terms of baseband video quality?



Seems like it should be pretty insignificant unless you have tons of EMI/RFI issues.


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## museav (Apr 10, 2009)

waynehoskins said:


> Seems like it should be pretty insignificant unless you have tons of EMI/RFI issues.


Agreed! For one thing, typical cable shielding is fairly ineffective for interference sources such as 60Hz EMI, that usually takes a barrier with greater loss at low frequencies such as metallic conduit. For another, much of the benefit actually comes from the twisted pair aspect. The signal is the voltage difference between the two conductors so any common mode interference introduced to both conductors does not affect the resulting difference. Twisting the conductors makes both conductors more equally exposed to any interference.

Shielding does have potential benefits (along with potential drawbacks such as Shield Current Induced Noise), but many people seem to attribute all of the EMI/RFI resistance to the shielding and do not understand the importance of the twisted pair aspect.


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