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CAT 5 distribution setups


Jeff Wexler

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I am planning on implementing a CAT 5 setup for my connection to the video assist department. This would simplify the cabling for what is already a very simple setup for me: typically I only need 2 video feeds to my monitors on the cart and 1 mono audio feed to the video assist cart. I have the proper baluns and all that but I don't know what people are using for the actual CAT 5 cable run. I like the idea of running 1 inexpensive CAT 5 cable but if that is always getting damaged what's the point. So the question:

Who makes pre-built high quality CAT 5 (or better) cable in 50 to 100 foot lengths? I would expect that these cables should be able to behave just like high quality mic cable we have running all over the set --- flexible, durable, kink-free, etc. It does not matter to me if these are pricey cables as I will not need a lot of them. I know that ANY CAT 5 cable will work but I can't imagine your average off the shelf budget cable will work well for set runs.

Regards,  Jeff Wexler

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Hi, Jeff

Whirlwind does make some special CAT5 products, but the baluns would need to be modified or refitted into another box to make use of them, since the RJ45 connectors are built into XLR connectors:

http://www.whirlwindusa.com/audadp01.html#digconns

Best regards,

Jim

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I bought 500 feet of stranded CAT5 from Pacific Radio and an inexpensive crimper set along with a bag of connectors.  I made 3 100' lengths, 3 50' lengths, and 2 25' lengths.  I thought these would get damaged pretty quickly, as they are not really made for what we do.  Boy was I wrong...  More than a year later and a season of rough and tumble TV as well as numerous commercial and 2nd unit days, these cables are still going strong.  It even got to be a test at one point to see what would do them in.  We started putting them out so that condors, scissor lifts and even a tank (yes a military tank) would drive over them just to test their durability.  The tank did a little jacket damage...but the cable still worked.

I recommend the stranded cable, as it wraps quite well.  The other stuff is made for installs and not made to coil up several times a day.

~PWP

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What are you guys using to interface with the cat5?  Custom dongles or are there premade ones out there?  I worked with another mixer a while back that was using cat5 to run sound to camera. The setup was definatly homebrew, it seemed fragile, but worked without issue.

Use an AV Balun on each end of the cat5 cable...

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I bought 500 feet of stranded CAT5 from Pacific Radio and an inexpensive crimper set along with a bag of connectors.  I made 3 100' lengths, 3 50' lengths, and 2 25' lengths.  I thought these would get damaged pretty quickly, as they are not really made for what we do.  Boy was I wrong...  More than a year later and a season of rough and tumble TV as well as numerous commercial and 2nd unit days, these cables are still going strong.  It even got to be a test at one point to see what would do them in.  We started putting them out so that condors, scissor lifts and even a tank (yes a military tank) would drive over them just to test their durability.  The tank did a little jacket damage...but the cable still worked.

I recommend the stranded cable, as it wraps quite well.  The other stuff is made for installs and not made to coil up several times a day.

~PWP

Phillip has a good point, and I know that the folks on "the Wire" - Bruce, Lorenzo and Ivan have used the CAT5 and balun solution for feeds to and from video this past season, at least occasionally. If it's good for a show that works that fast and in such challenging locations, it's fairly bulletproof. I have the vast part of a box of stranded CAT5 cable left from when it proved to be cheaper to buy a 1000' box than 200' of cut cable to run network connections in the house so the initial investment is low. It's also a good thought that the cable can be repaired without a soldering iron, the connectors are about 50 cents each and a long run for a special setup can be used and then recycled into shorter cables pretty easily and quickly. Sure beats running and then replacing a video/audio cable that costs $2.00 a foot, or several pieces of wire.

I'm also thinking (but willing to be corrected) that the baluns provide some isolation from ground, so power issues on location might be simpler.

Best regards,

Jim

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I'm also thinking (but willing to be corrected) that the baluns provide some isolation from ground, so power issues on location might be simpler.

Best regards,

Jim

Not necessarily.  The baluns that I use, Intelix AVO-V2A2, have a common ground and will suffer from the same issues.  However, I have noticed slightly less problems that I've encountered over the years with video snakes.  These can usually be remedied by lifting the AC ground at my end if needed.  I'm on battery charge most of the time anyway.  Some of the higher priced baluns do provide isolation, which will clean up most of the problems we usually see in our monitors.

I really have had great luck with my Intelix baluns, at less than $80 each and pennies for the CAT5 cable...it's become a no brainer.  We frequently add up to 400 feet to my video run when we have to keep it out of the shot (around the building or whatever).  No problems at all when running even longer than that.

~PWP

www.palmeraudio.net

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My experience has been the same as Phil's.  Last year I bought a 1000' reel of unbranded CAT-5 on EBay for $60 (complete with a crimper and a giant baggie of ethernet connectors).  When it arrived, I thought "no way" -- the cable seemed really flimsy and I couldn't imagine it standing up to the rigors of set use for very long at all.    I got on RAMPS and asked folks if there was a better alternative, and though a couple noted the more expensive Gepco/Neutrik alternatives, most said that their cheap stuff was working perfectly. 

Everyone was right -- a year later, I've had maybe one in ten cables I made from that stock fail, and they've been in heat, cold, snow, rain, run over by countless dollies and 18Ks on wheels, and crushed and flattened under doors along the way.  I think someone said  something like "as much as I've tried to destroy this cable, it still works fine" in a previous thread about this, and that's also been my experience. 

Occasionally a connector breaks off, but crimping a new one on takes about five minutes once you get the hang of it, and it seldom happens in the heat of action (usually if the cable end falls under a cart wheel or something).  All said, I've had to replace connectors and fix cable with that cheap CAT5 far less frequently than I used to do with traditional Canare LV-61S on BNCs.  The only complaint is that the cable *really* takes a long while to train (and even then it doesn't train all that well) -- you'll need some paper tape for your runs.  When it's new it's a bit of a nuisance.  After some use/abuse/repeated coiling, it tends to lay closer to flat.  (Don't throw that paper tape out, however). 

The main issue to look out for with the CAT5 system is not the cable but that the baluns have some ground isolation.  Otherwise you've also got to run your AC power to the same source as video (and "it's all coming from the same generator" is not enough -- the feed really has to be from the exact same run).  It hasn't been a problem with bigger video monitors, but it has been with the old-school 8" Sonys that show up on some sets for director's monitor and such.  I learned the hard way that the oft-used Intelix baluns are *not* isolated.

Hope that helps!

I bought 500 feet of stranded CAT5 from Pacific Radio and an inexpensive crimper set along with a bag of connectors.  I made 3 100' lengths, 3 50' lengths, and 2 25' lengths.  I thought these would get damaged pretty quickly, as they are not really made for what we do.  Boy was I wrong...  More than a year later and a season of rough and tumble TV as well as numerous commercial and 2nd unit days, these cables are still going strong.  It even got to be a test at one point to see what would do them in.  We started putting them out so that condors, scissor lifts and even a tank (yes a military tank) would drive over them just to test their durability.  The tank did a little jacket damage...but the cable still worked.

I recommend the stranded cable, as it wraps quite well.  The other stuff is made for installs and not made to coil up several times a day.

~PWP

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Regarding Isolation with Balun "boxes" - is there a specification to look for that indicates this needed property?

I'm a firm believer in the principal that you get what you pay for (Especially for us!)......

The limited research that I've done on Balun boxes has pricing from about 10 - 100 dollars....

a pretty wide gap... 

I found one that actually has designations of "Transmitter" and "Receiver" for each of the two boxes included in the set... they are bi-directional, right?

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I found one that actually has designations of "Transmitter" and "Receiver" for each of the two boxes included in the set... they are bi-directional, right?

Yes, they are bi-directional.  Not sure about the transmitter/receiver designation.  That doesn't make much sense for the passive units.  Baluns are pretty simple actually.  All they do is convert a balanced signal to unbalanced.  This allows the transmission over the CAT5 twisted pair cable.

~PWP

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  • 2 weeks later...

Wolf Seeburg has posted a rather extensive discussion of the use of baluns and Cat 5 cable on the Video Assist Group. He brings up an issue which I think has been overlooked or not well understood. I am only just scratching the surface here with my limited knowledge of these things so maybe someone here can enlighten us all. The issue regarding audio transmission is the common transformers that are used in the baluns we are typically using. According to Wolf, and this does make perfect sense, frequency response is severely impacted by the use of these very cheap transformers. So, this means that if you are feeding production audio to the video assist cart, that audio may well be of much lower quality than if it were sent over a normal mic cable as a balanced audio signal from our mixer. At the very least this means that using a Cat 5/balun distribution system would certainly not be appropriate for distributing primary microphone signals for use in a recording. It may be that the quality is adequate for video assist audio feed recording but I am not so sure.

Regards,  Jeff Wexler

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if you have balanced audio, you do not need a balun at either end!

cat5 / cat5e is 4 x twisted pair, (usually) unshielded .

That's not the point. If you want to use a single lightweight cable (Cat 5 variety) to send audio (either from a balanced output or an unbalanced output) and video, which is the typical use for this Cat 5 system we're talking about, you DO have to use baluns of some sort even if it is to allow connection to Cat 5 Rj connector.

Regards,  Jeff Wexler

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A few years ago, I read about how Mark Ulano used CAT 5 for his primary audio.  His system utilized a CAT 5/Audio interface (AVIOM, I think), to send line level signals from his mic preamps, which resided on the boom op cart (a 10-space 19" rack system) positioned close to set, back to the mixing cart.  I think he did it on Rocky Balboa, where the ice cold Philadelphia night exteriors meant long cable runs as he tried to stay indoors.

Sorry if this is off-topic, but I figured it might be worth asking him about CAT 5 usage for audio.

Brian

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A few years ago, I read about how Mark Ulano used CAT 5 for his primary audio.  His system utilized a CAT 5/Audio interface (AVIOM, I think)

Brian

Yes, Mark has sort of pioneered this new (for us) distribution concept but the Aviom system shares almost nothing in common, except the RJ connectors and Cat 5 cable, with the simple inexpensive balun-type setups I was talking about. The Aviom units are expensive and active rack mount units and would be total overkill for the simple video assist feeds. For Mark Ulano, who has always been into lots and lots of equipment, multiple communication systems, wireless everything, the Aviom system is a must. For most of the rest of us I don't think there will be any big move to that sort of setup for most jobs.

Regards,  Jeff Wexler

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I had the impression that there were lots of people who had gone over to the Cat5 system for video assist feeds--I'd like to hear their impression of what they hear at the other end of the feed.  I believe Scott F's new rig is balun-equipped, maybe he could listen to some audio and maybe a freq sweep test for us?

Philip Perkins

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Yes I have two (1 set) of the Intelix AVO-V2A2 Balun system, along with 300' (X2 100' and x2 50') of CAT5e cable. I have used this system on a couple of projects and the audio quality sounded really good to me. At least as good as the Comteks we use everyday.

Colemen Metts did a complete CAT5 setup for a show a few months back and a had positive things to say about that.

thanks

Philip Perkins

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I've always found it to sound fine.  Bear in mind, though, that most of the video assist playback is just coming through that little portable Fostex speaker that the video guys usually have, blaring out on a noisy set.  It's not really a critical-listening scenario.  There are more hi-fi video playback setups and scenarios, but in my experience those seem to be the exception rather than the rule.  As such, I tend to think the potential for overkill in this application is pretty huge.

.02 nvt

I had the impression that there were lots of people who had gone over to the Cat5 system for video assist feeds--I'd like to hear their impression of what they hear at the other end of the feed.  I believe Scott F's new rig is balun-equipped, maybe he could listen to some audio and maybe a freq sweep test for us?

Philip Perkins

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One reason for asking about the audio quality, even for video assist purposes, relates to a specific way in which I rely on video assist. One thing is that I am very diligent about insuring that I am sending them a really good true signal (not just some approximation of what our recordings sound like) and I also inquire about the spec for their particular setup (digital at 16 bit, 24 bit, sample rate 44.1, 48, compression codec, mpeg or true PCM, etc.). I also check on playback using headphones connected to what I can determine is the probably most clean, direct output. I also check how things will sound being played back through whatever speaker-playback setup they have going. There are 2 primary reasons for doing this: the first is that it is important professionally to provide for the director the best possible sound for them on playback which in today's world is almost 100% of the time off Video Assist (not off the sound cart or any of my equipment). The second reason is that I want to be able to rely on the video assist recording as a last ditch backup to my recording should EVERYTHING fail in my setup on some take. This is one of the reasons I do not feel the need to run a backup machine (I have discussed this whole idea many times) because the video assist person is generally running a fully qualified recording setup that I could utilize if there were ever catastrophic failures on my part.

Regards,  Jeff Wexler

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One reason for asking about the audio quality, even for video assist purposes, relates to a specific way in which I rely on video assist. One thing is that I am very diligent about insuring that I am sending them a really good true signal (not just some approximation of what our recordings sound like) and I also inquire about the spec for their particular setup (digital at 16 bit, 24 bit, sample rate 44.1, 48, compression codec, mpeg or true PCM, etc.). I also check on playback using headphones connected to what I can determine is the probably most clean, direct output. I also check how things will sound being played back through whatever speaker-playback setup they have going. There are 2 primary reasons for doing this: the first is that it is important professionally to provide for the director the best possible sound for them on playback which in today's world is almost 100% of the time off Video Assist (not off the sound cart or any of my equipment). The second reason is that I want to be able to rely on the video assist recording as a last ditch backup to my recording should EVERYTHING fail in my setup on some take. This is one of the reasons I do not feel the need to run a backup machine (I have discussed this whole idea many times) because the video assist person is generally running a fully qualified recording setup that I could utilize if there were ever catastrophic failures on my part.

Regards,  Jeff Wexler

I HAVE used the video assist audio, mostly during a run of bad luck I had with my first HHB DAT machine, so good point on that.  Beyond that.....I think your feature clients are a tougher room than the people I work for, at least as far as their expectations of video assist audio go.  The video assist guys I know say they would like me to go w/ Cat 5.

Philip Perkins

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  • 1 month later...

Hi.  Sorry for delayed response, and quick reply.  ( I am working 80 hours a week on a new tv show called MOONLIGHT). 

  I have been using cat 5 for a few years.  I have used it for video assist, as primary audio to video cams, and have 2 projects that recorded all image and audio to a custom built computer.  (there here...) 

  Ok, baluns do not stop ground loops.  You are still going to be putting the same load( or spliting the signal / degrading the signal..it's still a pice of cooper wire, and as I understand it, you do not even really need a balun to use cat 5, but I have not tried it.)  when you hook up a cat 5, same as using a bnc cable. 

You can use cat5 to send 8 tracks of digital audio from the DEVA to a computer.  ( major high teck computer type stuff...)    but no balun needed.  Call Glen for help, ha ha I do not know computers, but the computer guy said "Glen S. knows his stuff".

  Fu.. we are so busy 14.. 16...18 hour days

Coleman

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