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Tri-ax Question


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#1 Christopher T. Paul- SOC

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Posted 16 June 2006 - 04:19 PM

Howdy folks,

I've got a gig in the desert coming up in a few weeks, and it will be an HD camera (900 I think) and it will run Tri-ax to the truck where a live cut will occur with the other 5 cameras.

My question: Is there one Tri-Ax adapter that is the end-all/be-all for this conversion to a smaller cable? I have borrowed from generous operators in the past, but was never able to get the system to work and had to fly with the monster Tri-ax off the sled. No need to recap the unpleasantness of that endeavor, but I would like to have this in my kit- or at least have an intelligent idea of what to ask for during preproduction.

Any tips and suggestions are, as always, greatly appreciated!

Thanks in advance,

CP
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#2 Bryan Trieb SOC

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Posted 16 June 2006 - 06:58 PM

Hey Chris,

Look up Fred Davis on this site, he will have your answers. For the most part, from what I've encountered...most triax seems to be King connectors. Sometimes they are amphenol, or adc (not sure if that's correct) You're best to ask the mobile engineers which triax connectors they use before the gig if you can. Different triax connectors do work but don't communicate quite properly to each other. You risk your triax jumper failing if you connect to a different triax connector. With HD, some cameras use regular triax, while others use fibre cable, which isn't very bulky and you'd get away with not using a jumper cable if you manage your cable well.

Hope this helps!
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#3 Brant S. Fagan SOC

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Posted 16 June 2006 - 07:45 PM

Gents--

While there may be some rare connector mismatch issues across brand names, the real issue is where did the truck come from.

Most trucks in North America have the same SIZE triax connector no matter who the supplier when the truck was built. However, trucks built overseas, particularly those from the Orient have another size triax connector all together.

I realize the chances of your next job having a truck shipped from the Land Downunder are remote at best.

Seriously, just ask the truck folks before you leave for the job. Ask as many questions to as many people as it takes to get the answers you need to allow you the chance to arrive properly equipped.

Best,

Brant S. Fagan, SOC
Steadicam/Camera Operator
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#4 Kris Torch Wilson

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Posted 17 June 2006 - 12:39 AM

Truck guys usually have a triax to coax adapter available but if you want to buy your own check with Pacific Radio in Hollywood or Burbank. I had one fail just tonight. Some of them can unscrew and come apart. This one was a little loose and I took a couple of hits, luckily not while I was on the air. Also, be careful if you are using a TINY coax like I do. Strain relief both ends. They are very delicate. Best Wishes

Kris
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#5 Marc_Abernathy

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Posted 17 June 2006 - 01:33 AM

torch.
what class coax are you using? RG-6 or something more robust? RG-6 is probably too thin i would imagine...
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#6 Jeff Muhlstock SOC

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Posted 17 June 2006 - 07:28 AM

Howdy folks,

I've got a gig in the desert coming up in a few weeks, and it will be an HD camera (900 I think) and it will run Tri-ax to the truck where a live cut will occur with the other 5 cameras.

CP


Chris, if this is an HD job with a 900, its going to be fiber not triax. Major difference. The only HD camera's that run Triax, that I know of, are Thompsons. Better confirm this. If its fiber, look for the thin fiber jumpers.

good luck,
Jeff
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#7 Bryan Trieb SOC

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Posted 17 June 2006 - 08:32 AM

Speaking of HD fibre jumper cables.....I've not come across a mobile that has them available. Any advice on who could make this particular cable? Fred Davis perhaps?

Thanks!
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#8 Johanwindfeld

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Posted 18 June 2006 - 09:41 AM

Hey There..

I know that HD Fiber cabel is a tricky one... because you cant just go and make a cabel, its very hard to fix and repair. Ony special companys can make that steadicam cabel..

The fiber cabel will not work if there is the smallest error in the cabel.

In Denmark the major tv stations is converting to HD now.. and I have been working on Sony HD. "trust me many times the cabel had errors" Triax is mutch more stabel.

Hope for the best!
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#9 Kris Torch Wilson

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Posted 19 June 2006 - 06:47 PM

what class coax are you using? RG-6 or something more robust? RG-6 is probably too thin i would imagine...

Hi Marc,
I think the coax I use is RG 152. Really tiny. About as big around as the stem of a Q-tip. (I just got out of the shower) The engineer that helped me was very doubtful. He didn't think he would have full control of all the functions, matrix and a stuff I don't understand. But to his surprise it works like a champ. He was VERY careful when putting on the connectors. Making sure none of the sheild was touching the center pin. Says one can be a little sloppy when just sending video down a cable but not when it comes to all the controls that are fed down triax. The only problem we encountered was doing a "hot patch." Connecting the coax while the camera was in the 'on' position. Blew fuses in the tub (base station). As long as I turn the camera power switch off each time, make the connection and then turn back on...no problems. Triax connector is mounted behind my right shoulder. I have about 3 feet of the coax and equally tiny headset cable that I let hang straight down, makes a small loop then up through a caribeaner on my chest, then up and over my shoulder. The big loop to the knees that has been discussed on the forum is just not practical when dancing around vari-lights and band monitors. I put one drop of super glue every 6 inches to mate my cables together. much cleaner than tape, stays flexible and can be pulled apart easily if needed. Hope this helps.

Kris the Torch Wilson
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#10 Marc_Abernathy

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Posted 19 June 2006 - 09:09 PM

torch, thanks for the reply. yeah im told to always make sure the camera is OFF before plugging up. i think ill ask about my RG-6 idea next time. im still trying to find ways to run the coax...
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#11 Kris Torch Wilson

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Posted 20 June 2006 - 02:29 PM

Marc, I pulled the receipt for the coax and it is RG 174 mini 50.

Kris
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#12 Fred Davis

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Posted 20 June 2006 - 03:04 PM

Speaking of HD fibre jumper cables.....I've not come across a mobile that has them available. Any advice on who could make this particular cable? Fred Davis perhaps?


Thanx for thinking of me, but no, I can't service fiber products. Those polishing machines are hella 'spensive.

I can provide a mini-Triax jumper cable, 5mm jacket cable w/ KINGS connectors both ends, 6-8 ft. The popular solution seems to be to mate with the rope coming from the truck, secure the connectors to yer vest, and run the 6-8 ft jumper to the camera.

Trouble with TRIAX connrectors is they come in diffeerent sizes depending on the market. European Tri-lock connectors will not mate with N. American connectors,.........don't know why, but there U R, and I can't get the European spec parts
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#13 Brant S. Fagan SOC

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Posted 21 June 2006 - 09:49 AM

Gents--

For those interested in using a mini coax jumper, please make sure you purchase a 75 ohm product like Belden's 9221. Belden 9221 is cable group RG-179 and has a overall outer diameter of 0.10" and is flexible enough to be served as al dente linguini at a senior's afternoon buffet! This product has served me well both as a TriAx jumper and as well as a component of my Sled wiring for well over a decade now.

I even use a piece for jumping HD-SDI for hardwire situations.

Belden 9221 is available from Newark Electronics along with matching Pomona BNC connectors.

If you use a 50 ohm product, no matter what the size or cable group, you will have problems.

Best,

Brant S. Fagan, SOC
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#14 Christopher T. Paul- SOC

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Posted 22 June 2006 - 04:45 PM

Thanks for all of the input- the truck on this job will provide a jumper cable as Fred has described above. Fortunately they do this a lot and were familiar with my needs.

Thanks again for all of the help.

CP
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#15 AdamKeith

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Posted 24 June 2006 - 01:44 PM

I purchased a light weight Fiber Cable from

Jonathan Stevens
R. Orange Engineering
303 547-4897



Regards,
Adam Keith
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