• Registered: 2007-07-16
  • Posts: 3

Topic: Long coaxial MADI runs

I have an application of the HDSP MADI and the ADI-648 that calls for a 400 foot (121 meters) MADI run with coaxial cable.  Because the ADI648 will be mounted on a moving platform, it would be preferred to use coaxial cable to transmit the MADI instead of fiber optic.  I understand that the maximum length of cable RME specifies is 100m, so I am curious if there is anything that can be done to get the full 400 feet with coax.  Would anyone here be willing to offer some thoughts that might help us get this project up and working?

Peace,
-Nathan

2 Reply by sf

  • sf
  • ADAT user
  • Offline
  • Registered: 2007-05-20
  • Posts: 15

Re: Long coaxial MADI runs

We generally recommend fiber optic cable already for 100m or less. 'Moving platform' indicates that there may be electric disturbances due to motors etc. that would also speak against using BNC cable.
Can you tell us more about the moving platform? Why is coaxial cable preferred to optical cable?

Kind regards,
Stephan Flock

  • Registered: 2007-07-16
  • Posts: 3

Re: Long coaxial MADI runs

Beyond the complications of properly engineering the cable system for the fiber (Which is a rather large and entirely undesirable task), I don't know that there is a huge reason beyond the mechanical limitations of fiber.  Given the details of this installation we feel the need to use coaxial cable, even given this length restriction that we are dealing with now.  We have done the engineering work to determine that coaxial cable is the cable we want to use; the task is now to figure out how to get it to work.  I would like to give you more details about the installation, but I don't feel like I would be acting honestly to release any more information.

Thanks,
Nathan

  • JLU
  • New member
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  • From: Munich, Germany
  • Registered: 2007-06-11
  • Posts: 6

Re: Long coaxial MADI runs

Did you try to run the HDSP-MADI with the ADI-648 connected via 400 feet (121 meters) coax cable? if cable and connectors are high quality maybe it works.
But the comments about electric disturbances,as given by Stefan Flock, are still valid.

To give an idea about fiber specs., for Fiber-cables like we, but also most other, offer:

Weight: 4 kg / km
Tensile Load:  600N  [EN187000/501(IEC 60794-1-E1)]
Min. Bend Radius:  20x Outer ?  [EN187000/513(IEC 60794-1-E11)]
Operating Temperature:  -500 to + 800 C  [EN187000/601(IEC 60794-1-F1)]
Crush Resistance:  2000N  [EN187000/504(IEC 60794-1-E3)]
Impact Resistance:  200 impacts / 1 N.m  [EN187000/505(IEC 60794-1-E4)]
Flexing Resistance:  2000 cycles  [EN187000/509(IEC 60794-1-E8)]
(Based on military standards MIL-C 85045)

Joram Ludwig
Product Management
Synthax Audio AG
  • Registered: 2007-07-16
  • Posts: 3

Re: Long coaxial MADI runs

Thank you very much.  We will be plugging it in soon to see if it works.  I guess if worst comes to worst, we can always cut the cable and put in a reconstruction amplifier.

  • Knut
  • Knut
  • DAW Mastermind
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  • Registered: 2007-04-06
  • Posts: 1,618

Re: Long coaxial MADI runs

New! The website of the official RME partner for cableware & accessories is now online: www.alva-audio.com.

regards
K.