Sending LTC over XLR

[Adam Street]

So as part of a project I've got a requirement to send LTC to multiple buildings from a distributor. For reasons I won't go into, one of these cable runs has been calculated to be 510m. Has anyone had success in sending LTC over (balanced) XLR that far before? Or further? Or to put it another way, what's the furthest you've sent an LTC signal without encountering problems?

Cheers!

 

[Rob Timmerman]

You biggest headache specific to LTC over that long a run is likely going to be HF rolloff caused by cable capacitance. LTC wants a -3dB point on the link of about 14khz, which may be difficult to achieve with shielded wire over that distance. For reference, on a 500m cable, this will require cable with a ~36 pf/m capacitance at a 600 ohm drive impedance, but reducing either the drive impedance or the cable capacitance will help things. Obviously, things like grounding and shielding that apply to audio links also apply here as well.