Q: The maximum bandwidth of Category twisted pair cable is typically 500 MHz. How can this cable support HD-SDI which has a bandwidth requirement of 1.5 GHz?
A: The bandwidth of Category cable is primarily based on the ability to support Ethernet. On the other hand, SDI signal transmission is not as much dependent on whether the cable is twisted pair or coaxial but rather on cable length. Furthermore, since SDI has good equalization, signal attenuation (and therefore distance) is more important than bandwidth and therefore bandwidth is not defined the same way. From the technology standpoint, SDI may be compared to DSL modem technology.

Q: Can the unused twisted pairs be used for remote power without interfering with the SDI Balun video?
A: Passing DC remote power on the unused pairs should work fine. However, AC voltage maybe problematic as there can be some interference from the 60Hz AC voltage. This interference may affect the image quality depending on the type of display and its immunity to outside interference.

Q: What do you recommend for the best cable?
A: To send HD video you must use a coaxial cable with Bandwidth at least 1.5G and to send Full HD video must use coaxial cable with bandwidth at least 3G. The link cable recommended to use a high quality Coaxial Cable & BNC connector if you use a low quality coaxial cable it may case signal loss and affect the transmission distance and reliability. The tests on this HD-SDI to HDMI Adapter was with Belden 1694A RG6U cables.

Here is a distance and cable type guide that can be used with this converter: Recommended Transmission Distances.

Why not buy two - SDI Baluns today?