| || |
Audio Video and HDMI over Cat 5 e or Cat 6 - Video Balun
This is a specific type of balun which enables the transmission of HDTV video and digital audio using ordinary unshielded twisted pair (UTP) wire instead of coaxial (coax) cable. The word balun comes from combining the words “balanced” and “unbalanced” and a baluns function is to transform an un-balanced signal into a balanced signal.
When a video signal is transmitted through coax, the distance traveled by the signal is limited in part because the signal is in the form of an unbalanced signal which is susceptible to Electromagnetic / Radio Frequency interference or “NOISE”. In order to minimize noise, coax cables incorporate shielding which increases its cost and bulk.
These baluns transform the signals into a balanced form in which each wire in the twisted pair transmits an identical signal but with opposite polarized magnetic fields. Any radio frequency interference will affect each signal equally and when combined, the interference is cancelled out allowing for much longer cable runs between components without signal degradation.
In combination with a properly designed balun, unshielded twisted pair wire can transmit audio and video signals for much longer distances than coax cables, with the advantage of lower cable costs and easier installation.
UTP cable is significantly less than expensive than coax. The cost per foot of UTP can be 60% less than the cost per foot of coax. In addition, standard UTP cable contains 4 pairs of wire so one foot of UTP cable can do four times the work of one foot of coax.
3 Tips for Installing Cat 5/6 HDMI
Advantages of using Cat 5e / Cat 6 Cables -
Cat 5/6 cables can be field-terminated, while HDMI cables cannot. Not only fairly easy not to mention the fact that Cat cables are easy to install and a lot less expenisve.
Lots of positive information has been written about using Cat 5e / Cat 6 to run your Audio and Video signals over. Despite the positive data, there have been issues. Here are some simple but important rules integrators should follow when installing any Cat 5 or 6 systems.
Always be aware of timing problems. This involves our old friends, inter and intra pair skew limitations. Cat 5e and Cat6 are twisted pairs and look the same. They are just as easy to pull, pinch, stretch, and distort during installation. In many cases, the damage comes easier than with HDMI cable. These distortions with the cable can cause server timing and ISI (Inter Symbol Interference) issues, which can cause sparkles or intermittent video. Be careful installing Cat 5e Cat 6. No Sharp Turns or right angle or 90 degree turns.
Use Cat 6 if you have the option to choose between the two. Studies have proven Cat 6 will offer almost twice the distance you would normally get with Cat 5e. Plus Cat 6 is built with an inner sheath that keeps each twisted pair separated and flexible meaning that if you do pull it the wrong way, each twisted pair inside can move easier.
Don't forget about the DDC serial channel
Although video integrity is important in any of these converters, tests have proven that over Cat 5e and Cat 6 the data on this channel can be easily lost due to rise time issues. That means a high probability of EDID and HDCP failure.