As audio video systems and installations have become more complex over time, the need for sending multiple signal types and control over long distances has increased. With that, it seems there are an endless number of choices in signal extension hardware, which might have you wondering which product is the right choice for your installation. Naturally image quality and reliability should be your two biggest concerns, as well as explaining the technology and selling your customer on the need for this type of hardware.
Until a few short years ago, each manufacturer of signal extension hardware typically used their own proprietary technologies so that for example a Kramer branded transmitter would likely not work with a TrippLite branded receiver. Additionally there seemed to be a big variance in quality between brands, especially when it came to extending HDMI signals. The introduction of HDBaseT was a game changer in that you now have a consistent chipset used by all manufacturers so reliability is much more consistent between products, and since it is a standard platform you can mix and match devices. It is becoming more and more common now to see an HDBaseT input already integrated into the display device whether it is a flat panel or projector, removing the need for a separate receiver all together.
For extension products that use the HDBaseT chipset, most manufacturers will recommend the use of solid shielded Cat6 cable with shielded connectors. This type of cable can be terminated in the field or it can be purchased in specific lengths already terminated.
There are many scenarios where signal extension would be a good option, or even required. So where do we start?
Let’s start by looking at cable lengths. While a hard and fast distance limitation is not defined, there are general guidelines that you should follow when planning an installation. In addition, differences in cable quality and video resolution will have an impact on distance as well. With analog signals such as composite, s-video, VGA, and component video you can usually send your signal over cable runs of 100 to 150 feet without experiencing a dramatic reduction in image quality. DVI is mandated to transmit at 5 meters or roughly 16 feet, and HDMI runs typically should be no more than 50 to 75 feet. The use of signal extension products will allow you to send analog signals to distances exceeding 1500 feet and digital signals up to about 330 feet. This distance can be longer with the use of fiber instead of twisted pair.
Next you will want to consider the cost of traditional cable compared to category cable as well as any physical limitations that may make it difficult to pull standard video cable. While shorter HDMI cables are relatively inexpensive, longer cables can start to get pricey. Even though there is a cost associated with the transmitter and receiver hardware, this often can be offset by a savings in labor costs as well. Remember that with HDBaseT extension products you will have the ability to send video, audio, Ethernet, power, and control (RS-232) over a single cable reducing the need for multiple runs. This greatly simplifies planning your installation since you will not need to know ahead of time whether audio and control signals will accompany the video signal in order to choose the correct extension hardware.
Note that you are not limited to point-to-point extension either. Hardware vendors in this category offer distribution amplifiers for sending a single source to multiple displays using a single transmitter as well as matrix switches with the option for HDBaseT on both the input and output side for larger systems. Some receivers also give you the ability to daisy chain to additional displays through a twisted pair output on the receiver. It is important to look closely at the specifications of different extension products to make sure they match your requirements for signal, resolution, and distance. In most cases having an available power outlet for the receiver will be required as well
Other features that are available on certain extension products include Gain & EQ control as well as Skew Compensation. Gain & EQ control will allow you to make fine picture adjustments at the receiving end while Skew Compensation can adjust for different parts of the signal reaching the receiver at different times due to the variable twist rates of the individual pairs within the cable and is usually only required for cable runs of 500 feet or more. While these types of features will add cost to the products you choose, they will be the difference between a happy customer and a dis-satisfied one.
In summary, like with anything else, careful planning and product selection will be the key to a successful installation. You must consider resolution, distance, signal type or types, and physical layout when choosing a signal extension product.