Extending HDMI Cable Connections
Copper Wire, Wireless, and Fiber Optic Cables
Extending HDTV Beyond the Limitations of HDMI
HDMI cables have become the establish standard in HDTV connectivity; the ease with which it is possible to extend audio and video over the same interconnect has made HDMI a winner. It is no wonder that the number of HDMI-enabled devices by far exceeds that of any other AV interface.
Yet this digital interconnect standard is hampered by a relatively short cable run between source device and the display.
In this article, we discuss available HDMI extender options—from copper-wire based systems to wireless HDMI solutions and fiber optic technology—that will make it possible to run an HDTV connection beyond the practical distances supported by HDMI interconnects.
Affordable HDMI Extender from J-Tech Digital using dual runs of CAT 5E/6/7 cable - supporting up to 200ft over CAT6 with HDMI ver.1.2 and over CAT7 with HDMI ver. 1.3 at up to 10.2Gbps.
HDMI is capable of supporting the highest video resolutions possible today, yet the use of small-gauge copper twisted pair instead of coaxial cables leads to serious constraints with long cable runs.
HDMI is designed to operate at up to a maximum of 50-feet/15- meters, but actual performance is dependent on both the signal bit-rate one needs to handle and the HDMI cable quality.
As expressed elsewhere on our site, the problem with twisted pair is that it is not possible to maintain tight control over cable impedance. Poor impedance control leads to signal reflections along the HDMI cable between source and sink, interfering with the data bitstream originating from the source. In addition, there is also the distortion effect of cable impedance on leading and trailing edges of the voltage transitions representing the digital data; this distortion increases drastically with distance up to a point where it would be hard for the receiver to reconstruct the original bitstream. In digital standards where no error correction is used, the result is loss of information.
HDMI would still perform as long as the level of errors is contained in that the display would still re-constitute the image but with errors showing as 'pixel-dropouts', or 'sparkles'. Increase the length slightly further beyond the point at which sparkles start appearing and you would end with no image at all.
But even if you would not lose the image, the presence of pixel-dropouts will lead to an unpleasant HDTV viewing experience. HDTV is 'either all or nothing'; pixel-dropouts are hard to tolerate with an HDTV image. Once you arrive at this point, you need to look elsewhere to extend your high definition video.
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There are a number of available options that would allow you to extend your a high definition video beyond the limitations of a standard HDMI cable. These include copper-based HDMI extenders using CAT5e/6/7 cables between the two extender ends, HDMI booster amplifiers that reconstruct and amplify the HDMI signal to allow for a second length of HDMI cable between source device and display, wireless HDMI solutions that despite their limitations in supported range, deliver the convenience of wireless connectivity, and HDMI-over-Fiber.
Fiber optic based HD-video extenders are significantly more expensive than both wireless and copper wire systems. However, requirements in the home do not generally call for a fiber-optic based solution as these are mainly used in the case of extreme long cable runs.
Choosing one technology over another is mainly a matter of distance between source and display. As long as you remain within the limitations of the supported distance by the respective technology, all four technologies are capable of comparable performance. But as in the case of an HDMI cable, you should ensure that the selected solution is guaranteed both to handle the necessary data throughput at the required length for the high-definition video signal you are interested in, and also the HDMI features supported by your gear.
Which Method is Right for You?
As stated earlier on, technology choice is mainly a matter of distance between source and display; but there is also the issue of convenience. At the shorter to medium lengths, wireless HDMI represents a substitute to running an HDMI cable from source to display while still achieving longer distances than typically possible with good quality HDMI interconnects.
The use of a continuous standard copper cable of the proper length between source and display represents the best and cheapest approach. Do not expect long high-speed quality cables to come cheap. But as long as you would not insist on running a 1080p 60Hz video signal over some 50 feet, a suitable 50-ft good quality HDMI cable such as the Aurum High Speed HDMI Cable shown here should not cost more than $30. The Aurum is CL3-rated, meaning it is suitable for in-wall installations.
Copper cables are generally not a source of problem until cable lengths are factored in especially at the high-speeds required for HDTV. The maximum cable length is highly dependent not only on the cable built quality and the required bit-rate for the signal, but also on the quality and strength of the HDMI signal originating from the source.
In addition, care should be taken with manufacturers' cable bit rate specifications. You never really know how manufactures are handling data throughput and bit error rate tests. Thus, while an HDMI cable may pass the manufacturer bit rate test at the specified length, this is no guarantee it will still perform at the rated bit-rate with your source/display combination.
Our advice: Unless you can buy a cable from a manufacturer who offers an appropriate return policy, it is best to refrain from using HDMI cables at the maximum length supported by this standard. Instead, limit these to a maximum of 30 to 40 feet. Beyond this point, it is best to opt for alternative technology.
Wireless is an ideal option in the case of an HDTV wall installation or a ceiling-mounted video projector where you do not have the required AV terminations in place.
A wireless solution gives you the convenience of extending your HDTV connectivity without having unsightly AV cables running around while still avoiding putting holes in walls to pass HDMI cables through. However, expect to spend $200 and more for a suitable wireless HDMI solution.
Though wireless HDMI solutions support longer distances than possible with an HDMI cable connection, present wireless HDMI connectivity is the least suitable for long distances between source and display even though most of the latest systems using WHDi technology can support up to a claimed 100 feet range in a line-of-sight application; expect this to fall to around 65 feet when there are obstructions between the transmitter and receiver ends like walls, ceiling and even heavy furniture. In addition, radio frequency interference will also limit the maximum supported wireless range.
This means that wireless HDMI solutions are mainly suitable for same-room installations even though a few systems have sufficient range to let you broadcast a 1080p60Hz video signal from a source device in another room in the house. Typical range varies between 30ft and 70ft. In our test of the IOGear GW3DHDKit featured above, we got abound 77 feet with two walls a ceiling in between, but then keep in mind that 5GHz systems such as the IOGear support a greater range than wireless HDMI solutions using a 60GHz-based technology such as WiHD.
Two important things to take into consideration with HDMI wireless systems are HDCP compliance and system latency (especially with gaming applications). As explained elsewhere on our site, all active HDMI components should be HDCP compliant to ensure that the display device would not default to standard definition. On the other hand, latency is less of an issue in that with uncompressed video, most wireless HDMI systems have less than 1msec latency; however, this may increase to as much as 20ms to 30ms with compressed video transmission.
More information on wireless HDMI technology and systems is available in our Wireless HDMI Technology Guide.
A possible option to extend HDMI beyond the maximum distance supported by a single HDMI cable is the use of HDMI Booster or HDMI Repeaters.
Boosters sit between source and display connected with two HDMI cables of the appropriate length, one between source and booster, and the other between booster and display.
These devices work by regenerating the high definition video and digital audio received from the source and then transmit the amplified signal along to a second cable. The principle is basically the same as when using a USB hub to affectively achieve a longer USB cable run between your computer and a USB device.
The main difference between boosters and repeater amplifiers is that repeaters may be 'daisy-chained' to achieve greater distances between source and display. Distances up to 150 feet can be achieved in this manner. However, the use of multiple boosters as against possible use of an alternative technology should be weighed against both cost and performance implications.
Prices range from under $100 for an affordable HDMI booster such as the Tripp Lite B1222-000-60—capable of handling up to 1080p 60Hz video, to close to $300 for the Xantech HDMI booster shown above (excluding the interconnecting HDMI cables).
A few points worth taking note of:
Booster/Repeater solutions depend on the strength of the transmitted signal to ensure that the signal received at the display side is still error free; a weaker signal limits the maximum distance for correct operation.
Boosters amplify the signal to minimize loss, but they can only amplify an exact replica of the received signal at their end; any corrupted data will also get amplified in the process, leading to amplified pixel noise. This is the biggest problem associated with Boosters and Repeaters.
Boosters and Repeaters are not normally designed for in-wall installations, which may complicate cable installations even further.
This is a relatively affordable copper-wire based technology that is catching up fast. It uses two lengths of Cat-5e/6/7 computer network cables to extend HDTV signals up to 300ft. The ViewHD HDMI extender shown here is selling for under $70, yet it is capable of extending 1080p 24fps video up to 200ft over inexpensive CAT-6 STP cable.
Wall plate solutions are also readily available; one such option is the HDMI-Over-CAT5e/CAT6 Wallplate Extender Kit by Tripp Lite. The use of a wall plate makes HDMI-over Cat-5e/6 extenders transparent to the user in that once installation is complete, all that one would be doing is connecting two HDMI cables between source, display and the wall plates.
HDMI-over Cat5e/6/7 extenders makes the idea of extending HDMI beyond the limitations of standard HDMI cables, an inexpensive and user-friendly solution.
We say inexpensive because in comparison to high-quality HDMI cable, Ethernet cable comes at the fraction of the cost; 150ft of STP CAT-6a Cable is selling online at under $35!
Short for Category, CAT-5e, CAT-6, and CAT-7 are Ethernet standard cables that consist of four twisted pairs of copper wires. Cat-5e is an enhanced version over CAT-5 and supports speeds up to 1Gbps over short cable runs (330feet or 100m). CAT-6 can handle 2.5 times the spectral bandwidth of CAT-5e while CAT-7 can handle up to 6 times as much.
Use of CAT-6 or 7 is generally required when it comes to extending HDMI ver. 1.3 and upwards if support for 1080p/60 video and Deep Color is desired. Otherwise, CAT-5e should suffice to extend 1080p/24 video up to around 200ft. Note however that you will have to make use shielded twisted pair (STP) or foil twisted pair (FTP) cable instead of the common unshielded twisted pair (UTP) found in most home network installations since the later is more susceptible to interference.
While distances in the home theater do not generally justify the use of fiber optic solutions, there are instances when fiber optic based systems would represent a viable technical option at longer cable lengths.
Fiber Optic solutions give you the possibility to extend an HDTV signal up to 1500 feet using multi-mode fiber technology and up to several kilometers using single-mode fiber. Multi-mode and single-mode fiber technologies are comparable when it comes to signal quality performance; what determines the one to choose depends on distance. Single-mode fiber is substantially more expensive than multi-mode, however even a typical whole-house AV installation, the distances involved do not call for the use of single-mode fiber solutions.
Full Integrated Fiber Optic HDMI Cables
Fiber Optic HDMI Cable from Gefen
HDMI-Over-Fiber Cables: A few major manufactures in the field of high definition digital interconnects have come with self-powered fiber optic based HDMI cables that incorporate all necessary electronics and the DCC signals built into the cable and HDMI connectors.
This solution represents an immediate user-friendly approach to extending HDTV over fiber for distances up to 330 feet.
Also referred to active optical HDMI cables, these optical integrated HDMI cables do not come cheap—with HDMI extenders using CAT-6 and CAT-7 technology representing a much cheaper and user friendly alternative. Expect to pay around $500 for a 50-ft 'fiber optic based' HDMI cable, $1,000 for a 166ft run, and $2,000 for fiber-based 330-ft HDMI-over fiber solution. At these prices, a CAT-6 HDMI extender solution costs between one fourth the price for a 50ft run to one-ninth for a 150ft run!
But apart the expensive price, these active cable solutions carry another drawback, one that would surface during an in-wall installation. The reason is that these are not actually designed for in-wall installation. Try to do so and you would soon find that there is the need for a relatively large diameter conduit (approx. 1.5 inches) to allow for the end connectors to pass through!
In-wall fiber-based HDMI:
These represent the ultimate in HD-video over fiber and make use of dedicated sender and receiver units with a 'dark' fiber connection; short HDMI cables are then used to connect the sender and receiver units to source and display respectively. Connectivity between sender and receiver units would normally consists of a number of separate fiber strands to carry the red, green, blue and clock video signals and a Cat-5 cable to carry the HDCP/DCC and other control signals.
Price-wise, these represent a cheaper HDMI-over-fiber solution at the longer lengths than self-powered HDMI fiber optic cables. The Gefen HD-1000 kit pictured above sells for practically half the price of a self-powered cable solution. At $1,000 it comes complete with the sender and receiver units plus enough Cat-5e and four-strand LC-LC terminated fiber optic cables to cover 330-ft; and you can use longer cable lengths to cover distances in excess of 1000ft.
Fiber-based HDMI solutions are among the most expensive ways of extending high-definition video and audio over long distances from the source device. Remember however that here we are dealing with distances that it would be impossible to cover with cheaper copper-wire based technology. In fact, the real advantage of expensive fiber optic HDMI extenders is their ability to deliver a wide-enough bandwidth to handle all present HDTV resolutions and 36-bit Deep Color, at relatively long cable runs.