A (long) cable from the AV receiver to the television or projector is the cheapest way of transmitting images and sound.But what about wireless HDMI?We show alternatives such as WHDI, WiHD, WiGig and Chromecast that transmit HDMI signals wirelessly.Players such as streaming or cable boxes are usually located close to the 4K television (guide) and can therefore be easily connected to the display device via HDMI cable.However, as soon as the television is placed on the wall in a chic way or even a projector is to be used, this can become difficult.At least visually.Because the television loses the impression of "floating freely" through visible cables and the projector is often not even on the same wall as the player.With a lot of effort, you can get the connection to be invisible even with a long HDMI cable (keyword: laying the cable in the wall or ceiling), but if necessary, surface-mounted cable ducts can also be used in a reasonably aesthetic way.After all, they cannot be seen at first glance.Wireless solutions or those that rely on cables that have already been laid promise an alternative.They transmit signals wirelessly at 5 GHz or 60 GHz, alternatively via the existing power or network cable.In theory, this is hardly more expensive than a long HDMI cable.In practice, this promise can hardly be kept and there are other limitations.In terms of transmission rate, the current HDMI standard is far ahead of classic Ethernet.Up to 48 GBit/s of video and audio run over the cables.This works so well because the distances are short.HDMI cables should bridge about 8 meters.If the distance is longer, there can be problems with the transmission, the systems then usually switch to lower standards.For example, 4K only becomes a Full HD signal (which the receiver can then perhaps extrapolate again).Experience has shown that Full HD signals can also be sent through 15-meter-long copper HDMI cables without any problems – and that for prices of less than 30 euros for the cable.However, as soon as you want to transmit UHD videos including surround sound over 10 or 15 meters, errors can occur with copper cables.The remedy is HDMI cables, which use fiber optic lines for data transmission.Glass fiber allows high data transmission over significantly longer distances - one of the reasons why it is used for fast Internet.However, fiber optic cables also have disadvantages compared to the copper variants: They are significantly more expensive and can only be plugged in in one direction.Where it doesn't matter which plug is on which device with a normal HDMI cable, the plugs on the fiber optic HDMI cable are clearly marked with input and output.Otherwise, they differ neither visually nor in the type of connection.With the available cables you should pay close attention to the standard, the price and the ratings.There are numerous offers for HDMI 2.0, the manufacturer Lindy, for example, supplies cables with 30 meters or more.If you want to bring a game console of the latest generation (next-gen comparison: Xbox Series X and S or Playstation 5) to the projector, you need a cable with the HDMI 2.1 specification.Here you should go the easiest in the shallows of Amazon.Because at the time of the article, there was the largest selection of cables, even if some options are sold out again and again.The fiber optic HDMI cable from CDS made a good impression.Here you can choose from lengths from 10 meters, prices start from 60 euros.Also exciting, if only because of its braided red design, is the ANNNWZZD fiber optic cable.The length ranges from 5 meters to 100 meters, prices start at 43 euros.A reader referred us to FIBBR's HDMI fiber optic cable, with which he had good (next-gen) experiences.In addition to lengths of 15 meters and more, the manufacturer also has short fiber optic HDMI cables in its range.Depending on the cable, handshake problems can occur despite the alleged specifications, which are noticeable in brief picture dropouts - only trying it out helps here.The other connection option is radio.If cables cannot be routed nicely or sensibly, this option could be the solution.There are standards such as WHDI (Wireless Home Digital Interface), WiHD (Wireless HD), WiGig (Wireless Gigabit), Miracast or the proprietary variants Chromecast, AirPlay and Wireless Display Adapter, which offer different advantages and disadvantages.The sender/transmitter is connected via wireless HDMI to a player or ideally the AV receiver as a home cinema center (adviser), which then sends data to the receiver/receiver, which is connected to the television or projector via HDMI.In the meantime, many televisions already have internal options for wireless transmission of picture and sound via Miracast, AirPlay or Chromecast ex works.However, a corresponding smartphone or tablet serves as the transmitter here, so you can't get the Blu-ray signal on the big screen.Smartphone and television must be in the same (W)LAN.There are also a few projectors and televisions with WHDI receivers, and a transmission dongle is also supplied, which is plugged into the AV receiver, for example.The proprietary standard WiHD (Wireless HD) relies on radio in the 60 GHz range as the transmission frequency.Data rates of up to 7 Gbit/s per stream are permitted in the EU, and data rates of 28 Gbit/s are possible using MiMo (Multiple Input Multiple Output) multi-antenna technology.This allows the transmission of 4K signals without interference and largely without latency, but is well below the 48 GBit/s of HDMI 2.1.In return, only short ranges of up to 10 meters are possible without interference with this technology due to strong damping due to the high frequency, and the line of sight must not be disturbed for a longer period of time.A transmission to the next room does not usually work, even a suspended ceiling for the projector can be problematic.WiGig (Wireless Gigabit) is not compatible, but also operates in the 60 GHz spectrum.Since WiGig is now part of the Wi-Fi Alliance as the IEEE 802.11ad standard, it can not only be used to transmit HDMI up to 4K and can therefore be used more universally.However, this article is only about HDMI transmission, which is subject to the same consequences as WiHD due to the high frequency and the same strong attenuation.With both methods, signals according to the HDMI 1.4 standard can be transmitted.4K/30 is possible, 4K/60 or even 120, 8K or HDR is not.One use case for WiGig is the wireless retrofit kit for the VR glasses HTC Vive (test report).Here, too, problems arise if the line of sight is interrupted.WHDI (Wireless Home Digital Interface) relies on the 5 GHz band, which modern WiFi also uses.MiMo technology is also used here for the transmission of several parallel data streams in order to increase the bandwidth.WHDI offers the advantage that a direct line of sight is not necessary, and depending on the strength, the signal can also penetrate walls and ceilings.Depending on the manufacturer, the range is specified as 15 to 20 meters.More than Full HD including 3D content is not possible here.Because the frequency is the same as WLAN, there may be interference with the transmission, which should be minimized by using DFS (Dynamic Frequency Selection).If the distances get too long, repeaters can be used to amplify the HDMI signal.These little boxes take the signal, amplify it, and retransmit it.The idea is that these devices can counteract the damping.To do this, these boxes require an active power source, often they have either a direct power plug or a USB connection.So if you have a socket or a multiple plug with USB sockets (guide), you're in good hands.The amplifiers should be closer to the receiver than the transmitter.As with WiFi amplifiers (guide), HDMI extenders have a few pitfalls.First, you introduce an additional device into the connection and thus a potential source of error.In addition, no devices currently support the HDMI 2.1 standard, making them unusable for next-gen content.AirPlay 2, Miracast, Chromecast and Wireless Display Adapter do not use dedicated transmitters.Such dongles are therefore unsuitable for operation on the AV receiver as a distributor for televisions or projectors.It can work the other way around: connect Chromcast and Co. directly to the projector and use the streaming function, which is increasingly found as a built-in solution in AV receivers (guide), works.Or the other way around: TVs are now the majority, and this also applies to some projectors. This means that content can be transferred directly from the smartphone or tablet to the big screen.However, HDCP-protected videos (High-Bandwidth Digital Content Protection) in high resolution can cause problems and the output device must be HDCP-compliant.The data transfer also does not succeed uncompressed.In addition, this only works from cast-enabled apps such as Netflix or YouTube, since the content is not transmitted directly from the smartphone.Instead, the smartphone only selects what is to be watched, and the dongle then fetches the content via the Internet.Internet tabs in the Chrome browser are an exception.Conversely, this means that not every content can simply be viewed from a smartphone on a television or projector.Chromecast Ultra is now also capable of 4K and Google Chromecast with Google TV can now stream itself, like Amazon's FireTV sticks, without a smartphone having to be involved.However, all screen content can be mirrored with Miracast.The cross-manufacturer standard of the Wifi Alliance is generally supported by global players such as Apple, Google, Microsoft, Samsung and many more, but Apple relies fully on its own AirPlay standard and Google on its Chromecast development.Miracast resolution is limited to Full HD.Like Google's Chromcast, Apple's AirPlay understands 4K and even HDR.Microsoft's wireless display adapter now also offers 4K, but only with 30 frames per second and, like AirPlay and Miracast, on which it is based, allows any smartphone content to be mirrored on a large display.The third alternative is HDMI powerline and HDMI Ethernet adapters.Here, too, you can't do without cables, but the biggest advantage is the fact that at least power cables should already be available - after all, AV receivers and televisions/beamers need electricity.The transmission quality depends heavily on the wiring in the house.This works best when the transmitter and receiver sockets are in the same circuit, i.e. "on the same fuse", but at least are connected to the same FI.Theoretically, transmission to the next room is then no problem.Manufacturers like to talk about lossless transmission and ranges of up to 300 meters, but what is usually meant here is the transmission of Full HD signals.It is similar with HDMI Ethernet adapters.If you are looking for a way to transmit image and sound wirelessly to a television or projector, you will find it.However, there are a few things to consider: 4K/30 is the maximum, it becomes difficult even with HDR content.If you even want to connect a current next-gen game console such as Xbox X (test report), Xbox Series S (test report) or the Playstation 5 (test report) without a cable, look into the tube.Because they require HDMI 2.1 for 4K/120 and that is simply not possible wirelessly at the moment.With the existing wireless technologies, interested parties also have to pay attention to a few things such as range and placement.It should be clear that you have to dig deeper into your pocket to gain the convenience of not having to lay a cable.This appears to be having an impact on the spread of this technology.For this article, several manufacturers had declared on request that they no longer wanted to supply test devices because their products were "end of life", i.e. no longer produced.Successors don't seem to be in sight.So those interested will have to settle for what's available and hurry to grab any wireless technology that's still out there.As surprising as it may sound, it currently looks as if an “old” technology, namely the cable, would prevail.That's why we definitely recommend taking a look at the article HDMI cables from 5 euros: Differences, HDMI 2.1, 4K, HDR.A look at our home cinema theme world is also a good idea.We have published further guides there, such as loudspeakers, subwoofers and AV receivers: You really need that for good home cinema or Yamaha, Denon, Sony & Co.: That is why audio receivers need eARC, WLAN and Dolby Atmos.- The links marked with are commission links (affiliate links).If an order is placed via such a link, TechStage receives a commission.This does not result in any additional costs for the buyer.