An audio video transmitter, known as av sender, sometimes called a wireless tv transmitter, can be used to share the satellite TV connection in the living room with a TV in the bedroom or kitchen without moving any devices, and one set av sender contain a transmitter and a receiver. This can be a great convenience for people who have multiple televisions in their houses, and do not want to have to move a device like a DVD player from room to room, unplugging and plugging in cables and power cords, just to watch a movie on a different TV. Instead, users can send the information to the other television using an audio/video transmitter.
Transmitters are devices that broadcast a signal from one device to another, creating a larger distribution network and allowing more devices to connect to the service. Because they combine wireless technology with basic television technology, the specifications listed can be difficult to understand. Below is an explanation of each specification area and what to look for when making a purchase.
History of Transmission
The modern audio/video transmission system did not begin until 1936, when Don Lee began demonstrations and prototype testing for a broadcasting system that transmitted 30 lines. These transmissions contained only black and white images. The first color transmissions began in 1954, when compatible TVs became available on the market. Black and white transmissions were completely ended in 1975. In the mid-1990s, many stations began updating to
digital service, and offered users a digital option. In 2009, the United States eliminated
analog video transmissions, and began transmitting solely in digital.
Different Specification Areas
There a variety of different specifications that a user needs to be familiar with before purchasing a
wireless av sender.
Transmission Method
Today, there are two main types of transmission used, cable transmission and
wireless transmission. Cable transmission uses common
coaxial cable to connect the transmitter and the receiver. Wireless transmission systems use wireless radio signals, much like a
wireless router, to transmit the information to the receiver. Some older video/audio transmitters also used infrared signals to transmit information. When using infrared technology, the transmitter and receiver had to be in direct line with one another without barriers for information to be transmitted.
Wireless technology rapidly made these infrared devices obsolete. When looking at various audio/video transmitters, consider the transmission method that will
work in the locations where the transmitter will be used.
Watts
Video transmission systems for home use are available in one, two, and five watt varieties. Long-distance systems designed for business use, however, are available in 10 and 20 watt as well. The number of watts relates to the amount of power needed for operation and can affect transmission distance; however, a two-watt system is capable of
long distance transmission, so users need not be concerned with low wattage affecting performance. A low-watt system will save users money because they impact electrical bills less. Typically, one watt will transmit over 1000 feet, three watts will transmit over seven miles, and 20 watts will transmit over 50 miles. When looking at audio/video transmitters,
choose the lowest wattage possible to save on electrical expenses while still covering the necessary distance.
Frequency
The system's frequency dictates what radio frequency is used to transmit information between the transmitter and the receiver on wireless transmission models. If the transmitter is running on the same frequency as other household devices, it will cause interference and degrade the quality of the sound and video being transmitted. Common frequencies include 900 MHz, 1.2 GHz, 1.3 GHz, 2.4 GHz, 5.4 GHz, and 5.8 GHz. Which frequency is best for a user depends on what else is being used in the space that could cause interference. Many radios run on the 2.4 GHz bandwidth, as do remote controls, microwaves, phones, and even wireless routers. It is illegal to use 1.2 GHz devices in the United States because it is a reserved bandwidth. As a general rule, the higher the frequency of the audio/video transmitter, the less likely it is to experience serious interference from other devices in the home, and the more robust it is, making it less likely to deteriorate as it passes through barrier objects. Because of this, buyers should consider higher frequency audio/video transmitters and those on frequencies that are not already being used in the home or office
to avoid interference problems.
Range
Range determines the number of feet the audio/video transmitter will spread the information. All receivers working from the transmitter must be within this range to receive a strong and uninterrupted signal. Range is determined by a combination of the wattage, frequency, and signal strength emitted. Remember that the range given in the specifications section is a maximum range and is only an estimate. If there are barriers in between the transmitter and the receiver it will shorten the range; this happens because the signal strength will be lost to some degree as it passes through the barrier.
Number of Channels
Channels are labeled with letters rather than numbers, and do not refer to the number of television channels they can transmit; rather, changing the transmitter's channel means altering what air channel the transmitter is sending signals in. The transmitter and receiver must be set to the same channel for information to be appropriately transmitted. Small transmitters may only use one or two channels, while long-distance transmitters may have up to eight channels, such as PAKITE wireless av senders are 8 channels. By changing the channel that the audio/video transmitter is using, the user can eliminate part or all of any interference that is experienced and improve picture and sound quality.
Maximum Resolution
Resolution is a measure of lines being transmitted to a device. Keep in mind that the earliest transmissions had only 30 lines, and that the standard analog TV has 460 lines of color. Today, televisions typically have between 760 and 1080 lines. This number is also accompanied by a letter: p stands for progressive scan, and i stand for interlaced lines. Resolutions with progressive scan technology create a better picture than those with interlaced lines. It is important that the maximum resolution transmitted by the audio/video transmitter is at least as high as the resolution of the television being transmitted to. For example, if a television has a resolution of 760p, there is no need to have a transmitter that transmits at 1080.
1080p is the highest current resolution for high-definition televisions and transmitters.
Dimensions
The dimensions given, typically in millimeters (mm) or centimeters (cm), are the physical dimensions of the transmitter. These are important to know if the user has a specific space in mind for placing the transmitter and needs to make sure that the transmitter selected will fit. Dimensions are typically given in the LHW format, which means the first number given is the length, the second number given is the height, and the third number given is the width.
Transmitter Input Connection and Receiver Output Connections
The transmitter must be able to connect to the signal source, like the cable or satellite box, and the receiver must be able to connect to the television or viewing device. Below is a chart that shows the most common cable types, how they can be recognized, and what information they transmit. Make sure that the transmitter and receiver are fully compatible with the signal source and the viewing device before selecting a transmitter for purchase.
Cable Type
|
How to Recognize It
|
Information Carried
|
|---|
Coaxial Cable
|
This is a traditional antenna or satellite cable. It has a single pin in the center of a screw-on metal end.
|
Carries both audio and video in a single wire
|
Composite
|
RCA or AV port. Video is marked with a yellow end, and sound is marked with red and white, for the left and right sides.
|
Carries video and audio when all three cords are used in tandem. Some cord sets are individual and some are permanently bound by a plastic exterior.
|
S - Video
|
Has a 4-pin plug-in style connector.
|
Transmits video only; sound must be transmitted via composite sound cables.
|
Component
|
The cables are color-coded: blue, green, and red.
|
Three separate cables are used to carry brightness, color, and luminance. Red and white composite cables must be used for sound with this video system.
|
|
|
Multi-pin, long flat connection used to connect most high-definition devices.
|
The highest quality, highest speed cable connection. It's just used for HDMI av sender. It is only compatible with high-definition devices. |
USB
|
Rectangular USB end, like those on the end of flash drives and other computer products.
|
Sends both audio and video information using a high-speed USB cable. Useful in connecting to computers and projectors. Also necessary to load updates on updatable transmitters.
|
When selecting an audio/video transmitter, buyers should be sure to choose a transmitter with the right
connections for both the signal source and the receiver television.
Repeater Specifications
Transmitters may or may not come with a repeater. A repeater is exactly what it sounds like, a device that repeats the single being transmitted. A repeater connects to the transmitter remotely, and sends out a duplicate transmission signal. This means that it expands the range and enables devices that are outside of the transmitter's range to pick up the repeater's signal and access the information. They must be programmed to the same channel as the transmitter and the receiver.
