A video sender is a device for transmitting domestic video

Video

Video is the technology of electronically capturing, recording, processing, storing, transmitting, and reconstructing a sequence of still images representing scenes in motion.- History :...

 signals wirelessly from one room to another, as for example sending the output of a satellite TV decoder located in the lounge, to a television set

Television set

A television set is a device that combines a tuner, display, and speakers for the purpose of viewing television. Television sets became a popular consumer product after the Second World War, using vacuum tubes and cathode ray tube displays...

 in the bedroom.

Some video senders also incorporate a return path, to permit infrared remote controls to operate the equipment whose output is being sent.

The equipment requirement is usually either SCART

SCART

SCART is a French-originated standard and associated 21-pin connector for connecting audio-visual equipment together...

 (Europe) or composite video

Composite video

Composite video is the format of an analog television signal before it is combined with a sound signal and modulated onto an RF carrier. In contrast to component video it contains all required video information, including colors in a single line-level signal...

.

Video senders are usually analogue TV, and may be subject to RF interference from other household wireless appliances such as cordless telephone

Cordless telephone

A cordless telephone or portable telephone is a telephone with a wireless handset that communicates via radio waves with a base station connected to a fixed telephone line, usually within a limited range of its base station...

s or wireless network

Wireless network

Wireless network refers to any type of computer network that is not connected by cables of any kind. It is a method by which homes, telecommunications networks and enterprise installations avoid the costly process of introducing cables into a building, or as a connection between various equipment...

s. These devices are also one of the main causes of interference to WiFi

WIFI

WIFI is a radio station broadcasting a brokered format. Licensed to Florence, New Jersey, USA, the station is currently operated by Florence Broadcasting Partners, LLC.This station was previously owned by Real Life Broadcasting...

 networks. More information can be found in the article on electromagnetic interference at 2.4 GHz

Electromagnetic interference at 2.4 GHz

Electromagnetic interference at 2.4 GHz can affect various devices.This article details the different users of the 2.4 GHz band, how they cause interference to other users and how they are prone to interference from other users.-Phone:...

.

To avoid this, some video senders now use the less-used 5.8GHz ISM band

ISM band

The industrial, scientific and medical radio bands are radio bands reserved internationally for the use of radio frequency energy for industrial, scientific and medical purposes other than communications....

, but these are not legal in all the countries that use 2.4GHz ISM for videosenders.

They can suffer interference from WiFi, or disrupt WiFi. See http://www.techtir.ie/tv-radio/video-senders for explanation and mitigation

Usually there are four FM transmit channels, A, B, C & D, with L & R audio on 6.0MHz and 6.5MHz FM subcarriers added to the composite video baseband. The reverse remote control channel is usually 433.92MHz, fixed, using whatever modulation is on the 34kHz to 45kHz IR remote "carrier". ASK/OOK schemes such as RC5 and RC6 work best over the RF link as the receiver uses a data slicer and AGC designed for ASK/OOK with Manchester encoding.