Repeater system configurations

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The BATC repeater controller is designed to be a flexible but basic controller and requires to be configured with audio and video switches to become a complete repeater.

This page shows some typical configurations.

Basic HDMI repeater

This example uses a standard seamless HDMI switcher controlled by Infra Red with 4 inputs, one of which is the HDMI output of the controller RPi. An example fragment of the config file for this configuration is shown here Repeater system basic IR configuration.

Basic HDMI repeater with buffer

Experience has shown that although the switches are advertised as seamless, the switch between sources is not truly seamless.

This glitch is enough to cause any encoder following the switch to hang up. This problem is solved by using another HDMI seamless switch (#1) as a buffer between the main switch (#2) and the encoder. This may seem extravagant but is cheaper than a designed HDMI buffer!

HDMI repeater with Quad view

In the Basic HDMI repeater design above, the controller HDMI output is connected to the main switch, limiting the number of inputs available for recievers etc to 3. One input on the quad view facility would always show the controller.

To increase the number of inputs, a 3rd HDMI seamless switch is connected to input 2 of the 2nd HDMI switch. The repeater controller IR commands for any of those inputs and the quad view are set to also include the command to set the 2nd switch to the correct input.

Additional inputs can still be connected to the spare inputs on switch #2 but will not be seen in the quad view.

An example fragment of the configuration file for this, more complex, configuration is illustrated here: Repeater system full quad view IR configuration.

Audio switching

In the basic configuration, all audio switching is by the HDMI switch.

However, when using a quad facility, most HDMI switches will only carry the main audio channel meaning audio from any other receiver is not heard making the multiple receiver quad view useless.

To overcome this, the BATC controller will also command an external i2c controlled audio switch. It has been designed to be used with this switch DATV repeater audio switch

Using this audio switch, all analogue audio inputs are routed to the switch. When quad is selected, the controller will switch all 4 audio sources to the output.

Note - This configuration does require the use of an encoder with a separate analogue audio input. The Chinese encoder box use by several groups has this facility. https://www.aliexpress.com/item/4000645870955.html?spm=a2g0o.9042311.0.0.dab94c4d4GjfHS

Talkback audio

Most ATV repeaters carry the talkback audio channel (144.750) on a separate audio channel. Using the Chinese encoder box, this can be input as 1 channel on the analogue audio input.

DTMF control audio

The BATC repeater controller uses an onboard DTMF detector which detects DTMF from the mic input on a USB audio dongle (using a standard Portsdown white USB dongle). This can be fed from the main input audio, 144.750 rxr or a separate control rxr.

Analogue video switchers

The controller is designed primarily for use with an HDMI video switcher.

However, the controller does also output the video switch command as GPIO hardware switch lines. These can be used to drive an analogue video switcher.

A future release will be able to control video switchers via i2c.

Currently, the controller graphics output is HDMI only. The ability to output composite video may be included in a future release. However, HDMI to composite converters are easily available and can be used to generate PAL or NTSC graphics.