Which Version Do You Need, Stereo? or MPX?

Stereo with Audio Processing and Limiting

Most small radio stations and beginners will use this version, this is because it includes audio processing circuitry and suitable limiting to keep the transmitter in compliance with the maximum bandwidth permitted by the international regulations. There is also access to the MPX in and out on the back panel which allows all known RDS units to be connected


MPX Composite Input

This is the low cost version, but is not intended for the novice or beginners. The audio input is raw MPX without any audio limiting or stereo coder circuitry, this must be provided externally in accordance with the recommendations of:
https://www.aareff.com/ETR132.pdf


Stereo Version

This is identical to Mono/MPX version but with a stereo coder built in. RDS cannot be used with this. Again it does not include audio limiting, so it's not recommended for the novice or beginner. External limiting need to comply with the recommendations of:
https://www.aareff.com/ETR132.pdf


Mono and Audio Processing

This particular version is in mono only, so it not suitable for music stations. This would be used for talk stations, church broadcast etc. It includes audio processing circuitry and suitable limiting to keep the transmitter in compliance with the maximum bandwidth permitted by the international regulations and is suitable for the novice or beginner.