StereoTool has an in-built RDS Encoder, with support for a decent set of options. We even have support for StereoTool in MetaRadio – allowing you to send now-playing data from your radio automation system.

Trouble is, the StereoTool interface doesn’t show all the different data it’s outputting. If you have a modulation monitor and 192Khz soundcard, you could connect the MPX output to that, but it’s not very practical when you want to keep everything in software (not to mention the cost).

Thankfully, we can easily connect StereoTool to RDS Spy – a software-based RDS Decoder.

To make this connection in software, we use another free tool – Breakaway Pipeline. Breakaway Pipeline is like the excellent VB Audio Cable, but it works at 192Khz sample rate (necessary for full MPX transmission).

Step 1: Download and install the software

Before we get started, install the following three programs on your computer:

Step 2: Configure Breakaway Pipeline

Open up the Breakaway Pipeline Control Panel. We need to change three settings:

  1. Maximum Sample Rate = 192000
  2. Maximum Bit Depth = 32
  3. Minimum Number of Channels = 1

Once you’ve changed these three settings, press the ‘Set’ button (half way down the screen, on the right).

Step 3: Configure StereoTool for MPX Output

Next, we need to configure the Output Soundcard in StereoTool. This is fairly simple.

First, go to I/O > FM Transmitter, and check the box that says ‘Enabled’.

Next go to I/O > Sound Cards > FM Output. Change the ‘Device ID’ to ‘Line 1 (Breakaway Pipeline) WASAPI 192Khz‘. You’ll also need to check the box above that says “FM Output”.

Step 4: Enable RDS Output in StereoTool

To enable RDS Output in StereoTool, go to I/O > FM Transmitter. Check that box that says ‘Encode RDS’.

You may also wish to enable additional features, such as RadioText. Go to I/O > FM Transmitter > RDS. Check the various boxes to enable the appropriate features.

Step 5: Connect RDS Spy

The last step is to connect RDS Spy to the Breakaway Pipeline.

Go to Configure > Select RDS Source.

In the screen, select “Sound Card”, specific the input audio device as ‘Line 1 (Breakaway Pipeline)’, and the Input Mode as ‘Direct RDS/MPX (192Khz)’.

Once you press ‘OK’, you should see the group counter start incrementing, and various RDS details appear in the interface.

That’s it! This is all you need to know to connect StereoTool to RDS Spy. Savvy readers would also recognise this technique can be used to send the MPX signal other places too – such as a streaming encoder.