Rangecast FAQ
[FAQ-1230] Selecting the correct audio input for a VOX audio source



On some PCs recording audio from an audio source that is not a radio scanner, the Rangecast software must be set to identify the correct audio input to be monitored. Windows sometimes renumbers the audio inputs, breaking a working configuration and requiring manual correction.


Audio sources that are fed into Rangecast, but do not come from scanner radios over which the PC has remote control, are called VOX sources. From VOX sources, the PC determines the start and end times of each recording based on the audio level, trimming out periods of silence, and recording intervals with active audio.

Because the origin of VOX audio is not under PC control, the PC cannot automatically recognize the correct audio input (with scanners, this is done automatically by the software observing which audio input follows the command pattern as the radio is told to be noisy or quiet.) Therefore the choice of audio input must be made manually.


If the wrong audio input is selected for a VOX source, then you will not get recordings from that source over Rangecast. If the currently selected audio input is connected to a different device (such as a scanner radio), you may get recordings from this other audio source carried over Rangecast with the incorrect channel ID of your VOX source.

Windows sometimes renumbers audio inputs on its own initiative, so this symptom may occur from time to time, requiring manual correction. Some PCs are stable for years, others renumber audio inputs at semi-regular intervals, there is no known cause.


To change the specific audio input associated with a VOX source:

1) On the feed site PC, launch Rangecast and press CONFIGURATION.

2) Wait for the polling of hardware devices to complete ("Port Tests Complete" in the upper-left corner.)

3) Observe the "Special Settings" text entry box in the upper-right. For example, if Rangecast sender ID 12 is currently recording from audio input 4, then there may be text like "12:vox=4" in that box. (There may be other commands as well, each command separated with a comma.) For VOX sources, the default is audio input 0 (described below). If there is no command shown of the type "12:vox=4" then the PC is currently configured to use audio input 0 for the VOX source.

4) To select a different audio input (they are identified by number) you can change the number in the text box (e.g. "12:vox=3" to select audio input 3), then press SAVE. Wait for the polling of hardware devices to complete ("Port Tests Complete" in the upper-left corner), then close the software, and restart normally.

There is little guidance available for choosing the correct audio input.

If your PC is also connected to scanners, the Configuration screen will identify the audio inputs detected automatically for each scanner radio (for example, if you see A2 on the row for a scanner, that means audio input 2.) Since these audio inputs are known to be connected to radios, you can exclude these inputs from consideration.

The PCs "native audio input" (hardware internal to the PC, not an external sound card) is often identified as audio input 0. Other audio input numbers start at 1.

So if you are hunting for the correct audio input ID, it makes sense to start at 0 or 1 and work up (0 or 1 depending on whether the audio source is connected to the native sound card, or an external sound card), skipping any inputs known to come from scanner radios, until you get the expected results. The numbers for audio ports will not go higher than the number of actual audio inputs available on the PC.




Rangecast FAQ - ID 1230 - last updated 20 November 2018     Images shown - [block]