Rangecast FAQ
[FAQ-1068] Error Message: QUIET TRANSMISSIONS (Code 21)


Page Type: SYMPTOM


OVERVIEW

Quiet Transmissions means that a significant number of transmissions recorded on a scanner have had unusually low observed audio levels. The levels can be raised by adjusting a control in the Windows Sound user interface.


SYMPTOMS

In the normal default software configuration, transmissions with extremely low audio levels are rejected by the software (never sent into Rangecast). This is to screen out silent transmissions with no meaningful content (for example, mic clicks). If the audio level from the scanner is abnormally low, then real transmissions may be screen out by this filter, resulting in missing content on channels received by that scanner.

Note that since Multisync makes scanners collaborate on reception, so that each transmission is captured by only a single radio, this kind of error may result in missing content even if other radios in the same operational cluster are healthy. In other words, the presence of healthy scanners receiving the same content does NOT provide operational redundancy to mitigate the effect of this kind of error.


METHOD

Raise the audio levels in Windows Sound for the audio input from the scanner.


[FAQ-1067] Adjusting Windows audio input levels

The Rangecast audio recording process compresses audio to support a wide dynamic range, but if the levels are too high or low, quality is compromised (and some transmissions may even be discarded). A level control is available in Windows Sound to adjust the input levels from each scanner, and Rangecast provides information about observed levels to help determine when adjustments are needed.




It is recommended that the audio levels be checked on all scanners connected to this PC. When one scanner shows a "Quiet Transmissions" error, it is not uncommon for other scanners to have marginal quality audio levels (low, but not low enough to raise an alarm) that would benefit from adjustment. It is easy to check and correct the audio levels on all scanners connected to a single PC at the same time.


CITATIONS

INDEX


Rangecast FAQ - ID 1068 - last updated 02 August 2017     Images shown - [block]