Page Type: SYMPTOM
The 'DC Offset on Audio Input' error message indicates an electrical anomaly on the audio line from the scanner to the PC
A high DC offset on the audio line connecting the scanner and PC may interfere with the ability of the Rangecast software to automatically determine that this particular audio input is coming from a specific scanner radio. In particular, there are times when the scanner is silent, but Windows will see the audio line as carrying a background spurious signal, so the scanner will never appear to be silent to the Rangecast software. In severe cases, this may result in a No Audio Port message (possibly at different times than when the DC Offset is indicated.)
[FAQ-1014] Error Message: NO AUDIO PORT (Code 26)
The 'No Audio Port' error occurs when the Rangecast software is in communication with the radio scanner (over the com/data port), but is unable to find an audio input to the PC that appears to have this scanner's audio output. Therefore, Rangecast cannot capture the audio content from transmissions received on this scanner. The most common causes include a problem with the Windows audio or USB system, or a loose connection on an audio cable or to a sound card within the interface box. (Note this error does not mean that the audio port does not exist, but that the audio port cannot be located by software. This could be due to the port being missing, or an audio cable being disconnected, or a volume level problem resulting in no audio reaching the PC.)
If a "No Audio Port HNP" message is shown for any scanner connected to the same PC, that should be resolved first. HNP relates to a connectivity problem that can create the appearance of spurious audio levels, so an apparent DC Offset may be a phantom side-effect of the HNP issue.
If no HNP is indicated, then the first step is to reboot the PC and see if the DC Offset issue persists. If it does persist, then the likely recommendation will be to replace the external USB sound card connecting the PC and scanner.