DStar peculiar audio distortion?

[Wayne_H]

In my recent listening to a couple of local DStar repeaters, I sometimes hear a peculiar type of audio distortion. It sounds like an extreme nasal whine, or like someone is talking through a kazoo. Sometimes this distortion is mild, and sometimes it is bad enough that you can barely tell that it is someone talking at all, and not just some extraneous noise. Most of the DStar audio that I hear is very clear, and I have not yet figured out any commonality that might be causing the distortion, but that may be because I don't listen to DStar all that much.

A few Internet searches didn't turn up much. Most indications are that any of the digital modes either work, or they don't. There seem to be some differences of opinion on range and sensitivity, but I didn't really find anything that fit the description of what I have been hearing. I only have one DStar-capable radio, so maybe it is just my radio (Kenwood TH-D74), or my particular setup, but somehow I doubt it.

Or maybe my Internet Search Foo is just not up to snuff these days.

Any ideas?

 

[N1FKO]

Your first challenge might be determining what the source of the audio is. Even though it's a D-Star repeater that you are listening to, networking means the original signal might have started out as different protocol and been processed by multiple codecs.

I've not heard the distortion you described on conversations using D-Star hardware (Icom or Kenwood radios). The digital modes tend to work right up until they don't, with a bit of choppiness and familiar digital artifacts right at the edge.