31 August 2015

QYT KT8900 - digital noise on audio

One of the most noticeable defects of QYT KT8900 is a digital buzz that can be heard when the stock microphone is plugged in. This problem has been tracked down to the digital logic on the microphone communicating with the main radio board.

The picture shows how the loudspeaker signal looks like on an oscilloscope:

 

Spikes are about 25 mV peak, one every 3.5 ms or so. I couldn't get a stable trigger on the signal and the picture shows my best capture (100 MHz analog Tek, 100 MHz probe at 1x).

Any idea for a simple fix?

2 comments:

Jacob Reiding said...

Same here... I bought one today so I haven't got the time to find a solution. I'll look into it...
www.amateurtele.com

Paolo said...

After one year of mobile use I must admit that I do not hear the digital noise anymore. It IS there, but my brain filters it out especially on a busy frequency (and a noisy car).

Too bad QTY has not taken the time to fix the issue. And I guess all other problems are still there too.