I noticed with another Nano DDS, I had serial monitor commands being processed in my sketch, even though I didn't have the monitor open. I was getting digital noise and couldn't figure it out where it came from. As it turned out, the serial monitor was causing it. Solution was comment out the serial monitor commands in the sketch.
On Fri, Jan 20, 2017 at 10:22 AM, Jim Schliestett <aekjrs@...> wrote:
Thanks, I¡¯ll try that. I wasn¡¯t really referring to the ¡°tuning tick¡±, but if your mod eliminates that, I¡¯m sure it will take care of my other problem too. I suspected the noise was getting into the power buss. Also thanks to the others who responded to my post.
I was able to silence the tuning "tick" by inserting a 22 ohm, 2 watt resistor in series with the Raduino power wire and connnecting a 470 uF capacitor from each end of the resistor to ground (One resistor, two capacitors.).? You can easily do this right on the back of the volume control/power switch.? This indicates that it is a power filtering issue. Lower values of resistor and capacitors will work but I have not determined the optimum values.? Some serious bypass treatment on both input and output of the Raduino's 7805 regulator should help.
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Another suggestion to reduce audio distortion is to connect a 10 uF capacitor between pins 4 (gnd) and 7 (internal bypass) of the LM386.
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K9AC
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I just finished adding the Raduino upgrade to my BitX40. I¡¯m having quite a bit of whining noise and ticking noise in the receiver from the Raduino. Anyone else experiencing that? I tried adding a bypass cap to the Raduino power lead but it didn¡¯t help.
