[Elecraft] serial interface noise on 160m -- propagates through K3 to coax cables and grounds...

[Mitch Mitchell]

Hello, 

I have been hearing an annoying noise on 160m that has a pulse rate of about 1/3 of a second.   After observing the behavior when I do certain things with my K3 and my computer I found that the source of the pulsing is Ham Radio Deluxe polling the K3 for VFO changes -- it polls every 300ms.  However, when HRD is shut down (no other serial port activity) the noise is still present as a constant tone with no pulsing effect.  My first suspicion is the USB to Serial adapters on the computer, but I am also thinking that maybe the noise is coming from the USB hubs or their wall warts.  I can hear the noise on the K3, my winradio, and my handheld (which is picking up the noise on 80m).  I was wondering if anyone has seen something like this and whether this might be coming from inside the computer or the USB hubs.  I am going to pull out my desk from the wall and start tracking this down to the source but I wanted to see if anyone else had experience with this sort of thing and any thoughts or recommendations?

Best Regards,

Mitch Mitchell
AE5HO
mitchmitchell1616 at msn.com