Hello Again,
I just verified that the noise happens when the headset microphone is disconnected. Actually, the noise gets much louder with the microphone unplugged from the dongle. I unplugged the AC power from the laptop and the noise went away!
My friend had the dongle originally and I just have had the opportunity to test it locally. The noise appears to be coming from the AC adapter for the laptop. My friend had tried it on his desktop and had the same problem with noise. I did replace the USB cable that connects to the dongle with a known good one and verified that the noise is still there.
So, in conclusion, the dongle appears to work just fine without the AC connected to the computer. When the AC adapter is connected to the laptop AC hum is transmitted over the microphone input to the dongle. I will install it on my desktop sometime today and verifiy that I am having the same problem using the desktop computer as my friend did.
73, Joe, K1ike