FW: [Elecraft] Spectrogram plot interpetation

[Jim Brown]

On Sat, 3 Jan 2004 13:40:37 -0500, Guy Olinger, K2AV wrote:

>I have that same spike there. It goes away when I unplug the power
>supply and run on the internal battery.

The fact that it goes away when you run on battery confirms that it's
hum current on the shield of the interconnection to the computer, and
has NOTHING to do with the filter capacitor in your power supply.

>The large spike is at 120 Hz, and there is a much smaller one at 60
>Hz. Need more filtering on the power supply. 

Jim K9YC