I have an Instek GDS-2202 digital storage oscilloscope. I am trying to figure out how to setup my scope to minimize the pick up of stray 60Hz mains signal. If I change my scope's vertical sensitivity to 20mV/div, then I can see the 60Hz signal. The signal's amplitude increases even more when I turn on my DC power supply. I can pick this signal up without even connecting the probes to anything.
Should I connect the oscilloscope to another outlet instead of putting it in the same surge protector? How do I minimize the 60Hz pickup?
Also, I have a programmable signal generator that is pretty accurate. I put out a 1 kHz sine wave test signal with a low amplitude (about 200 mV), and it seems like I have some display issues. On a Tektronix scope, this signal looks pretty stable. But on my GDS-2202 the signal drifts a lot, so instead of seeing one sine wave, I see a non-inverted and inverted sine wave on top of each other.
I am new to this and would like to learn from you about the proper way of setting up instrumentation equipment.