After moving into a new house I plugged my oscilloscope in and turned it on. After booting there is a constant 1.4-2.0 MHz signal being picked up. If I ground the scope with my hand on the probe lead it doesn’t produce the expected mains hum.
Disconnecting the probe however produces the mains hum as expected.
I have tried switching probes, channels, and plugging it into a socket directly instead of a surge protector in case the surge protector earthing is bad. None of it solves the problem. Holding the probe up to various electronics equipment doesn’t produce a difference in signal. Raising the probe up and down seems to alter the amplitude but not the frequency.
What could be the issue? This is rendering my scope unusable.
I am using a Rigol DS1054Z. I have driven around a few blocks in any direction and I don’t see any towers that would be a source of distortion. I am near a WiFi router (the one I’ve always had) but that is operating at 2.x and 5.x GHz.
I am operating the probe in 10x but turning that off doesn’t do anything.
The period of the signal is around 500-900ns. The frequency varies between 1.13 and 2.59 MHz.
Took a multimeter to my sockets and discovered while it appears to be grounded, hot and neutral are reversed.
It would appear my oscope is ok. Connecting probe to test and grounding the plug on one of the bnc channels produces a clean square wave after hitting “auto”. Will need to construct a loop antenna to find the source now.