Noise spikes on board, System Blue

[Jorgeminator]

I'm seeing noise spikes which appear on the board. These spikes still appear with the H-field pre-amplifier unplugged. I'm guessing this could be the result of me not grounding the board? It only happens on channel 1A.

What are you using as an oscilloscope ?  I'm interested in getting one and would like some ideas of what to start looking at

Thanks
Michael

No oscilloscope, the signals can be viewed through the web interface   
If there's a lot of lightning activity it can be difficult to spot the "false positives" since the signals stay on the screen only for a fraction of a second.