Recently, I have noticed a few electrodes (often close to each other) showing the 60Hz noise problem that has been discussed before (viewtopic.php?f=1&t=631&hilit=60hz). Unlike the previous thread, I am not seeing it over all channels, but just at one or two sites. Sometime applying new gel to the offending site clears it up, other times it fades with time or remains throughout recording. Is this a case of not bundling the electrode cables (as mentioned in the previous post) or something else?
Thanks!