The Toshiba 425CDT notebook computer has no external DC power mode that would allow long term use directly on batteries. The battery is only good for about 2 hours of processing and the Lithium Ion batteries are expensive. It has a built-in AC switching power supply to run the computer off of line voltages and to charge the Lithium Ion battery. This supply generates moderate levels of LF interference. The noise seems to come out of the notebook at the AC power line connector.
Future use needs to look at some filtering.
A minor roadblock is that the AC connector is only two pins without a chassis connected pin. The ability to reduce this might help to improve signal to noise ratio in the LF case. The program was designed for weak signal detection on EME systems and the 2 Hz was probably dictated by the signal Doppler spread on an EME path. So far we have observed slow propagation fading which would indicate low Doppler spread. The program is compatible with the built-in sound card of the Toshiba 425CDT notebook.