Winrad software is superb for analysing signals over a wide and narrow band width.
Comparing the background noise on my Dual Core high spec. Laptop which has a Realtek HD Sound card with no audio input.
With my Celeron processor desktop with Delta44 Sound Card set up exactly the same.
Speaks for itself .............. literally.
Yes there is a volume difference due to my recording process on 2 different set ups. On the second one there is a much louder nothing.
Yes I have a Compaq Armarda 500 lap-top and it refuses to decode JT2 but sends it happily. Yet an old Dell tower will decode without a cough..