Last stored 24 hours:
These are not always contiguous or current, depending on my experimentation. Check the times and dates on the images.
The Signal Grabber employs a 2 meter whip mounted above the roof of my home. FET amplifiers buffer the signal to drive an HP3746A Selective Level Meter tuned to the indicated center frequency. The antenna circuit is isolated from the meter and computer by a video isolation transformer. A computer runs Argo to display the spectrum around the center frequency and an Image capture program (Irfanview) saves the image to a Dropbox folder every hour.