I have a Stanford SID Monitor, the small one in the round casing. It all worked nicely, and suddenly, it does not anymore.
Normally you see the day/night cycle of the ionosphere, but that is gone now.
If I detach the antenna, the live signal changes. If unplug the monitor from the power supply, the signal changes. So it appears to work, but the resulting signal is just not there anymore.
Did some of you maybe have the same error once? Can it be, that the monitor is just broken?
Could you please post the SuperSID spectrum plot? That might help identify the problem. It could be a change in the sound card settings. Which operating system are you using? What Naval transmitters are you observing, and where are you located?
I guess you mean frequency vs. amplitude?
This is a plot of the data averaged over one day, from april 3rd, where it still worked.
And this is from 23rd of August:
I am located in Germany, actually I dont know which station I am using. I tried different directions since then. It runs on a raspberry pi with a cheap usb soundcard. Nothing should have changed, because it runs day and night... and suddenly the day/night cycle was gone
Maybe the Ionosphere is gone :D kidding.
Looks like you had a very strong signal around 18 kHz, which may have been a transmitter in Russia, perhaps RDL. These tend to be unstable, or may even be mobile! Take a look at this frequency list for Naval station transmitters: https://sidstation.loudet.org/stations-list-en.xhtml
You might edit your config.cfg file in the configurations folder to record data from one of the other European stations like GBZ (19.8 kHz), ICV (20.27 kHz) or GQD (22.1 kHz), as there looks to be some weak signals above 20 kHz in your more recent plot. It's important to point your loop east-west to pick these stations up (except ICV), so you might experiment with pointing the loop in different directions, and watch the spectrum plot.
Can you post a picture of your antenna?