Today I finally found time to track down a useful radio frequency scanner for my software defined radio. Just for fun I tried to locate the radios used in the areas, and a good start would be to scan all the frequencies to see what is in use. I've tried to find a useful program earlier, but ran out of time before I managed to find a useful tool. This time I was more successful, and after a few false leads I found a description of rtlsdr-scanner over at the Kali site, and was able to track down the Kali package git repository to build a deb package for the scanner. Sadly the package is missing from the Debian project itself, at least in Debian Bullseye. Two runtime dependencies, python-visvis and python-rtlsdr had to be built and installed separately. Luckily 'gbp buildpackage' handled them just fine and no further packages had to be manually built. The end result worked out of the box after installation.
My initial scans for FM channels worked just fine, so I knew the scanner was functioning. But when I tried to scan every frequency from 100 to 1000 MHz, the program stopped unexpectedly near the completion. After some debugging I discovered USB software radio I used rejected frequencies above 948 MHz, triggering a unreported exception breaking the scan. Changing the scan to end at 957 worked better. I similarly found the lower limit to be around 15, and ended up with the following full scan:
Saving the scan did not work, but exporting it as a CSV file worked just fine. I ended up with around 477k CVS lines with dB level for the given frequency.
The save failure seem to be a missing UTF-8 encoding issue in the python code. Will see if I can find time to send a patch upstream later to fix this exception:
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/rtlsdr_scanner/main_window.py", line 485, in __on_save
save_plot(fullName, self.scanInfo, self.spectrum, self.locations)
File "/usr/lib/python3/dist-packages/rtlsdr_scanner/file.py", line 408, in save_plot
handle.write(json.dumps(data, indent=4))
TypeError: a bytes-like object is required, not 'str'
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/rtlsdr_scanner/main_window.py", line 485, in __on_save
save_plot(fullName, self.scanInfo, self.spectrum, self.locations)
File "/usr/lib/python3/dist-packages/rtlsdr_scanner/file.py", line 408, in save_plot
handle.write(json.dumps(data, indent=4))
TypeError: a bytes-like object is required, not 'str'
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