Spectrum Surveys using rtl_power

I have been doing various experiments with my RTL SDR dongle lately and wanted to see if there where any new software packages for these devices. I was primarily interest in scanners or methods to look at large areas of the spectrum, even if it took time to do the capture. There are some great capabilities within SDRSharp for scanning and capturing usage of those frequencies in the database, but I was interested in more of a continuous sweep.

It turns out that within the the osmocom drivers that most all RTL SDR dongle use there is a tool called rtl_power.exe. More details on rtl_power can be found HERE.

There are some GUI front-ends for rtl_power.exe that make it easier to use but running it at the command line has the most power. Use the GUI front-end to figure out what you want to do and then refine your capture at the command line was my approach.

The best way to get started using rtl_power with your RTL SDR dongle is to have a running installation of SDRSharp on you system. This is a quick way to know your dongle is working and to get all the drivers in place. Next, setup RTLPan per the instructions. This will get rtl_power on your system. Then using some of the examples on the rtl_power scripting web site you can begin your exploration. This was all done on a Windows 7 system but is available on Linux as well.

Here is a capture I did of the whole 2 meter band. Using the following command line:

rtl_power -f 144M:148M:5k -g 50 -i 10 -e 8h 2Mband.csv

The graphic below was processed using a Python script available HERE. The python script lets me view sections of the data collected above. Since I collected 8 hours of spectrum in the above capture, I used the following options in the Python script to produce this one hour segment:

python heatmap.py --begin "2015-01-11 05:00:00" --end "2015-01-11 06:00:00" 2Mband.csv 2Mband2.jpg

What you are looking for in the heat map plot is broken streaks that show usage of repeaters, etc. Since I was just using the tiny whip that came with the dongle it only hears strong signals. I did capture the usage of the 147.21 Mhz Sunset Repeater that is part of the WINS here in Southern California as well as another system streak that is the Keller Peak repeater on 146.385 Mhz towards the bottom center.

I think this is amazing capability for these inexpensive dongles and with the RTLPan GUI, a spectrum display is available as well. This could be useful for use with an HF up-converter on the dongle for checking the spectral response of HF transmitters and filters (poor mans spectrum analyser!).