A few days ago an RTL-SDR experimenter named Oliver managed to (incoherently) combine the bandwidths of two RTL-SDR dongles to create a 4.4 MHz FFT display in GNU Radio. Now Oliver has taken this idea further and produced an updated version of his GNU Radio program. Continue reading
The maximum usable and stable bandwidth of an RTL-SDR is about 2.4 MHz. In order to get larger bandwidths it is possible to combine two or more dongles, although doing so comes with a big limitation – since the clocks and signal phases between separate dongles would not be synchronised, it would be impossible to decode a wideband signal this way. However, combining dongles for larger bandwidths is still useful for visualizing the spectrum through an FFT plot, or perhaps for decoding various separate narrowband signals. Although creating a wide band FFT plot with multiple dongles is fairly simple, we haven’t seen much software do this before.