Recently I used the egg-beater antenna on the right, to capture more wideband signals in the 70cm band.  This design is based on the K5OE design  The horizontal tube above the ground plane arms contains a PGA103+ LNA. 


I've tried to write some octave scripts to identify LEO signals based on their time-frequency variations. This is more challenging than it seems due to the wide variation in satellite spectra.  The first figure below shows several hours of recording, with estimated LEOs marked in red symbols. This is quite a busy image, so the next figure shows a blowup of a small section. Observe that several LEOs have been located, but the algorithm has also made several errors.

Low cost SDR hardware makes it fairly easy to capture large bandwidths and look for interesting signals.   The figures below show plots of spectral peaks in the 70 cm amateur satellite band over several hours.  Since low-earth-orbit (LEO) satellites always approach the ground-station receiver then recede, their signals are Doppler shifted in a similar pattern.  (See this page for a brief review of Doppler.) 


The figures below show examples of LEO amateur satellites, with Doppler shifts of up to +/-10 kHz, over pass durations of up to about 15 minutes.  Rather than trying to capture a spectrogram (or waterfall plot) over several hours, these plots were generated by locating peaks about a given threshold, in each averaged power spectrum.  This gives a relatively compact spectral summary of the signals present.  In the first figure, by comparing the  pass times with satellite orbits from 'gpredict', some of satellites have been identified and labeled.  In addition to the satellite signals, various other stationary or transient sources of interference can be observed.  

A LEO Satellite 'Sniffer'

Blow up section of above, showing LEO satellites over South Australia, around 9pm March 4th, 2017,  A couple of LEOs around 437.35 MHz have been missed. 


With further improvements in the G/T and the LEO detection algorithm this might be a useful tool.  

First example of signals in 70cm satellite band