Measuring the Return Loss of a Coaxial filter with an RTL Key , a Noise Generator an SWR Bridge , some software and a laptop
I ended now to test the possibility to measure the Return Loss of a coaxial filter with some simple tools , like an RTL Key , a Noise Generator and a SWR Bridge , a software and a laptop .
I have used the following setup :
Of course there are big limitations due to the Range of Visualization that an RTL KEY ( that works with 8 bit ) can handle ( around 40dB) respect a professional Spectrum Analyzer ( 100dB) and also the RTL KEY receive spurious signals and images . We have to take off all the AGC of the RTL Key to make measurements .
See for instance signals displayed with a range of 100dB and the range of 40 dB in evidence .