SDR USB stick arrived, getting first spectra
Due to whatever I have now 2 RTL2832 USB sticks ./xpsa xpsa: start_sdr(): executing rtl_sdr -f 1575420000 -s 2048000 -d 0 -g 0 -b
262144 -n 0 - Found 1 device(s): 0: Generic, RTL2832U Using device 0: Generic RTL2832U (e.g. hama nano) Found Elonics E4000 tuner Tuned to 1575420000 Hz.That tuner is ebay item 221146636395. Very small, and very good.
./xpsa xpsa: start_sdr(): executing rtl_sdr -f 1575420000 -s 2048000 -d 0 -g 0 -b
262144 -n 0 - Found 1 device(s): 0: Realtek, RTL2838UHIDIR Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle Found Rafael Micro R820T tuner Tuned to 1575420000 Hz. Reading samples in async mode...That one with the R820T tuner chip was bought locally...
The 4000 tuner chip seems to be a better choice for spectrum analysis. Also seems to be more sensitive at around 1500 MHz.
All this software will need a lot of work... My program simply calls rtl_sdr, and does FFT over the samples in real time. Note the aliasing, and the mirror image, that needs to be fixed. This is L1 GPS spectrum from the main oscillator of my pseudo satellite, without modulation:
Lots of work ahead on this. I have rtl_fm (Linux) working to receive FM radio too.
So.. spectrum analysers do not have to be expensive. I have a RF converter now too, to go from DC and now up to > 2GHz, have not had a chance to test it yet (bought as a kit, connector was missing).
I wonder if the 4000 tuner chip can receive real GPS signals, I only see 1 bit noise ..... (hexeditor on rtl_srd output file). :-)
Maybe it needs a pre-amp. Somebody seems to have done it with some stick:
Hey, just having fun playing :-)