Releasing some code, made a web page for xpsa 'Xwindows Panteltje's Spectrum Analyzer'.
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Nothing new, revolutionary, or from other planets, but it works for me.
I cheated as I did not want to re-invent the wheel, so for radio I call sdr_fm. But rtl_fm tunes to a different frequency 'to avoid aliases' or whatever, and that changes the spectrum. So as rtl_fm works OK, I stop the spectrum display in radio mode.
Need to move on, needed the analyzer, not the radio.
The software requires xforms, which is not a commonly installed program. It is easily compiled.
The makefile has a bug in it. It tries to make a "man" file and crashes. The work around is to "make xpsa" rather than just make.
The program looks for a number of files: /setup/fontsizes /setup/general_settings /setup/search_settings /setup/beep_mode
The program can't open xpsa.xpm
It does find the dongle. Error message [R82T] PLL not locked for 305800Hz start_sdr(): failed to set center freq. xpsa: main(): could not start sdr thread, aborting
In bash, you will probably have to use the export command to get the program to run if xforms is not "native" to your installation. That is, the libform will go in usr/local/lib64 in my case.
Now that the price of setting a SDR is $10 on ebay, it is work getting one for hacking. But real hardware in most cases is better, mostly because these SDRs have no prefiltering. Regarding power, at the moment real radios win. Plenty of radios run on less than half a watt. With SDR, you are at least a few watts, and that is provided you are using a low power ARM type SBC.
Version 0.2 now on my site. Fixed some GUI stuff, added a 'harmonic' button system. This can select, by simply pressing a button, the second, third, up hundreds harmonic of the frequency you are looking at, and display the spectrum at that frequency. By setting gains to manual you can then easily see how much your harmonics are down.. It better than a wide scan, as that mostly contains info you do not need. And no need to type in anything, just press the next harmonic or previous harmonic button. The bandwidth at each harmonic is maximal about 1 MHz. I tried the tenth harmonic of 107.2 MHz.... Its cool :-)
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