2 out of 3 gains function in Gnuradio for Airspy

Martin Smith martin_z_smith at yahoo.ie
Tue Sep 1 06:06:30 UTC 2015


Hi,
There are three gains in the Airspy LNA,MIX and IF.
With GQRX these are all accessible and function as expected (https://i.imgur.com/g11kehx.png?1 ).
With osmocom_fft these are all accessible and function as expected ( osmocom_fft -a airspy=0 -f 88.5M -s 10M ) ( https://i.imgur.com/4Pu7sP9.png?1 ).
But with Gnuradio the MIX gain is not accessible, or the set_bb_gain() in not linked to anything in the case of an Airspy ( https://i.imgur.com/KCTBmsu.jpg?1 ). I can turn "Ch0: BB gain" from its minimum to its maximum value and it changes nothing. 


If it was broken for all three I would assume that the problem was with the gr-osmosdr block. That it works correctly for two programs that use this block and not correctly for Gnuradio made me suspect that the problem is with Gnuradio. The ticket I logged ( http://gnuradio.org/redmine/issues/834 ) was closed. They let me know that my two out of three guess was wrong and that this is an issue with the gr-osmosdr block, so they kindly pointed me in the direction of this mailing list for help.

I would try and debug it further but I have left my zone of knowledge to look any further.

Thanks in advance for any help that you can provide,

Martin



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