Nightly: Some LNA settings with SDRPlay RSP1 are out of bounds and cause the SDR to crash

[Zach Rutledge]

I've been testing the last few nightly builds with my two SDRPlay radios (an RSP1 and and RSPdxR2) and noticed that sometimes the RSP1 was "crashing out" and disappearing from the list of available tuners, but only in the nightly version.

When adjusting the gain manually (the auto feature has never gotten me any usable signals on any of my radios) I realized that there are far too many notches in the gain slider for this particular radio's LNA:

As best I can tell there are only 4 settings for the LNA and many choices are out of bounds (everything to the left of the blue slider in this picture).  If I manually move the slider there or let auto gain take control and it moves it, it throws an error:

Where it gets weird is that if the tuner isn't actually in use and the spectrum display is either off or showing a different radio, this is all that happens.  But if the spectrum display is on and in the foreground, the SDR crashes and disappears from the list of available tuners until after a restart.  And I think it's also locked out of use from other tuner apps, too, until SDRtrunk is quit.

In the current 0.6.1 final release, the notches for the RSP1 are spaced further out so there aren't as many invalid choices, and it doesn't crash. 

On a slightly related note, I've also noticed that the number of notches on the gain reduction slider for the RSPdxR2 varies at random. Sometimes there's like 50 notches and sometimes it's only like 15.  No idea why that happens but it doesn't seem to really affect performance too much.