[hpsdr] linhpsdr and multiple wsjtx receivers

[Rob Frohne]

Hi All,

I found that I could set up linhpsdr and wsjtx on Ubuntu 18.04 for at 
least three bands of simultaneous decoding for FT8 using pulseaudio 
virtual channel monitors.  I wish pulse wasn't so flaky.  I found that 
you need to mess with pavuctrl a lot, and sometimes it doesn't do what 
it says it should.  Also, I noted that it gets confusing sometimes, and 
you have to restart it to get the right number of channels, etc.  I'm 
using the documentation that came with linhpsdr for the setup.  There 
must be a better way to handle the audio.

Although CAT doesn't work for multiple receivers, it worked on RX0, and 
with RX0 when both RX0 and RX1 were running, but when I started RX3 it 
stopped working even for RX0.  I've had problems with pihpsdr and CAT in 
the past, and the source seems to suggest that the code is about the 
same.  I ended up not using CAT at all, but it would improve the ease of 
operation if CAT would work.  You have to be very careful to get the 
frequencies right when editing them by hand everywhere

Once when I was playing with two receivers decoding FT8, the CPU for 
linhpsdr was around 100%, but after starting over it was less than about 
30%, and starting it again was somewhere in between. The GUI is not as 
responsive with more than two receivers decoding on my 2011 laptop.  
There are a bunch of kidle_inject processes whose purpose is to help 
keep a hat on things, if I understand it correctly.   The CPU usage of 
linhpsdr seems to be a function of something random that changes when I 
restart the processes.   It goes from less than 30% to over 100% and the 
only thing I note of difference is which time I do it.

73,

Rob

KL7NA