Hi Marcus L. and Marcus M.,
Thanks for the tips, really appreciate the advice / help
from both of you. Marcus L., thanks so much for the practical
calibration advice, that will come in handy. Marcus M., thanks
also for your tips. Not sure what I was thinking with the
"watts squared" thing -- duh! Also, to respond to a point in
your previous email, I realize that WX GUI is deprecated, but
as a result of the fact that my project requires I work on an
old RedHat computer on National Radio Astronomy Observatory
servers, according to the system administrator I am limited to
working from GNU Radio version 3.7.11 -- which doesn't have
all the QT GUI functionality I need. Thus the outdated WX GUI
choice, and my inability to use the ZeroMQ blocks.
So, I've got another question for you all. I've reattached
my original flowgraph (ettus-filesink.grc, modified slightly).
I have been stepping through each stage and recording data
samples (i.e., I first attached the lower channel from the
De-Interleave block straight to a filesink, saved the file and
read it out using a python program, such as the one attached,
then connected the FFT block, saved the data, etc.). The point
of this exercise being to determine how the counts (which are,
presumably, proportional to voltage) change after each
processing step. After the samples are run through the FFT
block, the counts values are smaller than the input by about
1/fftsize (8192 in this case), which makes sense to me, but
then, after the stream is passed through the Complex to Mag^2
block, the count values go from around 10^-9 to roughly 0.01
(the values are slightly different, but the order of magnitude
is what I'm asking about here). Why is this the case? When I
use a system as in counts-conversion-test.grc, the output is
completely different (~10^-5) than that for Complex to Mag^2,
even though to my understanding they should be doing the same
thing, though maybe this is not the case. I would appreciate
hearing any insights you all have to share about this.
Thanks very much for your time and help -- have a good
evening!
Best,
Ellie