After transferring the saved file from just one recording session
yesterday evening to my big PC that can cope with 16K21 decoding....
A decode straightaway. Quite strong at 9.9dB see below.
My LF receiver appears to give a small DC spike in the centre of the
spectrum , which since it is taking input at 1kHz and multiplying in
firmware with I/Q square waves is a bit odd. That DC term wasn't
noticeable when I had the RF amplifier previously (the one that popped
with strong signals) but now gain has been moved to 1kHz IF, the line
can be seen. Perhaps an RF amplifier is necessary, but one that can
safely be overloaded
Anyway, I recorded the file with the Rx tuned 3Hz low so it gave its
IF at 1003Hz, with +3Hz data coming on the serial interface and saved
to the .WAV file. I discovered by trial and error The FreqOffset
window in EbNaut had ot be set to [minus] -3Hz to compensate for the
positive shift on the input - after spending a fruitless few minutes
trying at +3Hz . But I suppose this is the same meaning and sign as
the start time offset...
ebnaut-rx V0.3b
input file C:\EbNaut\151209_1859+3Hz_16K21A.WAV
sample rate 31.250000 per second
rx frequency 137370
file start time 2015-12-09 18:59:59.000
polynomial 16K21A
number of chars 6
block size 52
symbol period 2.000
number of symbols 1152
list length 6000
start offset 1.000
freq offset -3.000000
cores 2
initial reference phase 79.7
---------------------------------------------
found IZ7SLZ
list rank 0
reference phase 0 0 0 0
carrier RMS 1.160e+003 noise RMS 5.625e+001
carrier S/N 26.29 dB in 434.0 uHz
carrier Es/N0 -4.33 dB
carrier Eb/N0 10.95 dB
info bit period 67.37 seconds
symbol error rate 256/1152 = 22.222 %
Es/N0 from symbol errors -5.3 dB
Eb/N0 from symbol errors 9.8 dB
Shannon capacity 815.7 bits/hour
Shannon efficiency 6.6 %
symbols file C:\EbNaut\151209_1859+3Hz_16K21A-symbols.csv
elapsed 11 seconds
Andy G4JNT
On 9 December 2015 at 18:14, IZ7SLZ <[email protected]> wrote:
> GE all,
> some EbNaut test transmission from IZ7SLZ/JN80 this evening every hour until
> 23.00UT starting from 18:00UT.
>
> QRG = 137370.00 Hz
> parameters: 6C, 2S, 16K21A
>
> 73, Domenico / iz7slz
>
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