[Skimmertalk] Elad S2 vs Duo issue

[David Robbins]

Remember, the signal reports in the skimmer are not signal strengths, but
signal to noise ratios... so attenuators would not normally affect it unless
weak signals were dropped into the receiver internal noise and disappeared.
Can you run both of those receivers on a single piece of software, like
hdsdr or something similar?  If you can then try to compare known signals to
the receiver noise floor and see if there is a difference.  That is what I
found when I first tried the red pitaya, the rx noise floor was much higher
on the rp than the qs1r.  in that case it was due to digital noise on the
rp's ground bus getting coupled into the rf input through the input
attenuator, bypassing that reduced the noise floor and also increased signal
levels so it compared favorably with the qs1r.  further work by others in
creating a matching transformer for the input impedance has improved it even
more.  It could also be due to the number of bits in the a-d sampler and
other considerations in both hardware and software.

David Robbins K1TTT
e-mail: mailto:k1ttt at arrl.net
web: http://wiki.k1ttt.net
AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373



-----Original Message-----
From: Skimmertalk [mailto:skimmertalk-bounces at contesting.com] On Behalf Of
Don Moman VE6JY
Sent: Thursday, November 29, 2018 17:59
To: SkimmerTalk Reflector
Subject: [Skimmertalk] Elad S2 vs Duo issue

I've been noticing for some time that the S2 is not catching nearly as many
CW spots than the Duo, with both on identical antennas (fed from the same
multicoupler) and on identical bands.  On virtually identical W7 laptops.
Signal reports are like in the 20-30 range for the Duo and maybe in the
5-10 range for the S2. S a lot weaker.  I'm looking at the traffic in the
Aggregator 5.2 window.

I have reversed the antenna feeds - no change.  I have checked a weak signal
in the native Elad software, both are identical there. I have tried
different bands, from 630m to 20m and difference remains.  The difference is
significant and more than just what the antennuator being on would do.
I am using this .ini file from the Elad website...
http://sdr.eladit.com/FDM-S2%20Sampler/ExtIO%20Dlls%20for%20use%20with%20%20
third%20party%20software/Skimmer_Server_Dll_1_00/ELAD_FDMS2_SkimSRV.ini
  I have tried changing the ATT and LP values but they don't seem to make
any difference.

Any assistance or insight would be appreciated, thanks

Don
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