1903Re: [dxatlas] "Skimmer Server" with QS1R Receiver
- Apr 9, 2010Jeffrey:
The QS1R has a large FPGA chip on the board. Alex has written code that
runs on the FPGA chip and creates the seven receivers. The signals are then
sent by USB to the computer where they are processed. So you have seven
continuous streams of data of up to 192 kHz each.
In my hands the system has been pretty robust. The QS1R runs the rf from
the antenna almost directly into the ADC chip so there is no RF
pre-amplification. Consequently, it is a little insensitive, especially on
the higher bands. Since the front end is wide open, if you add lots of
pre-amplification and you are near broadcast transmitters, you get into IMD
problems. Some of us are using an 11 db preamp from Clifton Laboratories
which seems pretty good. Others are using pre-amps with a little more gain.
Clifton Laboratories also has a high pass filter for receivers with
broadcast band issues.
I put the system on a Intel I7 computer running Windows 7 64 bit despite the
fact that this is not an officially supported OS. For reasons I do not
understand, the Skimmer Server application begins to report "CPU Overload"
and starts to decode only a fraction of the signals when I reach about 1100
simultaneous decoders. This is despite the fact that the machine and the
application are reporting only about 6 to 8% CPU load. I do not know where
the bottleneck is. This issue may be unique to my machine. Perhaps a 32 bit
machine would be better.
Email me if I can be of further help.
6299 Route 413
PO Box 349
Pipersville, PA 18947
CW Skimmer CQ spots: ve7cc.net:7333
On Fri, Apr 9, 2010 at 9:16 AM, jmaass_moose <jmaass@...> wrote:
> How does the QS1R receiver with "Skimmer Server" provide up to seven bands
> at a time?
> Does it hop from band-to-band in sequence, or does it cover seven bands
> Who is using "Skimmer Server" with a QS1R? Good experience? Reliable
> We are planning an unattended installation of a Skimmer site on Curacao.
> We've been leaning towards what we've used before (multiple SDR-IQ
> receivers), but the QS1R is a more economical solution.
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