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Date: Thu, 28 Oct 2010 18:21:04 +0200
From: wolf_dl4yhf <dl4yhf@freenet.de>
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References: <1288122510.1536.51.camel@gerhard-desktop>
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Subject: Re: LF: New OE3GHB grabber online
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Hello Gerhard,

you wrote:
>
> Today I swapped the RX of my grabber to SDR and the antenna to a
> PA0RDT-design. I also did some minor changes to my grabber-page.
>
> (..)
> I do not use a I/Q-setup, though the RX is I/Q. I found out that for
> QRSS3 and QRSS60, the difference is minor and I/Q setup just uses a lot
> more processor time.
>
> Any comments/reports are welcome.
>

What kind of SDR are you using, SDR-IQ or Perseus ? (guess not one of 
the soundcard-based SDRs).
For the SDR-IQ, the CPU usage can be greatly reduced if you do run the 
radio at the lowest possible sampling rate, which of course requires to 
run it in true I / Q mode (and also the spectrum analyser).
This greatly reduces the CPU load, because the PC software doesn't need 
to run at very large sampling rates, instead the complex decimation will 
be done in the SDR's FPGA or digital downconverter.

Especially when running on a laptop this can save some power, and (here) 
completely eliminates the noise from a Thinkpad's internal cooling fan.

73,
    Wolf  DL4YHF .