capture a whole ham band

[Phil]

Gosh, what a lot of abbreviations and jargon. I've seen the whole medium wave (AM to you guys) broadcast band recorded for three hours on a domestic VHS video recorder, about twenty years ago. Who needs digital?

Phil M1GWZ



On 13 Apr 2013, at 07:33, <wb4jfi at knology.net> wrote:

> Yes, it is possible.  The entire 20M band is only 350kHz wide.  In general, if you want to capture that wide a spectrum swath, you are looking at direct down conversion (DDC) based SDR hardware, NOT QSD-based ones.  That implies more sophistication and higher cost.  Some of the better DDC-based SDR hardware packages can actually monitor more than one complete amateur band at once.
>  
> There are several SDR hardware/software packages that can suck in 384kHz or better, and store the I/Q on hard disc.  Then, it can be played back at a later time.  Noise versus signal is determined by dynamic range, etc.
>  
> I believe the SDR-IP or Net-SDR (bigger cousins of SDR-IQ) by RF Space can do that.  So can Perseus and the Quicksilver SDRs.  The openHPSDR Hermes project is being adjusted to do that, as is the multi-board openHPSDR boardset.  The HiQSDR can also do that.
>  
> The DDC-based SDR-IQ CANNOT, neither can any Flex deliverables at the moment, they are all QSD-based.  The new Flex 6000-series will be able to do much more than that.  Softrocks cannot do that, as they rely on soundcards for A/D conversion, and I’m not aware of any soundcards that sample higher than 192k.  Even if they did, the input filters would probably drop out well before 350kHz.
>  
> Our own Charleston SDR can also do that, as far as the hardware goes.  I have had my Charleston SDR RX and Quisk under Linux showing up to 960kHz of spectrum at a time, with excellent refresh rates.  That’s about its limit for now.  I know there has been some improvements to Quisk, and saving raw I/Q data is now included I believe.  So, it may be doable on a Charleston SDR setup.  But, the Charleston SDR Receiver uses a 12-bit A/D, so the dynamic range may be limited when compared to other options.  But it IS cheaper!!
> 73,
> Terry, WB4JFI
>  
>  
>  
> From: Alex Fraser
> Sent: Saturday, April 13, 2013 1:49 AM
> To: tacos at amrad.org
> Subject: capture a whole ham band
>  
> Is it possible to capture the entire 20 meter band and record it to disk?  I mean everything including the noise so if you played it back at a later time
> you wouldn't be able to tell it from the real live band.
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