[time-nuts] Ideas for a long-wave receiver sought

Lux, James P james.p.lux at jpl.nasa.gov
Mon Jun 22 12:13:01 EDT 2009

200kHz is a bit tricky for the top end.. That probably puts the standard music recording A/D out of the picture (although they have very high performance A/Ds in them, and because of large production volume, they're relatively inexpensive).

Almost any PC these days has enough processor to take a 400 ksps stream of samples and filter/decimate it.
Maybe the boards from the HPSDR folks might serve?

Do you need continuous stream of samples? One of the eval boards for high performance A/Ds with a USB might work for you, but last time I checked, they were more oriented to "capture a buffer, then analyze" sorts of approaches.

Your best long range approach might be to use a high quality A/D with a small FPGA behind it that implements a digital down converter, feeding the (lower rate after downconversion/filtering) samples through USB to an application like DL4YHF's spectrum lab.  DL4YHF is very interested in VLF receiving, and he might have good ideas on inexpensive approaches.

> -----Original Message-----
> From: time-nuts-bounces at febo.com 
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Brooke Clarke
> Sent: Monday, June 22, 2009 7:18 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Ideas for a long-wave receiver sought
> Hi Marc:
> The SDR-IQ has the ability to record everything between 500 
> Hz and 190 kHz when used with a fast enough PC.  This is the 
> best of the SDR series for use below 200 kHz.
> It can be used with SpectraVue or Winrad.
> Works with I2PHD WINRAD, SM5BSZ LINRAD, HOKA and DRM software.  See:
> http://www.rfspace.com/SDR-IQ.html
> http://groups.yahoo.com/group/SDR-IQ/
> Have Fun,
> Brooke Clarke
> http://www.prc68.com
> Marc Balmer wrote:
> > Hi
> > 
> > I want to build a small, cheap, yet precise long-wave 
> receiver which 
> > can be tuned from the computer in the 2KHz - 200 KHz range (the 
> > intended use is to receive various time signal stations).
> > 
> > Does a chip for such a receiver exist?  Should I take the SDR route?
> > I designed a DCF77 receivers some years ago, but I need 
> something more 
> > flexible (and a bit more modern...)
> > 
> > - Marc Balmer

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