Re: [time-nuts] Ideas for a long-wave receiver sought
Are you doing DGPS? An an alterative to the roll-your-own SDR, tou can build a direct conversion small receiver or IF converter with a SA602 chip, which contains a Gilbert cell mixer and a local oscillator. Here is a board that will do most of what you want, if you're willing to live with the SA602 limitation. http://home.att.net/~jacksonharbor/lfconv.htm You will get out of this board LO + (0 to 500 Khz), which you can the receive with an existing receiver that can receive the LO frequency. It comes with 4.0 and 10.0 MHz crystals. Here's an article about better input filtering against AM broadcast band interference, which will be useful for you no matter what route you take for LF and VLF reception. http://www.cliftonlaboratories.com/jackson_harbor_press_vlf_converter.htm There are many ham and non-hams who are using very low bit-rate signals in LF and VLF at micro power levels. As a result, they care about frequency stability, and some are building their own RX equipment. Here's a random sample: http://www.qrss.thersgb.net/Receiving-QRSS.html . Murray Greenman who is a member of this group did some pioneering work in VLF TX using the FE5680A as a transmitter, and he may have something to contribute on RX as well. If you need better phase noise and frequency stability, you won't get that from a product like the SA602, not the least because of its internal oscillator. You can build a receiver or IF converter yourself out of discrete mixers from Mini-Circuits, but you'll likely need a preamp as well as they generally require higher drive points (more loss), and output filters as well to deal with the image rejection. Leigh. 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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Ideas for a long-wave receiver sought
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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ideas for a long-wave receiver sought
In message 38553aad-ecc6-4af8-90b3-42bbec366...@msys.ch, Marc Balmer writes: 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...) Go SDR. There are ARM7 chips now that have sufficient ADC quality to do the job. See for instance: http://phk.freebsd.dk/AducLoran Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ideas for a long-wave receiver sought
Am 22.06.2009 um 10:14 schrieb Poul-Henning Kamp: In message 38553aad-ecc6-4af8-90b3-42bbec366...@msys.ch, Marc Balmer writes: 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...) Go SDR. There are ARM7 chips now that have sufficient ADC quality to do the job. Ok, thanks. I happen to have some Overp Earth boards, OMAP 3503 Application Processor with ARM Cortex-A8 CPU, do you think these will handle the job? (runnin at 600 MHz). They say it makes up 1200 dhrytsone mips (www.gumstix.com) See for instance: http://phk.freebsd.dk/AducLoran Thanks for the pointer, I already found that, nice work! - Marc Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ideas for a long-wave receiver sought
In message 70d1e333-26c4-4068-bfac-30d689bbf...@msys.ch, Marc Balmer writes: Ok, thanks. I happen to have some Overp Earth boards, OMAP 3503 Application Processor with ARM Cortex-A8 CPU, do you think these will handle the job? (runnin at 600 MHz). They say it makes up 1200 dhrytsone mips It's more a matter of what their ADC can do... -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ideas for a long-wave receiver sought
Am 22.06.2009 um 11:46 schrieb Poul-Henning Kamp: In message 70d1e333-26c4-4068-bfac-30d689bbf...@msys.ch, Marc Balmer writes: Ok, thanks. I happen to have some Overp Earth boards, OMAP 3503 Application Processor with ARM Cortex-A8 CPU, do you think these will handle the job? (runnin at 600 MHz). They say it makes up 1200 dhrytsone mips It's more a matter of what their ADC can do... unfortunately it's only a TI TPS65950 which has only an audio codec, the ADC doing 48kHz max. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ideas for a long-wave receiver sought
In message 0587cb86-96ef-4660-9fbe-8c1d1fdfb...@msys.ch, Marc Balmer writes: unfortunately it's only a TI TPS65950 which has only an audio codec, the ADC doing 48kHz max. That's still usable, you could for instance use a DRM frontend like the pappradio There are some links here: http://www.drmradio.dk/Byggesaet og konvertere-da.htm Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ideas for a long-wave receiver sought
Am 22.06.2009 um 16:18 schrieb Brooke Clarke: 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/ very nice, indeed, although it does not fit my definition of cheap. but then I'd like to get one of these, are the specs and docs open? I am not using Windows but rather Unix (BSD) 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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ideas for a long-wave receiver sought
In message 4a3f9299.9080...@pacific.net, Brooke Clarke writes: 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. I have looked at that earlier, but it does not look like it is feasible to lock its clock to an atomic reference :-/ -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ideas for a long-wave receiver sought
Hi Poul: The SDR-IQ has holes in the PCB for an SMA jack and there's a jumper/resistor used to select either the on board 66 MHz crystal oscillator or the external source. See: http://www.prc68.com/I/Bats.shtml#SDRIQ Have Fun, Brooke Clarke http://www.prc68.com Poul-Henning Kamp wrote: In message 4a3f9299.9080...@pacific.net, Brooke Clarke writes: 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. I have looked at that earlier, but it does not look like it is feasible to lock its clock to an atomic reference :-/ ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ideas for a long-wave receiver sought
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. http://freenet-homepage.de/dl4yhf/spectra1.html -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ideas for a long-wave receiver sought
It's not necessarily inexpensive, but here's one data point: an EVAL-AD7760 board is $150, and a Nexys2 FPGA board is $129. This combination can acquire DC-1 MHz with 100 dB SNR and 120 dB SFDR. There is no need for a hardware or FPGA-based DDC, as any modern PC can do host-based processing at these rates without breaking a sweat. In the setup I have been playing with, the FPGA is used only to transfer the AD7760's output to the USB 2.0 chip. With a 16 KB block-RAM FIFO in the FPGA and overlapped reads from the CyUSB driver, my test app has run for 2-3 days at 10 MBytes/sec without missing any samples. At 20 MBytes/sec, sending every 32-bit sample twice as a test, the FIFO overruns every couple of hours. Considering that you can spend $279 on a high-end sound card without trying very hard, the AD7760-based USB digitizer isn't too unreasonable, at least for single-channel applications. I'm still debating whether to spin a PCB that'll put the FX2 USB chip, FPGA, and AD7760 on one board... it's tempting, because I'd really like a two-channel digitizer, but it won't necessarily be much cheaper than the Nexys2/EVAL-AD7760 combo. The Nexys2 is a real bargain. I'm not quite ready to call the Verilog and ADC API code done, although anyone who wants to play with it is welcome to it, just write me offline. TI also has a new 24-bit sigma-delta ADC called the ADS1675 that digitizes at 4 MS/s and uses about half the power of the AD7760. You can buy the chips from DigiKey but there appears to be no official evaluation board yet. It's hard to compare the specs on an apples-to-apples basis, but my impression is that the overall performance isn't too far behind the AD7760 at 2.5 MSPS. Re: the SDR-IQ, yes, it comes with a public interface spec. It's based on ASCP (Amateur Station Control Protocol), which I'm not too familiar with. Great little box, usable as a general-purpose digitizer for narrowband HF applications that don't need to go all the way down to DC. -- john, KE5FX -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com]on Behalf Of Lux, James P Sent: Monday, June 22, 2009 9:13 AM To: bro...@pacific.net; Discussion of precise time andfrequency measurement Subject: Re: [time-nuts] Ideas for a long-wave receiver sought 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. http://freenet-homepage.de/dl4yhf/spectra1.html -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@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 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
