[time-nuts] Fluke 207-5 receiver available
Picked up subject receiver at a ham club auction in July. I thought it 'might' be useful as a generic VLF receiver, but perhaps not? Perhaps one of you will give it a better home? If not, does anyone have schematics? I'd certainly like to look at the diagrams. Thank you. KA3AIS ___ 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] Low noise powersupplies
Am 08.08.2014 um 02:13 schrieb Alexander Pummer: people who designing low noise PLLs solved that problem a while ego go to Charles Wenzels circuit collections he made a very low noise from DC to a few hundred kHz amplifier just to amplify the phase noise, here is: http://www.techlib.com/files/lowamp.pdf You can also try my preamp: http://www.hoffmann-hochfrequenz.de/downloads/lono.pdf with some preliminary results on batteries: http://www.hoffmann-hochfrequenz.de/downloads/Noise_Behaviour_Of_Chemical_Batteries_V1.0.pdf (very preliminary, could not get the 89441A to do a multi-decade FFT from 0.1Hz to 1 MHz, but figured out how to control it via the network over tcp/ip. Must take multiple measurements, paste it together and plot it with gnuplot, takes soo much time to write...) Since NiCds seem to max out the 220pV/sqrt Hz, I'm also working on a stereo version of the preamp so I can use the cross correlation feature to get another 25 dB. But even now the thermal noise of 60 Ohm (1nV/sqrtHZ) is consistently in the upper half of the plots :-) It will have all controls settable via tcp/ip and bistable relays a BeagleBoneBlack. There a too many possible errors if I try to do it by hand. Also, my preamp has 1 dB droop at 1 MHz, that's not really flat for my taste. regards, Gerhard (holidays in Bretagne, it rains, I wished I had the 89441 here...) ___ 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] Effects of noise on EFC line? - Resolved
Hi The 10811 is very unusual in that the EFC is not bypassed. It’s still got a modulation bandwidth. The important part is that the EFC has an inherent “lowpass due to FM to PM conversion. The EFC line on the 10811 should be bypassed to ground at the socket with at least a 1000 pf cap. Yes that’s not in the little manual. It’s the only way to knock out all of the RF tune effect on the EFC line. Of course if you are driving it with an op-amp that will terminate. Bob On Aug 7, 2014, at 10:08 PM, Bob Stewart b...@evoria.net wrote: Hi Bob, I hadn't even considered a filter in the OCXO. This isn't a 10811, but that's the OCXO I have a schematic of, so I'll assume that's the benchmark. Following the EFC in, it looks like it goes to a 100K resistor and then tees to the 100pf varicap and a 15pf to the xtal. Other caps are attached as well, but it doesn't look like it's bypassed to ground anywhere along the EFC line. I see that there's another 100K to a 6.4V reference with a 6.8uf cap. So, that means that the EFC line ranges from +6.4 to -6.4? I haven't worked out the time constant, but that wouldn't seem to apply for a 10MHz signal riding on the EFC voltage. Like I said, I don't have a 10811 on my GPSDO. It's my faithful Trimble 34310-T. Still, I would imagine that they at least looked at HP's design. As to Hal's comment about probe pickup. I was careful to specify the X10 position of the probe. In the X1 position there was a signal that wasn't visible in X10, but should have been. So, I assumed that was some sort of induced signal. I'm using a generic cheap Chinese probe available on ebay. Bob From: Bob Camp kb...@n1k.org To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, August 7, 2014 6:11 PM Subject: Re: [time-nuts] Effects of noise on EFC line? - Resolved Hi Your EFC line is probably bypassed internally to the OCXO. A 3db modulation bandwidth beyond 1 KHz is unlikely. A modulation bandwidth below 100 Hz is quite possible. Next thing to consider is that the EFC does FM on the OCXO. Phase noise is PM modulation. FM is 1/Fmod relative to PM. If I go up a decade in frequency with constant FM, my PM sideband will go down by 20 db. Yes that’s for small modulation indexes. That’s very likely the case if we are dealing with noise. You can calculate exactly what PM sideband in dbc you will get from a 1 Hz tone at 1 mV p-p on your EFC. From that you can pretty quickly work out what this or that number of microvolts will do at this or that frequency. The answer is normally that the noise you have from a reasonable regulator or op-amp isn’t a big deal. Bob ___ 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] Low noise powersupplies
An application note (http://cds.linear.com/docs/en/application-note/an124f.pdf) from Jim Williams and the related video (https://www.youtube.com/watch?v=Ta1ZuZTHYXA) may be informative. Edésio On Thu, Aug 07, 2014 at 01:41:32PM -0700, Chris Albertson wrote: Just practical question.. How would one measure noise at this level? If I were evaluate this what would I need? My scope lacks a nV/dev setting so is there some way to tell the difference between this and an LM317? Seriously, what kind of instrumentation would I need before I could measure an improvement over my standard LM317 On Wed, Aug 6, 2014 at 11:38 PM, Ole Petter Ronningen olep...@gmail.com wrote: Hello, all I thought it may be of interest to some of the members of this list that TI is selling evaluation modules for some ultra low noise regulators for $20 in their estore, shipping world wide included. The specs looks pretty decent to me, and I've ordered up a couple of boards to use as clean up boxes for my bench-supplies, to use on noise-sensitive projects. 1.4-30v output TPS7A4701EVM-094 3.5µVRMS (10Hz, 100KHz) 25 nV/???Hz (10Hz, 1MHz) Maximum Output Current of 1A +-15v version TPS7A30-49EVM-567: 15v rail: Noise: 12.7µVRMS (20Hz to 20kHz) 15.4µVRMS (10Hz to 100kHz) Power-Supply Ripple Rejection: 72dB (120Hz) ??? 52dB (10Hz to 400kHz) Maximum Output Current: 150mA -15v rail: Noise: 14µVRMS (20Hz to 20kHz) 15.1µVRMS (10Hz to 100kHz) Power-Supply Ripple Rejection: 72dB (120Hz) ??? 55dB (10Hz to 700kHz) Maximum Output Current: 200mA Ole ___ 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. -- Chris Albertson Redondo Beach, California ___ 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] WWVB BPSK patent status
From my reading of the archives and research it appears that the design for a BPSK WWVB receiver probably has a patent conflict. Isn't this a rehash of the old Heathkit patent on radio clocks that held back their adoption for years? I have begun work on a BPSK receiver for WWVB using an FPGA. Someone should look into why the NIST did this at all since the receiver design got a patent slapped on it right away. Mike Harpe, N4PLE Sellersburg, IN ___ 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] RFTG-u ref(1) stand-by
I have the RFTG-u ref(1) and ref(0) with the interconnect cable. The pair are working except the ref(1) is in stand-by. How can make the ref(1) active ? Thanks, Ron ___ 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] Fluke 207-5 receiver available
Yes indeed it sort of has a use. WWVB. Not much else down there. Even now that doesn't work. Granted you will here wwvb and you can poke around. But its a nice door stop. Regards Paul WB8TSL On Fri, Aug 8, 2014 at 2:55 AM, Bill Pileggi wpile...@netzero.net wrote: Picked up subject receiver at a ham club auction in July. I thought it 'might' be useful as a generic VLF receiver, but perhaps not? Perhaps one of you will give it a better home? If not, does anyone have schematics? I'd certainly like to look at the diagrams. Thank you. KA3AIS ___ 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] WWVB BPSK patent status
Mike not sure what the above means. As to the FPGA I suspect that may be a good approach i am messing with various micros and languages and they all sort of run out of steam especially when you need to be able to use numbers of instructions to make a DPLL. I did build a hardware counter that I could speed up slowdown or leave the same so that I could essentially build a phase accumulator. But not sure what patents are going to cause a problem. Regards Paul WB8TSL On Fri, Aug 8, 2014 at 10:01 AM, Mike Harpe m...@mikeharpe.com wrote: From my reading of the archives and research it appears that the design for a BPSK WWVB receiver probably has a patent conflict. Isn't this a rehash of the old Heathkit patent on radio clocks that held back their adoption for years? I have begun work on a BPSK receiver for WWVB using an FPGA. Someone should look into why the NIST did this at all since the receiver design got a patent slapped on it right away. Mike Harpe, N4PLE Sellersburg, IN ___ 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] multipath on GPS
Does anyone have a feel for what the minimum size reflector at some small distance would be detectable on a GPS timing receiver? WOuld you be able to see a change of a 1 meter square reflector 10 meters away? ___ 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] FTS1000A 05818-501 spec's
What I use: pin5 = gnd and pin8 = 24VDC, but Corby may have more info. I don't have specs on model 05818-501. For vintage parts like this an actual recent measurement is usually worth more than a vintage data sheet. I know from personal experience that many 5 MHz FTS/Datum 1000 and 1200 oscillators are stable to parts in ten to the -13th. I'll see if I can dig up phase noise plots for you. /tvb - Original Message - From: Ole Petter Ronningen olep...@gmail.com To: time-nuts@febo.com Sent: Tuesday, August 05, 2014 5:45 AM Subject: [time-nuts] FTS1000A 05818-501 spec's Hello, all I went a bit overboard on ebay and ended up with a FTS1000A model 05818-501. I've found the datasheet for the FTS1000 on ko4bb's site, but the model numbers does not match up. Does anyone know the spec for this particular model (phasenoise/stability), and if there's reason to suspect that the pinout is different for this particular model? Thank you all! ___ 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] WWVB BPSK patent status
Hi Mike: Do you have any patent numbers. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Mike Harpe wrote: From my reading of the archives and research it appears that the design for a BPSK WWVB receiver probably has a patent conflict. Isn't this a rehash of the old Heathkit patent on radio clocks that held back their adoption for years? I have begun work on a BPSK receiver for WWVB using an FPGA. Someone should look into why the NIST did this at all since the receiver design got a patent slapped on it right away. Mike Harpe, N4PLE Sellersburg, IN ___ 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] WWVB BPSK patent status
Without having seen the specific patent, what worries me is that there is a trend these days to write blanket patents that say you can't build any black box that, for example, receives this format, no matter how it works. They don't have to prove what is in your FPGA code. They then can shut down any competition with such a weak patent unless the competition has deep pockets for a lawyer. If they can prove you willfully infringed (whatever that means), they get triple damages. If you do any kind of patent search, do not keep any records or tell anyone about it. Possibly you could make the FPGA code available on the internet and have the end user be the infringer. Not being a lawyer, I'm not sure if this would get you off the hook. Maybe they can hang their hat on the digital copyright law (DCMA?) , in which case you become a criminal too. Rick Karlquist N6RK On 8/8/2014 3:24 PM, Brooke Clarke wrote: Hi Mike: Do you have any patent numbers. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Mike Harpe wrote: From my reading of the archives and research it appears that the design for a BPSK WWVB receiver probably has a patent conflict. Isn't this a rehash of the old Heathkit patent on radio clocks that held back their adoption for years? I have begun work on a BPSK receiver for WWVB using an FPGA. Someone should look into why the NIST did this at all since the receiver design got a patent slapped on it right away. Mike Harpe, N4PLE Sellersburg, IN ___ 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] WWVB BPSK patent status
How about these Xtendwave patents for a start: 8270465 - Timing and Time Information Extraction from a Phase Modulated Signal in a Radio Controlled Clock Receiver 8605778 - Adaptive radio controlled clock employing different modes of operation for different applications and scenarios 8774317 - System and Method for Phase Modulation Over a Pulse Width Modulated/Amplitude Modulated Signal for Use in a Radio Controlled Clock Receiver Application number: 20130121399 - Timing and Time Information Extraction in a Radio Controlled Clock Receiver And patent 8300687 of the same name but issued Oct 2012? Or did you mean Heath Co.? The only thing relevant there is 4582434 - Time corrected, continuously updated clock but that is for WWV/WWVH not WWVB. And it was granted in 1986, so no longer in effect anyway. Paul On Aug 8, 2014, at 6:24 PM, Brooke Clarke bro...@pacific.net wrote: Hi Mike: Do you have any patent numbers. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html ___ 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] WWVB BPSK patent status
look that also: 48 Ultra-accurate DSP-based DCF77 Timecode Receiver To extract the highest possible accuracy from the German DCF 77.5 kHz time - code broadcast this project uses DSP algorithms running on a low-cost dsPIC33 microcontroller to filter and demodulate both the AM and phase modulated signals, while also producing a very stable 10 Hz carrier-locked reference clock output. http://uploadkon.ir/uploads/4b5782ba531bb58ff30ceeaa383a9212.pdf On 8/8/2014 5:20 PM, Paul Davis wrote: How about these Xtendwave patents for a start: 8270465 - Timing and Time Information Extraction from a Phase Modulated Signal in a Radio Controlled Clock Receiver 8605778 - Adaptive radio controlled clock employing different modes of operation for different applications and scenarios 8774317 - System and Method for Phase Modulation Over a Pulse Width Modulated/Amplitude Modulated Signal for Use in a Radio Controlled Clock Receiver Application number: 20130121399 - Timing and Time Information Extraction in a Radio Controlled Clock Receiver And patent 8300687 of the same name but issued Oct 2012? Or did you mean Heath Co.? The only thing relevant there is 4582434 - Time corrected, continuously updated clock but that is for WWV/WWVH not WWVB. And it was granted in 1986, so no longer in effect anyway. Paul On Aug 8, 2014, at 6:24 PM, Brooke Clarke bro...@pacific.net wrote: Hi Mike: Do you have any patent numbers. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html ___ 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] WWVB BPSK patent status
there was a Swiss ingenieur who designed and published a receiver design for the DCF77 which has the same modulation format, also there was a Finish design a few years ego also published, therefore, that American company, which is promising the chip for a while but instead delivering the chip changes it's name... has to be very careful with patent writing. 73 Alex On 8/8/2014 4:44 PM, Richard (Rick) Karlquist wrote: Without having seen the specific patent, what worries me is that there is a trend these days to write blanket patents that say you can't build any black box that, for example, receives this format, no matter how it works. They don't have to prove what is in your FPGA code. They then can shut down any competition with such a weak patent unless the competition has deep pockets for a lawyer. If they can prove you willfully infringed (whatever that means), they get triple damages. If you do any kind of patent search, do not keep any records or tell anyone about it. Possibly you could make the FPGA code available on the internet and have the end user be the infringer. Not being a lawyer, I'm not sure if this would get you off the hook. Maybe they can hang their hat on the digital copyright law (DCMA?) , in which case you become a criminal too. Rick Karlquist N6RK On 8/8/2014 3:24 PM, Brooke Clarke wrote: Hi Mike: Do you have any patent numbers. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Mike Harpe wrote: From my reading of the archives and research it appears that the design for a BPSK WWVB receiver probably has a patent conflict. Isn't this a rehash of the old Heathkit patent on radio clocks that held back their adoption for years? I have begun work on a BPSK receiver for WWVB using an FPGA. Someone should look into why the NIST did this at all since the receiver design got a patent slapped on it right away. Mike Harpe, N4PLE Sellersburg, IN ___ 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. ___ 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] WWVB BPSK patent status
!!! http://blog.blinkenlight.net/experiments/dcf77/the-clock/ !!! On 8/8/2014 4:44 PM, Richard (Rick) Karlquist wrote: Without having seen the specific patent, what worries me is that there is a trend these days to write blanket patents that say you can't build any black box that, for example, receives this format, no matter how it works. They don't have to prove what is in your FPGA code. They then can shut down any competition with such a weak patent unless the competition has deep pockets for a lawyer. If they can prove you willfully infringed (whatever that means), they get triple damages. If you do any kind of patent search, do not keep any records or tell anyone about it. Possibly you could make the FPGA code available on the internet and have the end user be the infringer. Not being a lawyer, I'm not sure if this would get you off the hook. Maybe they can hang their hat on the digital copyright law (DCMA?) , in which case you become a criminal too. Rick Karlquist N6RK On 8/8/2014 3:24 PM, Brooke Clarke wrote: Hi Mike: Do you have any patent numbers. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Mike Harpe wrote: From my reading of the archives and research it appears that the design for a BPSK WWVB receiver probably has a patent conflict. Isn't this a rehash of the old Heathkit patent on radio clocks that held back their adoption for years? I have begun work on a BPSK receiver for WWVB using an FPGA. Someone should look into why the NIST did this at all since the receiver design got a patent slapped on it right away. Mike Harpe, N4PLE Sellersburg, IN ___ 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. ___ 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] Low noise powersupplies
An application note (http://cds.linear.com/docs/en/application-note/an124f.pdf) from Jim Williams and the related video (https://www.youtube.com/watch?v=Ta1ZuZTHYXA) may be informative. Edésio On Thu, Aug 07, 2014 at 01:41:32PM -0700, Chris Albertson wrote: Just practical question.. How would one measure noise at this level? If I were evaluate this what would I need? My scope lacks a nV/dev setting so is there some way to tell the difference between this and an LM317? Seriously, what kind of instrumentation would I need before I could measure an improvement over my standard LM317 On Wed, Aug 6, 2014 at 11:38 PM, Ole Petter Ronningen olep...@gmail.com wrote: Hello, all I thought it may be of interest to some of the members of this list that TI is selling evaluation modules for some ultra low noise regulators for $20 in their estore, shipping world wide included. The specs looks pretty decent to me, and I've ordered up a couple of boards to use as clean up boxes for my bench-supplies, to use on noise-sensitive projects. 1.4-30v output TPS7A4701EVM-094 3.5µVRMS (10Hz, 100KHz) 25 nV/???Hz (10Hz, 1MHz) Maximum Output Current of 1A +-15v version TPS7A30-49EVM-567: 15v rail: Noise: 12.7µVRMS (20Hz to 20kHz) 15.4µVRMS (10Hz to 100kHz) Power-Supply Ripple Rejection: 72dB (120Hz) ??? 52dB (10Hz to 400kHz) Maximum Output Current: 150mA -15v rail: Noise: 14µVRMS (20Hz to 20kHz) 15.1µVRMS (10Hz to 100kHz) Power-Supply Ripple Rejection: 72dB (120Hz) ??? 55dB (10Hz to 700kHz) Maximum Output Current: 200mA Ole ___ 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. -- Chris Albertson Redondo Beach, California ___ 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] WWVB BPSK patent status
also there is one FPGA based system already available unfortunately the description is in German : http://www.cadt.de/dieter/dcf/Praezisionsfrequenzmessungen.pdf On 8/8/2014 5:33 PM, Alex Pummer wrote: there was a Swiss ingenieur who designed and published a receiver design for the DCF77 which has the same modulation format, also there was a Finish design a few years ego also published, therefore, that American company, which is promising the chip for a while but instead delivering the chip changes it's name... has to be very careful with patent writing. 73 Alex On 8/8/2014 4:44 PM, Richard (Rick) Karlquist wrote: Without having seen the specific patent, what worries me is that there is a trend these days to write blanket patents that say you can't build any black box that, for example, receives this format, no matter how it works. They don't have to prove what is in your FPGA code. They then can shut down any competition with such a weak patent unless the competition has deep pockets for a lawyer. If they can prove you willfully infringed (whatever that means), they get triple damages. If you do any kind of patent search, do not keep any records or tell anyone about it. Possibly you could make the FPGA code available on the internet and have the end user be the infringer. Not being a lawyer, I'm not sure if this would get you off the hook. Maybe they can hang their hat on the digital copyright law (DCMA?) , in which case you become a criminal too. Rick Karlquist N6RK On 8/8/2014 3:24 PM, Brooke Clarke wrote: Hi Mike: Do you have any patent numbers. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html http://www.prc68.com/I/DietNutrition.html Mike Harpe wrote: From my reading of the archives and research it appears that the design for a BPSK WWVB receiver probably has a patent conflict. Isn't this a rehash of the old Heathkit patent on radio clocks that held back their adoption for years? I have begun work on a BPSK receiver for WWVB using an FPGA. Someone should look into why the NIST did this at all since the receiver design got a patent slapped on it right away. Mike Harpe, N4PLE Sellersburg, IN ___ 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. ___ 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] multipath on GPS
jim...@earthlink.net said: Does anyone have a feel for what the minimum size reflector at some small distance would be detectable on a GPS timing receiver? WOuld you be able to see a change of a 1 meter square reflector 10 meters away? I suspect it depends on the elevation angle of the reflector. My wise-ass answer is something like: Please try it and let us know what happens. A variation on that question is how do I tell which of two antenna positions is better? How would you measure that? With a good reference clock, would it be enough to just collect PPS offsets and then compare adev with/without? How much data would you need? How much variation is there due to the changing satellite patterns? What would you do if you don't have a good reference? Do GPS receivers provide enough signal quality data? -- I have often wondered if the reflections off a nearby 747 would cause troubles. I live roughly 20 miles off the end of the San Francisco airport. It's common for planes to fly over my house while they are getting lined up for the landing pattern. Most large planes now broadcast their position/speed. When I get time, I want to capture that data and see if I can find any correlation between planes nearby and something like a TBolt going into holdover or dips in the signal quality from a satellite. -- These are my opinions. I hate spam. ___ 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.
