[time-nuts] OCXO with ADEV of 1E-13 on Pluto Mission
Here is an interesting link to the New Horizons Mission to Pluto radio system design. Note last section describes an OCXO with ADEV = 1E-13 at 1s, and aging rate of 1E-11 per day. http://www.uhf-satcom.com/amateurdsn/Paper-969.pdf I wonder if their spares will show up on eBay? John Stuart, KM6QX Lafayette, CA ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
In message 55a757d3.9050...@mail.tele.dk, Ole Stender Nielsen writes: I use a home-made untuned loop antenna [...] A note about Loran-C and loop-antennas: The loop-antennas are sensitive to magnetic fields and therefore sensitive to direction. Depending on side of the loop you point at the Loran-C transmitter you will get a true or inverted signal. If you get an inverted signal, a Loran-C receiver will lock onto the wrong zero-crossing, which will increase your phase noise because only the 3rd positive crossing is truly steered. If you want to receive more than one Loran-C transmitter, the directivity of the loop-antenna is a disadvantage and you are better of with a monopole (electric) antenna. I can recommend Chris Trasks designs: http://www.home.earthlink.net/~christrask/ I built one from the Complementary Push-Pull Active Antenna Amplifiers document and it drags in signals from 4kHz to well north of 150Mhz. -- 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] Re GPS Leap Second
Le 16 juil. 2015 à 12:52, Blair Lade bla...@bettanet.net.au a écrit : Hi All, I've just joined time nuts so go easy on me! An interesting 'moment' in time was had during the leap second! The Symmetricon 2100 I have is fitted with the modified Heol GPS. According to the video I took of the front LCD displays, it repeated the first second, ie 58,59,00,01,01,02,03 I don’t think anyone else on the list has reported this. It might be worth while reporting it to the manufacturer , with your box’s firmware revision. They were very responsive to the initial rollover issue and may be able to confirm the origin. It could well be the 2100’s firmware rather than the receiver. I have an NTP server from ESE (an ES295) that we use for HD video OSD It went 58,59,00,01,02,02,03,04 The NMEA string from my Motorola M12 units all went 23:59:58 23:59:59 23:59:60 00:00:00 00:00:01 00:00:02 They are now all in sync as would be expected All in all, an acceptable outcome if not the expected outcome provided one doesn't look too closely. W/r to the Heol GPS, it is much more sensitive than the original ACE module, locks on much faster and appears to solve the GPS week roll around issue as well. Service from Heol was excellent, the module being received within a week. We also have a lot of seismic monitoring recorders around Australia that had applied the advertised leap second in January, these have all now sorted them selves out (till next time). It made for interesting data processing and earthquake location extraction fun..not. bla...@bettanet.net.au Blair Lade South Australia --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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. Ceux qui sont prêts à abandonner une liberté essentielle pour obtenir une petite et provisoire sécurité, ne méritent ni liberté ni sécurité. Benjimin Franklin ___ 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] Loran C returning to a station near you...
Look at how well a couple of projects have gone: o privatize NIST NTP server operation - the NTP pool is recommended everywhere and good enough for most; separate providers supply high accuracy, precision, and stability timing for financial markets internationally; and GPS serves the rest o provide WWVB PM decoders - older precision timing equipment no longer works; but compatibility for RC Atomic clocks and watches was maintained; does not appear that there is any commercial interest in developing decoders; the new PM features might as well be dropped, or they could go back to the old AM format. See also the UT1 NTP service http://www.nist.gov/pml/div688/grp40/ut1_ntp_description.cfm which states it will use IERS schedule A data, and may offer only the weekly official projections rather than the daily rapid predictions, which vary by 0.1ms; they also mention providing DUT1 and EOP data as a text string from a separate service. They may be looking at this for a UTC like backup if the ITU drops the leapsecond. But the US, EU, Russia, China, and Japan can each afford a GNSS constellation, with upgraded features as desired. If a country can not provide an adequate market for products, then they will have to either do without a backup, ormake do with what markets elsewhere demand - eLoran. OTOH the civil business focus of currently successful projects leads me to hope that the ITU will be told to leave UTC alone as a legal and political requirement for solar civil time, use TAI or GPS time if they want to keep to a uniform time scale, or come up with a better time scale of their own. -- Take care. Thanks, Brian Inglis On 2015-07-14 16:49, Bob Camp wrote: Not to be to much of a downer here but ….. Loran for timing and an “Eastern WWVB” are two projects that seem to each have a life of their own. They seem to come up on some sort of cycle related to sun spots. Both have zero (or possibly less than that) percent mind share among those who would need to implement them into systems. Since there is major cost on the systems end, it would take “mandatory use” legislation to get them designed in. Without those design in’s, *having* a backup system is pretty useless. You are talking about billions of dollars and years of effort to hook them up …. If you are talking about “infinite budget” military systems, some of that may happen. I notice in the papers that “infinite budget” does not seem to apply to the US DOD these days. For commercial systems, nobody will significantly cut into profits to do something like this. Should they do this - sure. Will they do it - nope. On Jul 14, 2015, at 4:49 PM, paul swed paulsw...@gmail.com wrote: The reason to stay with the LORAN C style pulses is very very simple. It allows our time-nuts Austrons and SRS to work. Its the only way I get any of my tax dollars back. :-) The good news is no official government person reads time-nuts. On Tue, Jul 14, 2015 at 12:16 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message 55a4ac81.1030...@rubidium.dyndns.org, Magnus Danielson writes: The safety is relative, in that it takes quite a bit of more infrastructure compared to the jamming of GPS, and that lies in the wavelength of the signal than anything else. If the goal is a reliable backup for GPS, there are smarter ways to use the 100kHz band than Loran-C pulses, and there really isn't much reason to stay compatible with Loran-C receivers. ___ 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] Loran C returning to a station near you...
Loran-C had absolute accuracy to 500nS but repeatability much better, usually to about 20 meters position or 60 nS (if you mark the position of a buoy you can get back to it very closely). eLoran is a significant improvement and appears to be able to get to 8 meters absolute position or about 25 nS timing. Each transmitter would have its own cesium clock instead of the slaves relying on the master and propagation corrections would be cataloged and disseminated. David N1HAC On 7/15/15 12:29 PM, paul swed wrote: John I don't know if there was. But the timing receivers like the Austrons and SRS could really derive very accurate frequencies especially if you lived 60 miles from the transmitter. :-) Regards Paul. WB8TSL On Wed, Jul 15, 2015 at 4:23 AM, John C. Westmoreland, P.E. j...@westmorelandengineering.com wrote: Time-Nuts, Was better than 500 nS accuracy ever achieved with Loran? 73's, John Westmoreland AJ6BC On Tue, Jul 14, 2015 at 10:18 PM, Dale Cannon dalec...@cfl.rr.com wrote: Folks, I know that there is a longing for LORAN-C to return, but this weekend, I did a Google Maps flyover of each of the US LORAN-C stations (takes less than an hour). Almost all of the antennas are gone and there are no cars in the parking lots (except at Seneca which became an Army depot). This means that the equipment is probably gone, too. Or maybe this stuff will show up at auction or on E-Bay and that would solve the Austron receiver problem.. Dale Cannon, KS4FA ___ 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] Loran C returning to a station near you...
In message 07538A701D6E4F8D804BD567DD794693@gnat, Alan Melia writes: I mean that a Loran-C signal designed as I proposed in a previous email would not do that, because it wouldn't have the groups and GRI-peridodicties which cause the splatter up and down the band. It just depends what you mean by that :-) I could lock to Lessay and Anthorn at frequencies in the 136kHz amateur band, using some S/N DSP software writen by Peter Matinez G3PLX. If you look at the spectral width of the existing Loran-C (or similar) waveform, it’s a massive thing. You would have a hard time coming up with something that spreads more crud around the VLF range. The reason Loran-C spreads crud is *only* the combinationa of the pulse-groups and the periodicity of the GRI. The pulses themselves are entirely contained inside the allocated frequency band. -- 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] UrsaNav LORAN next test date
Paul, thanks for that info. Very interesting. I've been enjoying all of the Loran talk on the mailing list recently. I just picked up a NOS 2100F on eBay to play around with. Maybe I'll be able to do something useful with it one day if they continue with eLoran tests. Dan On Jul 15, 2015, at 1:17 PM, paul swed paulsw...@gmail.com wrote: I reached out to UrsaNav and asked when the next test would be. They were very responsive. Wildwood, NJ will be on air from 0900 (local) on 20 July until 0900 (local) on 23 July for an eLoran test. So fire up your Austrons and SRS units. There will be additional tests and they may be from different sites. UrsaNav plans to post the schedules on their site when it firms up. Regards Paul WB8TSL ___ 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] Loran C returning to a station near you...
Hi I think the WWVB PM stuff is relevant to Loran in the US. We have (pretty much) the most involved group of “customers” for that signal here on the list. As far as I have seen, the only project that has gone past the talk stage is the converter to drive the old(er) WWVB gear. Even with our level of interest, there are no working decoder projects out there. We may not be the main target audience, but we are the ones most likely to toss together a home built receiver. Dropping something like Loran into an already working system faces the same sort of barriers. If the system is working (now) - why bother? If it’s not working, do the minimum cost (time / risk / labor) fix for the issue. Explaining to the boss why the (say) 5X higher cost solution is the one you picked is not going to get very far. Giving the same explanation to grandmother (when her bill goes up) is going to be a bit harder still. I would not be surprised if the number of GPS equipped devices US exceeded the population by some signifiant factor. They get used. The total population of Loran gear that was in use (not in storage, not in a rack powered down) in the US in 2000 probably would fit in my garage. The market speaks….. Bob On Jul 15, 2015, at 10:33 PM, Brian Inglis brian.ing...@systematicsw.ab.ca wrote: Look at how well a couple of projects have gone: o privatize NIST NTP server operation - the NTP pool is recommended everywhere and good enough for most; separate providers supply high accuracy, precision, and stability timing for financial markets internationally; and GPS serves the rest o provide WWVB PM decoders - older precision timing equipment no longer works; but compatibility for RC Atomic clocks and watches was maintained; does not appear that there is any commercial interest in developing decoders; the new PM features might as well be dropped, or they could go back to the old AM format. See also the UT1 NTP service http://www.nist.gov/pml/div688/grp40/ut1_ntp_description.cfm which states it will use IERS schedule A data, and may offer only the weekly official projections rather than the daily rapid predictions, which vary by 0.1ms; they also mention providing DUT1 and EOP data as a text string from a separate service. They may be looking at this for a UTC like backup if the ITU drops the leapsecond. But the US, EU, Russia, China, and Japan can each afford a GNSS constellation, with upgraded features as desired. If a country can not provide an adequate market for products, then they will have to either do without a backup, ormake do with what markets elsewhere demand - eLoran. OTOH the civil business focus of currently successful projects leads me to hope that the ITU will be told to leave UTC alone as a legal and political requirement for solar civil time, use TAI or GPS time if they want to keep to a uniform time scale, or come up with a better time scale of their own. -- Take care. Thanks, Brian Inglis On 2015-07-14 16:49, Bob Camp wrote: Not to be to much of a downer here but ….. Loran for timing and an “Eastern WWVB” are two projects that seem to each have a life of their own. They seem to come up on some sort of cycle related to sun spots. Both have zero (or possibly less than that) percent mind share among those who would need to implement them into systems. Since there is major cost on the systems end, it would take “mandatory use” legislation to get them designed in. Without those design in’s, *having* a backup system is pretty useless. You are talking about billions of dollars and years of effort to hook them up …. If you are talking about “infinite budget” military systems, some of that may happen. I notice in the papers that “infinite budget” does not seem to apply to the US DOD these days. For commercial systems, nobody will significantly cut into profits to do something like this. Should they do this - sure. Will they do it - nope. On Jul 14, 2015, at 4:49 PM, paul swed paulsw...@gmail.com wrote: The reason to stay with the LORAN C style pulses is very very simple. It allows our time-nuts Austrons and SRS to work. Its the only way I get any of my tax dollars back. :-) The good news is no official government person reads time-nuts. On Tue, Jul 14, 2015 at 12:16 PM, Poul-Henning Kamp p...@phk.freebsd.dk wrote: In message 55a4ac81.1030...@rubidium.dyndns.org, Magnus Danielson writes: The safety is relative, in that it takes quite a bit of more infrastructure compared to the jamming of GPS, and that lies in the wavelength of the signal than anything else. If the goal is a reliable backup for GPS, there are smarter ways to use the 100kHz band than Loran-C pulses, and there really isn't much reason to stay compatible with Loran-C receivers. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
[time-nuts] E4437B phase noise spurs. Any ideas?
Hi, I just got a used/refurbished E4437B which I wanted to use as a all-purpose RF generator primarily for 3-4 GHz. Unfortunately, I'm seeing strange spurs for frequencies above 2.4 GHz, see the green curve in the attached image. The yellow curve is an SMIQ03 for comparison. Observations: - For frequencies below 2.4 GHz none of the spurs appear. - It has an OCXO and I left the device in standby (oven on) for 12 hours. - If I leave the device ON for 1-2 hours, the spurs go down. Anybody else seeing this? Any ideas how to fix this? Does this look like a pre-failure sign? Regards, Wolfgang DL1SKY ___ 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] Re GPS Leap Second
Hi All, I've just joined time nuts so go easy on me! An interesting 'moment' in time was had during the leap second! The Symmetricon 2100 I have is fitted with the modified Heol GPS. According to the video I took of the front LCD displays, it repeated the first second, ie 58,59,00,01,01,02,03 I have an NTP server from ESE (an ES295) that we use for HD video OSD It went 58,59,00,01,02,02,03,04 The NMEA string from my Motorola M12 units all went 23:59:58 23:59:59 23:59:60 00:00:00 00:00:01 00:00:02 They are now all in sync as would be expected All in all, an acceptable outcome if not the expected outcome provided one doesn't look too closely. W/r to the Heol GPS, it is much more sensitive than the original ACE module, locks on much faster and appears to solve the GPS week roll around issue as well. Service from Heol was excellent, the module being received within a week. We also have a lot of seismic monitoring recorders around Australia that had applied the advertised leap second in January, these have all now sorted them selves out (till next time). It made for interesting data processing and earthquake location extraction fun..not. bla...@bettanet.net.au Blair Lade South Australia --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus ___ 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] ULA launch of GPS IIF-10
After this launch -- the U.S. will decommission (retire) one the remaining II-A (Rockwell/Collins) GPS satellites launched in 1990s. According to my reference -- only 3 of those II-A birds are still active or in backup status. I would expect those 3 birds to be decommissioned by 2017. g. beat w9gb Sent from iPhone 5S ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
ZOn 15 Jul 2015 22:18, Poul-Henning Kamp p...@phk.freebsd.dk wrote: David Kirkby - Kirkby Microwave Ltd writes: What's the best sort of antenna for these? I use a $20 loop antenna I have rigged up myself, it lives in my attic: http://phk.freebsd.dk/loran-c/Antenna/ Hi, Thank you for that. But it is a bit short of information. I appreciate your use of the nearest bent nail principles, but roughly how many turns were there on the coil? Do you have a circuit for the amplifier? The AD797 data sheet you link to is broken, but the error message is quite funny. I found the data sheet on the AD797 and see it is a very low noise op-amp. I must admit to knowing next to nothing about antennas at the Loran 100 kHz (+/- a lot) frequency. How does one go about testing the antennas? I'm about to place an order for an FS700, but will not have an antenna when it arrives. I have a short period of right of return, and I'd like to get something in place so I can quickly test this. I have an HP 4284A precision LCR meter which works at more than 8000 discrete frequencies between 20 Hz 1 MHz. Those frequencies include 60, 80, 100, 120 and 150 kHz. That's the only thing I have got that measures impedance as low as 100 kHz. There's a description of the active antenna for the FS700 in the manual, but with no circuit diagram, it is a bit tricky to understand. I assume that the FS700 has some sort of bias-T to pass DC up the cable to power the amplifier - is that so? If so, do you know the voltage? No doubt all these things will be revealed when I get the FS700, but I'd like to be ready to test it when it arrives. ___ 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] UrsaNav LORAN next test date
Dan I have several 2100s and 2100Fs and they are a really good unit. Feed in your local reference and it will tell you the offset from the loran station. The loran signal typically uses 3 CS references. Certainly distance and propagation enter into the picture as far as accuracy goes. But as an alternate reference to GPS you can't complain. If you can find a marine loran c boat preamp and antenna you are in business. Regards Paul. WB8TSL On Thu, Jul 16, 2015 at 1:45 AM, D W watsondani...@gmail.com wrote: Paul, thanks for that info. Very interesting. I've been enjoying all of the Loran talk on the mailing list recently. I just picked up a NOS 2100F on eBay to play around with. Maybe I'll be able to do something useful with it one day if they continue with eLoran tests. Dan On Jul 15, 2015, at 1:17 PM, paul swed paulsw...@gmail.com wrote: I reached out to UrsaNav and asked when the next test would be. They were very responsive. Wildwood, NJ will be on air from 0900 (local) on 20 July until 0900 (local) on 23 July for an eLoran test. So fire up your Austrons and SRS units. There will be additional tests and they may be from different sites. UrsaNav plans to post the schedules on their site when it firms up. Regards Paul WB8TSL ___ 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] 10MHz Square to Sine Wave Conversion
re: 10MHz Square to Sine Wave Conversion The GPSDO I recently acquired outputs a 10 MHz square wave. I'd like to convert it to a sine wave and I am looking for suggestions and info re any reasonable pre-made circuits and/or boards. No sense reinventing the wheel if I can avoid it. Otherwise I will start from scratch and make a new wheel Thank you in advance for your replies. Regards, skipp skipp025 at yahoo dot com ___ 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] OCXO with ADEV of 1E-13 on Pluto Mission
On 7/16/15 8:17 AM, John Stuart wrote: Here is an interesting link to the New Horizons Mission to Pluto radio system design. Note last section describes an OCXO with ADEV = 1E-13 at 1s, and aging rate of 1E-11 per day. That's no ordinary OCXO. That's a USO made at APL. The crystal is in a special low stress holder, in a vacuum bottle with a very good temperature controller, etc. http://www.uhf-satcom.com/amateurdsn/Paper-969.pdf I wonder if their spares will show up on eBay? Nope, they get repurposed onto subsequent spacecraft. GRAIL spares are being used in GRACE follow on, etc. They are sort of the ultimate in crystal oscillators (at least domestically produced in the US). ___ 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] OCXO with ADEV of 1E-13 on Pluto Mission
The crystal in the ref osv. came from Bliley. The part number is BG-61. I have no idea what the current cost is, but like most very good oscillators the crystals were hand sorted and graded. -Brian, WA1ZMS iPhone On Jul 16, 2015, at 11:17 AM, John Stuart j.w.stu...@comcast.net wrote: Here is an interesting link to the New Horizons Mission to Pluto radio system design. Note last section describes an OCXO with ADEV = 1E-13 at 1s, and aging rate of 1E-11 per day. http://www.uhf-satcom.com/amateurdsn/Paper-969.pdf I wonder if their spares will show up on eBay? John Stuart, KM6QX Lafayette, CA ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
In message canx10hbuahdwachb+whlken4wcwn5_r2uen9ajzmnvl8axz...@mail.gmail.com , Dr. David Kirkby (Kirkby Microwave Ltd) writes: but roughly how many turns were there on the coil? Probably too many, all things considered, but I have *no* idea. Do you have a circuit for the amplifier? It was based on/inspired by a schematic I found on vlf.it I must admit to knowing next to nothing about antennas at the Loran 100 kHz (+/- a lot) frequency. How does one go about testing the antennas? Plug it into a spectrum analyzer or oscilloscope. Use average mode. Trigger with a pulse generator with a period of: 6731 * 2 * 10µs) = 0.13462 Hz and you should see the pulses. If you have a good spectrum analyzer, you can probably do this with a few meters of wire as antenna. The result should look something like: http://phk.freebsd.dk/misc/dscf0275.jpg That's the only thing I have got that measures impedance as low as 100 kHz. 100 kHz is practically audio, impedances hardly matter: The reflections have wavelengths measured in km. -- 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] OCXO with ADEV of 1E-13 on Pluto Mission
The link below is an updated version of the same paper: http://www.boulder.swri.edu/~tcase/NH%20RF%20Telecom%20Sys%20ID1369%20FINAL_Deboy.pdf It has considerably more detail on the RF components as well as the USO module for which there is an entire page of additional information and a block diagram. Whatever happened to the spare components probably happened a decade ago at any rate. Not that they wouldn't eventually wind their way to ebay anyway! Regards, John K5IT On Thu, Jul 16, 2015 at 10:17 AM, John Stuart j.w.stu...@comcast.net wrote: Here is an interesting link to the New Horizons Mission to Pluto radio system design. Note last section describes an OCXO with ADEV = 1E-13 at 1s, and aging rate of 1E-11 per day. http://www.uhf-satcom.com/amateurdsn/Paper-969.pdf I wonder if their spares will show up on eBay? John Stuart, KM6QX Lafayette, CA ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
Ole, What is the value of the 2E21 resistor? Looks like a typo. 2k? Feel inspired to rig up something for my FS700. Will wooden frame my TP-cable wired to form a 8 turns times the cable-turns. Cheers, Magnus On 07/16/2015 09:05 AM, Ole Stender Nielsen wrote: I use a home-made untuned loop antenna with 4 windings of 2.5 mm2 insulated wire on a 80 x 80 cm wooden frame, and with a grounded base pre-amplifier mounted on the antenna frame. A schematic is enclosed for you to copy. The pre-amplifier is powered through the cable, and loads the FS700 input as required. I live about 290 km from the island of Sylt, and get nice noise margin figures from the FS700, normally about 40 dB, often up to 46 dB. For larger distances to the transmitter site, you may need to insert additional amplification between the grounded base pre-amplifier and the FS700, and that requires that you provide power to the pre-amplifier through a bias Tee, and that you load the FS700 input to keep it happy. A while after I installed the antenna in the attic, I added additional amplification, not due to a low signal level, but because I wanted to use the loop antenna for other longwave services too, and that required that I had to split out the signal. Best regards Ole Den 15-07-2015 kl. 18:02 skrev Dr. David Kirkby - Kirkby Microwave Ltd : Does anyone know of the latest firmware for the Stanford Research FS700 Loran-C frequency standard? I know someone who has one with firmware 1.20, but I don't know if there's any later firmware. I recall asking Stanford Research about firmware for the SR620 but got no response, so I don't know if I will have any better luck with the FS700. What's the best sort of antenna for these? I know Stanford sell one, and by the cost of new professional equipment, the $250 is not abnormally high, but I'd rather look at building something if I purchase one of these standards. I did think of using a half-wave dipole, but my garden is just a wee bit too small.:-) Dave ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
Hi Magnus, The 2E21 is a 2.21 Ohms resistor. The RC network was found useful to ensure loading at higher frequencies. Best regards Ole Den 16-07-2015 kl. 18:27 skrev Magnus Danielson: Ole, What is the value of the 2E21 resistor? Looks like a typo. 2k? Feel inspired to rig up something for my FS700. Will wooden frame my TP-cable wired to form a 8 turns times the cable-turns. Cheers, Magnus On 07/16/2015 09:05 AM, Ole Stender Nielsen wrote: I use a home-made untuned loop antenna with 4 windings of 2.5 mm2 insulated wire on a 80 x 80 cm wooden frame, and with a grounded base pre-amplifier mounted on the antenna frame. A schematic is enclosed for you to copy. The pre-amplifier is powered through the cable, and loads the FS700 input as required. I live about 290 km from the island of Sylt, and get nice noise margin figures from the FS700, normally about 40 dB, often up to 46 dB. For larger distances to the transmitter site, you may need to insert additional amplification between the grounded base pre-amplifier and the FS700, and that requires that you provide power to the pre-amplifier through a bias Tee, and that you load the FS700 input to keep it happy. A while after I installed the antenna in the attic, I added additional amplification, not due to a low signal level, but because I wanted to use the loop antenna for other longwave services too, and that required that I had to split out the signal. Best regards Ole Den 15-07-2015 kl. 18:02 skrev Dr. David Kirkby - Kirkby Microwave Ltd : Does anyone know of the latest firmware for the Stanford Research FS700 Loran-C frequency standard? I know someone who has one with firmware 1.20, but I don't know if there's any later firmware. I recall asking Stanford Research about firmware for the SR620 but got no response, so I don't know if I will have any better luck with the FS700. What's the best sort of antenna for these? I know Stanford sell one, and by the cost of new professional equipment, the $250 is not abnormally high, but I'd rather look at building something if I purchase one of these standards. I did think of using a half-wave dipole, but my garden is just a wee bit too small.:-) Dave ___ 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] Firmware and antenna for Stanford Research FS700 Loran C frequency standard
Hi Quick and simple: 1) Signal power is proportional to the area of the loop. Bigger is better. 2) Inductance is proportional to the turns squared. Turns do not directly affect signal to noise. 3) Inductance may be resonated with a capacitor. This gives a bandpass function. 4) The coil shapes are very common. The many inductance calculators on the web will give you an inductance estimate. 5) If the inductance is resonated, the system Q (and thus bandwidth) is a function of the coil losses and the amplifier’s input impedance. 6) More turns gives a power match into a higher impedance ( more voltage). 7) *Practical* matching of the amplifier to the antenna will give you an reasonable target number of turns. Bob On Jul 16, 2015, at 9:57 AM, Dr. David Kirkby (Kirkby Microwave Ltd) drkir...@kirkbymicrowave.co.uk wrote: ZOn 15 Jul 2015 22:18, Poul-Henning Kamp p...@phk.freebsd.dk wrote: David Kirkby - Kirkby Microwave Ltd writes: What's the best sort of antenna for these? I use a $20 loop antenna I have rigged up myself, it lives in my attic: http://phk.freebsd.dk/loran-c/Antenna/ Hi, Thank you for that. But it is a bit short of information. I appreciate your use of the nearest bent nail principles, but roughly how many turns were there on the coil? Do you have a circuit for the amplifier? The AD797 data sheet you link to is broken, but the error message is quite funny. I found the data sheet on the AD797 and see it is a very low noise op-amp. I must admit to knowing next to nothing about antennas at the Loran 100 kHz (+/- a lot) frequency. How does one go about testing the antennas? I'm about to place an order for an FS700, but will not have an antenna when it arrives. I have a short period of right of return, and I'd like to get something in place so I can quickly test this. I have an HP 4284A precision LCR meter which works at more than 8000 discrete frequencies between 20 Hz 1 MHz. Those frequencies include 60, 80, 100, 120 and 150 kHz. That's the only thing I have got that measures impedance as low as 100 kHz. There's a description of the active antenna for the FS700 in the manual, but with no circuit diagram, it is a bit tricky to understand. I assume that the FS700 has some sort of bias-T to pass DC up the cable to power the amplifier - is that so? If so, do you know the voltage? No doubt all these things will be revealed when I get the FS700, but I'd like to be ready to test it when it arrives. ___ 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] Ublox LEA-6T CFG-PRT command question
I want to change the UART1 port speed on my LEA-6T via message string from my GPSDO board. I had assumed that I would have to discover (or know) the baud rate already set on the LEA-6T in order to change it. But it appears that the LEA-6T can receive messages at any baud rate, but you need to send baud rate change commands at the baud rate you wish to change it to. Can anyone verify if this is the case? I can't find anything in the documentation I have that addresses this question. Maybe it's just obvious to everyone else? Bob - AE6RV ___ 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] OCXO with ADEV of 1E-13 on Pluto Mission
Hi There are some amazing things you can afford to do when you are targeting a 20 pcs / year market and have dozens of people to work on the product. Bob On Jul 16, 2015, at 3:24 PM, Brian, WA1ZMS wa1...@att.net wrote: The crystal in the ref osv. came from Bliley. The part number is BG-61. I have no idea what the current cost is, but like most very good oscillators the crystals were hand sorted and graded. -Brian, WA1ZMS iPhone On Jul 16, 2015, at 11:17 AM, John Stuart j.w.stu...@comcast.net wrote: Here is an interesting link to the New Horizons Mission to Pluto radio system design. Note last section describes an OCXO with ADEV = 1E-13 at 1s, and aging rate of 1E-11 per day. http://www.uhf-satcom.com/amateurdsn/Paper-969.pdf I wonder if their spares will show up on eBay? John Stuart, KM6QX Lafayette, CA ___ 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] OCXO with ADEV of 1E-13 on Pluto Mission
I'm not sure what happened to all of the spares, but I do know that the spare bird was assembled, coddled, polished, and hung from the ceiling of the Udvar Hazy Air and Space Museum in Chantilly, Virginia. I think everything is there except for the RPG, and Tombaugh's ashes. I'm pretty sure it even has a copy of the disk that has all of our names stored in it. My wife designed some of the ASICs used in New Horizons. -Chuck Harris John Laur wrote: The link below is an updated version of the same paper: http://www.boulder.swri.edu/~tcase/NH%20RF%20Telecom%20Sys%20ID1369%20FINAL_Deboy.pdf It has considerably more detail on the RF components as well as the USO module for which there is an entire page of additional information and a block diagram. Whatever happened to the spare components probably happened a decade ago at any rate. Not that they wouldn't eventually wind their way to ebay anyway! Regards, John K5IT ___ 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] UrsaNav LORAN next test date
The Dymec 100 active antenna systems are also a good choice and don't require a DC block between the Austron and antennas As they are split into an indoor and outdoor unit Content by Scott Typos by Siri On Jul 16, 2015, at 9:09 AM, paul swed paulsw...@gmail.com wrote: Dan I have several 2100s and 2100Fs and they are a really good unit. Feed in your local reference and it will tell you the offset from the loran station. The loran signal typically uses 3 CS references. Certainly distance and propagation enter into the picture as far as accuracy goes. But as an alternate reference to GPS you can't complain. If you can find a marine loran c boat preamp and antenna you are in business. Regards Paul. WB8TSL On Thu, Jul 16, 2015 at 1:45 AM, D W watsondani...@gmail.com wrote: Paul, thanks for that info. Very interesting. I've been enjoying all of the Loran talk on the mailing list recently. I just picked up a NOS 2100F on eBay to play around with. Maybe I'll be able to do something useful with it one day if they continue with eLoran tests. Dan On Jul 15, 2015, at 1:17 PM, paul swed paulsw...@gmail.com wrote: I reached out to UrsaNav and asked when the next test would be. They were very responsive. Wildwood, NJ will be on air from 0900 (local) on 20 July until 0900 (local) on 23 July for an eLoran test. So fire up your Austrons and SRS units. There will be additional tests and they may be from different sites. UrsaNav plans to post the schedules on their site when it firms up. Regards Paul WB8TSL ___ 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.
