[time-nuts] Re: PN2060C Phase Noise Analyzer progress
drew wollin
drew_wollin at hotmail.com
Mon Sep 25 09:25:00 UTC 2023
Hi All
There is some progress on PN2060C/D Phase Noise Analyzer development per the bg6khc website update update on 22 Sept.
The prototype of the new PN2060C with 4 ADCs is running and looking very good.
Regards Drew VK4ZXI
https://qsl.net/bg6khc/pn2060c_phase_noise_analyzer.htm
________________________________
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Subject: time-nuts Digest, Vol 233, Issue 24
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Today's Topics:
1. Re: Anyone else have their Loran receiver locked? (KR7D Scott)
2. Re: Eloran long test from now to August or September.
(David Taylor)
3. Re: Eloran long test from now to August or September. (paul swed)
4. Re: Eloran long test from now to August or September. (Bob Camp)
5. Re: Eloran long test from now to August or September. (Jim Lux)
6. Re: Eloran long test from now to August or September.
(JOHN HARTZELL)
7. Re: Eloran long test from now to August or September.
(jeanmichel.friedt at femto-st.fr)
8. Re: Eloran long test from now to August or September.
(Poul-Henning Kamp)
----------------------------------------------------------------------
Message: 1
Date: Sat, 23 Sep 2023 21:08:40 -0700
From: KR7D Scott <kr7d.scott at gmail.com>
Subject: [time-nuts] Re: Anyone else have their Loran receiver locked?
To: Discussion of precise time and frequency measurement
<time-nuts at lists.febo.com>
Message-ID: <CBB17895-6EFA-48A7-8FAD-0600029D2405 at gmail.com>
Content-Type: multipart/mixed;
boundary=Apple-Mail-24E47AB5-3E6D-4572-BB0B-C5832AF65468
For what it’s worth
I tuned my ham transceiver (unlocked icom 7610) to 100 kHz, with an 80-10 inverted V at 15 meters (outside of Portland OR). And to my surprise there are S9 pulses that sound like a tiny jackhammer. Wow!
Other than buying a 20th century legacy dedicated device to decode, are there any newer (SDR) suggestions? I have RPi and RSPn
Thanks,
Scott KR7D
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Sent from my iPhone
> On Sep 23, 2023, at 6:38 PM, Shaun Merrigan via time-nuts <time-nuts at lists.febo.com> wrote:
>
> I recommissioned my SRS FS700 (Option 1 unit) several days ago. It has been locked continuously for 84 hours (no unlocks reported). It is locked one of the slave stations as it also reports that there is no master station. At the moment frequency difference with the reference (GPS, Z3801) is 2E-11 . At this point I think I will put it in a rack with the Austron 2100F and let them run (why not?).
>
> I did note that the FS700 took much longer (45min - 1 hour) to achieve lock than did the Austrons (2100F, 2100R). My antenna is an LF engineering L-400B with about 16dB of attenuation in the line to get the best s/n. I am using the 420 ohm resistor hack to make the FS700 believe it is feeding an active antenna.
>
> With the changing geopolitical climate perhaps eLORAN will be here to stay.
>
> Shaun M (Central Alberta)
>
> -----Original Message-----
> From: Rodger via time-nuts <time-nuts at lists.febo.com>
> Sent: Friday, September 22, 2023 9:15 AM
> To: 'Discussion of precise time and frequency measurement' <time-nuts at lists.febo.com>
> Cc: 'Don Moman VE6JY' <ve6jy.1 at gmail.com>; rodger_adams at yahoo.com
> Subject: [time-nuts] Re: Anyone else have their Loran receiver locked?
>
> I'm trying my best to receive it in Charlotte, NC., though I realize it's probably a fool's errand. I have an Austron 2100 T with loop antenna. I've seen a green tracking light twice in the last few weeks. I'm trying to set up some monitoring with a virtual chart recorder to see if it might actually be locking occasionally. My 2100T has a GPIB interface so might see if it could be used to catch an occasional intermittent lock. I'm not expecting much, but it's fun to try.
>
> Rodger
>
>
> -----Original Message-----
> From: Don Moman VE6JY via time-nuts <time-nuts at lists.febo.com>
> Sent: Thursday, September 21, 2023 11:18 PM
> To: Discussion of precise time and frequency measurement <time-nuts at lists.febo.com>
> Cc: Don Moman VE6JY <ve6jy.1 at gmail.com>
> Subject: [time-nuts] Re: Anyone else have their Loran receiver locked?
>
> 100 khz seems active here in Alberta. here's my KIWI display a few minutes
> ago:
> [image: 2023-09-21 21_15_51.jpg]
>
>
>> On Thu, Sep 21, 2023 at 5:36 PM Skip Withrow via time-nuts < time-nuts at lists.febo.com> wrote:
>>
>> Well, I think I am a little late to the eLoran party. After trying
>> the old Austron 2100 in the city with no (well, a little) success. I
>> took it up to the mountain house yesterday to try it in a quieter
>> environment. No luck last night, so I checked a west coast SDR
>> receiver and see no sign of the eLoran signal.
>>
>> I assume that the test has been ended. If/when the eLoran signal
>> comes back I would be interested in knowing. Or, if someone is still
>> locked up please let us know. My assumption is that the tests are with GRI 5990.
>>
>> Regards,
>> Skip Withrow
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at lists.febo.com To unsubscribe send
>> an email to time-nuts-leave at lists.febo.com
>>
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------------------------------
Message: 2
Date: Sun, 24 Sep 2023 14:14:58 +0100
From: David Taylor <david-taylor at blueyonder.co.uk>
Subject: [time-nuts] Re: Eloran long test from now to August or
September.
To: time-nuts at lists.febo.com
Message-ID: <e5007d0c-6e17-4b26-b688-c957a4b3c3bd at blueyonder.co.uk>
Content-Type: text/plain; charset=UTF-8; format=flowed
On 15/09/2023 14:43, john.haine--- via time-nuts wrote:
> This discussion reminds me, there is one eLoran station operating in the UK,
> co-located with the MSF transmitter at Anthorn, for research purposes. There is
> also some discussion about licensing some new operators mainly for timing
> purposes. Does anyone have any information on the coverage available from
> Anthorn please? John.
Yes, I can confirm reception in Edinburgh using a Youloop antenna in an
attached garage.
So, is there any sort of software decoder for the signal? I don't have a
specialised hardware receiver, just the usual SDR boxes including an Airspy HF+
Discovery.
Thanks,
David
--
SatSignal Software - Quality software for you
Web: https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.satsignal.eu%2F&data=05%7C01%7C%7Cd4f7fde0013849edb7ae08dbbd9948c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638312238320138711%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=s86kHcL3V18Ralc2RiQg4Ru2KEdUOmBkm2unHI8tKRI%3D&reserved=0<https://www.satsignal.eu/>
Email: david-taylor at blueyonder.co.uk
Twitter: @gm8arv
------------------------------
Message: 3
Date: Sun, 24 Sep 2023 11:47:47 -0400
From: paul swed <paulswedb at gmail.com>
Subject: [time-nuts] Re: Eloran long test from now to August or
September.
To: Discussion of precise time and frequency measurement
<time-nuts at lists.febo.com>
Message-ID:
<CAD2JfAjTFHmw+QBdbHO8WDZ-GwcVqOeHOGoFwvkjRnYGSp+NyQ at mail.gmail.com>
Content-Type: text/plain; charset="UTF-8"
David
There have been various things posted in the past that have required A/Ds
and such. Poul here on Time-nuts did a semi software version. (I think) But
the fact is the old LORAN C receivers for frequency are a great way to go.
The only difference between LORAN C and eLORAN is the 9th pulse used as a
data channel. There was no 9th pulse in the old LORAN C. I have not seen
anything that describes the coding. It may be out there but I haven't been
interested in that. For many of us its an alternate very accurate Cesium
referenced source.
How it all develops if the governments supports it will be pretty
interesting. Certainly the old positioning is possible. The data channel
can provide propagation behaviors to allow for very accurate time and
positioning. The new generation receivers will all be SDR based.
I have actually seen an operational prototype numbers of years ago.
Regards
Paul
WB8TSL
On Sun, Sep 24, 2023 at 11:04 AM David Taylor via time-nuts <
time-nuts at lists.febo.com> wrote:
> On 15/09/2023 14:43, john.haine--- via time-nuts wrote:
> > This discussion reminds me, there is one eLoran station operating in the
> UK,
> > co-located with the MSF transmitter at Anthorn, for research purposes.
> There is
> > also some discussion about licensing some new operators mainly for
> timing
> > purposes. Does anyone have any information on the coverage available
> from
> > Anthorn please? John.
>
> Yes, I can confirm reception in Edinburgh using a Youloop antenna in an
> attached garage.
>
> So, is there any sort of software decoder for the signal? I don't have a
> specialised hardware receiver, just the usual SDR boxes including an
> Airspy HF+
> Discovery.
>
> Thanks,
> David
> --
> SatSignal Software - Quality software for you
> Web: https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.satsignal.eu%2F&data=05%7C01%7C%7Cd4f7fde0013849edb7ae08dbbd9948c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638312238320138711%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=s86kHcL3V18Ralc2RiQg4Ru2KEdUOmBkm2unHI8tKRI%3D&reserved=0<https://www.satsignal.eu/>
> Email: david-taylor at blueyonder.co.uk
> Twitter: @gm8arv
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe send an email to time-nuts-leave at lists.febo.com
>
------------------------------
Message: 4
Date: Sun, 24 Sep 2023 12:38:34 -0400
From: Bob Camp <kb8tq at n1k.org>
Subject: [time-nuts] Re: Eloran long test from now to August or
September.
To: Discussion of precise time and frequency measurement
<time-nuts at lists.febo.com>
Message-ID: <B77D5EFA-170B-4631-8117-99BA59C8AFDD at n1k.org>
Content-Type: text/plain; charset=utf-8
Hi
The issue with doing this with a low cost SDR board is not so much receiving / demodulating the
signal. It’s a pretty good bet somebody out there has been there / done that. The issue is pulling
an accurate “time pulse†out of your typical SDR setup. This is a somewhat unusual thing to want
to do. Finding a “stock†setup on a low cost board that does this will be a bit of a challenge.
Bob
> On Sep 24, 2023, at 11:47 AM, paul swed via time-nuts <time-nuts at lists.febo.com> wrote:
>
> David
> There have been various things posted in the past that have required A/Ds
> and such. Poul here on Time-nuts did a semi software version. (I think) But
> the fact is the old LORAN C receivers for frequency are a great way to go.
> The only difference between LORAN C and eLORAN is the 9th pulse used as a
> data channel. There was no 9th pulse in the old LORAN C. I have not seen
> anything that describes the coding. It may be out there but I haven't been
> interested in that. For many of us its an alternate very accurate Cesium
> referenced source.
> How it all develops if the governments supports it will be pretty
> interesting. Certainly the old positioning is possible. The data channel
> can provide propagation behaviors to allow for very accurate time and
> positioning. The new generation receivers will all be SDR based.
> I have actually seen an operational prototype numbers of years ago.
> Regards
> Paul
> WB8TSL
>
> On Sun, Sep 24, 2023 at 11:04 AM David Taylor via time-nuts <
> time-nuts at lists.febo.com> wrote:
>
>> On 15/09/2023 14:43, john.haine--- via time-nuts wrote:
>>> This discussion reminds me, there is one eLoran station operating in the
>> UK,
>>> co-located with the MSF transmitter at Anthorn, for research purposes.
>> There is
>>> also some discussion about licensing some new operators mainly for
>> timing
>>> purposes. Does anyone have any information on the coverage available
>> from
>>> Anthorn please? John.
>>
>> Yes, I can confirm reception in Edinburgh using a Youloop antenna in an
>> attached garage.
>>
>> So, is there any sort of software decoder for the signal? I don't have a
>> specialised hardware receiver, just the usual SDR boxes including an
>> Airspy HF+
>> Discovery.
>>
>> Thanks,
>> David
>> --
>> SatSignal Software - Quality software for you
>> Web: https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.satsignal.eu%2F&data=05%7C01%7C%7Cd4f7fde0013849edb7ae08dbbd9948c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638312238320138711%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=s86kHcL3V18Ralc2RiQg4Ru2KEdUOmBkm2unHI8tKRI%3D&reserved=0<https://www.satsignal.eu/>
>> Email: david-taylor at blueyonder.co.uk
>> Twitter: @gm8arv
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at lists.febo.com
>> To unsubscribe send an email to time-nuts-leave at lists.febo.com
>>
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe send an email to time-nuts-leave at lists.febo.com
------------------------------
Message: 5
Date: Sun, 24 Sep 2023 15:10:11 -0400
From: "Jim Lux" <jim at luxfamily.com>
Subject: [time-nuts] Re: Eloran long test from now to August or
September.
To: time-nuts at lists.febo.com
Cc:
Message-ID:
<1695582611.cx2tbgb6og4g0ooc at webmail.hosting.earthlink.net>
Content-Type: text/plain; charset=UTF-8
I agree. Most inexpensive SDRs, and more particularly, the gnuradio or other software, tends not to be designed for deterministic timing. It is true that you can run some tests and empirically determine the delay through the software, but then, you have to worry about the non-deterministic behavior of the host OS.
Typically, what you’d need is to simultaneously grab a counter running off the sample clock AND the ADC samples (presumably decimated in the hardware), and then you can deal with the uncertainty, and generate a count that can be compared against that same counter to generate an output pulse. Most of the SDR hardware out there uses one of the multitude of chips that implements some form of pre filtering and decimation and post filtering - but those are typically deterministic in delay. It’s everything after the interface to the host processor that’s non deterministic.
Now, if you’re implementing the SDR on a dedicated processor, with no OS, and careful use of interrupts, you can do it. But that’s what commercial timing receivers do.
On Sun, 24 Sep 2023 12:38:34 -0400, Bob Camp via time-nuts <time-nuts at lists.febo.com> wrote:
Hi
The issue with doing this with a low cost SDR board is not so much receiving / demodulating the
signal. It’s a pretty good bet somebody out there has been there / done that. The issue is pulling
an accurate “time pulse†out of your typical SDR setup. This is a somewhat unusual thing to want
to do. Finding a “stock†setup on a low cost board that does this will be a bit of a challenge.
Bob
> On Sep 24, 2023, at 11:47 AM, paul swed via time-nuts wrote:
>
> David
> There have been various things posted in the past that have required A/Ds
> and such. Poul here on Time-nuts did a semi software version. (I think) But
> the fact is the old LORAN C receivers for frequency are a great way to go.
> The only difference between LORAN C and eLORAN is the 9th pulse used as a
> data channel. There was no 9th pulse in the old LORAN C. I have not seen
> anything that describes the coding. It may be out there but I haven't been
> interested in that. For many of us its an alternate very accurate Cesium
> referenced source.
> How it all develops if the governments supports it will be pretty
> interesting. Certainly the old positioning is possible. The data channel
> can provide propagation behaviors to allow for very accurate time and
> positioning. The new generation receivers will all be SDR based.
> I have actually seen an operational prototype numbers of years ago.
> Regards
> Paul
> WB8TSL
>
> On Sun, Sep 24, 2023 at 11:04 AM David Taylor via time-nuts <
> time-nuts at lists.febo.com> wrote:
>
>> On 15/09/2023 14:43, john.haine--- via time-nuts wrote:
>>> This discussion reminds me, there is one eLoran station operating in the
>> UK,
>>> co-located with the MSF transmitter at Anthorn, for research purposes.
>> There is
>>> also some discussion about licensing some new operators mainly for
>> timing
>>> purposes. Does anyone have any information on the coverage available
>> from
>>> Anthorn please? John.
>>
>> Yes, I can confirm reception in Edinburgh using a Youloop antenna in an
>> attached garage.
>>
>> So, is there any sort of software decoder for the signal? I don't have a
>> specialised hardware receiver, just the usual SDR boxes including an
>> Airspy HF+
>> Discovery.
>>
>> Thanks,
>> David
>> --
>> SatSignal Software - Quality software for you
>> Web: https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.satsignal.eu%2F&data=05%7C01%7C%7Cd4f7fde0013849edb7ae08dbbd9948c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638312238320138711%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=s86kHcL3V18Ralc2RiQg4Ru2KEdUOmBkm2unHI8tKRI%3D&reserved=0<https://www.satsignal.eu/>
>> Email: david-taylor at blueyonder.co.uk
>> Twitter: @gm8arv
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at lists.febo.com
>> To unsubscribe send an email to time-nuts-leave at lists.febo.com
>>
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe send an email to time-nuts-leave at lists.febo.com
_______________________________________________
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To unsubscribe send an email to time-nuts-leave at lists.febo.com
------------------------------
Message: 6
Date: Sun, 24 Sep 2023 19:31:24 +0200
From: JOHN HARTZELL <johnhartzell at icloud.com>
Subject: [time-nuts] Re: Eloran long test from now to August or
September.
To: Discussion of precise time and frequency measurement
<time-nuts at lists.febo.com>
Message-ID: <A5B42A23-EEED-4A9D-9D56-81B37538701B at icloud.com>
Content-Type: text/plain; charset=utf-8
One word - UrsaNav.
Kind regards,
John
https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flinkedin.com%2Fin%2Fjohn-h-6a131b12%2F&data=05%7C01%7C%7Cd4f7fde0013849edb7ae08dbbd9948c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638312238320138711%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=VJhqaZ1cB36seIOULr5UHnaogB3f2OOeBxcoePiuo40%3D&reserved=0<https://linkedin.com/in/john-h-6a131b12/>
> On Sep 24, 2023, at 7:24 PM, Bob Camp via time-nuts <time-nuts at lists.febo.com> wrote:
>
> Hi
>
> The issue with doing this with a low cost SDR board is not so much receiving / demodulating the
> signal. It’s a pretty good bet somebody out there has been there / done that. The issue is pulling
> an accurate “time pulse†out of your typical SDR setup. This is a somewhat unusual thing to want
> to do. Finding a “stock†setup on a low cost board that does this will be a bit of a challenge.
>
> Bob
>
>> On Sep 24, 2023, at 11:47 AM, paul swed via time-nuts <time-nuts at lists.febo.com> wrote:
>>
>> David
>> There have been various things posted in the past that have required A/Ds
>> and such. Poul here on Time-nuts did a semi software version. (I think) But
>> the fact is the old LORAN C receivers for frequency are a great way to go.
>> The only difference between LORAN C and eLORAN is the 9th pulse used as a
>> data channel. There was no 9th pulse in the old LORAN C. I have not seen
>> anything that describes the coding. It may be out there but I haven't been
>> interested in that. For many of us its an alternate very accurate Cesium
>> referenced source.
>> How it all develops if the governments supports it will be pretty
>> interesting. Certainly the old positioning is possible. The data channel
>> can provide propagation behaviors to allow for very accurate time and
>> positioning. The new generation receivers will all be SDR based.
>> I have actually seen an operational prototype numbers of years ago.
>> Regards
>> Paul
>> WB8TSL
>>
>>> On Sun, Sep 24, 2023 at 11:04 AM David Taylor via time-nuts <
>>> time-nuts at lists.febo.com> wrote:
>>>
>>> On 15/09/2023 14:43, john.haine--- via time-nuts wrote:
>>>> This discussion reminds me, there is one eLoran station operating in the
>>> UK,
>>>> co-located with the MSF transmitter at Anthorn, for research purposes.
>>> There is
>>>> also some discussion about licensing some new operators mainly for
>>> timing
>>>> purposes. Does anyone have any information on the coverage available
>>> from
>>>> Anthorn please? John.
>>>
>>> Yes, I can confirm reception in Edinburgh using a Youloop antenna in an
>>> attached garage.
>>>
>>> So, is there any sort of software decoder for the signal? I don't have a
>>> specialised hardware receiver, just the usual SDR boxes including an
>>> Airspy HF+
>>> Discovery.
>>>
>>> Thanks,
>>> David
>>> --
>>> SatSignal Software - Quality software for you
>>> Web: https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.satsignal.eu%2F&data=05%7C01%7C%7Cd4f7fde0013849edb7ae08dbbd9948c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638312238320138711%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=s86kHcL3V18Ralc2RiQg4Ru2KEdUOmBkm2unHI8tKRI%3D&reserved=0<https://www.satsignal.eu/>
>>> Email: david-taylor at blueyonder.co.uk
>>> Twitter: @gm8arv
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at lists.febo.com
>>> To unsubscribe send an email to time-nuts-leave at lists.febo.com
>>>
>> _______________________________________________
>> time-nuts mailing list -- time-nuts at lists.febo.com
>> To unsubscribe send an email to time-nuts-leave at lists.febo.com
> _______________________________________________
> time-nuts mailing list -- time-nuts at lists.febo.com
> To unsubscribe send an email to time-nuts-leave at lists.febo.com
------------------------------
Message: 7
Date: Sun, 24 Sep 2023 19:59:12 +0000
From: jeanmichel.friedt at femto-st.fr
Subject: [time-nuts] Re: Eloran long test from now to August or
September.
To: "Discussion of precise time and frequency measurement"
<time-nuts at lists.febo.com>
Message-ID: <f1a9997543d8e29360e1f853f8f4276f at femto-st.fr>
Content-Type: text/plain; charset="utf-8"
> I agree. Most inexpensive SDRs, and more particularly, the gnuradio or other software, tends not
> to be designed for deterministic timing. It is true that you can run some tests and empirically
> determine the delay through the software, but then, you have to worry about the non-deterministic
> behavior of the host OS.
If I may disagree, the only part that matters when generating a timing information
from a SDR is the knowledge that not a single sample is lost in the periodic acquisition
by the ADC, and the time information encoded in the received message. Since both
information propagate through the asynchronous processing chain at the same rate, they
end up being decoded simultaneously and can be compared with each other to adjust e.g.
the clock of the ADC which also acts as the source of the 1-PPS generator. This is at
least what we did in https://aus01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fjmfriedt.free.fr%2Fifcs2021.pdf&data=05%7C01%7C%7Cd4f7fde0013849edb7ae08dbbd9948c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638312238320138711%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=mKPgd1iIXDBleOV5LEs9AvH0iLkBNZFIPBpTGGTn%2Bkw%3D&reserved=0:<http://jmfriedt.free.fr/ifcs2021.pdf> our initial error in this
investigation was indeed to try and steer the GP-CPU clock and use it to generate the
timing information, when the only deterministic part of the processing is in the FPGA
clocking the ADC.
Best, Jean-Michel
>
> Typically, what you’d need is to simultaneously grab a counter running off the sample clock AND the
> ADC samples (presumably decimated in the hardware), and then you can deal with the uncertainty, and
> generate a count that can be compared against that same counter to generate an output pulse. Most
> of the SDR hardware out there uses one of the multitude of chips that implements some form of pre
> filtering and decimation and post filtering - but those are typically deterministic in delay. It’s
> everything after the interface to the host processor that’s non deterministic.
>
> Now, if you’re implementing the SDR on a dedicated processor, with no OS, and careful use of
> interrupts, you can do it. But that’s what commercial timing receivers do.
>
> On Sun, 24 Sep 2023 12:38:34 -0400, Bob Camp via time-nuts <time-nuts at lists.febo.com> wrote:
>
> Hi
>
> The issue with doing this with a low cost SDR board is not so much receiving / demodulating the
> signal. It’s a pretty good bet somebody out there has been there / done that. The issue is pulling
> an accurate “time pulse†out of your typical SDR setup. This is a somewhat unusual thing to want
> to do. Finding a “stock†setup on a low cost board that does this will be a bit of a challenge.
>
> Bob
>
>> On Sep 24, 2023, at 11:47 AM, paul swed via time-nuts wrote:
>>
>> David
>> There have been various things posted in the past that have required A/Ds
>> and such. Poul here on Time-nuts did a semi software version. (I think) But
>> the fact is the old LORAN C receivers for frequency are a great way to go.
>> The only difference between LORAN C and eLORAN is the 9th pulse used as a
>> data channel. There was no 9th pulse in the old LORAN C. I have not seen
>> anything that describes the coding. It may be out there but I haven't been
>> interested in that. For many of us its an alternate very accurate Cesium
>> referenced source.
>> How it all develops if the governments supports it will be pretty
>> interesting. Certainly the old positioning is possible. The data channel
>> can provide propagation behaviors to allow for very accurate time and
>> positioning. The new generation receivers will all be SDR based.
>> I have actually seen an operational prototype numbers of years ago.
>> Regards
>> Paul
>> WB8TSL
>>
>> On Sun, Sep 24, 2023 at 11:04 AM David Taylor via time-nuts <
>> time-nuts at lists.febo.com> wrote:
>>
>>> On 15/09/2023 14:43, john.haine--- via time-nuts wrote:
>>
>> This discussion reminds me, there is one eLoran station operating in the
>>> UK,
>>
>> co-located with the MSF transmitter at Anthorn, for research purposes.
>>> There is
>>
>> also some discussion about licensing some new operators mainly for
>>> timing
>>
>> purposes. Does anyone have any information on the coverage available
>>> from
>>
>> Anthorn please? John.
>>> Yes, I can confirm reception in Edinburgh using a Youloop antenna in an
>>> attached garage.
>>>
>>> So, is there any sort of software decoder for the signal? I don't have a
>>> specialised hardware receiver, just the usual SDR boxes including an
>>> Airspy HF+
>>> Discovery.
>>>
>>> Thanks,
>>> David
>>> --
>>> SatSignal Software - Quality software for you
>>> Web: https://aus01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.satsignal.eu%2F&data=05%7C01%7C%7Cd4f7fde0013849edb7ae08dbbd9948c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638312238320138711%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=s86kHcL3V18Ralc2RiQg4Ru2KEdUOmBkm2unHI8tKRI%3D&reserved=0<https://www.satsignal.eu/>
>>> Email: david-taylor at blueyonder.co.uk
>>> Twitter: @gm8arv
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at lists.febo.com
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>>
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------------------------------
Message: 8
Date: Sun, 24 Sep 2023 20:08:26 +0000
From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
Subject: [time-nuts] Re: Eloran long test from now to August or
September.
To: Discussion of precise time and frequency measurement
<time-nuts at lists.febo.com>
Message-ID: <202309242008.38OK8Q8l011599 at critter.freebsd.dk>
Content-Type: text/plain; charset="us-ascii"
If you want to receive Loran-C with SDR, all you need is a 1MSPS ADC,
clocked from your house-standard.
Feel free to find inspiration:
https://aus01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fphk.freebsd.dk%2Floran-c%2F&data=05%7C01%7C%7Cd4f7fde0013849edb7ae08dbbd9948c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638312238320138711%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=LOD0HAk7gQ6ADQjqNgr6fzOJ2r%2FkUU%2FmFSBqrqQQTQk%3D&reserved=0<http://phk.freebsd.dk/loran-c/>
https://aus01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fphk.freebsd.dk%2FAducLoran%2F&data=05%7C01%7C%7Cd4f7fde0013849edb7ae08dbbd9948c6%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C638312238320138711%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=0WHjkm8R19LYZNTEib%2BlqnCqFuCg0IoOM8PacVQpC%2F8%3D&reserved=0<http://phk.freebsd.dk/AducLoran/>
I'd love to be proven wrong about the "last" bit :-)
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at 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.
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