Re: [time-nuts] RFDO - Experience and questions

[Magnus Danielson]

Hi,

Actually, even with some unknown fields, as you have the majority know 
through prediction, much of the gain is being had that way.


The actual information rate of even GPS is very low.

Cheers,
Magnus

On 03/06/2017 08:26 AM, Bob Camp wrote:

Hi

One way to “cheat” at recovering a time signal is to demodulate it with
known information. Once you know the information from the first “frame”
of data (time, date, etc) you can predict what the information in the next
frame will be. Yes it does take a little work. If the signal is completely 
defined
(no extra data about the weather forecast or something like that) you can
reduce your bandwidth significantly.

Bob


On Mar 5, 2017, at 11:42 PM, Iain Young  wrote:

On 05/03/17 20:23, paul swed wrote:


Gilles what signal is that at 162KHz. A European station? Nice thats its C
controlled.


That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry
the AM Station France Inter as well, but that went when France turned
off all LW, MW, and LORAN stations at the end of 2016.

The Time Signal is Phase Modulated (I have a gnuradio decoder which
works very well if anyone is interested)

See https://en.wikipedia.org/wiki/TDF_time_signal and
https://en.wikipedia.org/wiki/Allouis_longwave_transmitter

With no AM modulation, there are obvious benefits with regards to using
it as a frequency reference. Average phase and frequency deviation is
zero over 200msec (see link above for details)


Iain

PS, The signal is used by the French railways SNCF, the electricity
distributor ENEDIS, airports, hospitals according to the Allouis link
above

___
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] RFDO - Experience and questions

[Alan Melia]

Paul the off-air standards I have and another UK make I dont posses divide 
the 10MHz standard and the off-air carrier down to 2kHz for locking. It may 
not be the best but it is generally adequate for off air LF standard 
distribution. My unit will cover 162kHz or 198kHz.


Alan
G3NYK

- Original Message - 
From: "paul swed" <paulsw...@gmail.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts@febo.com>

Sent: Tuesday, March 07, 2017 5:52 PM
Subject: Re: [time-nuts] RFDO - Experience and questions



Gilles
I went back over the starting thread and believe your home brew oscillator
may prevent you from getting all of the accuracy out of TDF.
As I was thinking about a TRF radio and locking the question I arrived at
is how do you turn 162KHz into something useful like 100 KHz 5 MHz or 10
MHz??.
By getting to standard references there are many very good oven 
oscillators

available.
Regards
Paul.

On Mon, Mar 6, 2017 at 10:35 PM, paul swed <paulsw...@gmail.com> wrote:


Actually as I think about it from the earlier part of the thread. Locking
to the carrier with a 2-4 second time constant removes the phase 
modulation
since its only in the first 200 ms. The 0 Phase is 800 ms in length or 
more

for all bits.
Now to find some nice coils for 162 KHz.
Regards
Paul

On Mon, Mar 6, 2017 at 8:30 PM, paul swed <paulsw...@gmail.com> wrote:


A bit more reading if you block the phase comparison from -50ms to 150ms
of the tick you get a 0 carrier phase no modulation. That also explains 
why

I thought I could here some sort of phase modulation because there is.
So as an example if you use a GPS tick its really simple to block the
phase changes and only measure the 0 phase carrier. Essentially a 200 ms
carrier gap per second.
Thats quite a clean format you have to work with.
Regards
Paul
WB8TSL


On Mon, Mar 6, 2017 at 8:19 PM, paul swed <paulsw...@gmail.com> wrote:

I checked out 162KHz at 2000 local and now have what I believe to be 
TDF
using the 67 ft vertical antenna. I am reading -82 dbm near Boston in 
the

US or 3400 miles. A comfortable signal at least in the winter. As a
comparison wwvb at 60 KHz is -77dbm some 2000 miles but also not at a 2 
MW

power level like TDF.

Since I had not heard TDF before I listened to Pieters online SDR radio
to see what to listen for. The easiest point to notice is the 59 second
phase. Its funny that also seconds 0-10 should be the same phase but it 
did
not seem to be true. Unless what I am hearing is the local oscillator 
of

Pieters SDR radio.

So thanks for sharing some new knowledge with Time-nuts.
Regards
Paul
WB8TSL

On Mon, Mar 6, 2017 at 1:46 PM, Pieter-Tjerk de Boer <
ptdeb...@cs.utwente.nl> wrote:



On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote:

> That's TDF from France. Their equivalent of WWV/MSF/DCF.

> Average phase and frequency deviation is
> zero over 200msec (see link above for details)

This is not quite correct, since the transmitter does not just carry 
the

time data (one bit per second, in the first 200 ms of the second), but
also some more data during the next 700 ms of each second.
The latter data is coded in a way which does not guarantee that the
phase
or frequency average is zero other than when averaging over the entire
700 ms block.
Then again, I've been told that although there is a nicely defined
framing
format, in reality it has only ever transmitted idle frames, so in
practice
it's a fixed pattern which repeats every minute and thus could be
cancelled
for use as a frequency reference.

I have a live online decoder for TDF's signal at
   http://websdr.ewi.utwente.nl:8901/tdf/

Regards,
  Pieter-Tjerk, PA3FWM

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/m
ailman/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] RFDO - Experience and questions

[Poul-Henning Kamp]

In message 

Re: [time-nuts] RFDO - Experience and questions

[paul swed]

Gilles
I went back over the starting thread and believe your home brew oscillator
may prevent you from getting all of the accuracy out of TDF.
As I was thinking about a TRF radio and locking the question I arrived at
is how do you turn 162KHz into something useful like 100 KHz 5 MHz or 10
MHz??.
By getting to standard references there are many very good oven oscillators
available.
Regards
Paul.

On Mon, Mar 6, 2017 at 10:35 PM, paul swed  wrote:

> Actually as I think about it from the earlier part of the thread. Locking
> to the carrier with a 2-4 second time constant removes the phase modulation
> since its only in the first 200 ms. The 0 Phase is 800 ms in length or more
> for all bits.
> Now to find some nice coils for 162 KHz.
> Regards
> Paul
>
> On Mon, Mar 6, 2017 at 8:30 PM, paul swed  wrote:
>
>> A bit more reading if you block the phase comparison from -50ms to 150ms
>> of the tick you get a 0 carrier phase no modulation. That also explains why
>> I thought I could here some sort of phase modulation because there is.
>> So as an example if you use a GPS tick its really simple to block the
>> phase changes and only measure the 0 phase carrier. Essentially a 200 ms
>> carrier gap per second.
>> Thats quite a clean format you have to work with.
>> Regards
>> Paul
>> WB8TSL
>>
>>
>> On Mon, Mar 6, 2017 at 8:19 PM, paul swed  wrote:
>>
>>> I checked out 162KHz at 2000 local and now have what I believe to be TDF
>>> using the 67 ft vertical antenna. I am reading -82 dbm near Boston in the
>>> US or 3400 miles. A comfortable signal at least in the winter. As a
>>> comparison wwvb at 60 KHz is -77dbm some 2000 miles but also not at a 2 MW
>>> power level like TDF.
>>>
>>> Since I had not heard TDF before I listened to Pieters online SDR radio
>>> to see what to listen for. The easiest point to notice is the 59 second
>>> phase. Its funny that also seconds 0-10 should be the same phase but it did
>>> not seem to be true. Unless what I am hearing is the local oscillator of
>>> Pieters SDR radio.
>>>
>>> So thanks for sharing some new knowledge with Time-nuts.
>>> Regards
>>> Paul
>>> WB8TSL
>>>
>>> On Mon, Mar 6, 2017 at 1:46 PM, Pieter-Tjerk de Boer <
>>> ptdeb...@cs.utwente.nl> wrote:
>>>

 On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote:

 > That's TDF from France. Their equivalent of WWV/MSF/DCF.

 > Average phase and frequency deviation is
 > zero over 200msec (see link above for details)

 This is not quite correct, since the transmitter does not just carry the
 time data (one bit per second, in the first 200 ms of the second), but
 also some more data during the next 700 ms of each second.
 The latter data is coded in a way which does not guarantee that the
 phase
 or frequency average is zero other than when averaging over the entire
 700 ms block.
 Then again, I've been told that although there is a nicely defined
 framing
 format, in reality it has only ever transmitted idle frames, so in
 practice
 it's a fixed pattern which repeats every minute and thus could be
 cancelled
 for use as a frequency reference.

 I have a live online decoder for TDF's signal at
http://websdr.ewi.utwente.nl:8901/tdf/

 Regards,
   Pieter-Tjerk, PA3FWM

 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to https://www.febo.com/cgi-bin/m
 ailman/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] RFDO - Experience and questions

[paul swed]

Actually as I think about it from the earlier part of the thread. Locking
to the carrier with a 2-4 second time constant removes the phase modulation
since its only in the first 200 ms. The 0 Phase is 800 ms in length or more
for all bits.
Now to find some nice coils for 162 KHz.
Regards
Paul

On Mon, Mar 6, 2017 at 8:30 PM, paul swed  wrote:

> A bit more reading if you block the phase comparison from -50ms to 150ms
> of the tick you get a 0 carrier phase no modulation. That also explains why
> I thought I could here some sort of phase modulation because there is.
> So as an example if you use a GPS tick its really simple to block the
> phase changes and only measure the 0 phase carrier. Essentially a 200 ms
> carrier gap per second.
> Thats quite a clean format you have to work with.
> Regards
> Paul
> WB8TSL
>
>
> On Mon, Mar 6, 2017 at 8:19 PM, paul swed  wrote:
>
>> I checked out 162KHz at 2000 local and now have what I believe to be TDF
>> using the 67 ft vertical antenna. I am reading -82 dbm near Boston in the
>> US or 3400 miles. A comfortable signal at least in the winter. As a
>> comparison wwvb at 60 KHz is -77dbm some 2000 miles but also not at a 2 MW
>> power level like TDF.
>>
>> Since I had not heard TDF before I listened to Pieters online SDR radio
>> to see what to listen for. The easiest point to notice is the 59 second
>> phase. Its funny that also seconds 0-10 should be the same phase but it did
>> not seem to be true. Unless what I am hearing is the local oscillator of
>> Pieters SDR radio.
>>
>> So thanks for sharing some new knowledge with Time-nuts.
>> Regards
>> Paul
>> WB8TSL
>>
>> On Mon, Mar 6, 2017 at 1:46 PM, Pieter-Tjerk de Boer <
>> ptdeb...@cs.utwente.nl> wrote:
>>
>>>
>>> On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote:
>>>
>>> > That's TDF from France. Their equivalent of WWV/MSF/DCF.
>>>
>>> > Average phase and frequency deviation is
>>> > zero over 200msec (see link above for details)
>>>
>>> This is not quite correct, since the transmitter does not just carry the
>>> time data (one bit per second, in the first 200 ms of the second), but
>>> also some more data during the next 700 ms of each second.
>>> The latter data is coded in a way which does not guarantee that the phase
>>> or frequency average is zero other than when averaging over the entire
>>> 700 ms block.
>>> Then again, I've been told that although there is a nicely defined
>>> framing
>>> format, in reality it has only ever transmitted idle frames, so in
>>> practice
>>> it's a fixed pattern which repeats every minute and thus could be
>>> cancelled
>>> for use as a frequency reference.
>>>
>>> I have a live online decoder for TDF's signal at
>>>http://websdr.ewi.utwente.nl:8901/tdf/
>>>
>>> Regards,
>>>   Pieter-Tjerk, PA3FWM
>>>
>>> ___
>>> time-nuts mailing list -- time-nuts@febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/m
>>> ailman/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] RFDO - Experience and questions

[paul swed]

A bit more reading if you block the phase comparison from -50ms to 150ms of
the tick you get a 0 carrier phase no modulation. That also explains why I
thought I could here some sort of phase modulation because there is.
So as an example if you use a GPS tick its really simple to block the phase
changes and only measure the 0 phase carrier. Essentially a 200 ms carrier
gap per second.
Thats quite a clean format you have to work with.
Regards
Paul
WB8TSL


On Mon, Mar 6, 2017 at 8:19 PM, paul swed  wrote:

> I checked out 162KHz at 2000 local and now have what I believe to be TDF
> using the 67 ft vertical antenna. I am reading -82 dbm near Boston in the
> US or 3400 miles. A comfortable signal at least in the winter. As a
> comparison wwvb at 60 KHz is -77dbm some 2000 miles but also not at a 2 MW
> power level like TDF.
>
> Since I had not heard TDF before I listened to Pieters online SDR radio to
> see what to listen for. The easiest point to notice is the 59 second phase.
> Its funny that also seconds 0-10 should be the same phase but it did not
> seem to be true. Unless what I am hearing is the local oscillator of
> Pieters SDR radio.
>
> So thanks for sharing some new knowledge with Time-nuts.
> Regards
> Paul
> WB8TSL
>
> On Mon, Mar 6, 2017 at 1:46 PM, Pieter-Tjerk de Boer <
> ptdeb...@cs.utwente.nl> wrote:
>
>>
>> On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote:
>>
>> > That's TDF from France. Their equivalent of WWV/MSF/DCF.
>>
>> > Average phase and frequency deviation is
>> > zero over 200msec (see link above for details)
>>
>> This is not quite correct, since the transmitter does not just carry the
>> time data (one bit per second, in the first 200 ms of the second), but
>> also some more data during the next 700 ms of each second.
>> The latter data is coded in a way which does not guarantee that the phase
>> or frequency average is zero other than when averaging over the entire
>> 700 ms block.
>> Then again, I've been told that although there is a nicely defined framing
>> format, in reality it has only ever transmitted idle frames, so in
>> practice
>> it's a fixed pattern which repeats every minute and thus could be
>> cancelled
>> for use as a frequency reference.
>>
>> I have a live online decoder for TDF's signal at
>>http://websdr.ewi.utwente.nl:8901/tdf/
>>
>> Regards,
>>   Pieter-Tjerk, PA3FWM
>>
>> ___
>> time-nuts mailing list -- time-nuts@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/m
>> ailman/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] RFDO - Experience and questions

[paul swed]

I checked out 162KHz at 2000 local and now have what I believe to be TDF
using the 67 ft vertical antenna. I am reading -82 dbm near Boston in the
US or 3400 miles. A comfortable signal at least in the winter. As a
comparison wwvb at 60 KHz is -77dbm some 2000 miles but also not at a 2 MW
power level like TDF.

Since I had not heard TDF before I listened to Pieters online SDR radio to
see what to listen for. The easiest point to notice is the 59 second phase.
Its funny that also seconds 0-10 should be the same phase but it did not
seem to be true. Unless what I am hearing is the local oscillator of
Pieters SDR radio.

So thanks for sharing some new knowledge with Time-nuts.
Regards
Paul
WB8TSL

On Mon, Mar 6, 2017 at 1:46 PM, Pieter-Tjerk de Boer  wrote:

>
> On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote:
>
> > That's TDF from France. Their equivalent of WWV/MSF/DCF.
>
> > Average phase and frequency deviation is
> > zero over 200msec (see link above for details)
>
> This is not quite correct, since the transmitter does not just carry the
> time data (one bit per second, in the first 200 ms of the second), but
> also some more data during the next 700 ms of each second.
> The latter data is coded in a way which does not guarantee that the phase
> or frequency average is zero other than when averaging over the entire
> 700 ms block.
> Then again, I've been told that although there is a nicely defined framing
> format, in reality it has only ever transmitted idle frames, so in practice
> it's a fixed pattern which repeats every minute and thus could be cancelled
> for use as a frequency reference.
>
> I have a live online decoder for TDF's signal at
>http://websdr.ewi.utwente.nl:8901/tdf/
>
> Regards,
>   Pieter-Tjerk, PA3FWM
>
> ___
> 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] RFDO - Experience and questions

[Alberto di Bene]

On 3/6/2017 3:47 PM, Graham / KE9H wrote:


What antenna are you using that you call the "mini-whip?"

Specifically, how long is the "whip?"


http://dl1dbc.net/SAQ/miniwhip.html

73  Alberto  I2PHD


___
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] RFDO - Experience and questions

[paul swed]

Just for the heck of it fired up the hp3586 on 162KHz tuned +/- 2 Khz both
a vertical antenna 67 feet and horizontal dipole 160 ft. Nothing at 1800
utc near Boston Ma.
But in the sun for another7 hours.
Regards
Paul
WB8TSL

On Mon, Mar 6, 2017 at 9:47 AM, Graham / KE9H  wrote:

> Anders:
>
> What antenna are you using that you call the "mini-whip?"
>
> Specifically, how long is the "whip?"
>
> Thanks,
> --- Graham
>
> ==
>
> On Mon, Mar 6, 2017 at 3:57 AM, Anders Wallin  >
> wrote:
>
> > FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few
> days
> > ago. The signals look like this from our site:
> > http://www.anderswallin.net/wp-content/uploads/2017/02/MSF.jpg
> > http://www.anderswallin.net/wp-content/uploads/2017/02/DCF.jpg
> > http://www.anderswallin.net/wp-content/uploads/2017/02/TDF.jpg
> >
> > I guess the +/- 40 Hz side-bands on TDF are by design?
> >
> > I have an SDR set up also, so the gnu-radio demodulators could run in
> > parallel on each of these, and the sdr sampling clock could come from a
> > local clock. One more project on the to-do list...
> >
> > Anders
> >
> >
> > On Mon, Mar 6, 2017 at 12:42 AM, Iain Young  wrote:
> >
> > > On 05/03/17 20:23, paul swed wrote:
> > >
> > > Gilles what signal is that at 162KHz. A European station? Nice thats
> its
> > C
> > >> controlled.
> > >>
> > >
> > > That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry
> > > the AM Station France Inter as well, but that went when France turned
> > > off all LW, MW, and LORAN stations at the end of 2016.
> > >
> > > The Time Signal is Phase Modulated (I have a gnuradio decoder which
> > > works very well if anyone is interested)
> > >
> > > See https://en.wikipedia.org/wiki/TDF_time_signal and
> > > https://en.wikipedia.org/wiki/Allouis_longwave_transmitter
> > >
> > > With no AM modulation, there are obvious benefits with regards to using
> > > it as a frequency reference. Average phase and frequency deviation is
> > > zero over 200msec (see link above for details)
> > >
> > >
> > > Iain
> > >
> > > PS, The signal is used by the French railways SNCF, the electricity
> > > distributor ENEDIS, airports, hospitals according to the Allouis link
> > > above
> > >
> > >
> > > ___
> > > time-nuts mailing list -- time-nuts@febo.com
> > > To unsubscribe, go to https://www.febo.com/cgi-bin/m
> > > ailman/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] RFDO - Experience and questions

[Pieter-Tjerk de Boer]

On Sun, Mar 05, 2017 at 10:42:52PM +, Iain Young wrote:

> That's TDF from France. Their equivalent of WWV/MSF/DCF.

> Average phase and frequency deviation is
> zero over 200msec (see link above for details)

This is not quite correct, since the transmitter does not just carry the
time data (one bit per second, in the first 200 ms of the second), but
also some more data during the next 700 ms of each second.
The latter data is coded in a way which does not guarantee that the phase
or frequency average is zero other than when averaging over the entire
700 ms block.
Then again, I've been told that although there is a nicely defined framing
format, in reality it has only ever transmitted idle frames, so in practice
it's a fixed pattern which repeats every minute and thus could be cancelled
for use as a frequency reference.

I have a live online decoder for TDF's signal at
   http://websdr.ewi.utwente.nl:8901/tdf/

Regards,
  Pieter-Tjerk, PA3FWM

___
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] RFDO - Experience and questions

[Graham / KE9H]

Anders:

What antenna are you using that you call the "mini-whip?"

Specifically, how long is the "whip?"

Thanks,
--- Graham

==

On Mon, Mar 6, 2017 at 3:57 AM, Anders Wallin 
wrote:

> FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few days
> ago. The signals look like this from our site:
> http://www.anderswallin.net/wp-content/uploads/2017/02/MSF.jpg
> http://www.anderswallin.net/wp-content/uploads/2017/02/DCF.jpg
> http://www.anderswallin.net/wp-content/uploads/2017/02/TDF.jpg
>
> I guess the +/- 40 Hz side-bands on TDF are by design?
>
> I have an SDR set up also, so the gnu-radio demodulators could run in
> parallel on each of these, and the sdr sampling clock could come from a
> local clock. One more project on the to-do list...
>
> Anders
>
>
> On Mon, Mar 6, 2017 at 12:42 AM, Iain Young  wrote:
>
> > On 05/03/17 20:23, paul swed wrote:
> >
> > Gilles what signal is that at 162KHz. A European station? Nice thats its
> C
> >> controlled.
> >>
> >
> > That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry
> > the AM Station France Inter as well, but that went when France turned
> > off all LW, MW, and LORAN stations at the end of 2016.
> >
> > The Time Signal is Phase Modulated (I have a gnuradio decoder which
> > works very well if anyone is interested)
> >
> > See https://en.wikipedia.org/wiki/TDF_time_signal and
> > https://en.wikipedia.org/wiki/Allouis_longwave_transmitter
> >
> > With no AM modulation, there are obvious benefits with regards to using
> > it as a frequency reference. Average phase and frequency deviation is
> > zero over 200msec (see link above for details)
> >
> >
> > Iain
> >
> > PS, The signal is used by the French railways SNCF, the electricity
> > distributor ENEDIS, airports, hospitals according to the Allouis link
> > above
> >
> >
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/m
> > ailman/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] RFDO - Experience and questions

[paul swed]

Gilles,
I just looked at the signal behavior from the TDFlink you sent.There are 14
seconds worth of very controlled phase. There are additional bits also.
As Bob says if the format is controlled you can predict the change and
correct the phase. This is exactly what I created for the wwvb BPSK signal
in the US about 1-2 years ago. It runs on a small arduino and requires no
modification to any of the phase tracking receivers. It super simple with
few parts. It was my first arduino project and took maybe a week of time at
night.

Granted I like the rest of the work you are doing and the prediction
concept can very reasonably be put into you software for prediction.
You should not need to worry about a unpredictable phase flip. On wwvb
there are a couple bits that can not be predicted but never seen that yet.
Even if they do a 3-4 second loop constant like all of the old receivers
has removes the issue.

Plan to warm up the HP3586 tonight and take a listen at 162 KHz in the US.
Regards
Paul
WB8TSL

On Mon, Mar 6, 2017 at 4:57 AM, Anders Wallin 
wrote:

> FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few days
> ago. The signals look like this from our site:
> http://www.anderswallin.net/wp-content/uploads/2017/02/MSF.jpg
> http://www.anderswallin.net/wp-content/uploads/2017/02/DCF.jpg
> http://www.anderswallin.net/wp-content/uploads/2017/02/TDF.jpg
>
> I guess the +/- 40 Hz side-bands on TDF are by design?
>
> I have an SDR set up also, so the gnu-radio demodulators could run in
> parallel on each of these, and the sdr sampling clock could come from a
> local clock. One more project on the to-do list...
>
> Anders
>
>
> On Mon, Mar 6, 2017 at 12:42 AM, Iain Young  wrote:
>
> > On 05/03/17 20:23, paul swed wrote:
> >
> > Gilles what signal is that at 162KHz. A European station? Nice thats its
> C
> >> controlled.
> >>
> >
> > That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry
> > the AM Station France Inter as well, but that went when France turned
> > off all LW, MW, and LORAN stations at the end of 2016.
> >
> > The Time Signal is Phase Modulated (I have a gnuradio decoder which
> > works very well if anyone is interested)
> >
> > See https://en.wikipedia.org/wiki/TDF_time_signal and
> > https://en.wikipedia.org/wiki/Allouis_longwave_transmitter
> >
> > With no AM modulation, there are obvious benefits with regards to using
> > it as a frequency reference. Average phase and frequency deviation is
> > zero over 200msec (see link above for details)
> >
> >
> > Iain
> >
> > PS, The signal is used by the French railways SNCF, the electricity
> > distributor ENEDIS, airports, hospitals according to the Allouis link
> > above
> >
> >
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/m
> > ailman/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] RFDO - Experience and questions

[Anders Wallin]

FWIW, for fun I measured the LF stations MSF, DCF, and TDF just a few days
ago. The signals look like this from our site:
http://www.anderswallin.net/wp-content/uploads/2017/02/MSF.jpg
http://www.anderswallin.net/wp-content/uploads/2017/02/DCF.jpg
http://www.anderswallin.net/wp-content/uploads/2017/02/TDF.jpg

I guess the +/- 40 Hz side-bands on TDF are by design?

I have an SDR set up also, so the gnu-radio demodulators could run in
parallel on each of these, and the sdr sampling clock could come from a
local clock. One more project on the to-do list...

Anders


On Mon, Mar 6, 2017 at 12:42 AM, Iain Young  wrote:

> On 05/03/17 20:23, paul swed wrote:
>
> Gilles what signal is that at 162KHz. A European station? Nice thats its C
>> controlled.
>>
>
> That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry
> the AM Station France Inter as well, but that went when France turned
> off all LW, MW, and LORAN stations at the end of 2016.
>
> The Time Signal is Phase Modulated (I have a gnuradio decoder which
> works very well if anyone is interested)
>
> See https://en.wikipedia.org/wiki/TDF_time_signal and
> https://en.wikipedia.org/wiki/Allouis_longwave_transmitter
>
> With no AM modulation, there are obvious benefits with regards to using
> it as a frequency reference. Average phase and frequency deviation is
> zero over 200msec (see link above for details)
>
>
> Iain
>
> PS, The signal is used by the French railways SNCF, the electricity
> distributor ENEDIS, airports, hospitals according to the Allouis link
> above
>
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/m
> ailman/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] RFDO - Experience and questions

[Iain Young]

Hi Gilles,

You Wrote:


Indeed, the station is located in central France with a very powerful 
transmitter (up to 2MW).
It covers all Europe and it was a real pain for me when they stopped 
broadcasting the France Inter Station.


I understand the French government have a consultation out about what
to use the AM carrier for, so maybe another commercial AM station will
pick it up.


The longwave signal can be received anywhere, even in the basements (ground 
effect propagation).
No need for an external full sky antenna etc…
Hopefully they are still operating and sending the time code.


They are. I've written an SDR decoder for it, and with it being Phase
Modulated, it doesn't suffer from the varying signal strengths of both 
MSF and DCF.



And actually the signal is much clearer today in 2017 than when it was also 
amplitude modulated.
Good news, but how long will it last ... ?


Agreed, it's a nice clean carrier now :) I think it will last a good
time, Certainly with some of the things that use it in France, I
suspect it will be there for some time to come


Best Regards

Iain

___
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] RFDO - Experience and questions

[Bob Camp]

Hi

One way to “cheat” at recovering a time signal is to demodulate it with
known information. Once you know the information from the first “frame”
of data (time, date, etc) you can predict what the information in the next
frame will be. Yes it does take a little work. If the signal is completely 
defined 
(no extra data about the weather forecast or something like that) you can
reduce your bandwidth significantly.

Bob

> On Mar 5, 2017, at 11:42 PM, Iain Young  wrote:
> 
> On 05/03/17 20:23, paul swed wrote:
> 
>> Gilles what signal is that at 162KHz. A European station? Nice thats its C
>> controlled.
> 
> That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry
> the AM Station France Inter as well, but that went when France turned
> off all LW, MW, and LORAN stations at the end of 2016.
> 
> The Time Signal is Phase Modulated (I have a gnuradio decoder which
> works very well if anyone is interested)
> 
> See https://en.wikipedia.org/wiki/TDF_time_signal and
> https://en.wikipedia.org/wiki/Allouis_longwave_transmitter
> 
> With no AM modulation, there are obvious benefits with regards to using
> it as a frequency reference. Average phase and frequency deviation is
> zero over 200msec (see link above for details)
> 
> 
> Iain
> 
> PS, The signal is used by the French railways SNCF, the electricity
> distributor ENEDIS, airports, hospitals according to the Allouis link
> above
> 
> ___
> 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] RFDO - Experience and questions

[Gilles Clement]

Hi, 
Indeed, the station is located in central France with a very powerful 
transmitter (up to 2MW).
It covers all Europe and it was a real pain for me when they stopped 
broadcasting the France Inter Station. 
The longwave signal can be received anywhere, even in the basements (ground 
effect propagation). 
No need for an external full sky antenna etc… 
Hopefully they are still operating and sending the time code. 
And actually the signal is much clearer today in 2017 than when it was also 
amplitude modulated. 
Good news, but how long will it last ... ?
Best, 
Gilles. 


> Le 5 mars 2017 à 23:42, Iain Young  a écrit :
> 
> On 05/03/17 20:23, paul swed wrote:
> 
>> Gilles what signal is that at 162KHz. A European station? Nice thats its C
>> controlled.
> 
> That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry
> the AM Station France Inter as well, but that went when France turned
> off all LW, MW, and LORAN stations at the end of 2016.
> 
> The Time Signal is Phase Modulated (I have a gnuradio decoder which
> works very well if anyone is interested)
> 
> See https://en.wikipedia.org/wiki/TDF_time_signal and
> https://en.wikipedia.org/wiki/Allouis_longwave_transmitter
> 
> With no AM modulation, there are obvious benefits with regards to using
> it as a frequency reference. Average phase and frequency deviation is
> zero over 200msec (see link above for details)
> 
> 
> Iain
> 
> PS, The signal is used by the French railways SNCF, the electricity
> distributor ENEDIS, airports, hospitals according to the Allouis link
> above
> 
> ___
> 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] RFDO - Experience and questions

[Gilles Clement]

Hi David,
I have actually implemented the second option. Detecting the the sequences of 
"calms" where the modulation is off and gating the ADC sampling at those 
moments. There are plenty of calm zones between the sequence of modulated bits, 
in addition the modulation is off for the whole 59th second before each minute. 
I considered picking the signal only during that 59th second which could indeed 
lead to an improvement. Will try that. 
Thx, 
Gilles. 


> If the modulation is phased locked to the carrier which is common,
> then that suggests two other ways to extract the timing from the
> carrier without interference from the modulation.
> 1. Integrate the phase comparison over a whole number of modulation
> cycles; the modulation will then cancel out.  This could be seen as
> using a sin(x)/x frequency response with the nulls aligned to remove
> just the modulation components of the signal.
> 
> 2. Gate the phase comparison for periods where the modulation is not
> occurring.
> 
> On Sun, 5 Mar 2017 11:54:56 +0100, you wrote:
> 
> >I have been working for a "while"…>  on a reference oscillator disciplined 
> >by an 
> >RF signal (162khz), Cs stabilized, but phase modulated with time coding 
> >information. The phase modulation is quite significant : +/-1rad 10Hz 
> >triangular shape, leading to a frequency shift of +/- 20PI (+/-6,3Hz). 
> >Extracting the base signal was quite an interesting challenge…>  I tried 
> >many 
> >options (and even a bit more…> ) but it was - and is still - fun...
> >
> >...
> >
> >My questions to the respected audience:
> >- Can I get any better? 
> >- Have I reached the limit of what the RF signal can provide? 
> >(with all the perturbations encountered on the path from the transmitter to 
> >my 
> >antenna...)  
> >- Am I limited by the local oscillator? 
> >- Or the measurement gear?
> >- Or anything else…> ?  
> >
> >Thanks very much for your feedback,
> >
> >Gilles. 

___
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] RFDO - Experience and questions

[Iain Young]

On 05/03/17 20:23, paul swed wrote:


Gilles what signal is that at 162KHz. A European station? Nice thats its C
controlled.


That's TDF from France. Their equivalent of WWV/MSF/DCF. Used to carry
the AM Station France Inter as well, but that went when France turned
off all LW, MW, and LORAN stations at the end of 2016.

The Time Signal is Phase Modulated (I have a gnuradio decoder which
works very well if anyone is interested)

See https://en.wikipedia.org/wiki/TDF_time_signal and
https://en.wikipedia.org/wiki/Allouis_longwave_transmitter

With no AM modulation, there are obvious benefits with regards to using
it as a frequency reference. Average phase and frequency deviation is
zero over 200msec (see link above for details)


Iain

PS, The signal is used by the French railways SNCF, the electricity
distributor ENEDIS, airports, hospitals according to the Allouis link
above

___
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] RFDO - Experience and questions

[paul swed]

Gilles I should have mentioned.
I use eLoran at 100 KHz in the US and am 400 miles from the transmitter.
Measuring Cesium references I typically run down in the 5 e-12th.
I see various noise at that level that says thats about the limit without
some smarter filtering, tracking and plotting.
The comparison units are austron 2100 series. The Cesium's are HP5061A's.
Very interested in what you are doing.
Regards
Paul
WB8TSL

On Sun, Mar 5, 2017 at 11:35 AM, David  wrote:

> If the modulation is phased locked to the carrier which is common,
> then that suggests two other ways to extract the timing from the
> carrier without interference from the modulation.
>
> 1. Integrate the phase comparison over a whole number of modulation
> cycles; the modulation will then cancel out.  This could be seen as
> using a sin(x)/x frequency response with the nulls aligned to remove
> just the modulation components of the signal.
>
> 2. Gate the phase comparison for periods where the modulation is not
> occurring.
>
> On Sun, 5 Mar 2017 11:54:56 +0100, you wrote:
>
> >I have been working for a "while"… on a reference oscillator disciplined
> by an RF signal (162khz), Cs stabilized, but phase modulated with time
> coding information. The phase modulation is quite significant : +/-1rad
> 10Hz triangular shape, leading to a frequency shift of +/- 20PI (+/-6,3Hz).
> Extracting the base signal was quite an interesting challenge… I tried many
> options (and even a bit more…) but it was - and is still - fun...
> >
> >...
> >
> >My questions to the respected audience:
> >- Can I get any better?
> >- Have I reached the limit of what the RF signal can provide?
> >(with all the perturbations encountered on the path from the transmitter
> to my antenna...)
> >- Am I limited by the local oscillator?
> >- Or the measurement gear?
> >- Or anything else…?
> >
> >Thanks very much for your feedback,
> >
> >Gilles.
> ___
> 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] RFDO - Experience and questions

[paul swed]

Gilles what signal is that at 162KHz. A European station? Nice thats its C
controlled.
Regards
Paul
WB8TSL

On Sun, Mar 5, 2017 at 5:54 AM, Gilles Clement 
wrote:

> Hi all,
>
> I have been working for a "while"… on a reference oscillator disciplined
> by an RF signal (162khz), Cs stabilized, but phase modulated with time
> coding information. The phase modulation is quite significant : +/-1rad
> 10Hz triangular shape, leading to a frequency shift of +/- 20PI (+/-6,3Hz).
> Extracting the base signal was quite an interesting challenge… I tried many
> options (and even a bit more…) but it was - and is still - fun...
>
> Long story short, the "best" combination I came up with is the following:
> 1- local oscillator built around:  CD4060 Collpits + 5184Khz crystal +
> pulled by varactor diode + divide by 32
> 2- Phase detection with 4046 (XOR) with pp ouput voltage limited to 1 volt
> (input to 10bits ADC)
> 3- Filtering and VCO controlling with a PIC16F876, programmed in assembly
> language, implementing a 3rd order loop (much better than second order).
> Poles at 1E-5 and 1E-3, Zero at 1E-4 => 1E-10 attenuation at 10Hz (if my
> maths are correct).
> 4- 13 bits 20Khz PWM control of the VCO (K0=10-3 Hz/volt) with strong
> filtering (two RCs in cascade)
> 5- Crystal is temp controlled (NTC resistor) as well as the whole circuits
> placed in a foam isolated box.
> 6- ADEV measurements perfomed with HP53132A counter (high stability option
> 10 ocxo  HP10811) frequency input to TIMELAB through HPIB connection (I
> know it's not the best setup but simple and provides tool for comparison
> between trials)
>
> Results to date :
> . « Left side » of the ADEV 0.5s: pretty flat around 1E-9 up to
> tau =10s
> . « right side » of ADEV 0.5s plots: reaching 3*1E-11 at tau =
> 3000s
>
> Comment:
> 6,3Hz/162kHz = 4E-5 so attenuation of 1E10 should knock it down to 4E-15
> (well below 1E-11) ?
>
> My questions to the respected audience:
> - Can I get any better?
> - Have I reached the limit of what the RF signal can provide?
> (with all the perturbations encountered on the path from the transmitter
> to my antenna...)
> - Am I limited by the local oscillator?
> - Or the measurement gear?
> - Or anything else…?
>
> Thanks very much for your feedback,
>
> Gilles.
>
> Note: 1E-3 = 0.001
> ___
> 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] RFDO - Experience and questions

[David]

If the modulation is phased locked to the carrier which is common,
then that suggests two other ways to extract the timing from the
carrier without interference from the modulation.

1. Integrate the phase comparison over a whole number of modulation
cycles; the modulation will then cancel out.  This could be seen as
using a sin(x)/x frequency response with the nulls aligned to remove
just the modulation components of the signal.

2. Gate the phase comparison for periods where the modulation is not
occurring.

On Sun, 5 Mar 2017 11:54:56 +0100, you wrote:

>I have been working for a "while"… on a reference oscillator disciplined by an 
>RF signal (162khz), Cs stabilized, but phase modulated with time coding 
>information. The phase modulation is quite significant : +/-1rad 10Hz 
>triangular shape, leading to a frequency shift of +/- 20PI (+/-6,3Hz). 
>Extracting the base signal was quite an interesting challenge… I tried many 
>options (and even a bit more…) but it was - and is still - fun...
>
>...
>
>My questions to the respected audience:
>- Can I get any better? 
>- Have I reached the limit of what the RF signal can provide? 
>(with all the perturbations encountered on the path from the transmitter to my 
>antenna...)  
>- Am I limited by the local oscillator? 
>- Or the measurement gear?
>- Or anything else…?  
>
>Thanks very much for your feedback,
>
>Gilles. 
___
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] RFDO - Experience and questions

[Gilles Clement]

Hi all, 

I have been working for a "while"… on a reference oscillator disciplined by an 
RF signal (162khz), Cs stabilized, but phase modulated with time coding 
information. The phase modulation is quite significant : +/-1rad 10Hz 
triangular shape, leading to a frequency shift of +/- 20PI (+/-6,3Hz). 
Extracting the base signal was quite an interesting challenge… I tried many 
options (and even a bit more…) but it was - and is still - fun...

Long story short, the "best" combination I came up with is the following: 
1- local oscillator built around:  CD4060 Collpits + 5184Khz crystal + pulled 
by varactor diode + divide by 32 
2- Phase detection with 4046 (XOR) with pp ouput voltage limited to 1 volt 
(input to 10bits ADC)
3- Filtering and VCO controlling with a PIC16F876, programmed in assembly 
language, implementing a 3rd order loop (much better than second order). Poles 
at 1E-5 and 1E-3, Zero at 1E-4 => 1E-10 attenuation at 10Hz (if my maths are 
correct). 
4- 13 bits 20Khz PWM control of the VCO (K0=10-3 Hz/volt) with strong filtering 
(two RCs in cascade)
5- Crystal is temp controlled (NTC resistor) as well as the whole circuits 
placed in a foam isolated box.   
6- ADEV measurements perfomed with HP53132A counter (high stability option 10 
ocxo  HP10811) frequency input to TIMELAB through HPIB connection (I know it's 
not the best setup but simple and provides tool for comparison between trials)

Results to date : 
. « Left side » of the ADEV 0.5s: pretty flat around 1E-9 up to tau 
=10s 
. « right side » of ADEV 0.5s plots: reaching 3*1E-11 at tau = 3000s

Comment: 
6,3Hz/162kHz = 4E-5 so attenuation of 1E10 should knock it down to 4E-15 (well 
below 1E-11) ?

My questions to the respected audience:
- Can I get any better? 
- Have I reached the limit of what the RF signal can provide? 
(with all the perturbations encountered on the path from the transmitter to my 
antenna...)  
- Am I limited by the local oscillator? 
- Or the measurement gear?
- Or anything else…?  

Thanks very much for your feedback,

Gilles. 

Note: 1E-3 = 0.001
___
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.