Re: [time-nuts] WWVB SDR discussion

2020-08-21 Thread Chris Burford 
I have one of these wall clocks and it too has a minor misalignment of the
second hand. The second hand will overshoot the face marker by about
one-fourth of the distance between successive markings.

If the fix is not too terribly involved I might would give it a try,
otherwise, It will just have to remain a sub time-nuts piece of hardware.

Chris

-Original Message-
From: time-nuts  On Behalf Of Tom Van Baak
Sent: Thursday, August 20, 2020 22:59
To: time-nuts@lists.febo.com
Subject: Re: [time-nuts] WWVB SDR discussion

Mike,

I've used that seller a lot; no worries. They have 800+ items for sale,
mostly clock and weather products by La Crosse Technology [1]. It looks like
this eBay seller is their online retail store, as well as an outlet for
their overstock and refurbished items:

https://www.ebay.com/itm/274056463528
Seller: greatbigoutlet
Item location: La Crosse, Wisconsin, United States
Condition: Manufacturer refurbished

One of the complaints that I had about the La Crosse 404-1235UA-SS
UltrAtomic clock was that several of the ones I bought had misaligned hands
[2]. If you're into Lavet stepper motor watch movements using optical
feedback it's something you can fix yourself. The other solution is to
return it to the factory. It wouldn't surprise me that La Crosse has a pile
of these refurbished clocks for sale. Or maybe 1235UA just never sold well;
or maybe there's a new model coming; who knows.

And, yes, this is a deal for $35. They are so much better than older WWVB
clocks. AFAIK it is still the only LF radio clock that uses the new eWWVB PM
format. The smaller clocks and watches all use the legacy WWVB AM format.

/tvb

[1] https://www.lacrossetechnology.com/

[2] http://leapsecond.com/pages/ultratomic/


On 8/20/2020 8:00 PM, Mike Feher wrote:
> Hi Don -
>
> I got two of them on eBay. I got these 274056463528 . They were only 
> $35 each with free shipping, a bargain in my opinion. Of course you 
> can find smaller diameter ones as well. 73 - Mike
>
> Mike B. Feher, N4FS
> 89 Arnold Blvd.
> Howell NJ 07731
> 848-245-9115
>
> -Original Message-
> From: time-nuts  On Behalf Of DON 
> MURRAY via time-nuts
> Sent: Thursday, August 20, 2020 8:41 PM
> To: time-nuts@lists.febo.com
> Cc: DON MURRAY 
> Subject: Re: [time-nuts] WWVB SDR discussion
>
>
> Mike...
>
> Which model did you order?
>
>
> 73
> Don
> W4WJ
>
> On Thursday, August 20, 2020 Mike Feher  wrote:
> I just purchased 2 of those La Crosse 14" clocks and was totally 
> amazed. I live on the Jersey shore on one acre surrounded by trees and 
> about 8 miles from the ocean. After I placed batteries in the clock, 
> it went through its initially routine which was neat in itself, and 
> about an hour or less later the motors purred again and it went to the 
> exact time and continues to do so. This was on the first floor of my 
> Colonial in my office next to the computer and all sorts of other 
> digital and switching PS noise and only about a foot off the floor. My 
> old Junghans Mega 1000 could never do that. I have to take it upstairs 
> with me and place it by the front (South facing) window of the master 
> bedroom and sometime during the night it acquires and corrects if need 
> be. Regardless, I still like my Junghans, but this new waveform is 
> amazing. Thanks for mentioning it. Regards - Mike
>
>   
>
> Mike B. Feher, N4FS
>
> 89 Arnold Blvd.
>
> Howell NJ 07731
>
> 848-245-9115
>
>   
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go 
> to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

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Re: [time-nuts] WWVB SDR discussion

2020-08-21 Thread Charles Steinmetz 

Lester wrote:


That’s a unavailable EBAY listing number
What is the actual La Crosse model or part
number  for the new software 14" clocks


The link works for me, but apparently they sold out of the refurbished 
units so the listing is closed.


The same seller has a current listing for new (not refurb) clocks, at 
$50 each:




Part # is 404-1235UA-SS.  Also, La Crosse calls it an "UltrAtomic" clock.

Now a question:  As far as I am aware, no other La Crosse "atomic" 
clocks have the "UltrAtomic" designation, suggesting that the Model 
404-1235UA-SS is the ONLY La Crosse clock that decodes the new 
modulation.  Does anyone (Tom?) have any verified information (not idle 
speculation, or guesses) on this?


And another:  Is anyone aware of any other commercially-available WWVB 
clocks that decode the new modulation?


Is the La Crosse Model 404-1235UA-SS the only one??


Thank you,

Charles



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Re: [time-nuts] WWVB SDR discussion

2020-08-21 Thread Mike Feher 
That is because after my post the remaining 5 sold fast. Now, after you put
in the number look in completed listings. Alternately, you can try the
seller Tom suggested. 73 - Mike 

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115

-Original Message-
From: time-nuts  On Behalf Of Lester
Veenstra via time-nuts
Sent: Friday, August 21, 2020 10:56 AM
To: 'Discussion of precise time and frequency measurement'

Cc: Lester Veenstra 
Subject: Re: [time-nuts] WWVB SDR discussion

That’s a unavailable EBAY listing number What is the actual La Crosse model
or part number for the new software 14"
clocks

Lester B Veenstra  K1YCM  MØYCM  W8YCM   6Y6Y
les...@veenstras.com

452 Stable Ln (HC84 RFD USPS Mail)
Keyser WV 26726

GPS: 39.336826 N  78.982287 W (Google)
GPS: 39.33682 N  78.9823741 W (GPSDO)


Telephones:
Home:     +1-304-289-6057 US cell   
+1-304-790-9192 Jamaica cell:   +1-876-456-8898 
 

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Mike
Feher
Sent: Thursday, August 20, 2020 11:00 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] WWVB SDR discussion

Hi Don - 

I got two of them on eBay. I got these 274056463528 . They were only $35
each with free shipping, a bargain in my opinion. Of course you can find
smaller diameter ones as well. 73 - Mike 

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115



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Re: [time-nuts] WWVB SDR discussion

2020-08-21 Thread Lester Veenstra via time-nuts 
That’s a unavailable EBAY listing number
What is the actual La Crosse model or part number for the new software 14"
clocks

Lester B Veenstra  K1YCM  MØYCM  W8YCM   6Y6Y
les...@veenstras.com

452 Stable Ln (HC84 RFD USPS Mail)
Keyser WV 26726

GPS: 39.336826 N  78.982287 W (Google)
GPS: 39.33682 N  78.9823741 W (GPSDO)


Telephones:
Home:     +1-304-289-6057
US cell    +1-304-790-9192 
Jamaica cell:   +1-876-456-8898 
 

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Mike
Feher
Sent: Thursday, August 20, 2020 11:00 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] WWVB SDR discussion

Hi Don - 

I got two of them on eBay. I got these 274056463528 . They were only $35
each with free shipping, a bargain in my opinion. Of course you can find
smaller diameter ones as well. 73 - Mike 

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115

-Original Message-
From: time-nuts  On Behalf Of DON MURRAY
via time-nuts
Sent: Thursday, August 20, 2020 8:41 PM
To: time-nuts@lists.febo.com
Cc: DON MURRAY 
Subject: Re: [time-nuts] WWVB SDR discussion


Mike...

Which model did you order?


73
Don
W4WJ

On Thursday, August 20, 2020 Mike Feher  wrote:
I just purchased 2 of those La Crosse 14" clocks and was totally amazed. I
live on the Jersey shore on one acre surrounded by trees and about 8 miles
from the ocean. After I placed batteries in the clock, it went through its
initially routine which was neat in itself, and about an hour or less later
the motors purred again and it went to the exact time and continues to do
so. This was on the first floor of my Colonial in my office next to the
computer and all sorts of other digital and switching PS noise and only
about a foot off the floor. My old Junghans Mega 1000 could never do that. I
have to take it upstairs with me and place it by the front (South facing)
window of the master bedroom and sometime during the night it acquires and
corrects if need be. Regardless, I still like my Junghans, but this new
waveform is amazing. Thanks for mentioning it. Regards - Mike  

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

 


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Re: [time-nuts] WWVB SDR discussion

2020-08-21 Thread Phil Genera 
Has anyone probed the test points (which Tom so kindly took pictures of) to
find the pps & i2c lines between the es100 and clock face microcontroller
on one of these?

I'd like to build a WWVB refclock for fun, but with the
universal-solder dev board discontinued, buying a wall clock seems like the
easiest way to get a receiver, plus there's plenty of room in the battery
compartment for a raspberry pi zero, if you leave the batteries out... I'm
hesitant to buy one just to pull it apart and find the signals I'm looking
for are hard to get out, though.

-- 
Phil


-Original Message-
> From: time-nuts  On Behalf Of Tom Van
> Baak
> Sent: Tuesday, August 11, 2020 6:45 AM
> To: time-nuts@lists.febo.com
> Subject: Re: [time-nuts] WWVB SDR discussion
>
>
>
> Ray,
>
>
>
> I don't see a crystal filter. There is a 16 MHz crystal, but that's for the
> processor.
>
>
>
> "Inside the La Crosse 1235UA UltrAtomic Radio Controlled WWVB (Atomic) Wall
> Clock"
>
>  <http://leapsecond.com/pages/ultratomic/>
> http://leapsecond.com/pages/ultratomic/
>
>
>
> "ES100 datasheet, including block diagram, application circuit, and theory"
>
>  <http://leapsecond.com/pages/es100/ES100DataSheetver0p97.pdf>
> http://leapsecond.com/pages/es100/ES100DataSheetver0p97.pdf
>
>
>
> "Universal Solder ES100 cob dev kit"
>
>  <http://leapsecond.com/pages/es100/pins.htm>
> http://leapsecond.com/pages/es100/pins.htm
>
>
>
> /tvb
>
>
>
>
>
> On 8/10/2020 11:09 PM,  <mailto:rcb...@atcelectronics.com>
> rcb...@atcelectronics.com wrote:
>
> > Does the La Crosse UltrAtomic clock actually use a crystal filter or
>
> > do they digitally filter the signal? Has anyone ever looked inside of
>
> > one of the clocks? Just curious.
>
> >
>
> > Ray
>
> > AB7HE
>
> >
>
>
>
> ___
>
> time-nuts mailing list --  <mailto:time-nuts@lists.febo.com>
> time-nuts@lists.febo.com To unsubscribe, go to
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>
> and follow the instructions there.
>
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Re: [time-nuts] WWVB SDR discussion

2020-08-21 Thread Mike Feher 
So far I have only put batteries into one of them Tom and I agree with you. It 
is ever so slightly off. However, it is so small it is barely visible on the 
minute hand. The second hand seems right on. To use as is, as a clock, it is 
more than fine for my 75 year old eyes  . Nice hearing from you. It has 
probably been about 20 years since you got those HP journals from me and I got 
some nixies from you. I am no longer concerned about picoseconds as days and 
years go by way too fast. Stay Healthy - Regards - Mike 
 
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115

-Original Message-
From: time-nuts  On Behalf Of Tom Van Baak
Sent: Thursday, August 20, 2020 11:59 PM
To: time-nuts@lists.febo.com
Subject: Re: [time-nuts] WWVB SDR discussion

Mike,

I've used that seller a lot; no worries. They have 800+ items for sale, mostly 
clock and weather products by La Crosse Technology [1]. It looks like this eBay 
seller is their online retail store, as well as an outlet for their overstock 
and refurbished items:

https://www.ebay.com/itm/274056463528
Seller: greatbigoutlet
Item location: La Crosse, Wisconsin, United States
Condition: Manufacturer refurbished

One of the complaints that I had about the La Crosse 404-1235UA-SS UltrAtomic 
clock was that several of the ones I bought had misaligned hands [2]. If you're 
into Lavet stepper motor watch movements using optical feedback it's something 
you can fix yourself. The other solution is to return it to the factory. It 
wouldn't surprise me that La Crosse has a pile of these refurbished clocks for 
sale. Or maybe 1235UA just never sold well; or maybe there's a new model 
coming; who knows.

And, yes, this is a deal for $35. They are so much better than older WWVB 
clocks. AFAIK it is still the only LF radio clock that uses the new eWWVB PM 
format. The smaller clocks and watches all use the legacy WWVB AM format.

/tvb

[1] https://www.lacrossetechnology.com/

[2] http://leapsecond.com/pages/ultratomic/


On 8/20/2020 8:00 PM, Mike Feher wrote:
> Hi Don -
>
> I got two of them on eBay. I got these 274056463528 . They were only 
> $35 each with free shipping, a bargain in my opinion. Of course you 
> can find smaller diameter ones as well. 73 - Mike
>
> Mike B. Feher, N4FS
> 89 Arnold Blvd.
> Howell NJ 07731
> 848-245-9115
>
> -Original Message-
> From: time-nuts  On Behalf Of DON 
> MURRAY via time-nuts
> Sent: Thursday, August 20, 2020 8:41 PM
> To: time-nuts@lists.febo.com
> Cc: DON MURRAY 
> Subject: Re: [time-nuts] WWVB SDR discussion
>
>
> Mike...
>
> Which model did you order?
>
>
> 73
> Don
> W4WJ
>
> On Thursday, August 20, 2020 Mike Feher  wrote:
> I just purchased 2 of those La Crosse 14" clocks and was totally 
> amazed. I live on the Jersey shore on one acre surrounded by trees and 
> about 8 miles from the ocean. After I placed batteries in the clock, 
> it went through its initially routine which was neat in itself, and 
> about an hour or less later the motors purred again and it went to the 
> exact time and continues to do so. This was on the first floor of my 
> Colonial in my office next to the computer and all sorts of other 
> digital and switching PS noise and only about a foot off the floor. My 
> old Junghans Mega 1000 could never do that. I have to take it upstairs 
> with me and place it by the front (South facing) window of the master 
> bedroom and sometime during the night it acquires and corrects if need 
> be. Regardless, I still like my Junghans, but this new waveform is 
> amazing. Thanks for mentioning it. Regards - Mike
>
>   
>
> Mike B. Feher, N4FS
>
> 89 Arnold Blvd.
>
> Howell NJ 07731
>
> 848-245-9115
>
>   
>
>
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go 
> to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>

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Re: [time-nuts] WWVB SDR discussion

2020-08-20 Thread Tom Van Baak 

Mike,

I've used that seller a lot; no worries. They have 800+ items for sale, 
mostly clock and weather products by La Crosse Technology [1]. It looks 
like this eBay seller is their online retail store, as well as an outlet 
for their overstock and refurbished items:


https://www.ebay.com/itm/274056463528
Seller: greatbigoutlet
Item location: La Crosse, Wisconsin, United States
Condition: Manufacturer refurbished

One of the complaints that I had about the La Crosse 404-1235UA-SS 
UltrAtomic clock was that several of the ones I bought had misaligned 
hands [2]. If you're into Lavet stepper motor watch movements using 
optical feedback it's something you can fix yourself. The other solution 
is to return it to the factory. It wouldn't surprise me that La Crosse 
has a pile of these refurbished clocks for sale. Or maybe 1235UA just 
never sold well; or maybe there's a new model coming; who knows.


And, yes, this is a deal for $35. They are so much better than older 
WWVB clocks. AFAIK it is still the only LF radio clock that uses the new 
eWWVB PM format. The smaller clocks and watches all use the legacy WWVB 
AM format.


/tvb

[1] https://www.lacrossetechnology.com/

[2] http://leapsecond.com/pages/ultratomic/


On 8/20/2020 8:00 PM, Mike Feher wrote:

Hi Don -

I got two of them on eBay. I got these 274056463528 . They were only $35 each 
with free shipping, a bargain in my opinion. Of course you can find smaller 
diameter ones as well. 73 - Mike

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115

-Original Message-
From: time-nuts  On Behalf Of DON MURRAY via 
time-nuts
Sent: Thursday, August 20, 2020 8:41 PM
To: time-nuts@lists.febo.com
Cc: DON MURRAY 
Subject: Re: [time-nuts] WWVB SDR discussion


Mike...

Which model did you order?


73
Don
W4WJ

On Thursday, August 20, 2020 Mike Feher  wrote:
I just purchased 2 of those La Crosse 14" clocks and was totally amazed. I live 
on the Jersey shore on one acre surrounded by trees and about 8 miles from the 
ocean. After I placed batteries in the clock, it went through its initially routine 
which was neat in itself, and about an hour or less later the motors purred again 
and it went to the exact time and continues to do so. This was on the first floor of 
my Colonial in my office next to the computer and all sorts of other digital and 
switching PS noise and only about a foot off the floor. My old Junghans Mega 1000 
could never do that. I have to take it upstairs with me and place it by the front 
(South facing) window of the master bedroom and sometime during the night it 
acquires and corrects if need be. Regardless, I still like my Junghans, but this new 
waveform is amazing. Thanks for mentioning it. Regards - Mike

  


Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

  



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Re: [time-nuts] WWVB SDR discussion

2020-08-20 Thread Mike Feher 
Hi Don - 

I got two of them on eBay. I got these 274056463528 . They were only $35 each 
with free shipping, a bargain in my opinion. Of course you can find smaller 
diameter ones as well. 73 - Mike 

Mike B. Feher, N4FS
89 Arnold Blvd.
Howell NJ 07731
848-245-9115

-Original Message-
From: time-nuts  On Behalf Of DON MURRAY via 
time-nuts
Sent: Thursday, August 20, 2020 8:41 PM
To: time-nuts@lists.febo.com
Cc: DON MURRAY 
Subject: Re: [time-nuts] WWVB SDR discussion


Mike...

Which model did you order?


73
Don
W4WJ

On Thursday, August 20, 2020 Mike Feher  wrote:
I just purchased 2 of those La Crosse 14" clocks and was totally amazed. I live 
on the Jersey shore on one acre surrounded by trees and about 8 miles from the 
ocean. After I placed batteries in the clock, it went through its initially 
routine which was neat in itself, and about an hour or less later the motors 
purred again and it went to the exact time and continues to do so. This was on 
the first floor of my Colonial in my office next to the computer and all sorts 
of other digital and switching PS noise and only about a foot off the floor. My 
old Junghans Mega 1000 could never do that. I have to take it upstairs with me 
and place it by the front (South facing) window of the master bedroom and 
sometime during the night it acquires and corrects if need be. Regardless, I 
still like my Junghans, but this new waveform is amazing. Thanks for mentioning 
it. Regards - Mike  

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

 


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Re: [time-nuts] WWVB SDR discussion

2020-08-20 Thread DON MURRAY via time-nuts 

Mike...

Which model did you order?


73
Don
W4WJ

On Thursday, August 20, 2020 Mike Feher  wrote:
I just purchased 2 of those La Crosse 14" clocks and was totally amazed. I
live on the Jersey shore on one acre surrounded by trees and about 8 miles
from the ocean. After I placed batteries in the clock, it went through its
initially routine which was neat in itself, and about an hour or less later
the motors purred again and it went to the exact time and continues to do
so. This was on the first floor of my Colonial in my office next to the
computer and all sorts of other digital and switching PS noise and only
about a foot off the floor. My old Junghans Mega 1000 could never do that. I
have to take it upstairs with me and place it by the front (South facing)
window of the master bedroom and sometime during the night it acquires and
corrects if need be. Regardless, I still like my Junghans, but this new
waveform is amazing. Thanks for mentioning it. Regards - Mike  

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

 

-Original Message-
From: time-nuts  On Behalf Of Tom Van Baak
Sent: Tuesday, August 11, 2020 6:45 AM
To: time-nuts@lists.febo.com
Subject: Re: [time-nuts] WWVB SDR discussion

 

Ray,

 

I don't see a crystal filter. There is a 16 MHz crystal, but that's for the
processor.

 

"Inside the La Crosse 1235UA UltrAtomic Radio Controlled WWVB (Atomic) Wall
Clock"

 <http://leapsecond.com/pages/ultratomic/>
http://leapsecond.com/pages/ultratomic/

 

"ES100 datasheet, including block diagram, application circuit, and theory"

 <http://leapsecond.com/pages/es100/ES100DataSheetver0p97.pdf>
http://leapsecond.com/pages/es100/ES100DataSheetver0p97.pdf

 

"Universal Solder ES100 cob dev kit"

 <http://leapsecond.com/pages/es100/pins.htm>
http://leapsecond.com/pages/es100/pins.htm

 

/tvb

 

 

On 8/10/2020 11:09 PM,  <mailto:rcb...@atcelectronics.com>
rcb...@atcelectronics.com wrote:

> Does the La Crosse UltrAtomic clock actually use a crystal filter or 

> do they digitally filter the signal? Has anyone ever looked inside of 

> one of the clocks? Just curious.

> 

> Ray

> AB7HE

> 

 

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Re: [time-nuts] WWVB SDR discussion

2020-08-20 Thread Mike Feher 
I just purchased 2 of those La Crosse 14" clocks and was totally amazed. I
live on the Jersey shore on one acre surrounded by trees and about 8 miles
from the ocean. After I placed batteries in the clock, it went through its
initially routine which was neat in itself, and about an hour or less later
the motors purred again and it went to the exact time and continues to do
so. This was on the first floor of my Colonial in my office next to the
computer and all sorts of other digital and switching PS noise and only
about a foot off the floor. My old Junghans Mega 1000 could never do that. I
have to take it upstairs with me and place it by the front (South facing)
window of the master bedroom and sometime during the night it acquires and
corrects if need be. Regardless, I still like my Junghans, but this new
waveform is amazing. Thanks for mentioning it. Regards - Mike  

 

Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115

 

-Original Message-
From: time-nuts  On Behalf Of Tom Van Baak
Sent: Tuesday, August 11, 2020 6:45 AM
To: time-nuts@lists.febo.com
Subject: Re: [time-nuts] WWVB SDR discussion

 

Ray,

 

I don't see a crystal filter. There is a 16 MHz crystal, but that's for the
processor.

 

"Inside the La Crosse 1235UA UltrAtomic Radio Controlled WWVB (Atomic) Wall
Clock"

 <http://leapsecond.com/pages/ultratomic/>
http://leapsecond.com/pages/ultratomic/

 

"ES100 datasheet, including block diagram, application circuit, and theory"

 <http://leapsecond.com/pages/es100/ES100DataSheetver0p97.pdf>
http://leapsecond.com/pages/es100/ES100DataSheetver0p97.pdf

 

"Universal Solder ES100 cob dev kit"

 <http://leapsecond.com/pages/es100/pins.htm>
http://leapsecond.com/pages/es100/pins.htm

 

/tvb

 

 

On 8/10/2020 11:09 PM,  <mailto:rcb...@atcelectronics.com>
rcb...@atcelectronics.com wrote:

> Does the La Crosse UltrAtomic clock actually use a crystal filter or 

> do they digitally filter the signal? Has anyone ever looked inside of 

> one of the clocks? Just curious.

> 

> Ray

> AB7HE

> 

 

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Re: [time-nuts] WWVB SDR discussion

2020-08-12 Thread Graham / KE9H 
What would the optimum bandwidth for a WWVB receiver be?

For the AM signal, there are three different symbols, 0.8 seconds on/0.2
sec off; 0.5 sec on/0.5 sec off; and 0.2 sec on, 0.8 seconds off.
This suggests to me that the two non-symmetrical symbols have strong
modulation sidebands at +/- 2.5 Hz, or a minimum (AM-DSB) bandwidth of 5
Hz, plus any frequency tuning error requirements.
This would give me a soft edge with a 100 ms rise and fall time.

The next stop for significant improvement would be to catch the third
harmonic of the AM modulation component, which would require a 15 Hz total
filter bandwidth, plus any frequency tuning errors, and an edge rise and
fall time in the 33 ms range.

 Am I looking at this correctly?

I am assuming that any phase modulation sidebands would fit inside the AM
filter requirements.

--- Graham

==
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Re: [time-nuts] WWVB SDR discussion

2020-08-12 Thread Bob kb8tq 
Hi

> On Aug 11, 2020, at 10:27 PM, paul swed  wrote:
> 
> How do the small AM WWVB clocks work then. They use the 60 KHz crystal and
> they don't actually do anything special. In measuring those clocks they are
> about 2-6 hz wide.

They pop up once a night and grab time from WWVB. The rest of the day, they 
drift around based on their local crystal oscillator. If they are off by 1/10 
second,
there are very few people who are going to notice ….


> On the spectracoms the crystal is huge. Looks like a HC6
> but 3" long. About 1-2 Hz wide.

Which is how 60 KHz crystals were done before the watch industry converted to 
crystals. The larger package *might* give you higher Q and better TC. That’s not
from the package, but from the cut of crystal you would be able to use in the 
bigger package. 

> Using the same small crystals in BPF filters does work and does not
> seriously change within reasonable temperature. The one thing they do
> is follow the crystal with a hi Z amplifier.

The high-z amp is needed to keep losses down. 

This is not a super duper hard circuit to model. Drop it into LTSpice and take 
a 
look. The motional parameters for the crystal can be derived from it’s 
resistance
and Q ….

Bob


> Just saying they work for all those atomic clocks for $10.
> But back to the discussion here. Need some gain and filtering. There are
> many good answers.
> John night time is cheating. I get seriously crazy levels in Boston many
> nights.
> Enjoying the thread.
> Regards
> Paul.
> 
> On Tue, Aug 11, 2020 at 7:45 PM John Magliacane via time-nuts <
> time-nuts@lists.febo.com> wrote:
> 
>> On Tuesday, August 11, 2020, 07:14:12 PM EDT, Bob kb8tq 
>> wrote:
>> 
>>> The problem with the crystal is that it has a temperature coefficient.
>> As a
>>> narrow band filter, it will have a *lot* of delay. Crystal resonance
>> moves
>>> (with temperature) and the delay changes.
>> 
>> I agree. The crystal needs to be ovenized. ;-)
>> 
>> That very concern led me in my design to derive nearly all my receiver
>> selectivity at baseband (DC) using op-amps, forgo any crystal filters, and
>> keep the Q of the loop antenna low.
>> 
>> 
>> 73.000 de John, KD2BD
>> 
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Re: [time-nuts] WWVB SDR discussion

2020-08-12 Thread rcbuck 
> deriving exact time to way closer than a second from the signal


To the average consumer if the clock is accurate to within a minute or
so they are happy. The clocks also run on a RTC and only use WWVB to
keep the RTC more or less accurate. The clocks are also only looking at
the carrier level change of a signal somewhere around 60 kHz. The newer
BPSK method should be easy to detect in the full power portion of each
second.

I am in Phoenix and the signal should be fairly strong here even during
the day. I know my $15 wrist watch can synchronize during the day if I
take it to a window and point it NE toward Ft Collins. When I visit my
family in north GA the watch always manages to synchronize back there at
3 am each morning.


I bread boarded a RF front end last week end to examine the WWVB signal.
I could not see the signal coming out of my RF front end during daylight
hours. I was using my spectrum analyzer to monitor the output. But by 10
pm the sine wave was clearly visible and fairly strong. I could easily
see the power level drop when it occurred each second.

I have ordered more parts from Mouser (better op amps and FET) to
improve the performance of the front end. I needed more gain since I am
using a modified ferrite rod antenna out of an old AM radio. Hopefully I
will have the new design working by this week end. I am going to build a
clock that uses the BPSK signal. I am not interested in measuring
frequency based on the WWVB signal. I have a GPSDO unit for that.

Ray,
AB7HE

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Re: [time-nuts] WWVB SDR discussion

2020-08-11 Thread David I. Emery 
On Tue, Aug 11, 2020 at 10:27:33PM -0400, paul swed wrote:

> Just saying they work for all those atomic clocks for $10.

Those don't give a damn about 60 KHz delay/phase provided it
doesn't change very fast (as it wouldn't due to thermal effects).

But monitoring frequency or drift of an oscillator by comparing
it the 60 KHz WWVB carrier through the filter would show frequency and phase
shifts due to the thermal shifts.   That would result in false indications
of drift and instability and certainly cause issues with anything that
depended on deriving exact time to way closer than a second from the signal.

(And yes ionospheric shifts are real and of this magnitude too).


-- 
  Dave Emery N1PRE/AE, d...@dieconsulting.com  DIE Consulting, Weston, Mass 
02493
"An empty zombie mind with a forlorn barely readable weatherbeaten
'For Rent' sign still vainly flapping outside on the weed encrusted pole - in 
celebration of what could have been, but wasn't and is not to be now either."


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Re: [time-nuts] WWVB SDR discussion

2020-08-11 Thread paul swed 
How do the small AM WWVB clocks work then. They use the 60 KHz crystal and
they don't actually do anything special. In measuring those clocks they are
about 2-6 hz wide. On the spectracoms the crystal is huge. Looks like a HC6
but 3" long. About 1-2 Hz wide.
Using the same small crystals in BPF filters does work and does not
seriously change within reasonable temperature. The one thing they do
is follow the crystal with a hi Z amplifier.
Just saying they work for all those atomic clocks for $10.
But back to the discussion here. Need some gain and filtering. There are
many good answers.
John night time is cheating. I get seriously crazy levels in Boston many
nights.
Enjoying the thread.
Regards
Paul.

On Tue, Aug 11, 2020 at 7:45 PM John Magliacane via time-nuts <
time-nuts@lists.febo.com> wrote:

>  On Tuesday, August 11, 2020, 07:14:12 PM EDT, Bob kb8tq 
> wrote:
>
> > The problem with the crystal is that it has a temperature coefficient.
> As a
> > narrow band filter, it will have a *lot* of delay. Crystal resonance
> moves
> > (with temperature) and the delay changes.
>
> I agree. The crystal needs to be ovenized. ;-)
>
> That very concern led me in my design to derive nearly all my receiver
> selectivity at baseband (DC) using op-amps, forgo any crystal filters, and
> keep the Q of the loop antenna low.
>
>
> 73.000 de John, KD2BD
>
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Re: [time-nuts] WWVB SDR discussion

2020-08-11 Thread John Magliacane via time-nuts 
 I'm seeing more than 100mV p-p right now (7:09 PM) (2309 UTC) on the output of 
my preamp from the east coast of New Jersey, 1622 miles east of WWVB.

During my early days of WWVB experimenting, I found the signal is easier to 
spot (since it's buried in noise) if the scope's horizontal sweep is externally 
triggered by a stable and variable oscillator running at some sub-multiple of 
60 kHz. The sweep generator in my Tek 465 was just too unstable and difficult 
to control, otherwise.


73.000 de John, KD2BD
  
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Re: [time-nuts] WWVB SDR discussion

2020-08-11 Thread John Magliacane via time-nuts 
 On Tuesday, August 11, 2020, 07:14:12 PM EDT, Bob kb8tq  wrote:

> The problem with the crystal is that it has a temperature coefficient. As a
> narrow band filter, it will have a *lot* of delay. Crystal resonance moves
> (with temperature) and the delay changes.

I agree. The crystal needs to be ovenized. ;-)

That very concern led me in my design to derive nearly all my receiver 
selectivity at baseband (DC) using op-amps, forgo any crystal filters, and keep 
the Q of the loop antenna low.


73.000 de John, KD2BD
  
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Re: [time-nuts] WWVB SDR discussion

2020-08-11 Thread Bob kb8tq 
Hi

The problem with the crystal is that it has a temperature coefficient. As a 
narrow band filter, it will have a *lot* of delay. Crystal resonance moves 
(with temperature) and the delay changes. 

How much delay depends a lot on a bunch of fiddly details. A 10 to 100 Hz wide
bandpass could easily have delay in the > 100 ms range. 

How much change?

The crystal could be in the 10’s of ppm / C range (might be lower, could be 
higher).
At 60K Hz 10 ppm is 0.6 Hz. With a modest sort of basement temperature swing
you *could* get 10% of the delay changing around. 

Yes, that’s a bunch of guesses.

Net result would be delay variation in the 1 to 10 ms range. 

Bob

> On Aug 11, 2020, at 3:37 PM, paul swed  wrote:
> 
> Mark
> His antenna hit a preamp as I recall about 20 db of gain. To see something
> on a scope add 40 more db approx. Unfortunately a purely broadband solution
> will show 40 db of pure garbage these days. Using the 60 KHz watch crystals
> $2.00 for 20 out of China you can most likely find a reasonable match.
> Thats what I did. It is hi Z so it feeds one side of an opamp. Look at the
> spectracom schematics to get a sense of what to do. I made a small socket
> to plug them in and found the one that worked. As an alternative you can
> build a bandpass filter with opamps lots of variations. Anything to get the
> received bandwidth reduced. Look at Johns front end also.
> Regards
> Paul
> 
> On Tue, Aug 11, 2020 at 3:20 PM Mark Haun  wrote:
> 
>> Hi Detlef,
>> 
>> On 11-Aug-20 3:46 AM, Detlef Schuecker via time-nuts wrote:
>>> you do not necessarily need a variable ( physical ) oscillator. You mix
>>> the signal down in the digital domain. A 'digital local oscilator' is a
>>> mere complex value, which is rotated and the power is adjusted:
>> My proposed block diagram does actually have a digital LO, only mine is
>> 1, 0, -1, 0... (in-phase) and 0, -1, 0, 1...  (quadrature).  You could
>> of course use an variable-frequency NCO, but I need a physical
>> oscillator in any case to clock the MCU.  I am also thinking in terms of
>> a WWVB-DO where I want a stable local reference to steer.  (Although in
>> fairness, for WWVB I think you probably want stability over the diurnal
>> propagation variation, and my crappy OCXO has no chance at that.)
 part, unfortunately.  My tuned loop seems still too broadband, even
 after a couple more poles of op-amp filter.  I have a bunch of 60-kHz
 tuning-fork crystals and wanted to try a crystal filter like the "pros"
>>> Good point.
>>> Firstly I tried a tuned resonant LC circuit with a BF245 preamplifier to
>>> keep a high Q.
>> Besides having minimal analog design experience, I think what is
>> confusing me is these crystals have a really high impedance far away
>> from their parallel resonance.  Even at series resonance the motional
>> resistance is in the 10s of kohms, IIRC.  So I'm not exactly sure how to
>> deploy one in place of an LC tank circuit, e.g. in a collector or drain
>> circuit.
>>> Secondly an accurate ADC is an option. With 24Bit you get more than
>> 100dB
>>> dynamic range, so you dont care about a 60dB stronger nearby interferer.
>> 
>> Fancier ADC shouldn't make any difference.  Even though the STM32L4 ADC
>> has an SNR of (IIRC) ~ 69 dB, you can sample at several MHz.  After
>> downsampling to something like 100 Hz (post LO), the SNR is well over
>> 100 dB, which should be plenty.
>> 
>> (Of course, this presupposes that there are not strong interferers or
>> SMPS noise spurs, etc. within a 100-Hz BW centered on 60 kHz.  But if
>> there are, a fancy ADC wouldn't help you anyway.  The main thing is to
>> make sure the interference isn't causing any clipping or nonlinearity
>> before you sample.)
>> 
>> I should note that my big tuned air loop and preamp, which is modeled
>> after Joe Magliacane's, may be adequate even though I can't see WWVB on
>> the oscilloscope.  I was hoping to build confidence there before hooking
>> it up to the MCU and doing SDR stuff.  I also want a small loopstick
>> version of this so I can embed it in my own nixie wall clock, hence the
>> interest in crystal filters, etc.
>> 
>> Mark
>> 
>> 
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Re: [time-nuts] WWVB SDR discussion

2020-08-11 Thread paul swed 
Should add that on the East Coast the signal is about 10 uv. On the large
10' X 10' loop I get about 63 uv during the day. That loop at night can
easily hit 1000 uv.
Regards
Paul

On Tue, Aug 11, 2020 at 3:37 PM paul swed  wrote:

> Mark
> His antenna hit a preamp as I recall about 20 db of gain. To see something
> on a scope add 40 more db approx. Unfortunately a purely broadband solution
> will show 40 db of pure garbage these days. Using the 60 KHz watch crystals
> $2.00 for 20 out of China you can most likely find a reasonable match.
> Thats what I did. It is hi Z so it feeds one side of an opamp. Look at the
> spectracom schematics to get a sense of what to do. I made a small socket
> to plug them in and found the one that worked. As an alternative you can
> build a bandpass filter with opamps lots of variations. Anything to get the
> received bandwidth reduced. Look at Johns front end also.
> Regards
> Paul
>
> On Tue, Aug 11, 2020 at 3:20 PM Mark Haun  wrote:
>
>> Hi Detlef,
>>
>> On 11-Aug-20 3:46 AM, Detlef Schuecker via time-nuts wrote:
>> > you do not necessarily need a variable ( physical ) oscillator. You mix
>> > the signal down in the digital domain. A 'digital local oscilator' is a
>> > mere complex value, which is rotated and the power is adjusted:
>> My proposed block diagram does actually have a digital LO, only mine is
>> 1, 0, -1, 0... (in-phase) and 0, -1, 0, 1...  (quadrature).  You could
>> of course use an variable-frequency NCO, but I need a physical
>> oscillator in any case to clock the MCU.  I am also thinking in terms of
>> a WWVB-DO where I want a stable local reference to steer.  (Although in
>> fairness, for WWVB I think you probably want stability over the diurnal
>> propagation variation, and my crappy OCXO has no chance at that.)
>> >> part, unfortunately.  My tuned loop seems still too broadband, even
>> >> after a couple more poles of op-amp filter.  I have a bunch of 60-kHz
>> >> tuning-fork crystals and wanted to try a crystal filter like the "pros"
>> > Good point.
>> > Firstly I tried a tuned resonant LC circuit with a BF245 preamplifier
>> to
>> > keep a high Q.
>> Besides having minimal analog design experience, I think what is
>> confusing me is these crystals have a really high impedance far away
>> from their parallel resonance.  Even at series resonance the motional
>> resistance is in the 10s of kohms, IIRC.  So I'm not exactly sure how to
>> deploy one in place of an LC tank circuit, e.g. in a collector or drain
>> circuit.
>> > Secondly an accurate ADC is an option. With 24Bit you get more than
>> 100dB
>> > dynamic range, so you dont care about a 60dB stronger nearby interferer.
>>
>> Fancier ADC shouldn't make any difference.  Even though the STM32L4 ADC
>> has an SNR of (IIRC) ~ 69 dB, you can sample at several MHz.  After
>> downsampling to something like 100 Hz (post LO), the SNR is well over
>> 100 dB, which should be plenty.
>>
>> (Of course, this presupposes that there are not strong interferers or
>> SMPS noise spurs, etc. within a 100-Hz BW centered on 60 kHz.  But if
>> there are, a fancy ADC wouldn't help you anyway.  The main thing is to
>> make sure the interference isn't causing any clipping or nonlinearity
>> before you sample.)
>>
>> I should note that my big tuned air loop and preamp, which is modeled
>> after Joe Magliacane's, may be adequate even though I can't see WWVB on
>> the oscilloscope.  I was hoping to build confidence there before hooking
>> it up to the MCU and doing SDR stuff.  I also want a small loopstick
>> version of this so I can embed it in my own nixie wall clock, hence the
>> interest in crystal filters, etc.
>>
>> Mark
>>
>>
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>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
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>>
>
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Re: [time-nuts] WWVB SDR discussion

2020-08-11 Thread paul swed 
Mark
His antenna hit a preamp as I recall about 20 db of gain. To see something
on a scope add 40 more db approx. Unfortunately a purely broadband solution
will show 40 db of pure garbage these days. Using the 60 KHz watch crystals
$2.00 for 20 out of China you can most likely find a reasonable match.
Thats what I did. It is hi Z so it feeds one side of an opamp. Look at the
spectracom schematics to get a sense of what to do. I made a small socket
to plug them in and found the one that worked. As an alternative you can
build a bandpass filter with opamps lots of variations. Anything to get the
received bandwidth reduced. Look at Johns front end also.
Regards
Paul

On Tue, Aug 11, 2020 at 3:20 PM Mark Haun  wrote:

> Hi Detlef,
>
> On 11-Aug-20 3:46 AM, Detlef Schuecker via time-nuts wrote:
> > you do not necessarily need a variable ( physical ) oscillator. You mix
> > the signal down in the digital domain. A 'digital local oscilator' is a
> > mere complex value, which is rotated and the power is adjusted:
> My proposed block diagram does actually have a digital LO, only mine is
> 1, 0, -1, 0... (in-phase) and 0, -1, 0, 1...  (quadrature).  You could
> of course use an variable-frequency NCO, but I need a physical
> oscillator in any case to clock the MCU.  I am also thinking in terms of
> a WWVB-DO where I want a stable local reference to steer.  (Although in
> fairness, for WWVB I think you probably want stability over the diurnal
> propagation variation, and my crappy OCXO has no chance at that.)
> >> part, unfortunately.  My tuned loop seems still too broadband, even
> >> after a couple more poles of op-amp filter.  I have a bunch of 60-kHz
> >> tuning-fork crystals and wanted to try a crystal filter like the "pros"
> > Good point.
> > Firstly I tried a tuned resonant LC circuit with a BF245 preamplifier to
> > keep a high Q.
> Besides having minimal analog design experience, I think what is
> confusing me is these crystals have a really high impedance far away
> from their parallel resonance.  Even at series resonance the motional
> resistance is in the 10s of kohms, IIRC.  So I'm not exactly sure how to
> deploy one in place of an LC tank circuit, e.g. in a collector or drain
> circuit.
> > Secondly an accurate ADC is an option. With 24Bit you get more than
> 100dB
> > dynamic range, so you dont care about a 60dB stronger nearby interferer.
>
> Fancier ADC shouldn't make any difference.  Even though the STM32L4 ADC
> has an SNR of (IIRC) ~ 69 dB, you can sample at several MHz.  After
> downsampling to something like 100 Hz (post LO), the SNR is well over
> 100 dB, which should be plenty.
>
> (Of course, this presupposes that there are not strong interferers or
> SMPS noise spurs, etc. within a 100-Hz BW centered on 60 kHz.  But if
> there are, a fancy ADC wouldn't help you anyway.  The main thing is to
> make sure the interference isn't causing any clipping or nonlinearity
> before you sample.)
>
> I should note that my big tuned air loop and preamp, which is modeled
> after Joe Magliacane's, may be adequate even though I can't see WWVB on
> the oscilloscope.  I was hoping to build confidence there before hooking
> it up to the MCU and doing SDR stuff.  I also want a small loopstick
> version of this so I can embed it in my own nixie wall clock, hence the
> interest in crystal filters, etc.
>
> Mark
>
>
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Re: [time-nuts] WWVB SDR discussion

2020-08-11 Thread Mark Haun 
Hi Detlef,

On 11-Aug-20 3:46 AM, Detlef Schuecker via time-nuts wrote:
> you do not necessarily need a variable ( physical ) oscillator. You mix 
> the signal down in the digital domain. A 'digital local oscilator' is a 
> mere complex value, which is rotated and the power is adjusted:
My proposed block diagram does actually have a digital LO, only mine is
1, 0, -1, 0... (in-phase) and 0, -1, 0, 1...  (quadrature).  You could
of course use an variable-frequency NCO, but I need a physical
oscillator in any case to clock the MCU.  I am also thinking in terms of
a WWVB-DO where I want a stable local reference to steer.  (Although in
fairness, for WWVB I think you probably want stability over the diurnal
propagation variation, and my crappy OCXO has no chance at that.)
>> part, unfortunately.  My tuned loop seems still too broadband, even
>> after a couple more poles of op-amp filter.  I have a bunch of 60-kHz
>> tuning-fork crystals and wanted to try a crystal filter like the "pros"
> Good point. 
> Firstly I tried a tuned resonant LC circuit with a BF245 preamplifier to 
> keep a high Q.
Besides having minimal analog design experience, I think what is
confusing me is these crystals have a really high impedance far away
from their parallel resonance.  Even at series resonance the motional
resistance is in the 10s of kohms, IIRC.  So I'm not exactly sure how to
deploy one in place of an LC tank circuit, e.g. in a collector or drain
circuit.
> Secondly an accurate ADC is an option. With 24Bit you get more than 100dB 
> dynamic range, so you dont care about a 60dB stronger nearby interferer.

Fancier ADC shouldn't make any difference.  Even though the STM32L4 ADC
has an SNR of (IIRC) ~ 69 dB, you can sample at several MHz.  After
downsampling to something like 100 Hz (post LO), the SNR is well over
100 dB, which should be plenty.

(Of course, this presupposes that there are not strong interferers or
SMPS noise spurs, etc. within a 100-Hz BW centered on 60 kHz.  But if
there are, a fancy ADC wouldn't help you anyway.  The main thing is to
make sure the interference isn't causing any clipping or nonlinearity
before you sample.)

I should note that my big tuned air loop and preamp, which is modeled
after Joe Magliacane's, may be adequate even though I can't see WWVB on
the oscilloscope.  I was hoping to build confidence there before hooking
it up to the MCU and doing SDR stuff.  I also want a small loopstick
version of this so I can embed it in my own nixie wall clock, hence the
interest in crystal filters, etc.

Mark


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Re: [time-nuts] WWVB SDR discussion

2020-08-11 Thread Detlef Schuecker via time-nuts 
Hi,

you do not necessarily need a variable ( physical ) oscillator. You mix 
the signal down in the digital domain. A 'digital local oscilator' is a 
mere complex value, which is rotated and the power is adjusted:

#define CMUL(_a,_b,_c)  \
{ _c.re = _a.re*_b.re-_a.im*_b.im; \
  _c.im = _a.re*_b.im+_a.im*_b.re; }
#define CROT(_a,_w) 
{ fcomplex_t hh; \
  CMUL(_a,_w,hh); \
  _a.re=hh.re*hh.re+hh.im*hh.im; \
  if(_a.re<1.0f){ \
 hh.re *= (1.0f+1e-6); \
 hh.im *= (1.0f+1e-6); \
  } else { \
 hh.re *= (1.0f-1e-6);  \
 hh.im *= (1.0f-1e-6);  \
  } \
  _a.re=hh.re; \
  _a.im=hh.im; \
}


The sample rate is not an integer multiple of the signal frequency, that 
is not necessary. 


> part, unfortunately.  My tuned loop seems still too broadband, even
> after a couple more poles of op-amp filter.  I have a bunch of 60-kHz
> tuning-fork crystals and wanted to try a crystal filter like the "pros"

Good point. 
Firstly I tried a tuned resonant LC circuit with a BF245 preamplifier to 
keep a high Q.
Secondly an accurate ADC is an option. With 24Bit you get more than 100dB 
dynamic range, so you dont care about a 60dB stronger nearby interferer.

I want to phase track at least 2 time broadcasters eg Anthorn and DCF77 
and try to do a hyperbolic navigation with the phase difference. The LC is 
tuned by MOSFET switched capacitors. A STM32 should suffice for the thing. 
See, how far ( or near, in terms of navigation ) I can get :).

Cheers
Detlef
DD4WV
 





 

Detlef Schücker


"time-nuts"  schrieb am 10.08.2020 
23:18:29:

> Von: "Mark Haun" 
> An: time-nuts@lists.febo.com
> Datum: 11.08.2020 00:29
> Betreff: Re: [time-nuts] WWVB SDR discussion
> Gesendet von: "time-nuts" 
> 
> No more so than for a GPSDO using a microcontroller.  In this case, the
> MCU would steer an external oscillator using an appropriately long time
> constant, based on a phase tracking loop.  In my tentative block
> diagram, the oscillator is a cheap 26 MHz OCXO which supplies the MCU
> clock and (as a byproduct) the internal ADC sample rate.  The basic plan
> for an STM32L4 was something like
> 
> 26 MHz clock input from OCXO
> 78 MHz MCU clock (x3 via internal PLL)
> 3.12 MHz ADC sample rate (78 MHz / 25)
> 13x downsample to 240 kHz using DFSDM block (hardware CIC)
> sign flip and deinterleave into I and Q channels (I, Q, -I, -Q, ...)
> downsample again, to ~ 10 Hz or so; do SDR stuff at this rate
> carrier tracking loop runs back outside the MCU to the OCXO control
> input, via PWM DAC
> 
> With care, the internal ADC gives you about 11 good bits at the high
> sampling rate.  Assuming white noise (questionable I suppose), this
> yields something like 18 noise-free bits at the low rate where the phase
> tracking and decoding happens.
> 
> Prerequisite is an analog input centered around 60 kHz with less than
> 3.6Vp-p amplitude.  There are no particular bandwidth requirements
> (Nyquist is 1.5 MHz!) as long as it is narrow enough to avoid clipping
> from strong interfering signals.  I am having a hard time with this
> part, unfortunately.  My tuned loop seems still too broadband, even
> after a couple more poles of op-amp filter.  I have a bunch of 60-kHz
> tuning-fork crystals and wanted to try a crystal filter like the "pros"
> do in cheap consumer clocks, but I can't figure out a circuit to do this
> (weak on analog).  So if anyone wants to tackle that and send me a
> working design, I'm happy to do the easy stuff, i.e. the DSP/SDR parts 
;)
> 
> Mark
> 
> On 10-Aug-20 11:45 AM, paul swed wrote:
> > Hello to the group.
> > Have been looking forward to seeing how the STM32 SDR project might be
> > going.
> > SDR is a weak spot for me. So been reading. And believe the answer is 
that
> > a SDR solution may work for AM code and even BPSK code to an extent. 
But
> > doesn't the sampling destroy the quality of the incoming signal for
> > establishing a locked reference?
> > Regards
> > Paul
> > WB8TSL
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> nuts_lists.febo.com
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> >
> 
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Re: [time-nuts] WWVB SDR discussion

2020-08-11 Thread Tom Van Baak 

Ray,

I don't see a crystal filter. There is a 16 MHz crystal, but that's for 
the processor.


"Inside the La Crosse 1235UA UltrAtomic Radio Controlled WWVB (Atomic) 
Wall Clock"

http://leapsecond.com/pages/ultratomic/

"ES100 datasheet, including block diagram, application circuit, and theory"
http://leapsecond.com/pages/es100/ES100DataSheetver0p97.pdf

"Universal Solder ES100 cob dev kit"
http://leapsecond.com/pages/es100/pins.htm

/tvb


On 8/10/2020 11:09 PM, rcb...@atcelectronics.com wrote:

Does the La Crosse UltrAtomic clock actually use a crystal filter or do
they digitally filter the signal? Has anyone ever looked inside of one
of the clocks? Just curious.

Ray
AB7HE



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Re: [time-nuts] WWVB SDR discussion

2020-08-10 Thread Mark Haun 
No more so than for a GPSDO using a microcontroller.  In this case, the
MCU would steer an external oscillator using an appropriately long time
constant, based on a phase tracking loop.  In my tentative block
diagram, the oscillator is a cheap 26 MHz OCXO which supplies the MCU
clock and (as a byproduct) the internal ADC sample rate.  The basic plan
for an STM32L4 was something like

26 MHz clock input from OCXO
78 MHz MCU clock (x3 via internal PLL)
3.12 MHz ADC sample rate (78 MHz / 25)
13x downsample to 240 kHz using DFSDM block (hardware CIC)
sign flip and deinterleave into I and Q channels (I, Q, -I, -Q, ...)
downsample again, to ~ 10 Hz or so; do SDR stuff at this rate
carrier tracking loop runs back outside the MCU to the OCXO control
input, via PWM DAC

With care, the internal ADC gives you about 11 good bits at the high
sampling rate.  Assuming white noise (questionable I suppose), this
yields something like 18 noise-free bits at the low rate where the phase
tracking and decoding happens.

Prerequisite is an analog input centered around 60 kHz with less than
3.6Vp-p amplitude.  There are no particular bandwidth requirements
(Nyquist is 1.5 MHz!) as long as it is narrow enough to avoid clipping
from strong interfering signals.  I am having a hard time with this
part, unfortunately.  My tuned loop seems still too broadband, even
after a couple more poles of op-amp filter.  I have a bunch of 60-kHz
tuning-fork crystals and wanted to try a crystal filter like the "pros"
do in cheap consumer clocks, but I can't figure out a circuit to do this
(weak on analog).  So if anyone wants to tackle that and send me a
working design, I'm happy to do the easy stuff, i.e. the DSP/SDR parts ;)

Mark

On 10-Aug-20 11:45 AM, paul swed wrote:
> Hello to the group.
> Have been looking forward to seeing how the STM32 SDR project might be
> going.
> SDR is a weak spot for me. So been reading. And believe the answer is that
> a SDR solution may work for AM code and even BPSK code to an extent. But
> doesn't the sampling destroy the quality of the incoming signal for
> establishing a locked reference?
> Regards
> Paul
> WB8TSL
> ___
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> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
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>

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Re: [time-nuts] WWVB SDR discussion

2020-08-10 Thread Bob kb8tq 
Hi

As long as you sample “fast enough”, you can recover phase. Indeed, even if
you sub-sample (sample to slow), you can still get phase back with a few 
relatively minor constraints. Since one of those is “don’t sub sample at exactly
a fraction of the carrier”, a sub-sample “locked” receiver would be a challenge.

Bob

> On Aug 10, 2020, at 2:45 PM, paul swed  wrote:
> 
> Hello to the group.
> Have been looking forward to seeing how the STM32 SDR project might be
> going.
> SDR is a weak spot for me. So been reading. And believe the answer is that
> a SDR solution may work for AM code and even BPSK code to an extent. But
> doesn't the sampling destroy the quality of the incoming signal for
> establishing a locked reference?
> Regards
> Paul
> WB8TSL
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
> To unsubscribe, go to 
> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.


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Re: [time-nuts] WWVB SDR discussion

2020-08-10 Thread jimlux 

On 8/10/20 11:45 AM, paul swed wrote:

Hello to the group.
Have been looking forward to seeing how the STM32 SDR project might be
going.
SDR is a weak spot for me. So been reading. And believe the answer is that
a SDR solution may work for AM code and even BPSK code to an extent. But
doesn't the sampling destroy the quality of the incoming signal for
establishing a locked reference?



Not really.  Consider you want to know the phase of a sinewave, and 
you're sampling at 3.5321 samples/cycle (i.e. it doesn't have to be 
integer samples/cycle).  You can solve for the phase of the sinewave to 
any level of precision, limited essentially by the SNR of the samples 
(including any quantization effects).



You can do this repeatedly - and implement all you need in terms of a 
phase locked loop - entirely in the digital domain.


As it happens, some things are *easier* if you, for instance sample at 4 
times the frequency of the input signal - various clock rate noises 
alias to places that are not near the input signal.


So, sample with enough bits, digitally filter, run your PLL, and you can 
conceivably steer your processor's VCXO to be in a fixed frequency 
relationship with the input.(and maybe phase).



This is essentially what we do with modern deep space transponders - we 
digitize the received uplink signal (actually, at the IF), run that 
through a PLL tracking loop using the frequency error term to drive a 
DDS which generates the downlink signal. So we can keep the transmit 
frequency exactly at 880/749*receive frequency (For X-band, anyway).


There is some arithmetic involved to make sure that all the ratios come 
out right - and some design involved to make sure that errors (i.e. 
noise on the reference oscillator, which is fixed frequency) cancel 
appropriately.


The previous generation of transponders did a quasi digital PLL - the IF 
was digitized and processed to generate an error signal, which was then 
used to push the VCTCXO around - so the reference frequency was always a 
fixed fraction of the receive frequency (usually around 78-80MHz, for 
historical reasons). Then the transmit side just multiplied the 
oscillator up.


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