GB
Gregory Beat
Fri, Oct 2, 2015 11:06 PM
Dan -
I have been following your experimentation with the surplus Lucent KS-24361 REF-0 module, to transform it into a standalone GPSDO.
The original usage of the classic Oncore UT+ GPS receiver for KS-24361 REF-1, by Symmetricom / Datum for Lucent, was deliberate.
For usage at a cellular data/telecom site, the focus was on the timing and frequency discipline from the GPS satellite transmission, rather than the position or dead reckoning aspects -- used by smartphones, automobiles, and other GPS applications on the market.
A couple of comments.
While I can appreciate being economical (main criteria) and selecting the NEO-6M receiver, I believe that a u-Blox timing specific module (like LEA-6T) would be more desirable in this application.
In addition, the u-Blox 6-series is the trailing edge of product support (market demand dictates its continuance), while the 7 and 8-series are their current modules (largely for the cellular / mobile industry (smartphones or cell sites themselves)
u-Blox 6-series Timing Application Note (using the LEA-6T)
https://www.u-blox.com/sites/default/files/products/documents/Timing_AppNote_%28GPS.G6-X-11007%29.pdf
IF you successfully adopt the u-Blox module to correctly "mimic" the Oncore UT+ GPS receiver command suite, THEN you open up a larger audience of "time-nuts" and Frequency Standard users (HP Z3801A frequency standard universe) as a receiver alternative.
http://www.realhamradio.com/GPS_Frequency_Standard.htm
These users may desire a "newer" GPS receiver that has more channels (8-channel); latest generation receiver; access to the newest GPS constellations.
TAPR might be interested in sponsoring, as a kit/module, if a wider audience existed.
The Heol Designs N024 receiver (France) accomplished this replacement role for the Trimble ACE II/III GPS receiver used in the Symmetricom/Datum TymServe TS2100.
Their solution resolved shortcomings in the mid-1990 Trimble receiver design and giving this Symmetricom NTP server, time IRIG-B time code generator, and 10 MHz reference appliance a new lease on life (no longer a door stop).
http://www.heoldesign.com/index.php?module=products&action=catalog&cat=14&id=54
w9gb
Sent from iPad Air
Dan -
I have been following your experimentation with the surplus Lucent KS-24361 REF-0 module, to transform it into a standalone GPSDO.
The original usage of the classic Oncore UT+ GPS receiver for KS-24361 REF-1, by Symmetricom / Datum for Lucent, was deliberate.
For usage at a cellular data/telecom site, the focus was on the timing and frequency discipline from the GPS satellite transmission, rather than the position or dead reckoning aspects -- used by smartphones, automobiles, and other GPS applications on the market.
===
A couple of comments.
While I can appreciate being economical (main criteria) and selecting the NEO-6M receiver, I believe that a u-Blox timing specific module (like LEA-6T) would be more desirable in this application.
In addition, the u-Blox 6-series is the trailing edge of product support (market demand dictates its continuance), while the 7 and 8-series are their current modules (largely for the cellular / mobile industry (smartphones or cell sites themselves)
u-Blox 6-series Timing Application Note (using the LEA-6T)
https://www.u-blox.com/sites/default/files/products/documents/Timing_AppNote_%28GPS.G6-X-11007%29.pdf
IF you successfully adopt the u-Blox module to correctly "mimic" the Oncore UT+ GPS receiver command suite, THEN you open up a larger audience of "time-nuts" and Frequency Standard users (HP Z3801A frequency standard universe) as a receiver alternative.
http://www.realhamradio.com/GPS_Frequency_Standard.htm
These users may desire a "newer" GPS receiver that has more channels (8-channel); latest generation receiver; access to the newest GPS constellations.
TAPR might be interested in sponsoring, as a kit/module, if a wider audience existed.
The Heol Designs N024 receiver (France) accomplished this replacement role for the Trimble ACE II/III GPS receiver used in the Symmetricom/Datum TymServe TS2100.
Their solution resolved shortcomings in the mid-1990 Trimble receiver design and giving this Symmetricom NTP server, time IRIG-B time code generator, and 10 MHz reference appliance a new lease on life (no longer a door stop).
http://www.heoldesign.com/index.php?module=products&action=catalog&cat=14&id=54
w9gb
Sent from iPad Air
BC
Bob Camp
Sat, Oct 3, 2015 12:32 AM
Hi
Given that eBay is awash in various older uBlox devices at really low prices, going for the > $200 a unit single piece price of the LEA-8T seems a bit much. You get all of the core timing functions in the “not T” parts (including sawtooth data). The main thing you get with the 7’s (vs the 5 and 6) is the ability to switch over to Glonass. With the 8’s you get the ability to run Glonass plus GPS at the same time. In both cases, you get nothing from the Glonass constellation that’s worth the switch. In a timing application you likely would run “pure GPS”.
The net effect is that you only loose the position hold mode with the “not T” devices. With a reasonable antenna location the timing performance of these units is actually quite good in “not hold” mode. If you are combining one with a $25 REF-0, then a $20 GPS makes a lot of sense. You might be giving up 5 ns to 10 ns a day of wander due to position issues.
Even with the location hold, you still have about 10 to 30 ns of daily wander from ionosphere issues. Your money probably would be better spent on an L1/L2 GPS that takes this out rather than on a position hold device. eBay has these sort of devices for (almost) the same sort of money as the LEA-8T single.
Bob
On Oct 2, 2015, at 7:06 PM, Gregory Beat w9gb@icloud.com wrote:
Dan -
I have been following your experimentation with the surplus Lucent KS-24361 REF-0 module, to transform it into a standalone GPSDO.
The original usage of the classic Oncore UT+ GPS receiver for KS-24361 REF-1, by Symmetricom / Datum for Lucent, was deliberate.
For usage at a cellular data/telecom site, the focus was on the timing and frequency discipline from the GPS satellite transmission, rather than the position or dead reckoning aspects -- used by smartphones, automobiles, and other GPS applications on the market.
A couple of comments.
While I can appreciate being economical (main criteria) and selecting the NEO-6M receiver, I believe that a u-Blox timing specific module (like LEA-6T) would be more desirable in this application.
In addition, the u-Blox 6-series is the trailing edge of product support (market demand dictates its continuance), while the 7 and 8-series are their current modules (largely for the cellular / mobile industry (smartphones or cell sites themselves)
u-Blox 6-series Timing Application Note (using the LEA-6T)
https://www.u-blox.com/sites/default/files/products/documents/Timing_AppNote_%28GPS.G6-X-11007%29.pdf
IF you successfully adopt the u-Blox module to correctly "mimic" the Oncore UT+ GPS receiver command suite, THEN you open up a larger audience of "time-nuts" and Frequency Standard users (HP Z3801A frequency standard universe) as a receiver alternative.
http://www.realhamradio.com/GPS_Frequency_Standard.htm
These users may desire a "newer" GPS receiver that has more channels (8-channel); latest generation receiver; access to the newest GPS constellations.
TAPR might be interested in sponsoring, as a kit/module, if a wider audience existed.
The Heol Designs N024 receiver (France) accomplished this replacement role for the Trimble ACE II/III GPS receiver used in the Symmetricom/Datum TymServe TS2100.
Their solution resolved shortcomings in the mid-1990 Trimble receiver design and giving this Symmetricom NTP server, time IRIG-B time code generator, and 10 MHz reference appliance a new lease on life (no longer a door stop).
http://www.heoldesign.com/index.php?module=products&action=catalog&cat=14&id=54
w9gb
Sent from iPad Air
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.
Hi
Given that eBay is awash in various older uBlox devices at really low prices, going for the > $200 a unit single piece price of the LEA-8T seems a bit much. You get all of the core timing functions in the “not T” parts (including sawtooth data). The main thing you get with the 7’s (vs the 5 and 6) is the ability to switch over to Glonass. With the 8’s you get the ability to run Glonass plus GPS at the same time. In both cases, you get nothing from the Glonass constellation that’s worth the switch. In a timing application you likely would run “pure GPS”.
The net effect is that you only loose the position hold mode with the “not T” devices. With a reasonable antenna location the timing performance of these units is actually quite good in “not hold” mode. If you are combining one with a $25 REF-0, then a $20 GPS makes a lot of sense. You *might* be giving up 5 ns to 10 ns a day of wander due to position issues.
Even with the location hold, you still have about 10 to 30 ns of daily wander from ionosphere issues. Your money probably would be better spent on an L1/L2 GPS that takes this out rather than on a position hold device. eBay has these sort of devices for (almost) the same sort of money as the LEA-8T single.
Bob
> On Oct 2, 2015, at 7:06 PM, Gregory Beat <w9gb@icloud.com> wrote:
>
> Dan -
>
> I have been following your experimentation with the surplus Lucent KS-24361 REF-0 module, to transform it into a standalone GPSDO.
>
> The original usage of the classic Oncore UT+ GPS receiver for KS-24361 REF-1, by Symmetricom / Datum for Lucent, was deliberate.
> For usage at a cellular data/telecom site, the focus was on the timing and frequency discipline from the GPS satellite transmission, rather than the position or dead reckoning aspects -- used by smartphones, automobiles, and other GPS applications on the market.
> ===
> A couple of comments.
> While I can appreciate being economical (main criteria) and selecting the NEO-6M receiver, I believe that a u-Blox timing specific module (like LEA-6T) would be more desirable in this application.
>
> In addition, the u-Blox 6-series is the trailing edge of product support (market demand dictates its continuance), while the 7 and 8-series are their current modules (largely for the cellular / mobile industry (smartphones or cell sites themselves)
>
> u-Blox 6-series Timing Application Note (using the LEA-6T)
> https://www.u-blox.com/sites/default/files/products/documents/Timing_AppNote_%28GPS.G6-X-11007%29.pdf
>
> IF you successfully adopt the u-Blox module to correctly "mimic" the Oncore UT+ GPS receiver command suite, THEN you open up a larger audience of "time-nuts" and Frequency Standard users (HP Z3801A frequency standard universe) as a receiver alternative.
> http://www.realhamradio.com/GPS_Frequency_Standard.htm
>
> These users may desire a "newer" GPS receiver that has more channels (8-channel); latest generation receiver; access to the newest GPS constellations.
> TAPR might be interested in sponsoring, as a kit/module, if a wider audience existed.
>
> The Heol Designs N024 receiver (France) accomplished this replacement role for the Trimble ACE II/III GPS receiver used in the Symmetricom/Datum TymServe TS2100.
> Their solution resolved shortcomings in the mid-1990 Trimble receiver design and giving this Symmetricom NTP server, time IRIG-B time code generator, and 10 MHz reference appliance a new lease on life (no longer a door stop).
> http://www.heoldesign.com/index.php?module=products&action=catalog&cat=14&id=54
>
> w9gb
>
> Sent from iPad Air
> _______________________________________________
> 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.
DW
Daniel Watson
Sat, Oct 3, 2015 12:48 AM
Gregory,
Thanks for your comments. You are absolutely right that a timing GPS module
is required to make this a proper Time-Nuts solution. I know that many on
the list have been thinking the same thing when they read my posts. Cost
alone is what has prevented me from going directly to that approach. Even
at eBay or Ali Express prices, 6T modules are six to seven times more
expensive than the 6M modules. I have decided to develop this in an
iterative fashion using lower-cost modules for testing. This way I can get
the bulk of the development done at a low cost, and then add in a higher
grade module when the time is right.
I am already working on a version of the board that uses the LEA-6T module.
The footprint on the board would be upwards-compatible with the LEA-M8T
module, with it's GNSS all-in-view features. That would surely interest a
lot of folks. Of course, that would come at a significantly increased cost,
but at least the option will be there.
I also agree that translating the GPS strings to the Oncore format would
open up the usage of this board to more applications. This is one of the
reasons I have had a microcontroller between the GPS and REF-0 from the
very beginning. Early on this enabled the quick fix of sending canned
strings. But newer versions of my code instead translate important
information such as fix status and sawtooth correction. This can easily be
extended to correctly populate all of the messages. And with even more time
invested, the micro can be programmed to translate two-way messages and
commands to fully replicate an Oncore. The hardware will soon be done to
enable all of that.
What you see in the Denuo GPS board is just one more step forward in the
project. I hope I can eventually bring it to a very satisfying and
Time-Nutty conclusion.
Best regards,
Dan W.
On Fri, Oct 2, 2015 at 7:06 PM, Gregory Beat w9gb@icloud.com wrote:
Dan -
I have been following your experimentation with the surplus Lucent
KS-24361 REF-0 module, to transform it into a standalone GPSDO.
The original usage of the classic Oncore UT+ GPS receiver for KS-24361
REF-1, by Symmetricom / Datum for Lucent, was deliberate.
For usage at a cellular data/telecom site, the focus was on the timing and
frequency discipline from the GPS satellite transmission, rather than the
position or dead reckoning aspects -- used by smartphones, automobiles, and
other GPS applications on the market.
A couple of comments.
While I can appreciate being economical (main criteria) and selecting the
NEO-6M receiver, I believe that a u-Blox timing specific module (like
LEA-6T) would be more desirable in this application.
In addition, the u-Blox 6-series is the trailing edge of product support
(market demand dictates its continuance), while the 7 and 8-series are
their current modules (largely for the cellular / mobile industry
(smartphones or cell sites themselves)
u-Blox 6-series Timing Application Note (using the LEA-6T)
https://www.u-blox.com/sites/default/files/products/documents/Timing_AppNote_%28GPS.G6-X-11007%29.pdf
IF you successfully adopt the u-Blox module to correctly "mimic" the
Oncore UT+ GPS receiver command suite, THEN you open up a larger audience
of "time-nuts" and Frequency Standard users (HP Z3801A frequency standard
universe) as a receiver alternative.
http://www.realhamradio.com/GPS_Frequency_Standard.htm
These users may desire a "newer" GPS receiver that has more channels
(8-channel); latest generation receiver; access to the newest GPS
constellations.
TAPR might be interested in sponsoring, as a kit/module, if a wider
audience existed.
The Heol Designs N024 receiver (France) accomplished this replacement role
for the Trimble ACE II/III GPS receiver used in the Symmetricom/Datum
TymServe TS2100.
Their solution resolved shortcomings in the mid-1990 Trimble receiver
design and giving this Symmetricom NTP server, time IRIG-B time code
generator, and 10 MHz reference appliance a new lease on life (no longer a
door stop).
http://www.heoldesign.com/index.php?module=products&action=catalog&cat=14&id=54
w9gb
Sent from iPad Air
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.
Gregory,
Thanks for your comments. You are absolutely right that a timing GPS module
is required to make this a proper Time-Nuts solution. I know that many on
the list have been thinking the same thing when they read my posts. Cost
alone is what has prevented me from going directly to that approach. Even
at eBay or Ali Express prices, 6T modules are six to seven times more
expensive than the 6M modules. I have decided to develop this in an
iterative fashion using lower-cost modules for testing. This way I can get
the bulk of the development done at a low cost, and then add in a higher
grade module when the time is right.
I am already working on a version of the board that uses the LEA-6T module.
The footprint on the board would be upwards-compatible with the LEA-M8T
module, with it's GNSS all-in-view features. That would surely interest a
lot of folks. Of course, that would come at a significantly increased cost,
but at least the option will be there.
I also agree that translating the GPS strings to the Oncore format would
open up the usage of this board to more applications. This is one of the
reasons I have had a microcontroller between the GPS and REF-0 from the
very beginning. Early on this enabled the quick fix of sending canned
strings. But newer versions of my code instead translate important
information such as fix status and sawtooth correction. This can easily be
extended to correctly populate all of the messages. And with even more time
invested, the micro can be programmed to translate two-way messages and
commands to fully replicate an Oncore. The hardware will soon be done to
enable all of that.
What you see in the Denuo GPS board is just one more step forward in the
project. I hope I can eventually bring it to a very satisfying and
Time-Nutty conclusion.
Best regards,
Dan W.
On Fri, Oct 2, 2015 at 7:06 PM, Gregory Beat <w9gb@icloud.com> wrote:
> Dan -
>
> I have been following your experimentation with the surplus Lucent
> KS-24361 REF-0 module, to transform it into a standalone GPSDO.
>
> The original usage of the classic Oncore UT+ GPS receiver for KS-24361
> REF-1, by Symmetricom / Datum for Lucent, was deliberate.
> For usage at a cellular data/telecom site, the focus was on the timing and
> frequency discipline from the GPS satellite transmission, rather than the
> position or dead reckoning aspects -- used by smartphones, automobiles, and
> other GPS applications on the market.
> ===
> A couple of comments.
> While I can appreciate being economical (main criteria) and selecting the
> NEO-6M receiver, I believe that a u-Blox timing specific module (like
> LEA-6T) would be more desirable in this application.
>
> In addition, the u-Blox 6-series is the trailing edge of product support
> (market demand dictates its continuance), while the 7 and 8-series are
> their current modules (largely for the cellular / mobile industry
> (smartphones or cell sites themselves)
>
> u-Blox 6-series Timing Application Note (using the LEA-6T)
>
> https://www.u-blox.com/sites/default/files/products/documents/Timing_AppNote_%28GPS.G6-X-11007%29.pdf
>
> IF you successfully adopt the u-Blox module to correctly "mimic" the
> Oncore UT+ GPS receiver command suite, THEN you open up a larger audience
> of "time-nuts" and Frequency Standard users (HP Z3801A frequency standard
> universe) as a receiver alternative.
> http://www.realhamradio.com/GPS_Frequency_Standard.htm
>
> These users may desire a "newer" GPS receiver that has more channels
> (8-channel); latest generation receiver; access to the newest GPS
> constellations.
> TAPR might be interested in sponsoring, as a kit/module, if a wider
> audience existed.
>
> The Heol Designs N024 receiver (France) accomplished this replacement role
> for the Trimble ACE II/III GPS receiver used in the Symmetricom/Datum
> TymServe TS2100.
> Their solution resolved shortcomings in the mid-1990 Trimble receiver
> design and giving this Symmetricom NTP server, time IRIG-B time code
> generator, and 10 MHz reference appliance a new lease on life (no longer a
> door stop).
>
> http://www.heoldesign.com/index.php?module=products&action=catalog&cat=14&id=54
>
> w9gb
>
> Sent from iPad Air
> _______________________________________________
> 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.
>
BH
Bill Hawkins
Sat, Oct 3, 2015 2:44 AM
Actually, the Lucent software uses RAIM, and reports the value in its
status message. If the position appears to have drifted off, or there
aren't enough satellites to calculate the position, the software
declares the oscillators to be free-wheeling, an expression meaning that
the oscillators are free from discipline and are now drifting.
So yes, the positioning aspects matter.
Disclaimer: I haven't studied RAIM (or TRAIM) enough to know exactly
what goes on, but that's the behavior I've observed.
Bill Hawkins
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Gregory
Beat
Sent: Friday, October 02, 2015 6:07 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] KS-24361 REF-0 standalone
Dan -
I have been following your experimentation with the surplus Lucent
KS-24361 REF-0 module, to transform it into a standalone GPSDO.
The original usage of the classic Oncore UT+ GPS receiver for KS-24361
REF-1, by Symmetricom / Datum for Lucent, was deliberate.
For usage at a cellular data/telecom site, the focus was on the timing
and frequency discipline from the GPS satellite transmission, rather
than the position or dead reckoning aspects -- used by smartphones,
automobiles, and other GPS applications on the market.
A couple of comments.
While I can appreciate being economical (main criteria) and selecting
the NEO-6M receiver, I believe that a u-Blox timing specific module
(like LEA-6T) would be more desirable in this application.
In addition, the u-Blox 6-series is the trailing edge of product support
(market demand dictates its continuance), while the 7 and 8-series are
their current modules (largely for the cellular / mobile industry
(smartphones or cell sites themselves)
u-Blox 6-series Timing Application Note (using the LEA-6T)
https://www.u-blox.com/sites/default/files/products/documents/Timing_App
Note_%28GPS.G6-X-11007%29.pdf
IF you successfully adopt the u-Blox module to correctly "mimic" the
Oncore UT+ GPS receiver command suite, THEN you open up a larger
audience of "time-nuts" and Frequency Standard users (HP Z3801A
frequency standard universe) as a receiver alternative.
http://www.realhamradio.com/GPS_Frequency_Standard.htm
These users may desire a "newer" GPS receiver that has more channels
(8-channel); latest generation receiver; access to the newest GPS
constellations.
TAPR might be interested in sponsoring, as a kit/module, if a wider
audience existed.
The Heol Designs N024 receiver (France) accomplished this replacement
role for the Trimble ACE II/III GPS receiver used in the
Symmetricom/Datum TymServe TS2100.
Their solution resolved shortcomings in the mid-1990 Trimble receiver
design and giving this Symmetricom NTP server, time IRIG-B time code
generator, and 10 MHz reference appliance a new lease on life (no longer
a door stop).
http://www.heoldesign.com/index.php?module=products&action=catalog&cat=1
4&id=54
w9gb
Actually, the Lucent software uses RAIM, and reports the value in its
status message. If the position appears to have drifted off, or there
aren't enough satellites to calculate the position, the software
declares the oscillators to be free-wheeling, an expression meaning that
the oscillators are free from discipline and are now drifting.
So yes, the positioning aspects matter.
Disclaimer: I haven't studied RAIM (or TRAIM) enough to know exactly
what goes on, but that's the behavior I've observed.
Bill Hawkins
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Gregory
Beat
Sent: Friday, October 02, 2015 6:07 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] KS-24361 REF-0 standalone
Dan -
I have been following your experimentation with the surplus Lucent
KS-24361 REF-0 module, to transform it into a standalone GPSDO.
The original usage of the classic Oncore UT+ GPS receiver for KS-24361
REF-1, by Symmetricom / Datum for Lucent, was deliberate.
For usage at a cellular data/telecom site, the focus was on the timing
and frequency discipline from the GPS satellite transmission, rather
than the position or dead reckoning aspects -- used by smartphones,
automobiles, and other GPS applications on the market.
===
A couple of comments.
While I can appreciate being economical (main criteria) and selecting
the NEO-6M receiver, I believe that a u-Blox timing specific module
(like LEA-6T) would be more desirable in this application.
In addition, the u-Blox 6-series is the trailing edge of product support
(market demand dictates its continuance), while the 7 and 8-series are
their current modules (largely for the cellular / mobile industry
(smartphones or cell sites themselves)
u-Blox 6-series Timing Application Note (using the LEA-6T)
https://www.u-blox.com/sites/default/files/products/documents/Timing_App
Note_%28GPS.G6-X-11007%29.pdf
IF you successfully adopt the u-Blox module to correctly "mimic" the
Oncore UT+ GPS receiver command suite, THEN you open up a larger
audience of "time-nuts" and Frequency Standard users (HP Z3801A
frequency standard universe) as a receiver alternative.
http://www.realhamradio.com/GPS_Frequency_Standard.htm
These users may desire a "newer" GPS receiver that has more channels
(8-channel); latest generation receiver; access to the newest GPS
constellations.
TAPR might be interested in sponsoring, as a kit/module, if a wider
audience existed.
The Heol Designs N024 receiver (France) accomplished this replacement
role for the Trimble ACE II/III GPS receiver used in the
Symmetricom/Datum TymServe TS2100.
Their solution resolved shortcomings in the mid-1990 Trimble receiver
design and giving this Symmetricom NTP server, time IRIG-B time code
generator, and 10 MHz reference appliance a new lease on life (no longer
a door stop).
http://www.heoldesign.com/index.php?module=products&action=catalog&cat=1
4&id=54
w9gb
BC
Bob Camp
Sat, Oct 3, 2015 1:47 PM
Hi
If indeed you are into a professional system, where holdover matters then
a lashup on a bunch of surplus gear likely isn’t going to measure up. Based
on about 10,000 previous posts on the list I’d say that holdover does not appear
to matter to Time Nuts. It would be difficult to find a thread where holdover performance
was the main topic. The focus (rightly) seems to be to keep the box locked to
GPS all the time. That approach (if you can do it) will always give you the best
timing.
The “not a T” uBlox units do put out “TRAIM" information in the words you
can get at. The data is valid and it can be used if you wish to put the unit
in holdover. I’m sure it works better with a well known position, but that it not
a requisite.
TRAIM was a really big deal back in the mid 90’s. That’s when Motorola put it on
the Oncore’s and did a lot of publicity on the topic. They saw it as a way to differentiate
their product in the marketplace. Much of our view of TRAIM is slanted by the
Motorola information on the topic.
Here’s one way to look at TRAIM:
If you are in position hold, you can get timing off of a single satellite. TRAIM
(just like any estimator) looks at the single input it has and says “that must be
correct”. Give it two inputs and it can look at the solution for each and decide if
they are close enough (your TRAIM threshold) to be correct. As you get up to 8 or
12 inputs, the right answer may be to throw away the single one that is (say) a microsecond
off from the rest. Somewhere between 3 satellites and 6 satellites, the “I need
a solid position” thing becomes less of a factor.
There are other ways to put the device into holdover. One is to simply look at the
number of satellites. If you are locked on to less than 4 sats, go into holdover. It’s not
elegant, but it does work. In the case of a lash up, just translate the “I have <= 3 sats” info into
“my TRAIM is junk”. Instant holdover.
Bob
On Oct 2, 2015, at 10:44 PM, Bill Hawkins bill@iaxs.net wrote:
Actually, the Lucent software uses RAIM, and reports the value in its
status message. If the position appears to have drifted off, or there
aren't enough satellites to calculate the position, the software
declares the oscillators to be free-wheeling, an expression meaning that
the oscillators are free from discipline and are now drifting.
So yes, the positioning aspects matter.
Disclaimer: I haven't studied RAIM (or TRAIM) enough to know exactly
what goes on, but that's the behavior I've observed.
Bill Hawkins
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Gregory
Beat
Sent: Friday, October 02, 2015 6:07 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] KS-24361 REF-0 standalone
Dan -
I have been following your experimentation with the surplus Lucent
KS-24361 REF-0 module, to transform it into a standalone GPSDO.
The original usage of the classic Oncore UT+ GPS receiver for KS-24361
REF-1, by Symmetricom / Datum for Lucent, was deliberate.
For usage at a cellular data/telecom site, the focus was on the timing
and frequency discipline from the GPS satellite transmission, rather
than the position or dead reckoning aspects -- used by smartphones,
automobiles, and other GPS applications on the market.
A couple of comments.
While I can appreciate being economical (main criteria) and selecting
the NEO-6M receiver, I believe that a u-Blox timing specific module
(like LEA-6T) would be more desirable in this application.
In addition, the u-Blox 6-series is the trailing edge of product support
(market demand dictates its continuance), while the 7 and 8-series are
their current modules (largely for the cellular / mobile industry
(smartphones or cell sites themselves)
u-Blox 6-series Timing Application Note (using the LEA-6T)
https://www.u-blox.com/sites/default/files/products/documents/Timing_App
Note_%28GPS.G6-X-11007%29.pdf
IF you successfully adopt the u-Blox module to correctly "mimic" the
Oncore UT+ GPS receiver command suite, THEN you open up a larger
audience of "time-nuts" and Frequency Standard users (HP Z3801A
frequency standard universe) as a receiver alternative.
http://www.realhamradio.com/GPS_Frequency_Standard.htm
These users may desire a "newer" GPS receiver that has more channels
(8-channel); latest generation receiver; access to the newest GPS
constellations.
TAPR might be interested in sponsoring, as a kit/module, if a wider
audience existed.
The Heol Designs N024 receiver (France) accomplished this replacement
role for the Trimble ACE II/III GPS receiver used in the
Symmetricom/Datum TymServe TS2100.
Their solution resolved shortcomings in the mid-1990 Trimble receiver
design and giving this Symmetricom NTP server, time IRIG-B time code
generator, and 10 MHz reference appliance a new lease on life (no longer
a door stop).
http://www.heoldesign.com/index.php?module=products&action=catalog&cat=1
4&id=54
w9gb
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.
Hi
If indeed you are into a professional system, where holdover matters then
a lashup on a bunch of surplus gear likely isn’t going to measure up. Based
on about 10,000 previous posts on the list I’d say that holdover does not appear
to matter to Time Nuts. It would be difficult to find a thread where holdover performance
was the main topic. The focus (rightly) seems to be to keep the box locked to
GPS all the time. That approach (if you can do it) will always give you the best
timing.
The “not a T” uBlox units *do* put out “TRAIM" information in the words you
can get at. The data is valid and it can be used if you wish to put the unit
in holdover. I’m sure it works better with a well known position, but that it not
a requisite.
TRAIM was a really big deal back in the mid 90’s. That’s when Motorola put it on
the Oncore’s and did a lot of publicity on the topic. They saw it as a way to differentiate
their product in the marketplace. Much of our view of TRAIM is slanted by the
Motorola information on the topic.
Here’s one way to look at TRAIM:
If you are in position hold, you can get timing off of a single satellite. TRAIM
(just like any estimator) looks at the single input it has and says “that must be
correct”. Give it two inputs and it can look at the solution for each and decide if
they are close enough (your TRAIM threshold) to be correct. As you get up to 8 or
12 inputs, the right answer may be to throw away the single one that is (say) a microsecond
off from the rest. Somewhere between 3 satellites and 6 satellites, the “I need
a solid position” thing becomes less of a factor.
There are other ways to put the device into holdover. One is to simply look at the
number of satellites. If you are locked on to less than 4 sats, go into holdover. It’s not
elegant, but it does work. In the case of a lash up, just translate the “I have <= 3 sats” info into
“my TRAIM is junk”. Instant holdover.
Bob
> On Oct 2, 2015, at 10:44 PM, Bill Hawkins <bill@iaxs.net> wrote:
>
> Actually, the Lucent software uses RAIM, and reports the value in its
> status message. If the position appears to have drifted off, or there
> aren't enough satellites to calculate the position, the software
> declares the oscillators to be free-wheeling, an expression meaning that
> the oscillators are free from discipline and are now drifting.
>
> So yes, the positioning aspects matter.
>
> Disclaimer: I haven't studied RAIM (or TRAIM) enough to know exactly
> what goes on, but that's the behavior I've observed.
>
> Bill Hawkins
>
>
> -----Original Message-----
> From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Gregory
> Beat
> Sent: Friday, October 02, 2015 6:07 PM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] KS-24361 REF-0 standalone
>
> Dan -
>
> I have been following your experimentation with the surplus Lucent
> KS-24361 REF-0 module, to transform it into a standalone GPSDO.
>
> The original usage of the classic Oncore UT+ GPS receiver for KS-24361
> REF-1, by Symmetricom / Datum for Lucent, was deliberate.
> For usage at a cellular data/telecom site, the focus was on the timing
> and frequency discipline from the GPS satellite transmission, rather
> than the position or dead reckoning aspects -- used by smartphones,
> automobiles, and other GPS applications on the market.
> ===
> A couple of comments.
> While I can appreciate being economical (main criteria) and selecting
> the NEO-6M receiver, I believe that a u-Blox timing specific module
> (like LEA-6T) would be more desirable in this application.
>
> In addition, the u-Blox 6-series is the trailing edge of product support
> (market demand dictates its continuance), while the 7 and 8-series are
> their current modules (largely for the cellular / mobile industry
> (smartphones or cell sites themselves)
>
> u-Blox 6-series Timing Application Note (using the LEA-6T)
> https://www.u-blox.com/sites/default/files/products/documents/Timing_App
> Note_%28GPS.G6-X-11007%29.pdf
>
> IF you successfully adopt the u-Blox module to correctly "mimic" the
> Oncore UT+ GPS receiver command suite, THEN you open up a larger
> audience of "time-nuts" and Frequency Standard users (HP Z3801A
> frequency standard universe) as a receiver alternative.
> http://www.realhamradio.com/GPS_Frequency_Standard.htm
>
> These users may desire a "newer" GPS receiver that has more channels
> (8-channel); latest generation receiver; access to the newest GPS
> constellations.
> TAPR might be interested in sponsoring, as a kit/module, if a wider
> audience existed.
>
> The Heol Designs N024 receiver (France) accomplished this replacement
> role for the Trimble ACE II/III GPS receiver used in the
> Symmetricom/Datum TymServe TS2100.
> Their solution resolved shortcomings in the mid-1990 Trimble receiver
> design and giving this Symmetricom NTP server, time IRIG-B time code
> generator, and 10 MHz reference appliance a new lease on life (no longer
> a door stop).
> http://www.heoldesign.com/index.php?module=products&action=catalog&cat=1
> 4&id=54
>
> w9gb
>
>
> _______________________________________________
> 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.
PS
paul swed
Sat, Oct 3, 2015 4:09 PM
Dan it looks like the thread has re-developed.
As my early test of your simple solution demonstrated. Better PPS better
stability (Used a TBolt to test this) in the form of semi-short term
jitter. The beauty of Dans solution is the user can select the quality and
cost of the receiver used. Anything can work.
I used the 6M also because of the $11 cost and at the time as a alpha
tester there could have been issues. Reality, the 6M was on the shelf.
Regards
Paul
WB8TSL
On Sat, Oct 3, 2015 at 9:47 AM, Bob Camp kb8tq@n1k.org wrote:
Hi
If indeed you are into a professional system, where holdover matters then
a lashup on a bunch of surplus gear likely isn’t going to measure up. Based
on about 10,000 previous posts on the list I’d say that holdover does not
appear
to matter to Time Nuts. It would be difficult to find a thread where
holdover performance
was the main topic. The focus (rightly) seems to be to keep the box locked
to
GPS all the time. That approach (if you can do it) will always give you
the best
timing.
The “not a T” uBlox units do put out “TRAIM" information in the words you
can get at. The data is valid and it can be used if you wish to put the
unit
in holdover. I’m sure it works better with a well known position, but that
it not
a requisite.
TRAIM was a really big deal back in the mid 90’s. That’s when Motorola put
it on
the Oncore’s and did a lot of publicity on the topic. They saw it as a way
to differentiate
their product in the marketplace. Much of our view of TRAIM is slanted by
the
Motorola information on the topic.
Here’s one way to look at TRAIM:
If you are in position hold, you can get timing off of a single satellite.
TRAIM
(just like any estimator) looks at the single input it has and says “that
must be
correct”. Give it two inputs and it can look at the solution for each and
decide if
they are close enough (your TRAIM threshold) to be correct. As you get up
to 8 or
12 inputs, the right answer may be to throw away the single one that is
(say) a microsecond
off from the rest. Somewhere between 3 satellites and 6 satellites, the “I
need
a solid position” thing becomes less of a factor.
There are other ways to put the device into holdover. One is to simply
look at the
number of satellites. If you are locked on to less than 4 sats, go into
holdover. It’s not
elegant, but it does work. In the case of a lash up, just translate the “I
have <= 3 sats” info into
“my TRAIM is junk”. Instant holdover.
Bob
On Oct 2, 2015, at 10:44 PM, Bill Hawkins bill@iaxs.net wrote:
Actually, the Lucent software uses RAIM, and reports the value in its
status message. If the position appears to have drifted off, or there
aren't enough satellites to calculate the position, the software
declares the oscillators to be free-wheeling, an expression meaning that
the oscillators are free from discipline and are now drifting.
So yes, the positioning aspects matter.
Disclaimer: I haven't studied RAIM (or TRAIM) enough to know exactly
what goes on, but that's the behavior I've observed.
Bill Hawkins
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Gregory
Beat
Sent: Friday, October 02, 2015 6:07 PM
To: time-nuts@febo.com
Subject: Re: [time-nuts] KS-24361 REF-0 standalone
Dan -
I have been following your experimentation with the surplus Lucent
KS-24361 REF-0 module, to transform it into a standalone GPSDO.
The original usage of the classic Oncore UT+ GPS receiver for KS-24361
REF-1, by Symmetricom / Datum for Lucent, was deliberate.
For usage at a cellular data/telecom site, the focus was on the timing
and frequency discipline from the GPS satellite transmission, rather
than the position or dead reckoning aspects -- used by smartphones,
automobiles, and other GPS applications on the market.
A couple of comments.
While I can appreciate being economical (main criteria) and selecting
the NEO-6M receiver, I believe that a u-Blox timing specific module
(like LEA-6T) would be more desirable in this application.
In addition, the u-Blox 6-series is the trailing edge of product support
(market demand dictates its continuance), while the 7 and 8-series are
their current modules (largely for the cellular / mobile industry
(smartphones or cell sites themselves)
u-Blox 6-series Timing Application Note (using the LEA-6T)
https://www.u-blox.com/sites/default/files/products/documents/Timing_App
Note_%28GPS.G6-X-11007%29.pdf
IF you successfully adopt the u-Blox module to correctly "mimic" the
Oncore UT+ GPS receiver command suite, THEN you open up a larger
audience of "time-nuts" and Frequency Standard users (HP Z3801A
frequency standard universe) as a receiver alternative.
http://www.realhamradio.com/GPS_Frequency_Standard.htm
These users may desire a "newer" GPS receiver that has more channels
(8-channel); latest generation receiver; access to the newest GPS
constellations.
TAPR might be interested in sponsoring, as a kit/module, if a wider
audience existed.
The Heol Designs N024 receiver (France) accomplished this replacement
role for the Trimble ACE II/III GPS receiver used in the
Symmetricom/Datum TymServe TS2100.
Their solution resolved shortcomings in the mid-1990 Trimble receiver
design and giving this Symmetricom NTP server, time IRIG-B time code
generator, and 10 MHz reference appliance a new lease on life (no longer
a door stop).
http://www.heoldesign.com/index.php?module=products&action=catalog&cat=1
4&id=54
w9gb
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
and follow the instructions there.
Dan it looks like the thread has re-developed.
As my early test of your simple solution demonstrated. Better PPS better
stability (Used a TBolt to test this) in the form of semi-short term
jitter. The beauty of Dans solution is the user can select the quality and
cost of the receiver used. Anything can work.
I used the 6M also because of the $11 cost and at the time as a alpha
tester there could have been issues. Reality, the 6M was on the shelf.
Regards
Paul
WB8TSL
On Sat, Oct 3, 2015 at 9:47 AM, Bob Camp <kb8tq@n1k.org> wrote:
> Hi
>
> If indeed you are into a professional system, where holdover matters then
> a lashup on a bunch of surplus gear likely isn’t going to measure up. Based
> on about 10,000 previous posts on the list I’d say that holdover does not
> appear
> to matter to Time Nuts. It would be difficult to find a thread where
> holdover performance
> was the main topic. The focus (rightly) seems to be to keep the box locked
> to
> GPS all the time. That approach (if you can do it) will always give you
> the best
> timing.
>
> The “not a T” uBlox units *do* put out “TRAIM" information in the words you
> can get at. The data is valid and it can be used if you wish to put the
> unit
> in holdover. I’m sure it works better with a well known position, but that
> it not
> a requisite.
>
> TRAIM was a really big deal back in the mid 90’s. That’s when Motorola put
> it on
> the Oncore’s and did a lot of publicity on the topic. They saw it as a way
> to differentiate
> their product in the marketplace. Much of our view of TRAIM is slanted by
> the
> Motorola information on the topic.
>
> Here’s one way to look at TRAIM:
>
> If you are in position hold, you can get timing off of a single satellite.
> TRAIM
> (just like any estimator) looks at the single input it has and says “that
> must be
> correct”. Give it two inputs and it can look at the solution for each and
> decide if
> they are close enough (your TRAIM threshold) to be correct. As you get up
> to 8 or
> 12 inputs, the right answer may be to throw away the single one that is
> (say) a microsecond
> off from the rest. Somewhere between 3 satellites and 6 satellites, the “I
> need
> a solid position” thing becomes less of a factor.
>
> There are other ways to put the device into holdover. One is to simply
> look at the
> number of satellites. If you are locked on to less than 4 sats, go into
> holdover. It’s not
> elegant, but it does work. In the case of a lash up, just translate the “I
> have <= 3 sats” info into
> “my TRAIM is junk”. Instant holdover.
>
> Bob
>
>
> > On Oct 2, 2015, at 10:44 PM, Bill Hawkins <bill@iaxs.net> wrote:
> >
> > Actually, the Lucent software uses RAIM, and reports the value in its
> > status message. If the position appears to have drifted off, or there
> > aren't enough satellites to calculate the position, the software
> > declares the oscillators to be free-wheeling, an expression meaning that
> > the oscillators are free from discipline and are now drifting.
> >
> > So yes, the positioning aspects matter.
> >
> > Disclaimer: I haven't studied RAIM (or TRAIM) enough to know exactly
> > what goes on, but that's the behavior I've observed.
> >
> > Bill Hawkins
> >
> >
> > -----Original Message-----
> > From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Gregory
> > Beat
> > Sent: Friday, October 02, 2015 6:07 PM
> > To: time-nuts@febo.com
> > Subject: Re: [time-nuts] KS-24361 REF-0 standalone
> >
> > Dan -
> >
> > I have been following your experimentation with the surplus Lucent
> > KS-24361 REF-0 module, to transform it into a standalone GPSDO.
> >
> > The original usage of the classic Oncore UT+ GPS receiver for KS-24361
> > REF-1, by Symmetricom / Datum for Lucent, was deliberate.
> > For usage at a cellular data/telecom site, the focus was on the timing
> > and frequency discipline from the GPS satellite transmission, rather
> > than the position or dead reckoning aspects -- used by smartphones,
> > automobiles, and other GPS applications on the market.
> > ===
> > A couple of comments.
> > While I can appreciate being economical (main criteria) and selecting
> > the NEO-6M receiver, I believe that a u-Blox timing specific module
> > (like LEA-6T) would be more desirable in this application.
> >
> > In addition, the u-Blox 6-series is the trailing edge of product support
> > (market demand dictates its continuance), while the 7 and 8-series are
> > their current modules (largely for the cellular / mobile industry
> > (smartphones or cell sites themselves)
> >
> > u-Blox 6-series Timing Application Note (using the LEA-6T)
> > https://www.u-blox.com/sites/default/files/products/documents/Timing_App
> > Note_%28GPS.G6-X-11007%29.pdf
> >
> > IF you successfully adopt the u-Blox module to correctly "mimic" the
> > Oncore UT+ GPS receiver command suite, THEN you open up a larger
> > audience of "time-nuts" and Frequency Standard users (HP Z3801A
> > frequency standard universe) as a receiver alternative.
> > http://www.realhamradio.com/GPS_Frequency_Standard.htm
> >
> > These users may desire a "newer" GPS receiver that has more channels
> > (8-channel); latest generation receiver; access to the newest GPS
> > constellations.
> > TAPR might be interested in sponsoring, as a kit/module, if a wider
> > audience existed.
> >
> > The Heol Designs N024 receiver (France) accomplished this replacement
> > role for the Trimble ACE II/III GPS receiver used in the
> > Symmetricom/Datum TymServe TS2100.
> > Their solution resolved shortcomings in the mid-1990 Trimble receiver
> > design and giving this Symmetricom NTP server, time IRIG-B time code
> > generator, and 10 MHz reference appliance a new lease on life (no longer
> > a door stop).
> > http://www.heoldesign.com/index.php?module=products&action=catalog&cat=1
> > 4&id=54
> >
> > w9gb
> >
> >
> > _______________________________________________
> > 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.
>
