Re: [time-nuts] HP Stories: Frequency Counter business decline, Modulation Domain Analyzers, geeks as models

[Magnus Danielson]

Hi Hugh,

Enjoying your stories.

On 2019-01-21 01:57, Rice, Hugh (IPH Writing Systems) wrote:

Like all breakthrough measurements, the next 20+ years was spent refining the concept.
Better "front end" amplifiers, able to measure low amplitude signals.   Faster 
counters, that could capture higher frequency signals.Microwave front ends, to either 
divide the signal by 8 or 16 or whatever before being counted, or using some other down 
conversation technique.Somewhere in the early 1970's (guess), the reciprocal counter 
was invented.  Rather than open the gate for 1 second,  use the input signal to open the 
gate for one period, and count a very high frequency time base instead.It was much 
faster, and for lower frequency signals, much much higher resolution.   Now, if you had a 
~1KHz unknown signal, rather than only getting 4 significant digits in a one second 
measurement, if you counted a 100MHz time base for 1 millisecond, you would 5 digits of 
resolution.  Open the gate for a thousand cycles, and 8 digits of resolution were 
available.


The HP5360A calculating counter was the first reciprocal counter that I 
know of, released in 1970.


The reciprocal counter principle can be found described in HP AN200:

http://www.hpmemoryproject.org/an/pdf/an_200.pdf


The premium universal counter in the early 1980's was the 5370A/B.  It's specialty was extremely 
high precision time interval measurements, with resolutions down to 20 pico seconds. An idea 
was made to extend the time interval measurement into continuous real time, and measure dynamic 
time intervals, as a function of time.   HP called this "Modulation Domain" analysis.   I 
think that David Chu, one of the senior scientists at SCD in the 1970s and 1980s was a key inventor 
of this. The 5371A was the outcome of this work.It was followed by the 5372 and 5373.
There also was a lower cost version call the 53310 ("Stonehenge"?). The measurement 
was novel and unique.   You all know what oscilloscopes and spectrum analyzers do, but this was a 
new spin:  You could look at the phase of a signal as a function of time.


David Chu is a good name as one search for HP patents.

The really shining details about the 5371 series of products is that the 
event rate can be up to 10 MHz or 13,3 MHz depending on mode. The 
resolution is 200 ps. I think the main step with the 5372A was the 
hardware histogram, that would accumulate histograms faster than the CPU 
would. You would need to adhere to some limitations, but gets much 
higher speeds and hence higher amount of counts in return. For the type 
of applications it was intended, it was a huge step forward.


We still operate a 5372A in the lab.

Thanks again for a nice tale. I just wanted to add a few comments that 
may be useful.


The HP Application Notes is always rewarding, just as the old HP Journal 
numbers.


Cheers,
Magnus


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Re: [time-nuts] Calculating time of lunar eclipse

[jimlux]

On 1/21/19 9:18 AM, jimlux wrote:
egregious error cauhgt


Here in Southern California, it was about 9PM local, so we were farther 
away from the moon than folks on the US East Coast watching at local 
midnight. Why that's almost 2000km - 6 microseconds.  


6 milliseconds..

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Re: [time-nuts] HP Stories: Frequency Counter business

[paul swed]

Been seriously enjoying the discussion. Especially the insights of HP. I
have several 5245 and 5248Ms (Better oven osc)
Just had to do a few minor repairs over Christmas. That said the binary
counter to nixie decoders are just a crazy engineering marvel. Neon bulbs
light that change a photo cell that illuminates the nixie number. I have
seen the 52X series long ago and stayed clear of them.
But this winter they may have been helpful in keeping warm.
Keep sharing.
Regards
Paul
WB8TSL

On Mon, Jan 21, 2019 at 7:04 PM Don  wrote:

> http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1951-01.pdf
> On Mon, 2019-01-21 at 14:15 -0500, Gordon Batey wrote:
> > Greetings to all,
> >
> > I believe that was the HP 525 counter.  I had one as my first
> > counter
> > which I picked up surplus many years ago.  It had several plug-ins
> > for
> > different
> > frequency ranges.  Kept the basement warm in the winter time.  The
> > vhf
> > plugin was a heterodyne mixer as I recall.  This unit ontained MANY
> > tubes
> > and a
> > fairly large fan to remove the heat.  I gave it to another ham
> > several years
> > ago.
> >
> >
> > I really enjoy the HP stories.
> >
> > Gordon Batey
> > WA4FJC
> >
> >
> >
> > Hi,
> > I used an HP counter in 1961 that had these vertical strings of neon
> > tubes
> > behind numbers, and the two least significant decimals were read off
> > two
> > milliamp meters numbered 0 to 10. For each count the needles would
> > point to
> > the number to be read. The whole instrument was a 2 foot cube that
> > sat on a
> > trolley.
> > After all this time I can not remember the model number. Our company
> > repaired Air force instruments and recalibration of frequency
> > ?meters?
> > (calibrated heterodyne oscillators).
> > Cheers,
> > Neville Michie
> >
> >
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nut
> > s_lists.febo.com
> > and follow the instructions there.
> ___
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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Bob kb8tq]

Hi

At least at this point things like sawtooth correction outputs are still a “who 
knows if there is one”
kind of thing. Doing a GPSDO and not having sawtooth corrected out is sort of a 
letdown ….
Stuff gets better from L1 / L2, but then gets worse when you put hanging 
bridges back in ….
Keep in mind that hanging bridges do not *always* average out.

Bob

> On Jan 21, 2019, at 4:43 PM, J. Grizzard  wrote:
> 
> Per the integration guide 
> (https://www.u-blox.com/sites/default/files/ZED-F9P_IntegrationManual_%28UBX-18010802%29.pdf),
>  the recommended antenna should be between 30dB and 40dB of gain.
> 
> Additional note: ublox is releasing an eval board (p/n C099-F9P) which is 
> similar to the sparkfun board, except a less annoying form factor (can work 
> as a standalone thing, or fit on an arduino), additional interface options 
> (wifi and bluetooth, pretty useful if you're doing RTK), less annoying 
> connectors (SMA), and ships with the ublox multi-band antenna ... all for $50 
> more than the sparkfun, according to digi-key. They're not available yet, but 
> I imagine the will be soon. See 
> https://www.u-blox.com/en/product/c099-f9p-application-board#tab-documentation-resources
>  for more details.
> 
> On a vaguely related note, I wonder if it would be possible to retrofit 
> something like a AE6RV GPSDO with one of these. The footprint is pretty 
> different (and there's a big pile of ground/thermal connections on the bottom 
> of the new chip), but it seems like the actual electrical interface is 
> probably the same in the important ways, so it might be possible to make an 
> adapter board, maybe...
> 
> -j
> 
> On 1/21/19 8:32 AM, Bob kb8tq wrote:
>> Hi
>> 
>> Based on the F9P data sheet, you will need an L1 / L2 antenna that is wide 
>> enough
>> to get the Galileo E5B as well as the Glonass L1OF and L2OF bands. The gotcha
>> is that (so far) I have not found a gain number for the target antenna. As 
>> we have
>> found on other modules, you do want to get the right gain. L1/L2 antennas 
>> range
>> from 50+ db down to below 30 db. Simply tacking a pad on a 50 db antenna is 
>> not
>> the best way to do things if you are in an urban area.
>> 
>> There also is the issue of powering the antenna. It is not clear what sort 
>> of antenna
>> bias circuit the SparkFun module has on it. If it simply is using the 
>> module’s bias setup
>> that also could be an issue. Max Vcc on the module is 3.6V. The VCC_RF pin 
>> can have
>> main Vcc - 0.1V max on it. If that *really* means that 3.3V is about it for 
>> antenna bias,
>> that eliminates roughly 100% of all the used antennas out there. It also 
>> eliminates a
>> number of the new ones.
>> 
>> If you put in an external bias setup, there are a lot of antennas to pick 
>> from on eBay.
>> They come and go. The used stuff generally will be 12V powered. It also is 
>> likely
>> to have a pretty good data sheet on it. The new stuff from China seems to be 
>> sold
>> by a variety of people who pop up for a while and then go away for a while. 
>> Making
>> sure of what you are getting is a bit tough as a result. There are extensive 
>> stories
>> in the archives …..
>> 
>> Bob
>> 
>>> On Jan 21, 2019, at 10:21 AM, Graham / KE9H  wrote:
>>> 
>>> What kind of antenna is needed to simultaneously hear all of the systems at
>>> once?
>>> My PCTel GPS antenna has a filter that limits it to only the US GPS system.
>>> 
>>> --- Graham
>>> 
>>> ==
>>> 
>>> On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess  wrote:
>>> 
 If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
 ZED-F9P.  I would have gladly paid $14 more for a version of the
 SparkFun board using the T(iming) version instead :(.
 
 On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:
> Hi
> 
> From a *very* quick read of the doc’s:
> 
> 1) The device *does* have a position hold capability
> 
> 2) There is some level of data on the time pulse. It it only 1 ns
 resolution?
> 3) It does appear to support Galileo and Glonas in addition to GPS.
> 
> 4) It is clearly multi-band for GPS. It is unclear from a quick read if
 it is multi-band for the other systems.
> 5) If you get one, make sure you have the RF cable connector it needs.
> 
> 6) I have not (yet) found a recommendation for the antenna gain.
> 
> Again, all from a quick read ….
> 
> Bob
> 
>> On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
>> 
>> Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a
 board ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2
 data.  It outputs carrier phase data and has survey-in and fixed position
 support along with RTK support (10 mm accuracy).   Looks like the F9P has 1
 time pulse output.
>> ___
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>> To unsubscribe, go to
 

Re: [time-nuts] HP Stories: Frequency Counter business

[Dave Mallery]

in high school, i had a summer job at the NYU EE dept up in the Bronx
campus (where my dad taught english!)

this was the summer of 1956 and 57.  in the lab equipment issuing room
there lived a 524 with the vertical neon lites.
along with a plethora of other now ancient equipment.

long ago in a galaxy far away...

73

dave mallery



On Mon, Jan 21, 2019 at 5:04 PM Don  wrote:

> http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1951-01.pdf
> On Mon, 2019-01-21 at 14:15 -0500, Gordon Batey wrote:
> > Greetings to all,
> >
> > I believe that was the HP 525 counter.  I had one as my first
> > counter
> > which I picked up surplus many years ago.  It had several plug-ins
> > for
> > different
> > frequency ranges.  Kept the basement warm in the winter time.  The
> > vhf
> > plugin was a heterodyne mixer as I recall.  This unit ontained MANY
> > tubes
> > and a
> > fairly large fan to remove the heat.  I gave it to another ham
> > several years
> > ago.
> >
> >
> > I really enjoy the HP stories.
> >
> > Gordon Batey
> > WA4FJC
> >
> >
> >
> > Hi,
> > I used an HP counter in 1961 that had these vertical strings of neon
> > tubes
> > behind numbers, and the two least significant decimals were read off
> > two
> > milliamp meters numbered 0 to 10. For each count the needles would
> > point to
> > the number to be read. The whole instrument was a 2 foot cube that
> > sat on a
> > trolley.
> > After all this time I can not remember the model number. Our company
> > repaired Air force instruments and recalibration of frequency
> > ?meters?
> > (calibrated heterodyne oscillators).
> > Cheers,
> > Neville Michie
> >
> >
> > ___
> > time-nuts mailing list -- time-nuts@lists.febo.com
> > To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nut
> > s_lists.febo.com
> > and follow the instructions there.
> ___
> time-nuts mailing list -- time-nuts@lists.febo.com
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> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
> and follow the instructions there.
>


-- 
Dave Mallery, K5EN (ubuntu linux 18-10)
80018 Lobo CP Grants,  NM  87020

  linux counter #64628 (since 1997)
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Re: [time-nuts] Metastability

[Magnus Danielson]

Hi Rick,

On 2019-01-21 16:31, Richard (Rick) Karlquist wrote:

I designed a state machine running on a 32 MHz clock
to resync 4 MHz clock edges.  A number of engineers
know just enough to be dangerous and suggested the
technique is to just make a shift register and run
the incoming edge through n flip flops. "Everyone knew" that
was the thing to do.  NOT.  Actually, I only had to
reclock 2 times, but the delay between the two registers
had to be MUCH longer than the 31 ns period of the
32 MHz clock.  I characterized the flip flops I
was using to make a probability curve of metastability
events per year vs delay time using a special fixturing
board.  I ended up choosing a time delay that extrapolated
to something like 1 event in 10 years, just about "never".
In those days, 32 MHz clocking was considered very high
speed for the available TTL logic.

Today as we design these things, the same basic "cure" is used in order 
to handle meta-stability. We re-clock 2 times, but often the data can be 
hand-shaked over the clock domain border so only a few lines is needed 
in each direction to be double-clocked. As we build modern designs, 
clock domain borders is a pain, but a known pain and it just needs 
enough learning to handle it. Often we try to keep most of the logic in 
one or a few core domains. The basic problem is as valid as back then. 
Over the years the practical way to solve it has changed with available 
technologies. Even in modern FPGA times it can cause... interesting 
problems. All the Register-Transfer-Logic type of the design is well 
confined, but clock-domain borders always remain "interesting". 
Dual-port memories or FIFOs tolerating clock domains shifts only solve 
"so much" it turns out.


Even when operating synchronously madness can hit, for sure. Those 
experience include issues with Signal Integrity problems.


The real morale of these stories is that it actually takes a lot of 
effort to make digital designs... behave digitally and robust. It is 
however worth the effort.


Meta-stability is never fully "solved", but sufficiently surpressed. 
This is just as with bit-errors, which we never really get rid of, just 
move them out of sufficiently often to be annoying.


Cheers,
Magnus


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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Tom Knox]

Hopefully Jackson Labs (If possible) will offer an update of their M12M 
replacement that I believe currently uses M8T. I have been preparing for this 
inevitable evolution for a while updating all my antenna system with all band 
GNSS antennas, distribution amps, as well as fiber links I use to protect from 
possible lighting strikes. In metrology applications this should prove a big 
step forward using GPS as a replacement in many lab applications currently 
using Cesium standards when disciplining a ULPN clean-up oscillator. Cheers Tom


From: time-nuts  on behalf of Mark Sims 

Sent: Sunday, January 20, 2019 3:42 PM
To: time-nuts@lists.febo.com
Subject: [time-nuts] Ublox F9P multi-band GPS receiver

Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a board 
($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2 data.  It 
outputs carrier phase data and has survey-in and fixed position support along 
with RTK support (10 mm accuracy).   Looks like the F9P has 1 time pulse output.
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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Bob kb8tq]

Hi

Here’s an ad for a somewhat different antenna with some barely readable 
bandwidth testing data:

https://www.aliexpress.com/item/RTK-system-HIGH-GAIN-GNSS-antennas-GPS-Glonass-Galileo-Bei-Dou-High-Precision-waterproof-survey-antenna/32826409839.html?aff_platform=promotion=1548110255481=i6Ujaqn_trace_key=b8dab77ba20845429ffa1fc31fd6d51f-1548110255481-09708-i6Ujaqn_id=2cf8f236a50d4cd79c67cb1d789ca57c
 


The antenna also shows up on other sites from time to time. It appears to run 
off of 3.3V it’s a bit more expensive than the first one. It’s still about 
1/10th  
the price of some of the non-Chinese sourced products. 

The data in this ad

https://www.aliexpress.com/store/product/New-RTK-system-GNSS-antennaS-GPS-Glonass-Beidou-High-Precision-waterproof-survey-antenna-HIGH-GAIN-support/1920594_32805500077.html?spm=2114.12010612.8148356.60.2d4f6261ui9nrX
 


That *might* apply to the first one I mentioned (or might not …) suggests that 
this one may be a better bet for E5. 

Again, no experience with the seller. No idea what antenna you actually will 
get. The world may end tomorrow :) 

Bob

> On Jan 21, 2019, at 2:44 PM, MLewis  wrote:
> 
> Like these?
> http://www.tallysman.com/index.php/gnss/products/antennas-triple-band/
> 
> On 21/01/2019 12:33 PM, Bob kb8tq wrote:
>> Hi
>> 
>> To be more precise, what you want is a L1/L2/L5 triple band antenna.
>> 
>> Bob
>> 
>>> On Jan 21, 2019, at 11:32 AM, Bob kb8tq  wrote:
>>> 
>>> Hi
>>> 
>>> Based on the F9P data sheet, you will need an L1 / L2 antenna that is wide 
>>> enough
>>> to get the Galileo E5B as well as the Glonass L1OF and L2OF bands. The 
>>> gotcha
>>> is that (so far) I have not found a gain number for the target antenna. As 
>>> we have
>>> found on other modules, you do want to get the right gain. L1/L2 antennas 
>>> range
>>> from 50+ db down to below 30 db. Simply tacking a pad on a 50 db antenna is 
>>> not
>>> the best way to do things if you are in an urban area.
>>> 
>>> There also is the issue of powering the antenna. It is not clear what sort 
>>> of antenna
>>> bias circuit the SparkFun module has on it. If it simply is using the 
>>> module’s bias setup
>>> that also could be an issue. Max Vcc on the module is 3.6V. The VCC_RF pin 
>>> can have
>>> main Vcc - 0.1V max on it. If that *really* means that 3.3V is about it for 
>>> antenna bias,
>>> that eliminates roughly 100% of all the used antennas out there. It also 
>>> eliminates a
>>> number of the new ones.
>>> 
>>> If you put in an external bias setup, there are a lot of antennas to pick 
>>> from on eBay.
>>> They come and go. The used stuff generally will be 12V powered. It also is 
>>> likely
>>> to have a pretty good data sheet on it. The new stuff from China seems to 
>>> be sold
>>> by a variety of people who pop up for a while and then go away for a while. 
>>> Making
>>> sure of what you are getting is a bit tough as a result. There are 
>>> extensive stories
>>> in the archives …..
>>> 
>>> Bob
>>> 
 On Jan 21, 2019, at 10:21 AM, Graham / KE9H  wrote:
 
 What kind of antenna is needed to simultaneously hear all of the systems at
 once?
 My PCTel GPS antenna has a filter that limits it to only the US GPS system.
 
 --- Graham
 
 ==
 
 On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess  
 wrote:
 
> If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
> ZED-F9P.  I would have gladly paid $14 more for a version of the
> SparkFun board using the T(iming) version instead :(.
> 
> On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:
>> Hi
>> 
>> From a *very* quick read of the doc’s:
>> 
>> 1) The device *does* have a position hold capability
>> 
>> 2) There is some level of data on the time pulse. It it only 1 ns
> resolution?
>> 3) It does appear to support Galileo and Glonas in addition to GPS.
>> 
>> 4) It is clearly multi-band for GPS. It is unclear from a quick read if
> it is multi-band for the other systems.
>> 5) If you get one, make sure you have the RF cable connector it needs.
>> 
>> 6) I have not (yet) found a recommendation for the antenna gain.
>> 
>> Again, all from a quick read ….
>> 
>> Bob
>> 
>>> On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
>>> 
>>> Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a
> board ($219).  The F9P supports 

Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Bob kb8tq]

Hi

My first though was that something like this:

https://www.ebay.com/itm/CORS-RTK-GNSS-Survey-Antenna-high-gain-measurement-GNSS-GPS-GLONASS-BDS/253786590956?hash=item3b16dc0eec:g:p8sAAOSwu7hbNoe0:rk:1:pf:0
 


Would be the most economical choice. I know noting about the exact antenna you 
will get or the seller. It simply is the 
first thing that popped up on a search. At least based on the pictures it will 
run off of 3.3V. Depending on which
part of the page you read it will cover (or might cover) everything on all of 
the bands. 

Bob

> On Jan 21, 2019, at 2:44 PM, MLewis  wrote:
> 
> Like these?
> http://www.tallysman.com/index.php/gnss/products/antennas-triple-band/
> 
> On 21/01/2019 12:33 PM, Bob kb8tq wrote:
>> Hi
>> 
>> To be more precise, what you want is a L1/L2/L5 triple band antenna.
>> 
>> Bob
>> 
>>> On Jan 21, 2019, at 11:32 AM, Bob kb8tq  wrote:
>>> 
>>> Hi
>>> 
>>> Based on the F9P data sheet, you will need an L1 / L2 antenna that is wide 
>>> enough
>>> to get the Galileo E5B as well as the Glonass L1OF and L2OF bands. The 
>>> gotcha
>>> is that (so far) I have not found a gain number for the target antenna. As 
>>> we have
>>> found on other modules, you do want to get the right gain. L1/L2 antennas 
>>> range
>>> from 50+ db down to below 30 db. Simply tacking a pad on a 50 db antenna is 
>>> not
>>> the best way to do things if you are in an urban area.
>>> 
>>> There also is the issue of powering the antenna. It is not clear what sort 
>>> of antenna
>>> bias circuit the SparkFun module has on it. If it simply is using the 
>>> module’s bias setup
>>> that also could be an issue. Max Vcc on the module is 3.6V. The VCC_RF pin 
>>> can have
>>> main Vcc - 0.1V max on it. If that *really* means that 3.3V is about it for 
>>> antenna bias,
>>> that eliminates roughly 100% of all the used antennas out there. It also 
>>> eliminates a
>>> number of the new ones.
>>> 
>>> If you put in an external bias setup, there are a lot of antennas to pick 
>>> from on eBay.
>>> They come and go. The used stuff generally will be 12V powered. It also is 
>>> likely
>>> to have a pretty good data sheet on it. The new stuff from China seems to 
>>> be sold
>>> by a variety of people who pop up for a while and then go away for a while. 
>>> Making
>>> sure of what you are getting is a bit tough as a result. There are 
>>> extensive stories
>>> in the archives …..
>>> 
>>> Bob
>>> 
 On Jan 21, 2019, at 10:21 AM, Graham / KE9H  wrote:
 
 What kind of antenna is needed to simultaneously hear all of the systems at
 once?
 My PCTel GPS antenna has a filter that limits it to only the US GPS system.
 
 --- Graham
 
 ==
 
 On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess  
 wrote:
 
> If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
> ZED-F9P.  I would have gladly paid $14 more for a version of the
> SparkFun board using the T(iming) version instead :(.
> 
> On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:
>> Hi
>> 
>> From a *very* quick read of the doc’s:
>> 
>> 1) The device *does* have a position hold capability
>> 
>> 2) There is some level of data on the time pulse. It it only 1 ns
> resolution?
>> 3) It does appear to support Galileo and Glonas in addition to GPS.
>> 
>> 4) It is clearly multi-band for GPS. It is unclear from a quick read if
> it is multi-band for the other systems.
>> 5) If you get one, make sure you have the RF cable connector it needs.
>> 
>> 6) I have not (yet) found a recommendation for the antenna gain.
>> 
>> Again, all from a quick read ….
>> 
>> Bob
>> 
>>> On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
>>> 
>>> Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a
> board ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks 
> L1/L2
> data.  It outputs carrier phase data and has survey-in and fixed position
> support along with RTK support (10 mm accuracy).   Looks like the F9P has 
> 1
> time pulse output.
>>> ___
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>> 
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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[J. Grizzard]

Per the integration guide 
(https://www.u-blox.com/sites/default/files/ZED-F9P_IntegrationManual_%28UBX-18010802%29.pdf), 
the recommended antenna should be between 30dB and 40dB of gain.


Additional note: ublox is releasing an eval board (p/n C099-F9P) which 
is similar to the sparkfun board, except a less annoying form factor 
(can work as a standalone thing, or fit on an arduino), additional 
interface options (wifi and bluetooth, pretty useful if you're doing 
RTK), less annoying connectors (SMA), and ships with the ublox 
multi-band antenna ... all for $50 more than the sparkfun, according to 
digi-key. They're not available yet, but I imagine the will be soon. See 
https://www.u-blox.com/en/product/c099-f9p-application-board#tab-documentation-resources 
for more details.


On a vaguely related note, I wonder if it would be possible to retrofit 
something like a AE6RV GPSDO with one of these. The footprint is pretty 
different (and there's a big pile of ground/thermal connections on the 
bottom of the new chip), but it seems like the actual electrical 
interface is probably the same in the important ways, so it might be 
possible to make an adapter board, maybe...


-j

On 1/21/19 8:32 AM, Bob kb8tq wrote:

Hi

Based on the F9P data sheet, you will need an L1 / L2 antenna that is wide 
enough
to get the Galileo E5B as well as the Glonass L1OF and L2OF bands. The gotcha
is that (so far) I have not found a gain number for the target antenna. As we 
have
found on other modules, you do want to get the right gain. L1/L2 antennas range
from 50+ db down to below 30 db. Simply tacking a pad on a 50 db antenna is not
the best way to do things if you are in an urban area.

There also is the issue of powering the antenna. It is not clear what sort of 
antenna
bias circuit the SparkFun module has on it. If it simply is using the module’s 
bias setup
that also could be an issue. Max Vcc on the module is 3.6V. The VCC_RF pin can 
have
main Vcc - 0.1V max on it. If that *really* means that 3.3V is about it for 
antenna bias,
that eliminates roughly 100% of all the used antennas out there. It also 
eliminates a
number of the new ones.

If you put in an external bias setup, there are a lot of antennas to pick from 
on eBay.
They come and go. The used stuff generally will be 12V powered. It also is 
likely
to have a pretty good data sheet on it. The new stuff from China seems to be 
sold
by a variety of people who pop up for a while and then go away for a while. 
Making
sure of what you are getting is a bit tough as a result. There are extensive 
stories
in the archives …..

Bob


On Jan 21, 2019, at 10:21 AM, Graham / KE9H  wrote:

What kind of antenna is needed to simultaneously hear all of the systems at
once?
My PCTel GPS antenna has a filter that limits it to only the US GPS system.

--- Graham

==

On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess  wrote:


If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
ZED-F9P.  I would have gladly paid $14 more for a version of the
SparkFun board using the T(iming) version instead :(.

On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:

Hi

 From a *very* quick read of the doc’s:

1) The device *does* have a position hold capability

2) There is some level of data on the time pulse. It it only 1 ns

resolution?

3) It does appear to support Galileo and Glonas in addition to GPS.

4) It is clearly multi-band for GPS. It is unclear from a quick read if

it is multi-band for the other systems.

5) If you get one, make sure you have the RF cable connector it needs.

6) I have not (yet) found a recommendation for the antenna gain.

Again, all from a quick read ….

Bob


On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:

Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a

board ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2
data.  It outputs carrier phase data and has survey-in and fixed position
support along with RTK support (10 mm accuracy).   Looks like the F9P has 1
time pulse output.

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Re: [time-nuts] HP Stories: Frequency Counter business

[Don]

http://www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1951-01.pdf
On Mon, 2019-01-21 at 14:15 -0500, Gordon Batey wrote:
> Greetings to all,
> 
> I believe that was the HP 525 counter.  I had one as my first
> counter 
> which I picked up surplus many years ago.  It had several plug-ins
> for
> different 
> frequency ranges.  Kept the basement warm in the winter time.  The
> vhf 
> plugin was a heterodyne mixer as I recall.  This unit ontained MANY
> tubes
> and a 
> fairly large fan to remove the heat.  I gave it to another ham
> several years
> ago.
> 
> 
> I really enjoy the HP stories.
> 
> Gordon Batey
> WA4FJC
> 
> 
> 
> Hi,
> I used an HP counter in 1961 that had these vertical strings of neon
> tubes
> behind numbers, and the two least significant decimals were read off
> two
> milliamp meters numbered 0 to 10. For each count the needles would
> point to
> the number to be read. The whole instrument was a 2 foot cube that
> sat on a
> trolley.
> After all this time I can not remember the model number. Our company
> repaired Air force instruments and recalibration of frequency
> ?meters?
> (calibrated heterodyne oscillators).
> Cheers,
> Neville Michie
> 
> 
> ___
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> s_lists.febo.com
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Re: [time-nuts] HP Stories: Frequency Counter business

[Don Murray via time-nuts]

I was spoiled...
I spent 3 years in Ethiopia, '65 - '68, with the ArmySecurity Agency.  Our shop 
looked like a TEK andHP Catalog!!  Our FREQ REF rack was the GSQ-53A,dual 
Sulzer 5MHz ovenized oscillators which we phase compared against GBR on 16KHz.
 
We ran the phase chart 24/7 to make sure we kept things stable!  The Sulzer 
oscillators were very impressive.  Very little tweaking was needed to keep the 
chart trackingdown the middle during light/light and dark/dark times!
As far as our counter was concerned...  It was thesweet HP 5245L, with a bunch 
of plug-ins takingus beyond 17GHz.
Whenever the "calibration" truck would come to oursite, we would feed our REF 
5MHz out to them so theycould check their standard!  ;-)
We had a very large DMM, and they would check theirstandard cell with it!
It was a FUN time!!
73DonW4WJex ET3FMA


In a message dated 1/21/2019 4:02:55 PM Central Standard Time, 
dgmin...@mediacombb.net writes:

More likely, the counter Neville used was the model 524B (see picture 
attached).  The 525 was a series of frequency converters that enabled the 524 
counter to measure frequencies up to 500 MHz (Megacycles (Mc) in the vernacular 
of the time).Surely is good to learn about the beginnings of the HP culture and 
saddening to hear of the hard times that have befallen, but technology never 
stands still..

Dave M.
Gordon Batey wrote:> Greetings to all,>> I believe that was the HP 525 counter. 
 I had one as my first counter> which I picked up surplus many years ago.  It 
had several plug-ins for> different> frequency ranges.  Kept the basement warm 
in the winter time.  The vhf> plugin was a heterodyne mixer as I recall.  This 
unit ontained MANY> tubes> and a> fairly large fan to remove the heat.  I gave 
it to another ham> several years> ago.>>> I really enjoy the HP stories.>> 
Gordon Batey> WA4FJC Hi,> I used an HP counter in 1961 that had these 
vertical strings of neon> tubes> behind numbers, and the two least significant 
decimals were read off> two> milliamp meters numbered 0 to 10. For each count 
the needles would> point to> the number to be read. The whole instrument was a 
2 foot cube that> sat on a> trolley.> After all this time I can not remember 
the model number. Our company> repaired Air force instruments and recalibration 
of frequency ?meters?> (calibrated heterodyne oscillators).> Cheers,> Neville 
Michie>>> ___> 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.
When the people fear the government, there is tyranny. When thegovernment fears 
the people, there is liberty -- Thomas Jefferson

Dave M ___
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Re: [time-nuts] HP Stories: Frequency Counter business

[vilgotch]

Hi all,

That would be a 524B counter, all 90 tubes (depending on the plugin) and 600
watts of it. I still have one in going condition but it's not to be used in
the Australian summer with 42C forecast for later  this week.

The ovenised 100 KHz vacuum mounted crystal in it still performs pretty well
for its age but of course is not in the same class as later instruments in
my lab that are locked to a GPSDO.

I first saw one as an EE student in the late 1960s when it was the ultimate
in frequency measurement technology. The police used to bring their
pneumatic tube electromechanical speed detectors into the university to have
them calibrated against it. 

Cheers,

Morris


From: Neville Michie 
Subject: Re: [time-nuts] HP Stories: Frequency Counter business
decline, Modulation Domain Analyzers, geeks as models

Hi,
I used an HP counter in 1961 that had these vertical strings of neon tubes
behind numbers, and the two least significant decimals were read off two
milliamp meters numbered 0 to 10. For each count the needles would point to
the number to be read. The whole instrument was a 2 foot cube that sat on a
trolley.
After all this time I can not remember the model number. Our company
repaired Air force instruments and recalibration of frequency ?meters?
(calibrated heterodyne oscillators).
Cheers,
Neville Michie

***


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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Bob kb8tq]

Hi

Taking a quick look at what’s in view right now, the GPS L2C population is 
about half of the total. 
The L5 population is about half of the L2C group. No idea if that is true of 
the entire fleet.
Also no idea if my snow covered antennas are throwing things off a bit. 

All of the Glonass sats in view seem to be putting out both L1 and L2. They all 
seem to have the
same “format” flags on them.  Again, no idea if that represents anything or 
not. Glonass L3 is
enabled on the receiver. I see no indication in the tables if it’s doing 
anything or not. Probably 
a firmware bug that I can fix for a chunk of change ….could also be pilot 
error. 

I’m too cheap to have an Galileo upgrade on the gear I have here now. No idea 
about 
that side of things. 

Bob

> On Jan 21, 2019, at 12:17 PM, Ole Petter Rønningen  
> wrote:
> 
> Indeed. Getting a *quality* antenna with that coverage will likely be a more 
> costly affair than getting the actual receiver..
> 
> Of course, a cheap puck-style antenna is an option, but I am curious as to 
> what improvements will actually be observed, at least for the time being - 
> IIRC only about half of the sats transmit L2C..
> 
> Ole
> 
>> 21. jan. 2019 kl. 17:32 skrev Bob kb8tq :
>> 
>> Hi
>> 
>> Based on the F9P data sheet, you will need an L1 / L2 antenna that is wide 
>> enough 
>> to get the Galileo E5B as well as the Glonass L1OF and L2OF bands. The 
>> gotcha 
>> is that (so far) I have not found a gain number for the target antenna. As 
>> we have
>> found on other modules, you do want to get the right gain. L1/L2 antennas 
>> range 
>> from 50+ db down to below 30 db. Simply tacking a pad on a 50 db antenna is 
>> not 
>> the best way to do things if you are in an urban area. 
>> 
>> There also is the issue of powering the antenna. It is not clear what sort 
>> of antenna
>> bias circuit the SparkFun module has on it. If it simply is using the 
>> module’s bias setup
>> that also could be an issue. Max Vcc on the module is 3.6V. The VCC_RF pin 
>> can have
>> main Vcc - 0.1V max on it. If that *really* means that 3.3V is about it for 
>> antenna bias,
>> that eliminates roughly 100% of all the used antennas out there. It also 
>> eliminates a 
>> number of the new ones. 
>> 
>> If you put in an external bias setup, there are a lot of antennas to pick 
>> from on eBay. 
>> They come and go. The used stuff generally will be 12V powered. It also is 
>> likely 
>> to have a pretty good data sheet on it. The new stuff from China seems to be 
>> sold
>> by a variety of people who pop up for a while and then go away for a while. 
>> Making
>> sure of what you are getting is a bit tough as a result. There are extensive 
>> stories
>> in the archives …..
>> 
>> Bob
>> 
>>> On Jan 21, 2019, at 10:21 AM, Graham / KE9H  wrote:
>>> 
>>> What kind of antenna is needed to simultaneously hear all of the systems at
>>> once?
>>> My PCTel GPS antenna has a filter that limits it to only the US GPS system.
>>> 
>>> --- Graham
>>> 
>>> ==
>>> 
 On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess  
 wrote:
 
 If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
 ZED-F9P.  I would have gladly paid $14 more for a version of the
 SparkFun board using the T(iming) version instead :(.
 
> On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:
> 
> Hi
> 
> From a *very* quick read of the doc’s:
> 
> 1) The device *does* have a position hold capability
> 
> 2) There is some level of data on the time pulse. It it only 1 ns
 resolution?
> 
> 3) It does appear to support Galileo and Glonas in addition to GPS.
> 
> 4) It is clearly multi-band for GPS. It is unclear from a quick read if
 it is multi-band for the other systems.
> 
> 5) If you get one, make sure you have the RF cable connector it needs.
> 
> 6) I have not (yet) found a recommendation for the antenna gain.
> 
> Again, all from a quick read ….
> 
> Bob
> 
>> On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
>> 
>> Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a
 board ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2
 data.  It outputs carrier phase data and has survey-in and fixed position
 support along with RTK support (10 mm accuracy).   Looks like the F9P has 1
 time pulse output.
>> ___
>> time-nuts mailing list -- time-nuts@lists.febo.com
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 http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com
>> and follow the instructions there.
> 
> 
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Re: [time-nuts] Calculating time of lunar eclipse

[John Hawkinson]

Is it not the case that atmospheric effects end up shifting the time of 
observation by several seconds depending on location and condition?

I was going to write, "We should be weary of specifying precision we do not 
have," but rather it maybe better to write, "Perhaps we should be explicit 
about bounding the uncertainty associated with each estimate."

--jh...@mit.edu
  John Hawkinson

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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Michael Wouters]

If you scroll down to the bottom of the product pages for the zed-f9x
modules, you'll see the 'ANN-MB', a L1/L2/E5b antenna that ublox is
presumably making to go with the ZED-F9. It's still marked 'preorder'

Cheers
Michael




On Tue, 22 Jan 2019 at 6:00 am, Bob kb8tq  wrote:

> Hi
>
> To be more precise, what you want is a L1/L2/L5 triple band antenna.
>
> Bob
>
> > On Jan 21, 2019, at 11:32 AM, Bob kb8tq  wrote:
> >
> > Hi
> >
> > Based on the F9P data sheet, you will need an L1 / L2 antenna that is
> wide enough
> > to get the Galileo E5B as well as the Glonass L1OF and L2OF bands. The
> gotcha
> > is that (so far) I have not found a gain number for the target antenna.
> As we have
> > found on other modules, you do want to get the right gain. L1/L2
> antennas range
> > from 50+ db down to below 30 db. Simply tacking a pad on a 50 db antenna
> is not
> > the best way to do things if you are in an urban area.
> >
> > There also is the issue of powering the antenna. It is not clear what
> sort of antenna
> > bias circuit the SparkFun module has on it. If it simply is using the
> module’s bias setup
> > that also could be an issue. Max Vcc on the module is 3.6V. The VCC_RF
> pin can have
> > main Vcc - 0.1V max on it. If that *really* means that 3.3V is about it
> for antenna bias,
> > that eliminates roughly 100% of all the used antennas out there. It also
> eliminates a
> > number of the new ones.
> >
> > If you put in an external bias setup, there are a lot of antennas to
> pick from on eBay.
> > They come and go. The used stuff generally will be 12V powered. It also
> is likely
> > to have a pretty good data sheet on it. The new stuff from China seems
> to be sold
> > by a variety of people who pop up for a while and then go away for a
> while. Making
> > sure of what you are getting is a bit tough as a result. There are
> extensive stories
> > in the archives …..
> >
> > Bob
> >
> >> On Jan 21, 2019, at 10:21 AM, Graham / KE9H 
> wrote:
> >>
> >> What kind of antenna is needed to simultaneously hear all of the
> systems at
> >> once?
> >> My PCTel GPS antenna has a filter that limits it to only the US GPS
> system.
> >>
> >> --- Graham
> >>
> >> ==
> >>
> >> On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess 
> wrote:
> >>
> >>> If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
> >>> ZED-F9P.  I would have gladly paid $14 more for a version of the
> >>> SparkFun board using the T(iming) version instead :(.
> >>>
> >>> On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:
> 
>  Hi
> 
>  From a *very* quick read of the doc’s:
> 
>  1) The device *does* have a position hold capability
> 
>  2) There is some level of data on the time pulse. It it only 1 ns
> >>> resolution?
> 
>  3) It does appear to support Galileo and Glonas in addition to GPS.
> 
>  4) It is clearly multi-band for GPS. It is unclear from a quick read
> if
> >>> it is multi-band for the other systems.
> 
>  5) If you get one, make sure you have the RF cable connector it needs.
> 
>  6) I have not (yet) found a recommendation for the antenna gain.
> 
>  Again, all from a quick read ….
> 
>  Bob
> 
> > On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
> >
> > Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a
> >>> board ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks
> L1/L2
> >>> data.  It outputs carrier phase data and has survey-in and fixed
> position
> >>> support along with RTK support (10 mm accuracy).   Looks like the F9P
> has 1
> >>> time pulse output.
> > ___
> > 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.
> 
> 
>  ___
>  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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> >>> and follow the instructions there.
> >>>
> >> ___
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>
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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[MLewis]

Like these?
http://www.tallysman.com/index.php/gnss/products/antennas-triple-band/

On 21/01/2019 12:33 PM, Bob kb8tq wrote:

Hi

To be more precise, what you want is a L1/L2/L5 triple band antenna.

Bob


On Jan 21, 2019, at 11:32 AM, Bob kb8tq  wrote:

Hi

Based on the F9P data sheet, you will need an L1 / L2 antenna that is wide 
enough
to get the Galileo E5B as well as the Glonass L1OF and L2OF bands. The gotcha
is that (so far) I have not found a gain number for the target antenna. As we 
have
found on other modules, you do want to get the right gain. L1/L2 antennas range
from 50+ db down to below 30 db. Simply tacking a pad on a 50 db antenna is not
the best way to do things if you are in an urban area.

There also is the issue of powering the antenna. It is not clear what sort of 
antenna
bias circuit the SparkFun module has on it. If it simply is using the module’s 
bias setup
that also could be an issue. Max Vcc on the module is 3.6V. The VCC_RF pin can 
have
main Vcc - 0.1V max on it. If that *really* means that 3.3V is about it for 
antenna bias,
that eliminates roughly 100% of all the used antennas out there. It also 
eliminates a
number of the new ones.

If you put in an external bias setup, there are a lot of antennas to pick from 
on eBay.
They come and go. The used stuff generally will be 12V powered. It also is 
likely
to have a pretty good data sheet on it. The new stuff from China seems to be 
sold
by a variety of people who pop up for a while and then go away for a while. 
Making
sure of what you are getting is a bit tough as a result. There are extensive 
stories
in the archives …..

Bob


On Jan 21, 2019, at 10:21 AM, Graham / KE9H  wrote:

What kind of antenna is needed to simultaneously hear all of the systems at
once?
My PCTel GPS antenna has a filter that limits it to only the US GPS system.

--- Graham

==

On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess  wrote:


If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
ZED-F9P.  I would have gladly paid $14 more for a version of the
SparkFun board using the T(iming) version instead :(.

On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:

Hi

 From a *very* quick read of the doc’s:

1) The device *does* have a position hold capability

2) There is some level of data on the time pulse. It it only 1 ns

resolution?

3) It does appear to support Galileo and Glonas in addition to GPS.

4) It is clearly multi-band for GPS. It is unclear from a quick read if

it is multi-band for the other systems.

5) If you get one, make sure you have the RF cable connector it needs.

6) I have not (yet) found a recommendation for the antenna gain.

Again, all from a quick read ….

Bob


On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:

Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a

board ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2
data.  It outputs carrier phase data and has survey-in and fixed position
support along with RTK support (10 mm accuracy).   Looks like the F9P has 1
time pulse output.

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Re: [time-nuts] HP Stories: Frequency Counter business

[Gordon Batey]

Greetings to all,

I believe that was the HP 525 counter.  I had one as my first counter 
which I picked up surplus many years ago.  It had several plug-ins for
different 
frequency ranges.  Kept the basement warm in the winter time.  The vhf 
plugin was a heterodyne mixer as I recall.  This unit ontained MANY tubes
and a 
fairly large fan to remove the heat.  I gave it to another ham several years
ago.


I really enjoy the HP stories.

Gordon Batey
WA4FJC



Hi,
I used an HP counter in 1961 that had these vertical strings of neon tubes
behind numbers, and the two least significant decimals were read off two
milliamp meters numbered 0 to 10. For each count the needles would point to
the number to be read. The whole instrument was a 2 foot cube that sat on a
trolley.
After all this time I can not remember the model number. Our company
repaired Air force instruments and recalibration of frequency ?meters?
(calibrated heterodyne oscillators).
Cheers,
Neville Michie


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Re: [time-nuts] Calculating sidereal time

[Björn]

Hi Brooke,

SV position in circular orbit repeats at 12h sidereal, but ground relative 
az/el repeats at 24h sidereal. This is because of the earth 24h rotation rate. 
After 12h your earth position will be 180deg away from (inertil) start position.

—

   Björn 

Sent from my iPhone

> On 21 Jan 2019, at 03:35, Brooke Clarke  wrote:
> 
> Hi Didier:
> 
> I'm still very much interested.  The main reason is the GPS satellites come 
> close to following the same ground track.
> So I'd expect the elevation and azimuth to a given SVN to be the same on a 12 
> sidereal hour basis.
> 
> -- 
> Have Fun,
> 
> Brooke Clarke
> https://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
> axioms:
> 1. The extent to which you can fix or improve something will be limited by 
> how well you understand how it works.
> 2. Everybody, with no exceptions, holds false beliefs.
> 
>  Original Message 
>> Actually not a specific requirement. I made (and am in the process of
>> making a new batch of) an assembled kit which is used to monitor the data
>> stream from a Trimble Thunderbolt GPSDO and display time and vital
>> information on a small LCD display.
>> 
>> A long time ago, Brooke Clarke, on this list asked if I could make it
>> display sidereal time. I had no idea what it was so I researched it and
>> found out I needed to be able to process double precision calculations,
>> which the original 8 bit microcontroller was totally incapable of.
>> 
>> So I set this aside but I recently came across an inexpensive ARM chip and
>> decided to make a new version of my monitor with it. The toolchain is
>> excellent and supports double precision so I decided to fullfil Brooke's
>> request, who by now has probably lost interest in it but for the fun of it
>> and to learn something.
>> 
>> So while I understand sidereal time is used by astronomers, I am not one so
>> I have no personal practical use for it, which has the advantage of setting
>> the bar pretty low to decide when I am done :) That said, I am open to
>> suggestions to actually make it more useful if possible.
>> 
>> It is so easy to load an app in your phone if you actually need sidereal
>> time that I do not believe my kit will be used for that purpose but it was
>> an interesting exercise for me and I am glad it is working.
>> 
>> I learned quite a bit and discovered, through your postings and the
>> associated links how complex that subject actually is.
>> 
>> I love this list.
>> 
>> Didier KO4BB
>> 
>> 
>>> On Sat, Jan 19, 2019, 8:01 PM Steve Allen >> 
>>> On Sat 2019-01-19T12:15:28-0800 Steve Allen hath writ:
 The most expedient place to find them are roughly pages B7 to B12 in a
 current Astronomical Almanac.  See for example
 
>>> https://babel.hathitrust.org/cgi/pt?id=uc1.31822038913307;view=1up;seq=116
>>> 
>>> Emphasizing one point, it has always been important to use expressions
>>> for GMST and such things which are designed for use in the same
>>> reference frame as the star catalog.  Current star catalogs do not use
>>> an equinox as any kind of reference point, therefore any expression
>>> for GMST does not simply correspond to the longitude-like coordinate
>>> of a current star catalog.  GMST now coresponds to a new fictitious
>>> point in the sky which is defined with much more complexity than in
>>> the old days.
>>> 
>>> What exactly is the intended use case for this project?
>>> 
>>> --
>>> Steve Allen  WGS-84 (GPS)
>>> UCO/Lick Observatory--ISB 260  Natural Sciences II, Room 165  Lat
>>> +36.99855
>>> 1156 High Street   Voice: +1 831 459 3046 Lng
>>> -122.06015
>>> Santa Cruz, CA 95064   https://www.ucolick.org/~sla/  Hgt +250 m
>>> 
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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Bob via time-nuts]

Hi
    Just purchased one of the 100 bux  10 MHz/1pps GPS units.  Seems to fire up 
and lock ok, but wondering if anyone else has experience with these rascals.  
Bought mine from an Amazon source.  I've got it hooked up to my HP Hi Rez 
counter (can't recall the model number)  Have not had time to compare it to my 
Rubidium Scheme.
    Bob, KE6F


-Original Message-
From: Bob kb8tq 
To: Discussion of precise time and frequency measurement 

Sent: Sun, Jan 20, 2019 10:10 pm
Subject: Re: [time-nuts] Ublox F9P multi-band GPS receiver

Hi

From a *very* quick read of the doc’s:

1) The device *does* have a position hold capability 

2) There is some level of data on the time pulse. It it only 1 ns resolution? 

3) It does appear to support Galileo and Glonas in addition to GPS. 

4) It is clearly multi-band for GPS. It is unclear from a quick read if it is 
multi-band for the other systems.

5) If you get one, make sure you have the RF cable connector it needs.

6) I have not (yet) found a recommendation for the antenna gain.

Again, all from a quick read ….

Bob

> On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
> 
> Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a board 
> ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2 data.  
> It outputs carrier phase data and has survey-in and fixed position support 
> along with RTK support (10 mm accuracy).  Looks like the F9P has 1 time pulse 
> output.
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Re: [time-nuts] Calculating time of lunar eclipse

[jimlux]

On 1/21/19 5:50 AM, Magnus Danielson wrote:

Hi,

On 2019-01-21 08:07, Mark Sims wrote:
While on the subject of the accuracy/reliability of various algorithms 
and web pages showing various astronomical data, we had a full moon / 
total lunar eclipse in the northern hemisphere.  And not just any full 
moon, but a Super Blood Werewolf Zombie Apocalypse full moon (or some 
such drivel spouted by all the TV stations).


Anyway, I wanted to know when the eclipse was at it's maximum.  Most 
web sites gave a time here as 23:12,  some differed by several 
minutes.  None gave the time to the second.  That just won't do for a 
moon worshiping time-nut, will it?  So, I tricked up a version of Lady 
Heather to do a screen dump when the difference of the  sun and moon 
azimuth and elevation were at a (180 degree) minimum.  Looks like it 
happened at 23:12:04


Well, the best time as we see it is actually about a second after it 
actually occurred, due to the time it takes for the light of the moon to 
reach us. So the time for the actual event and the time for observation 
becomes notisable different.


Cheers,
Magnus


Magnus, this is time-nuts.. "about a second"?

There's a whole bunch of factors that need to be taken into account.

We are close to lunar perigee, where the distance is 357344 km - 1.2 
seconds (approx, see below), were we at apogee in a couple weeks 406555 
km that would add 150 milliseconds (approx).



Here in Southern California, it was about 9PM local, so we were farther 
away from the moon than folks on the US East Coast watching at local 
midnight. Why that's almost 2000km - 6 microseconds.  (Forgive my 
"approximate" here - the intent is to form an 1 sig fig estimate of the 
potential error - if needed, we can discuss making this more precise)


Solid Earth tides (assuming the observer is on land)will lead to a few 
nanoseconds difference as well you might be closer or farther.  For the 
lucky folks watching at moon set or moonrise, this effect will be 
minimized, since the tidal motion is orthogonal to the line of sight. 
For water borne observers, the tidal motion is more complex, and you'll 
have swells to worry about as well.


One should also take into account the density and properties of the 
atmosphere, which changes the propagation speed of light. One should, of 
course, also account for the dispersion - red light travels at a 
different speed than blue - but perhaps the red moon was sufficiently 
monochromatic that this isn't an issue?



As it happens, it was overcast here, so there was no direct viewing 
possible, so my viewing, such as it was, had to be mediated through the 
internet, which has its own set of time lags, some of which we have 
discussed on the list.



In all seriousness, computations of the observing times of astronomical 
events does need to take a variety of factors into account, and light 
speed is but one of them.


In my own professional field of spacecraft telecom, as beamwidths get 
narrower (i.e. going to optical wavelengths instead of RF) knowing the 
precise relative position at a specified time is important.  This is 
biting lots of "cubesat" folks as they move from UHF with 30 degree 
beamwidths to ground station antennas with 1 degree beamwidth.


And, when looking at links to outer planets, with transit time in hours, 
do you need to "point ahead" (earth moves about 30km/sec in its orbit) - 
from Mars at a sort of average 1AU, that's about 0.007 degrees. 
Probably not an issue with a 1 degree beamwidth antenna.


A typical 20cm optical aperture will produce a beamwidth of 1500 km at 1 
AU, a bit less than 1 minute's motion of Earth.


One thing I'll note is that for the most part, folks realize the 
impracticality of computing all this stuff open loop - you do a 
calculation to get you close enough, then use closed loop tracking to do 
the final pointing. But think about this - if I'm pointing my telescope 
back at Earth, finding Earth is easy.  Pointing to the centroid of Earth 
is easy. But my "spot" is only 1500km wide, on a 14,000km wide earth, so 
I need to know "where on the Earth disk" to point.



http://kiss.caltech.edu/workshops/optcomm/presentations/Sburlan.pdf is a 
nice high level presentation on Optical Comm from a few years ago.


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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Ole Petter Rønningen]

Indeed. Getting a *quality* antenna with that coverage will likely be a more 
costly affair than getting the actual receiver..

Of course, a cheap puck-style antenna is an option, but I am curious as to what 
improvements will actually be observed, at least for the time being - IIRC only 
about half of the sats transmit L2C..

Ole

> 21. jan. 2019 kl. 17:32 skrev Bob kb8tq :
> 
> Hi
> 
> Based on the F9P data sheet, you will need an L1 / L2 antenna that is wide 
> enough 
> to get the Galileo E5B as well as the Glonass L1OF and L2OF bands. The gotcha 
> is that (so far) I have not found a gain number for the target antenna. As we 
> have
> found on other modules, you do want to get the right gain. L1/L2 antennas 
> range 
> from 50+ db down to below 30 db. Simply tacking a pad on a 50 db antenna is 
> not 
> the best way to do things if you are in an urban area. 
> 
> There also is the issue of powering the antenna. It is not clear what sort of 
> antenna
> bias circuit the SparkFun module has on it. If it simply is using the 
> module’s bias setup
> that also could be an issue. Max Vcc on the module is 3.6V. The VCC_RF pin 
> can have
> main Vcc - 0.1V max on it. If that *really* means that 3.3V is about it for 
> antenna bias,
> that eliminates roughly 100% of all the used antennas out there. It also 
> eliminates a 
> number of the new ones. 
> 
> If you put in an external bias setup, there are a lot of antennas to pick 
> from on eBay. 
> They come and go. The used stuff generally will be 12V powered. It also is 
> likely 
> to have a pretty good data sheet on it. The new stuff from China seems to be 
> sold
> by a variety of people who pop up for a while and then go away for a while. 
> Making
> sure of what you are getting is a bit tough as a result. There are extensive 
> stories
> in the archives …..
> 
> Bob
> 
>> On Jan 21, 2019, at 10:21 AM, Graham / KE9H  wrote:
>> 
>> What kind of antenna is needed to simultaneously hear all of the systems at
>> once?
>> My PCTel GPS antenna has a filter that limits it to only the US GPS system.
>> 
>> --- Graham
>> 
>> ==
>> 
>>> On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess  wrote:
>>> 
>>> If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
>>> ZED-F9P.  I would have gladly paid $14 more for a version of the
>>> SparkFun board using the T(iming) version instead :(.
>>> 
 On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:
 
 Hi
 
 From a *very* quick read of the doc’s:
 
 1) The device *does* have a position hold capability
 
 2) There is some level of data on the time pulse. It it only 1 ns
>>> resolution?
 
 3) It does appear to support Galileo and Glonas in addition to GPS.
 
 4) It is clearly multi-band for GPS. It is unclear from a quick read if
>>> it is multi-band for the other systems.
 
 5) If you get one, make sure you have the RF cable connector it needs.
 
 6) I have not (yet) found a recommendation for the antenna gain.
 
 Again, all from a quick read ….
 
 Bob
 
> On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
> 
> Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a
>>> board ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2
>>> data.  It outputs carrier phase data and has survey-in and fixed position
>>> support along with RTK support (10 mm accuracy).   Looks like the F9P has 1
>>> time pulse output.
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> and follow the instructions there.
 
 
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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Bob kb8tq]

Hi

To be more precise, what you want is a L1/L2/L5 triple band antenna.

Bob

> On Jan 21, 2019, at 11:32 AM, Bob kb8tq  wrote:
> 
> Hi
> 
> Based on the F9P data sheet, you will need an L1 / L2 antenna that is wide 
> enough 
> to get the Galileo E5B as well as the Glonass L1OF and L2OF bands. The gotcha 
> is that (so far) I have not found a gain number for the target antenna. As we 
> have
> found on other modules, you do want to get the right gain. L1/L2 antennas 
> range 
> from 50+ db down to below 30 db. Simply tacking a pad on a 50 db antenna is 
> not 
> the best way to do things if you are in an urban area. 
> 
> There also is the issue of powering the antenna. It is not clear what sort of 
> antenna
> bias circuit the SparkFun module has on it. If it simply is using the 
> module’s bias setup
> that also could be an issue. Max Vcc on the module is 3.6V. The VCC_RF pin 
> can have
> main Vcc - 0.1V max on it. If that *really* means that 3.3V is about it for 
> antenna bias,
> that eliminates roughly 100% of all the used antennas out there. It also 
> eliminates a 
> number of the new ones. 
> 
> If you put in an external bias setup, there are a lot of antennas to pick 
> from on eBay. 
> They come and go. The used stuff generally will be 12V powered. It also is 
> likely 
> to have a pretty good data sheet on it. The new stuff from China seems to be 
> sold
> by a variety of people who pop up for a while and then go away for a while. 
> Making
> sure of what you are getting is a bit tough as a result. There are extensive 
> stories
> in the archives …..
> 
> Bob
> 
>> On Jan 21, 2019, at 10:21 AM, Graham / KE9H  wrote:
>> 
>> What kind of antenna is needed to simultaneously hear all of the systems at
>> once?
>> My PCTel GPS antenna has a filter that limits it to only the US GPS system.
>> 
>> --- Graham
>> 
>> ==
>> 
>> On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess  wrote:
>> 
>>> If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
>>> ZED-F9P.  I would have gladly paid $14 more for a version of the
>>> SparkFun board using the T(iming) version instead :(.
>>> 
>>> On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:
 
 Hi
 
 From a *very* quick read of the doc’s:
 
 1) The device *does* have a position hold capability
 
 2) There is some level of data on the time pulse. It it only 1 ns
>>> resolution?
 
 3) It does appear to support Galileo and Glonas in addition to GPS.
 
 4) It is clearly multi-band for GPS. It is unclear from a quick read if
>>> it is multi-band for the other systems.
 
 5) If you get one, make sure you have the RF cable connector it needs.
 
 6) I have not (yet) found a recommendation for the antenna gain.
 
 Again, all from a quick read ….
 
 Bob
 
> On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
> 
> Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a
>>> board ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2
>>> data.  It outputs carrier phase data and has survey-in and fixed position
>>> support along with RTK support (10 mm accuracy).   Looks like the F9P has 1
>>> time pulse output.
> ___
> 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.
 
 
 ___
 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] Ublox F9P multi-band GPS receiver

[Bob kb8tq]

Hi

Based on the F9P data sheet, you will need an L1 / L2 antenna that is wide 
enough 
to get the Galileo E5B as well as the Glonass L1OF and L2OF bands. The gotcha 
is that (so far) I have not found a gain number for the target antenna. As we 
have
found on other modules, you do want to get the right gain. L1/L2 antennas range 
from 50+ db down to below 30 db. Simply tacking a pad on a 50 db antenna is not 
the best way to do things if you are in an urban area. 

There also is the issue of powering the antenna. It is not clear what sort of 
antenna
bias circuit the SparkFun module has on it. If it simply is using the module’s 
bias setup
that also could be an issue. Max Vcc on the module is 3.6V. The VCC_RF pin can 
have
main Vcc - 0.1V max on it. If that *really* means that 3.3V is about it for 
antenna bias,
that eliminates roughly 100% of all the used antennas out there. It also 
eliminates a 
number of the new ones. 

If you put in an external bias setup, there are a lot of antennas to pick from 
on eBay. 
They come and go. The used stuff generally will be 12V powered. It also is 
likely 
to have a pretty good data sheet on it. The new stuff from China seems to be 
sold
by a variety of people who pop up for a while and then go away for a while. 
Making
sure of what you are getting is a bit tough as a result. There are extensive 
stories
in the archives …..

Bob

> On Jan 21, 2019, at 10:21 AM, Graham / KE9H  wrote:
> 
> What kind of antenna is needed to simultaneously hear all of the systems at
> once?
> My PCTel GPS antenna has a filter that limits it to only the US GPS system.
> 
> --- Graham
> 
> ==
> 
> On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess  wrote:
> 
>> If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
>> ZED-F9P.  I would have gladly paid $14 more for a version of the
>> SparkFun board using the T(iming) version instead :(.
>> 
>> On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:
>>> 
>>> Hi
>>> 
>>> From a *very* quick read of the doc’s:
>>> 
>>> 1) The device *does* have a position hold capability
>>> 
>>> 2) There is some level of data on the time pulse. It it only 1 ns
>> resolution?
>>> 
>>> 3) It does appear to support Galileo and Glonas in addition to GPS.
>>> 
>>> 4) It is clearly multi-band for GPS. It is unclear from a quick read if
>> it is multi-band for the other systems.
>>> 
>>> 5) If you get one, make sure you have the RF cable connector it needs.
>>> 
>>> 6) I have not (yet) found a recommendation for the antenna gain.
>>> 
>>> Again, all from a quick read ….
>>> 
>>> Bob
>>> 
 On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
 
 Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a
>> board ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2
>> data.  It outputs carrier phase data and has survey-in and fixed position
>> support along with RTK support (10 mm accuracy).   Looks like the F9P has 1
>> time pulse output.
 ___
 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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[time-nuts] Metastability (was: Re: HP Stories: Frequency Counter business decline, Modulation Domain Analyzers, geeks as models)

[Richard (Rick) Karlquist]

Circa 1982:

After the cancellation of the HP 10816 mini rubidium
product, I worked on the 5183 "Waveform Recorder"
(the name was a euphemism to deflect charter wars
with the scope division which was just getting into
digital scopes).  I was tasked with designing a DRAM
memory board, to replace the SRAM memory boards used
previously.  I designed a FIFO buffer to collect
samples coming in during refresh intervals.

The samples came in a 4 MHz, but memory was clocked
at 4.6 MHz, which I determined was sufficient to allow
refreshing without an overflow.  The data had to be
resynched with the 4.6 MHz clock.  Somehow I became
aware of metastability, which was new to me, and
unknown to most engineers at SCD.

I designed a state machine running on a 32 MHz clock
to resync 4 MHz clock edges.  A number of engineers
know just enough to be dangerous and suggested the
technique is to just make a shift register and run
the incoming edge through n flip flops. "Everyone knew" that
was the thing to do.  NOT.  Actually, I only had to
reclock 2 times, but the delay between the two registers
had to be MUCH longer than the 31 ns period of the
32 MHz clock.  I characterized the flip flops I
was using to make a probability curve of metastability
events per year vs delay time using a special fixturing
board.  I ended up choosing a time delay that extrapolated
to something like 1 event in 10 years, just about "never".
In those days, 32 MHz clocking was considered very high
speed for the available TTL logic.

I authored my very first patent covering the DRAM system.
If interested, search on my name for inventor and go to
the oldest listing, early 1980's.

Later in the project we had a problem where about once a
day, the HPIB chip would hang.  I built a special triggering
circuit to catch it in the act and capture the smoking gun
on the logic analyzer.  The smoking gun was that the bus
would go into "serial poll" mode, which it should "never"
have done.  The general concensus was that this
was caused by metastability in the "PHI" chip as it was
called.  I don't remember the fix, maybe something like
a watch dog that would use my trigger to just clear the error.
You'd get a daily corrupted measurement, but at least it
wouldn't hang.

Rick N6RK

On 1/20/2019 10:10 PM, Hal Murray wrote:


When did people designing counter/timers start paying attention to
metastability?

I learned about it in the late 70s or early 80s.  In the mid 80s, I went to a
trade show that had a panel on it, and one of the panelists actually claimed
it wasn't a problem.





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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Graham / KE9H]

What kind of antenna is needed to simultaneously hear all of the systems at
once?
My PCTel GPS antenna has a filter that limits it to only the US GPS system.

--- Graham

==

On Mon, Jan 21, 2019 at 4:01 AM Dustin Marquess  wrote:

> If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
> ZED-F9P.  I would have gladly paid $14 more for a version of the
> SparkFun board using the T(iming) version instead :(.
>
> On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:
> >
> > Hi
> >
> > From a *very* quick read of the doc’s:
> >
> > 1) The device *does* have a position hold capability
> >
> > 2) There is some level of data on the time pulse. It it only 1 ns
> resolution?
> >
> > 3) It does appear to support Galileo and Glonas in addition to GPS.
> >
> > 4) It is clearly multi-band for GPS. It is unclear from a quick read if
> it is multi-band for the other systems.
> >
> > 5) If you get one, make sure you have the RF cable connector it needs.
> >
> > 6) I have not (yet) found a recommendation for the antenna gain.
> >
> > Again, all from a quick read ….
> >
> > Bob
> >
> > > On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
> > >
> > > Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a
> board ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2
> data.  It outputs carrier phase data and has survey-in and fixed position
> support along with RTK support (10 mm accuracy).   Looks like the F9P has 1
> time pulse output.
> > > ___
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> >
> >
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Re: [time-nuts] Calculating time of lunar eclipse

[Magnus Danielson]

Hi,

On 2019-01-21 08:07, Mark Sims wrote:

While on the subject of the accuracy/reliability of various algorithms and web 
pages showing various astronomical data, we had a full moon / total lunar 
eclipse in the northern hemisphere.  And not just any full moon, but a Super 
Blood Werewolf Zombie Apocalypse full moon (or some such drivel spouted by all 
the TV stations).

Anyway, I wanted to know when the eclipse was at it's maximum.  Most web sites 
gave a time here as 23:12,  some differed by several minutes.  None gave the 
time to the second.  That just won't do for a moon worshiping time-nut, will 
it?  So, I tricked up a version of Lady Heather to do a screen dump when the 
difference of the  sun and moon azimuth and elevation were at a (180 degree) 
minimum.  Looks like it happened at 23:12:04


Well, the best time as we see it is actually about a second after it 
actually occurred, due to the time it takes for the light of the moon to 
reach us. So the time for the actual event and the time for observation 
becomes notisable different.


Cheers,
Magnus


Heather's sun position code (based on Grena's algorithm 5) is VERY accurate 
(and quite simple).  The moon position code is pretty good... a better version 
would require several thousand lines of code evaluating a zillion polynomials 
with hundreds of terms.

Anyway,, attached is a copy of the screen dump.  Note the difference in the 
sun/moon az/el values and also the calculated moon phase.

Does anybody know of a reliable source of the true time of the lunar eclipse 
down to the second (or better)?

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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Bob kb8tq]

Hi

Ok, so the “product summary” page on DigiKey very clearly shows the 
frequency coverage information. If that data sheet was on SparkFun ….
I must have gone right past it.

The equivalent F9T sheet starts out right at the top talking about correcting 
ionosphere delay to deliver better timing. One would *assume* the F9P 
does the same thing. It never seems to show up in quite the same big bold
print….

Bob

> On Jan 21, 2019, at 8:44 AM, Bob kb8tq  wrote:
> 
> Hi
> 
> 
>> On Jan 21, 2019, at 1:41 AM, Mark Sims > > wrote:
>> 
>>> It is clearly multi-band for GPS. It is unclear from a quick read if it is 
>>> multi-band for the other systems.
>> 
>> Here's what they say it supports:
>> 
>> 184-channel u-blox F9 engine 
>> GPS L1C/A L2C, 
>> GLO L1OF L2OF, 
>> GAL E1B/C E5b, 
>> BDS B1I B2I, 
>> QZSS L1C/A L2C
> 
> If that’s in the docs on the module, I missed it. My concern is the frequency 
> range of the front end 
> SAW’s (that are external to the chip set). 
> 
>> 
>> Here's the link to the Sparkfun device.  I think it uses a u.FL antenna 
>> connector.
>> https://www.sparkfun.com/products/15136 
>> 
> 
> Yup and they aren’t crazy expensive compared to the module. The usual auction 
> sites also have
> the same sort of thing for a bit less money.
> 
> Bob
> 
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Re: [time-nuts] HP Stories: Frequency Counter business decline, Modulation Domain Analyzers, geeks as models

[Neville Michie]

Hi,
I used an HP counter in 1961 that had these vertical strings of
neon tubes behind numbers, and the two least significant decimals were read off
two milliamp meters numbered 0 to 10. For each count the needles would point to 
the 
number to be read. The whole instrument was a 2 foot cube that sat on a trolley.
After all this time I can not remember the model number. Our company repaired 
Air force instruments and recalibration of frequency “meters” (calibrated 
heterodyne 
oscillators).
Cheers, 
Neville Michie

> On 21 Jan 2019, at 13:44, Brooke Clarke  wrote:
> 
> Hi:
> 
> I think there were some versions prior to transistors.  For example:
> https://prc68.com/I/HPac4a.shtml
> A friend of the family worked at HP and gave these to me.
> 
> -- 
> Have Fun,
> 
> Brooke Clarke
> https://www.PRC68.com
> http://www.end2partygovernment.com/2012Issues.html
> axioms:
> 1. The extent to which you can fix or improve something will be limited by 
> how well you understand how it works.
> 2. Everybody, with no exceptions, holds false beliefs.
> 
>  Original Message 
>> Hello Time Nuts,
>> 
>> Hopefully some of you will find this snapshot of HP's "Santa Clara 
>> Division", the home of Frequency Standards and Frequency Counters 
>> interesting.   Send me a note if you want me to keep writing old HP stories.
>> 
>> 
>> When I arrived at HP Santa Clara Division (SCD, Division 02, as in the 
>> second HP division ever) in 1984, the beginning of the end of the 
>> "frequency" business was starting to be felt.
>> 
>> This product line dates to the 1950's with the invention of the first 
>> frequency counter.   Breakthrough for its time, it enabled precision 
>> measurements of frequency, using "digital" techniques.   The basic idea:  
>> Open a "gate" for 1 second, and count the number of positive zero crossings 
>> of a signal.  The count was the frequency to 1Hz resolution.Longer gate 
>> times (10 seconds) would give more resolution, etc.   This required the 
>> invention of fast digital counting circuits (essentially a chain of 
>> flip-flops, likely implemented with the very earliest discrete transistors), 
>> some binary to decimal conversion for the display, and there you have it:  
>> Something that can measure frequency.
>> 
>> Like all breakthrough measurements, the next 20+ years was spent refining 
>> the concept.Better "front end" amplifiers, able to measure low amplitude 
>> signals.   Faster counters, that could capture higher frequency signals.
>> Microwave front ends, to either divide the signal by 8 or 16 or whatever 
>> before being counted, or using some other down conversation technique.
>> Somewhere in the early 1970's (guess), the reciprocal counter was invented.  
>> Rather than open the gate for 1 second,  use the input signal to open the 
>> gate for one period, and count a very high frequency time base instead.
>> It was much faster, and for lower frequency signals, much much higher 
>> resolution.   Now, if you had a ~1KHz unknown signal, rather than only 
>> getting 4 significant digits in a one second measurement, if you counted a 
>> 100MHz time base for 1 millisecond, you would 5 digits of resolution.  Open 
>> the gate for a thousand cycles, and 8 digits of resolution were available.
>> 
>> With the reciprocal counter, it was essentially measuring a time interval 
>> (one period of the input signal), and calculating frequency.The obvious 
>> extension was an instrument to measure time intervals directly, using two 
>> inputs.  Channel A to start and Channel B to stop.  And the "Universal 
>> Counter" was born.
>> 
>> All of these required an accurate frequency source to precisely open the 
>> gate, or to be counted in reciprocal counters or time interval measurements. 
>>   This is what drove the market for PFS - precision frequency sources.A 
>> progression of improved quartz oscillators were invented, and then the 
>> cesium standards starting in 1965.   Now, from HP you could buy it all:  The 
>> perfect time base, and the high resolution counter.   All your frequency 
>> measurement dreams supplied from wonderful HP.   This was a great 
>> compliment to HPs frequency generator product lines.  (Remember HPs first 
>> product in 1939 was the 200A audio oscillator.)A frequency counter, 
>> using a precision time base, was able to calibrate (or perhaps tune) an 
>> oscillator or frequency generator to create a complete system to generate 
>> very accurate signals.Lots of great applications for all of this.   
>> Growth, profits, happiness.  I'll guess that the mid 1970's were the peak of 
>> the business.In 1984, SCD was a ~$100M business per year, with frequency 
>> counters being over half of it.   (SCD also made laser interferometers, 
>> which was about ¼ of the business)
>> 
>> But as the 1970s became the 1980s, things started to go flat.   Frequency 
>> sources (Cesium standards, etc.) last for a very long time.  Did 

Re: [time-nuts] Calculating time of lunar eclipse

[Chris Burford]

Mr. Eclipse, hosted by Fred Espenak,  is your go-to page for this. The data for 
both solar and lunar eclipse events seems to be accurate based on my experience 
of past events.

http://www.eclipsewise.com/lunar/LEprime/2001-2100/LE2019Jan21Tprime.html


 Mark Sims  wrote: 
> While on the subject of the accuracy/reliability of various algorithms and 
> web pages showing various astronomical data, we had a full moon / total lunar 
> eclipse in the northern hemisphere.  And not just any full moon, but a Super 
> Blood Werewolf Zombie Apocalypse full moon (or some such drivel spouted by 
> all the TV stations).

Anyway, I wanted to know when the eclipse was at it's maximum.  Most web sites 
gave a time here as 23:12,  some differed by several minutes.  None gave the 
time to the second.  That just won't do for a moon worshiping time-nut, will 
it?  So, I tricked up a version of Lady Heather to do a screen dump when the 
difference of the  sun and moon azimuth and elevation were at a (180 degree) 
minimum.  Looks like it happened at 23:12:04

Heather's sun position code (based on Grena's algorithm 5) is VERY accurate 
(and quite simple).  The moon position code is pretty good... a better version 
would require several thousand lines of code evaluating a zillion polynomials 
with hundreds of terms.

Anyway,, attached is a copy of the screen dump.  Note the difference in the 
sun/moon az/el values and also the calculated moon phase.

Does anybody know of a reliable source of the true time of the lunar eclipse 
down to the second (or better)?

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Re: [time-nuts] Calculating time of lunar eclipse

[Bill Beam]

According to my copy of Guide9 (Pluto project) full moon occurred at 21 Jan 
05:16:04 UTC.

On Mon, 21 Jan 2019 07:07:31 +, Mark Sims wrote:

>While on the subject of the accuracy/reliability of various algorithms and web 
>pages showing various astronomical data, we had a full moon / 
total lunar eclipse in the northern hemisphere.  And not just any full moon, 
but a Super Blood Werewolf Zombie Apocalypse full moon (or 
some such drivel spouted by all the TV stations).

>Anyway, I wanted to know when the eclipse was at it's maximum.  Most web sites 
>gave a time here as 23:12,  some differed by several 
minutes.  None gave the time to the second.  That just won't do for a moon 
worshiping time-nut, will it?  So, I tricked up a version of Lady 
Heather to do a screen dump when the difference of the  sun and moon azimuth 
and elevation were at a (180 degree) minimum.  Looks like it 
happened at 23:12:04

>Heather's sun position code (based on Grena's algorithm 5) is VERY accurate 
>(and quite simple).  The moon position code is pretty good... 
a better version would require several thousand lines of code evaluating a 
zillion polynomials with hundreds of terms.

>Anyway,, attached is a copy of the screen dump.  Note the difference in the 
>sun/moon az/el values and also the calculated moon phase.

>Does anybody know of a reliable source of the true time of the lunar eclipse 
>down to the second (or better)?


Bill Beam
NL7F




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Re: [time-nuts] Ublox F9P multi-band GPS receiver

[Dustin Marquess]

If DigiKey's pricing is accurate, the ZED-F9T is $13.89 more than a
ZED-F9P.  I would have gladly paid $14 more for a version of the
SparkFun board using the T(iming) version instead :(.

On Mon, Jan 21, 2019 at 12:10 AM Bob kb8tq  wrote:
>
> Hi
>
> From a *very* quick read of the doc’s:
>
> 1) The device *does* have a position hold capability
>
> 2) There is some level of data on the time pulse. It it only 1 ns resolution?
>
> 3) It does appear to support Galileo and Glonas in addition to GPS.
>
> 4) It is clearly multi-band for GPS. It is unclear from a quick read if it is 
> multi-band for the other systems.
>
> 5) If you get one, make sure you have the RF cable connector it needs.
>
> 6) I have not (yet) found a recommendation for the antenna gain.
>
> Again, all from a quick read ….
>
> Bob
>
> > On Jan 20, 2019, at 5:42 PM, Mark Sims  wrote:
> >
> > Sparkfun is now selling the Ublox F9P L1/L2 GPS receiver module on a board 
> > ($219).  The F9P supports GPS/Galileo/Glonass/Beidou and tracks L1/L2 data. 
> >  It outputs carrier phase data and has survey-in and fixed position support 
> > along with RTK support (10 mm accuracy).   Looks like the F9P has 1 time 
> > pulse output.
> > ___
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[time-nuts] GPS satellite orbits (was: Calculating sidereal time)

[Mark Sims]

I also expected that, but when I added the ability of Lady Heather to plot the 
SNR/az/el/carrier phase/pseudorange of a given satellite, I found that they 
repeat every 24-ish hours.  At 12-ish hours the SNR and time the receiver had 
usable signal was greatly reduced.



>The main reason is the GPS satellites come close to following the same ground 
>track.
So I'd expect the elevation and azimuth to a given SVN to be the same on a 12 
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Re: [time-nuts] HP Stories: Frequency Counter business decline, Modulation Domain Analyzers, geeks as models

[Bruce Griffiths]

https://www.arl.wustl.edu/~jst/cse/260/glitchChaney.pdf
suggests metastability was noticed in the 1940's but not taken seriously for 
decades thereafter.

Bruce
> On 21 January 2019 at 19:10 Hal Murray  wrote:
> 
> 
> 
> When did people designing counter/timers start paying attention to 
> metastability?
> 
> I learned about it in the late 70s or early 80s.  In the mid 80s, I went to a 
> trade show that had a panel on it, and one of the panelists actually claimed 
> it wasn't a problem.
> 
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
> 
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[time-nuts] Ublox F9P multi-band GPS receiver

[Mark Sims]

>  It is clearly multi-band for GPS. It is unclear from a quick read if it is 
> multi-band for the other systems.

Here's what they say it supports:

184-channel u-blox F9 engine 
GPS L1C/A L2C, 
GLO L1OF L2OF, 
GAL E1B/C E5b, 
BDS B1I B2I, 
QZSS L1C/A L2C

Here's the link to the Sparkfun device.  I think it uses a u.FL antenna 
connector.
https://www.sparkfun.com/products/15136
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