[time-nuts] Introduction, new list member, Ms Tisha Hayes, AA4HA

[Tisha Hayes]

Greetings to all of the time-nuts on this list. I too have an interest
(obsession?) with precision frequency measurement. I have known, visited
and had dinner with Perry Sandeen (also a list member) while he lived in
Tennessee where we shared a common interest in the beloved R-390A receiver
and test equipment.

Perry and I would make our pilgrimages to the Huntsville Ham Fest and
usually I ended up buying equipment from him. One of the items he sent my
way was an HP 3586B that I am finally beginning to put to use.

I am trying to find out how to fix the tuning control on the HP3586B and
that led me back to this list. If anyone has suggestions on making repairs
I would appreciate the info; I am very capable of troubleshooting and
making component level repairs, even if I have to take the tuning control
apart to fix the optical chopper light source.

*Ms. Tisha Hayes, AA4HA*
*(Senior Engineer with 4RF USA)*

*Gadsden, Alabama*
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[time-nuts] Teardown of Chinese made eBay GPS antenna.

[Mark Sims]

I can confirm that they work well on Glonass and Beidou.   I have not tried 
them on my Z12 with L2 signals.

Last night a big lightning strike across the street took out a tree.   Antenna 
survived without damage, but my antenna is on a 3 foot tripod on the ground...  
it was quite a brown-trousers producing, ear-ringing strike.  

BTW,  the HP/Symmeticom 58517A antenna splitter/amplifier seems to work well 
with Glonass/Beidou.  I don't think it does L2, etc.
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Gary E. Miller]

Yo Bob!

On Wed, 28 Mar 2018 16:37:07 -0400
Bob kb8tq  wrote:

> So, after only two months in transit my examples of the “Chinese GPS
> Antenna” are here to poke at.

Cool.  I just ordered one.  I'm finding some GPS need the 40dB LNA
this claims, as opposed to the usual 23dB or so.  Then I can stop
swapping L1/L2 and L1/GLONASS antennas.

RGDS
GARY
---
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
g...@rellim.com  Tel:+1 541 382 8588

Veritas liberabit vos. -- Quid est veritas?
"If you can’t measure it, you can’t improve it." - Lord Kelvin


pgpOHrl8RWkxw.pgp
Description: OpenPGP digital signature
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[time-nuts] European grid phase heading back

[Pieter-Tjerk de Boer]

Hello,

It looks like the European (ENTSOE) mains grid phase is now heading back
to what it was before the large deviation of February.
See my measurements at 
http://wwwhome.ewi.utwente.nl/~ptdeboer/misc/mains-2018.html
The ENTSOE website doesn't mention this correction yet, other than as a
future "step 2".

One can wonder how useful this correction is, though: just last weekend,
daylight savings time started in Europe, so most mains-driven clocks have
probably been manually set to the correct time on that occasion. Those will
soon be some 5 minutes fast...

Regards,
  Pieter-Tjerk (PA3FWM)

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Re: [time-nuts] Setting correct date on Trimble Thunderbolt receiver

[Tom Van Baak]

> Tom,
>
> In my TB monitor kit, I used your Julian date routines, adapted to the 8051
> (no variable greater than 32 bits since my compiler does not support them
> either) to apply the GPS offset correction. It was very helpful.
>
> Didier KO4BB

Right. There are many ways to address the 1024 week rollover. Mark uses JD and 
floating point because his program contains lots of astronomical features and 
JD is useful and popular in that context. I suspect the code you're using is 
from this demo -- http://leapsecond.com/tools/tbolt1.c -- which is based on MJD 
and integer only.

The code I mentioned today -- http://leapsecond.com/tools/gpsdn.c -- is similar 
except its based on GPSDN instead of MJD. I came up with GPSDN because it's 
easier to work with GPS cycles when the origin of GPS time is GPSDN = 0 instead 
of something like MJD = 44244, or JD = 2444244.5, or unix_time_t = 315964800, 
or Excel date 29226.

If you display GPSDN as hex or binary, GPS rollovers are a picture-worthy 
ripple-carry binary odometers:

1999-08-21 = GPSDN 7167 = 0x1BFF = 0b11011
1999-08-22 = GPSDN 7168 = 0x1C00 = 0b11100

2019-04-06 = GPSDN 14335 = 0x37FF = 0b110111
2019-04-07 = GPSDN 14336 = 0x3800 = 0b111000

2038-11-20 = GPSDN 21503 = 0x53FF = 0b1010011
2038-11-21 = GPSDN 21504 = 0x5400 = 0b1010100

2058-07-06 = GPSDN 28671 = 0x6FFF = 0b110
2058-07-07 = GPSDN 28672 = 0x7000 = 0b111

While I'm at it, and for newcomers to the group, note that GPS rollovers occur 
about every 19.6 years (1024 weeks) and occur in "GPS time", which is offset 
from "UTC time" by a particular number of leap seconds. That's why GPS 
rollovers do not occur at precisely midnight on the dates listed above. Also 
why it's not possible to list the exact time of future GPS rollovers as UTC 
date & time. Hint: stay well away from self-driving vehicles during leap 
seconds and GPS rollovers.

/tvb

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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Bob kb8tq]

Hi

So, after only two months in transit my examples of the “Chinese GPS Antenna” 
are
here to poke at. They are from www.stotoncn.com  and 
are labeled as being their
part number GN-GGB0710. They clearly show 3.3V to 18V as the operating voltage
on the  box they came in and on the antennas. All labeling is in English. It 
appears 
they will happily sell you as many as you want on AliExpress for ~$67. All data 
indicates
they will run L1/L2 GPS, Glonass, and Beidu. That is what the labeling on the 
parts
indicates. There is some conflicting data on the web about L5 operation …. 
we’lll see 
how that part goes. All packaging, labeling, and QA stickers match what show up 
in 
pictures on the web site. As best I can tell from Mr Google , they are indeed  
legit 3.3V 
to 18V devices.

Bob

> On Feb 22, 2018, at 2:48 PM, John Green  wrote:
> 
> For those who have been following the saga of the Chinese made, eBay
> purchased antenna that failed, I may have an answer as to why it failed.
> I had to destructively disassemble it. I just could not get it apart any
> other way. I used a Chinese version of a Dremel tool with a metal saw
> blade. After making a huge mess with plastic particles everywhere, it
> revealed a circular FR4 board with two patch antennas mounted, one atop the
> other. I assume the smaller one to be the L1, and the larger to be L2. This
> part looks almost identical to the Trimble Microcentered antenna I worked
> on recently. On the back side of this is a metal shield  about 3 by 3
> inches soldered to the circular FR4 board. I switched to a abrasive wheel
> and took off some of the solder holding the shield to the board. Then,
> using a small screw driver, I went around the shield breaking the solder
> loose. The shield off revealed that the coax goes to some capacitors that
> couple RF out and through an inductor with some capacitors to ground and
> finally to a SOT23-5 package labelled LK33. This appears to be a Micrel
> MIC5203 3.3 volt regulator. It is shorted on the input side. I believe that
> putting anything over 7.5 volts on the input exceeded the power dissipation
> rating and caused it to fail. I plan on wiring up a more robust 3.3 volt
> regulator in its place and trying again. It looks like I will be able to re
> solder the shield back. The watertight integrity is gone for good. I think
> I can find a plastic box I can mount it in so I can at least experiment
> with it. I have sent a message to the seller detailing my findings. The
> Micrel part lists a 20 volt maximum input voltage, so in theory at least,
> this might have worked, and there might be some of these out there that
> don't fail.
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[time-nuts] Setting correct date on Trimble Thunderbolt receiver

[Mark Sims]

Thanks,  excellent code to do the fixup on Arduinos, etc.   Heather already has 
Julian <-> Gregorian routines that use double precision numbers and allows 
date/time tweaks to millisecond levels, so I used those.

I am modifying the rollover adjustment code to not latch onto a specific 
rollover compensation value.  That was originally done for a couple of old 
receivers that did things rather bizarrely.   Subsequent improvements  to the 
code made that no longer necessary. So now Heather will be able to recover from 
date/time issues due to bogus dates that occur during receiver startup.



> Ah, more complicated math to solve a problem vs. simpler math to avoid a 
> problem in the first place.
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Re: [time-nuts] Setting correct date on Trimble Thunderbolt receiver

[Didier Juges]

Tom,

In my TB monitor kit, I used your Julian date routines, adapted to the 8051
(no variable greater than 32 bits since my compiler does not support them
either) to apply the GPS offset correction.
It was very helpful.

Didier KO4BB

On Wed, Mar 28, 2018, 7:13 AM Tom Van Baak  wrote:

> Hi Mark,
>
> > Heather keeps all times as a double precision Julian date.  Using
> Heather's code can
> > be a problem on Arduinos since their "double" precision numbers are
> actually 32 bit
> > single precision,  so you would need to do some more complicated math.
>
> Ah, more complicated math to solve a problem vs. simpler math to avoid a
> problem in the first place.
>
> Here's a simple "GPS Day Number" example: www.leapsecond.com/tools/gpsdn.c
>
> To add 1024 weeks to a given date use:
>
> gpsdn = date_to_gpsdn(year, month, day);
> gpsdn += 1024 * 7;
> gpsdn_to_ymd(gpsdn, &year, &month, &day);
>
> That's it. It uses 32 bit integers; no floating point required; works on
> any OS, or Arduino.
>
> /tvb
>
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Re: [time-nuts] Setting correct date on Trimble Thunderbolt receiver

[Bob kb8tq]

Hi



> On Mar 28, 2018, at 12:10 AM, Mark Sims  wrote:
> 
> Lady Heather's automatic rollover fixer works by looking at the year in any 
> time message that it sees.  If it sees 10 consecutive year values less than 
> 2016,  it assumes the receiver has rollover issues and then adds 1024 weeks 
> worth of seconds to the Julian date/time calculated from the receiver 
> time/date message until the resulting year is past 2016.
> 
> One problem with this is when a receiver is first powered up... most of them 
> send dates in the 1980s to 1990s until they start tracking satellites.   Once 
> Heather detects a rollover condition, the code does not currently undo it if 
> the receiver starts sending good dates.
> 
> Heather keeps all times as a double precision Julian date.  Using Heather's 
> code can be a problem on Arduinos since their "double" precision numbers are 
> actually 32 bit single precision,  so you would need to do some more 
> complicated math.
> 
> Heather's rollover compensation value is actually in double precision 
> seconds.  You can manually specify a rollover correction to sub-second 
> resolution and tweak the displayed time/date to anything you want...  comes 
> in handy for testing calendar/eclipse/sunrise/sunset/etc code.
> 
> Speaking of rollovers,  the GPS system has a 1024 week rollover next year 
> (April 6th-7th).  A lot of older receivers had code that could handle the 
> first system rollover in 1999,  but might have issues this time.

There are a surprising number of GPS modules that really don’t handle the 
rollover very well. That includes a significant number of designs that came out 
after 1999. 

Bob


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Re: [time-nuts] Vectron OCXO 204-8888

[Andrea Baldoni]

Hello all.

A friend just made me notice that I should read pin numbers clockwise, he has
an older but very similar unit made by "Electronic Research Co." with number
marks. Besides pin numbering, he too hasn't any information.

So, this is the updated pinout:

1 NC
2,3 GND (but there's not any wire connected to 2 and 3 in my case)
4 black wire (8.5k to GND)
5 red wire (7.6k to GND)
6 white wire (47k to GND) (probably EFC in)
7 white/black wire GND

Best regards,
Andrea Baldoni
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Re: [time-nuts] Vectron OCXO 204-8888

[Heinz Breuer]

Hello,

it seems that I have an similar (?) unit here. It says:
ELECTRONIC RESEARCH CO
EROS-800-A1
AMD135-30698
5.00 MHz
S/N 23   Date Code 90-10

Same dimensions but other pinout: 
It has two coax cables attached

Pin 1 NC
Pins 2, 3 and 7 are GND
Pin 4 Coax cable center, no connection
Pin 5 Coax cable center connector with 8.3 kOhms to GND

There is a SMA connector which probably is 5 MHz output

Unfortunately I don't have any data on it. 

I would appreciate any data about it.

Best regards
Heinz Breuer DH2FA, KM5VT 

Von meinem iPhone gesendet

> Am 28.03.2018 um 13:30 schrieb Andrea Baldoni :
> 
> Hello!
> 
> Anyone knows anything about the Vectron Model 204- (P/N A23652)?
> It's a 5MHz OCXO, perhaps DOCXO, with SMA output and a 7 circuit 45 degrees
> 1 cm diameter round connection block with solderable pins, similar in shape to
> the inside of a DIN connector.
> 
> At the moment, proceeding counterclockwise, pin 1 (connected to case GND) has
> a white/black wire, pin 2 has a white wire, pin 3 a red, pin 4 a black, 5, 6, 
> 7
> NC.
> 
> If pinout and voltage are known, it would be nice, prior to start
> a trial and error procedure.
> 
> The unit is a parallelepiped, 51x51mm base, 101mm high, with round corners.
> Connectors are on the base, on the opposite side there is the screw covered 
> hole
> with trimmer.
> 
> On photos of identical units found in Internet, I see:
> sticker CRYST.OSC.ASSY 00500-B43024-1
> sticker CRYS/ISOL ASSY 00500-B43024-1
> wire B50858-1
> 
> Best regards
> Andrea Baldoni
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Re: [time-nuts] Setting correct date on Trimble Thunderbolt receiver

[Tom Van Baak]

Hi Mark,

> Heather keeps all times as a double precision Julian date.  Using Heather's 
> code can
> be a problem on Arduinos since their "double" precision numbers are actually 
> 32 bit
> single precision,  so you would need to do some more complicated math.

Ah, more complicated math to solve a problem vs. simpler math to avoid a 
problem in the first place.

Here's a simple "GPS Day Number" example: www.leapsecond.com/tools/gpsdn.c

To add 1024 weeks to a given date use:

gpsdn = date_to_gpsdn(year, month, day);
gpsdn += 1024 * 7;
gpsdn_to_ymd(gpsdn, &year, &month, &day);

That's it. It uses 32 bit integers; no floating point required; works on any 
OS, or Arduino.

/tvb

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[time-nuts] Vectron OCXO 204-8888

[Andrea Baldoni]

Hello!

Anyone knows anything about the Vectron Model 204- (P/N A23652)?
It's a 5MHz OCXO, perhaps DOCXO, with SMA output and a 7 circuit 45 degrees
1 cm diameter round connection block with solderable pins, similar in shape to
the inside of a DIN connector.

At the moment, proceeding counterclockwise, pin 1 (connected to case GND) has
a white/black wire, pin 2 has a white wire, pin 3 a red, pin 4 a black, 5, 6, 7
NC.

If pinout and voltage are known, it would be nice, prior to start
a trial and error procedure.

The unit is a parallelepiped, 51x51mm base, 101mm high, with round corners.
Connectors are on the base, on the opposite side there is the screw covered hole
with trimmer.

On photos of identical units found in Internet, I see:
sticker CRYST.OSC.ASSY 00500-B43024-1
sticker CRYS/ISOL ASSY 00500-B43024-1
wire B50858-1

Best regards
Andrea Baldoni
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[time-nuts] Setting correct date on Trimble Thunderbolt receiver

[Mark Sims]

Lady Heather's automatic rollover fixer works by looking at the year in any 
time message that it sees.  If it sees 10 consecutive year values less than 
2016,  it assumes the receiver has rollover issues and then adds 1024 weeks 
worth of seconds to the Julian date/time calculated from the receiver time/date 
message until the resulting year is past 2016.

One problem with this is when a receiver is first powered up... most of them 
send dates in the 1980s to 1990s until they start tracking satellites.   Once 
Heather detects a rollover condition, the code does not currently undo it if 
the receiver starts sending good dates.

Heather keeps all times as a double precision Julian date.  Using Heather's 
code can be a problem on Arduinos since their "double" precision numbers are 
actually 32 bit single precision,  so you would need to do some more 
complicated math.

Heather's rollover compensation value is actually in double precision seconds.  
You can manually specify a rollover correction to sub-second resolution and 
tweak the displayed time/date to anything you want...  comes in handy for 
testing calendar/eclipse/sunrise/sunset/etc code.

Speaking of rollovers,  the GPS system has a 1024 week rollover next year 
(April 6th-7th).  A lot of older receivers had code that could handle the first 
system rollover in 1999,  but might have issues this time.
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