[time-nuts] Z3815A

Wed May 29 15:40:08 EDT 2013

This is an excerpt of my Z3815A's efc_rep:
efc_rep
5537.347168 680715.5 3 6.795356e+05 2.123928e-01 0.000000e+00
5538.347168 680711.3 3 6.796912e+05 1.842245e-01 0.000000e+00
...
5535.347168 680712.7 3 6.792462e+05 2.646178e-01 0.000000e+00
5536.347168 680720.1 3 6.793305e+05 2.494512e-01 0.000000e+00
p4th D >


On Wed, May 29, 2013 at 7:04 PM, Bob Camp <lists at rtty.us> wrote:
> Hi
>
> I suspect that until the beast starts playing nice, you won't get a holdover
> prediction. I believe my 3815 took a couple of days to come up with a
> number. My *guess* would be that it does not even bother to try if the OCXO
> is moving faster than some limit.
>
> Bob
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Mark C. Stephens
> Sent: Wednesday, May 29, 2013 12:02 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Z3815A
>
> Hmm, Something is awry with this particular Z3815A:
> e.g.
> p4th D > efc_rep
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
> 0.000000 0.0 0 0.000000e+00 0.000000e+00 0.000000e+00
>
> If I could figure out how to populate it...
> efc_comp looks like a likely candidate but, to quote TVB, "I got a little
> nervous about playing pforth roulette" ...
>
>
> -marki
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Azelio Boriani
> Sent: Thursday, 30 May 2013 12:00 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Z3815A
>
> Here the figures are the same, except: start ptr is 24 and stop ptr is
> 23 and last efc average is 680694.8 and not 0.0
>
> On Wed, May 29, 2013 at 3:53 PM, Azelio Boriani <azelio.boriani at screen.it>
> wrote:
>> I haven't tracked the Z3815A startup so can't tell when the
>> uncertainty was available. Looking at the log (diag:log:read:all?) I
>> can tell that after the power on you should have a GPS reference valid
>> (~12 minutes later) then a GPS lock started and an ACT from unlock (~1
>> second later). Two hours later you should have a position hold mode
>> started and I think that the uncertainty must be available at that
>> point. It will look high but should be available.
>>
>> On Wed, May 29, 2013 at 3:33 PM, Mark C. Stephens <marks at non-stop.com.au>
> wrote:
>>> Thanks Azelio, That's what I wanted to hear, it does display predicted
> holdover uncertainty.
>>> It still hasn't come up on mine and it's been of for more than 48
>>> hours (uh-oh, everyone says) Without resetting it, can you, from memory,
> remember when the PHU was displayed?
>>> Like right after GPS lock (as per other smart clocks) or some time later?
>>>
>>>
>>> -marki
>>>
>>>
>>> -----Original Message-----
>>> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]
>>> On Behalf Of Azelio Boriani
>>> Sent: Wednesday, 29 May 2013 11:09 PM
>>> To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] Z3815A
>>>
>>> The Z3815A here has (right now) 3.4us/24h of holdover uncertainty and
> -7.0ns PPS relative to GPS. The health monitor and the self test show OK
> everywhere. It is ON since 12, 2011.
>>>
>>> On Wed, May 29, 2013 at 1:03 PM, Bob Camp <lists at rtty.us> wrote:
>>>> Hi
>>>>
>>>> Well, probably as good as the manual ... we have the guy who designed it
> (Rick Karlquist) lurking around here somewhere. I don't think I've ever seen
> a manual.
>>>>
>>>> How long have you had the 3815? If not so long, I'd contact the seller.
> You have indeed convinced me to quickly fire up the next one I have coming
> in.
>>>>
>>>> Bob
>>>>
>>>>
>>>> On May 29, 2013, at 2:14 AM, Mark C. Stephens <marks at non-stop.com.au>
> wrote:
>>>>
>>>>> Wow the 2 black heatsinks on the puck are really hot - too hot to
> touch.
>>>>> I don't think that would be normal deign.
>>>>> They are probably the excessive current sink culprits.
>>>>> Anyone got a manual for the e1398a OCXO?
>>>>>
>>>>>
>>>>> -marki
>>>>>
>>>>> -----Original Message-----
>>>>> From: time-nuts-bounces at febo.com
>>>>> [mailto:time-nuts-bounces at febo.com]
>>>>> On Behalf Of Mark C. Stephens
>>>>> Sent: Wednesday, 29 May 2013 12:36 PM
>>>>> To: Discussion of precise time and frequency measurement
>>>>> Subject: Re: [time-nuts] Z3815A
>>>>>
>>>>> I believe these were all rescued from the Tip (Dump, Trash) judging by
> the water damage and bent cases.
>>>>>
>>>>> Mine had been tested in Japan and had approximate co-ordinates in it:
>>>>> https://www.google.com/search?q=34+44'+N+135+21'+E&oq=34+44'+N+135+
>>>>> 21
>>>>> '+E
>>>>>
>>>>> Initially I had a OCXO communication error which I fixed by a
>>>>> :syst:pres (shrug, I thought it was pretty major at the time, I can
>>>>> tell you!)
>>>>>
>>>>> At the moment it's in an air scrubbed and temperature controlled room,
> naked, without its case.
>>>>> Both heatsinks are just slightly warm to the touch.
>>>>> However the Puck is fairly warm..
>>>>>
>>>>> I still have "Holdover Uncertainty Predict: --" which is a bit of a
> worry.
>>>>>
>>>>> Also the 1PPS TI is always about -100ns relative to GPS, which is way
> out there..
>>>>>
>>>>>
>>>>> -marki
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> -----Original Message-----
>>>>> From: time-nuts-bounces at febo.com
>>>>> [mailto:time-nuts-bounces at febo.com]
>>>>> On Behalf Of Stewart Cobb
>>>>> Sent: Wednesday, 29 May 2013 8:13 AM
>>>>> To: time-nuts at febo.com
>>>>> Subject: Re: [time-nuts] Z3815A
>>>>>
>>>>> Your Z3815A may need more cooling than it's getting, especially if
>>>>> you have it resting "horizontally" as it looks like it should.  I
>>>>> bought one of those "kits from China" about a year and a half ago.
>>>>> Powered it up, waited for it to lock ... and it was dead within a
>>>>> week, with the unmistakable smell of overheated electronics.  One
>>>>> of the Vicor power bricks inside
>>>>> (probably) overheated and shorted out.  Here's what I learned:
>>>>>
>>>>> The Z3815A board was designed to go into a VXI-like mainframe, with a
> carefully specified amount of cooling airflow.  I think that particular
> board was designed to require that airflow, and overheats without it.
>>>>> There's a group in Australia which has experience with these boxes, and
> I got the impression from my contacts with them that they see the Vicor
> bricks fail pretty regularly.  That would imply that they're not getting the
> cooling they need, because Vicor bricks in other applications are pretty
> reliable in my experience.
>>>>>
>>>>> You can see a photo of the original Z3815A on TVB's website here:
>>>>>
>>>>> <http://www.leapsecond.com/museum/z3815a/>
>>>>>
>>>>> The Z3815A I got from China was in a different case, just two bent
> pieces of sheet aluminum.  The case _looks_ official, with the right label
> on the front and silkscreen on the back.  But the board inside had a lot
> more crud and corrosion than the nice clean case did, and parts of the
> plastic edge connector on the back of the board were broken.  Worst of all,
> the coaxial cable from the antenna connector ended in a one-inch flying lead
> soldered to the board.  The "shield" of the coax cable ended in another
> flying lead, soldered to ground somewhere else.  (Any RF engineers reading
> this are probably cringing now.)  I'm pretty sure that no one at HP designed
> or approved that connection.  Once I saw it, I understood why the GPS
> receiver appeared to be "deaf."  Even connected to a very good antenna, it
> never saw more than 4 satellites, and even those had weak signals.
>>>>>
>>>>> Did someone in China find a cache of bare Z3815 boards in a scrapyard
> somewhere, and fab an official-looking case to match?  I don't know, but it
> might be the way to bet.  Meanwhile, take the lid off your Z3815A and feel
> the heatsinks on the power bricks.  If they're too hot to touch, they're too
> hot; give them some air.
>>>>>
>>>>> Cheers!
>>>>> --Stu
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
>>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>>> and follow the instructions there.
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
>>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>>> and follow the instructions there.
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
>>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>>> and follow the instructions there.
>>>>
>>>> _______________________________________________
>>>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
>>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>>> and follow the instructions there.
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>>
>>>
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.