Re: [time-nuts] Thunderbolt question

[Charles Steinmetz]

Arthur wrote:


I’d say it would be an MMIC amp similar to this device  [Avago MGA-87563]


If a chip similar to the Avago part Arthur referenced is what is 
installed, which seems plausible, the 0.749v on the RF input (Pin 3) is 
a fault and is caused by an external source of voltage (3.417v) imposed 
on the RF output (Pin 6) through the internal feedback resistor to Pin 
3, attenuated by the gate resistor.


Avago says this particular chip needs to have 0vDC at Pins 3 and 6, so 
if the connected parts would impose any DC voltage on those pins, 
external blocking capacitors must be used on Pins 3 and 6.  You might 
check to see if there are blocking caps (at least at Pin 6), and if they 
are good.  (Alternatively, the internal output capacitor from Pin 6 back 
to the output FET source may be bad.)


Of course, don't expect a bad external cap to be the only other problem 
-- if it is bad, the 6-pin amp may well be bad, as well as whatever is 
connected to the other side of the cap.


Best regards,

Charles


___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Thunderbolt question

[Attila Kinali]

On Sat, 5 Aug 2017 10:47:40 -0400
paul swed  wrote:

> The .5 on the f connector is an issue and thats through the filter on top
> of the board made of traces and 3 caps. From Arthur's digging I would agree
> he found the chip or one that would work. But that chips voltages seem to
> match so most likely not the issue. What does the F connector measure to
> ground? A strike could have burned the internals of the F connector. Above
> the DC filer will be some form of current limiting. Maybe an inductor or
> resistor.

Not necessarily. You need quite a bit of energy to leave visible
burn marks on a connector. It's more likely that the spike at the
input just reached a couple 100V. Too little to damage the connector,
but enough to fry a few components and make them go *pop*.


Attila Kinali

-- 
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering.  -- The Doctor
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Thunderbolt question

[paul swed]

The .5 on the f connector is an issue and thats through the filter on top
of the board made of traces and 3 caps. From Arthur's digging I would agree
he found the chip or one that would work. But that chips voltages seem to
match so most likely not the issue. What does the F connector measure to
ground? A strike could have burned the internals of the F connector. Above
the DC filer will be some form of current limiting. Maybe an inductor or
resistor.

On Sat, Aug 5, 2017 at 12:00 AM, Chris Waldrup  wrote:

> Hi,
>
> I've changed the blown MMBT3904 in the antenna sense circuit and I still
> have no 5V to the antenna. I measure 0.5V DC on the F connector.
> There are two Murata filters (F2 and F3) on the RF path to the antenna. In
> between the two silver colored filters  is a 6 lead SOT package marked 51A.
> The PCB silkscreen says Q13.
>  I have measured the following voltages on this part:
> Pin 1= 0v
> Pin 2= 0v
> Pin 3= 0.749V
> Pin 4= 4.892v
> Pin 5= 0v
> Pin 6= 3.417v
>
> The trace from pin 3 of this part goes to the F2 filter and the output of
> F2 goes to the F connector. I'm getting 0.5V on the output of this filter.
>  I'm suspecting this Q13 part may be bad but I'm not sure what the part is.
> Searching the net for 51A marking came up with a large 2 pin shottky which
> this isn't.
>
> Chris
> KD4PBJ
>
> > On Aug 4, 2017, at 5:27 PM, Chris Waldrup  wrote:
> >
> > Thanks guys.
> > I've opened up my T bolt and noticed a SOT23 packaged part has the top
> blown off.
> > The PPS BNC jack has U19 beside it.
> > The next part is blown. Could someone take a closeup of the five parts
> around U19?
> > The intact parts are marked:
> > 5Dz
> > 1AM
> > and two 2Az parts.
> >
> >
> > Chris
> >
> >> On Aug 4, 2017, at 4:13 PM, Arthur Dent 
> wrote:
> >>
> >> Actually that isn't my photo I linked to but one I just Googled. That is
> >> probably a board revision most people don't have but it was the first
> one
> >> I saw so I used it just to show that the GPS receiver is part of the
> >> only circuit board and not another easily replaceable board like in some
> >> other units.
> >>
> >> I just took a couple of photos of the later revision of the board for
> >> anyone interested in seeing what might be fried. In the photo of the
> >> top of the board the signal comes into a filter then to a 25db amp
> >> marked AM50002 by Macom. Above the filter near the input is where the
> >> decoupled +5VDC for the antenna is connected. If you are only reading
> >> 0.5VDC, if your're lucky it might only be the amp is fried and that
> >> could be an easy fix. If the 5VDC is ok with the amp input pin lifted,
> >> it might be the only problem. I wouldn't bet on it though. The 4031 I
> >> believe is a 1575.42 SAW filter
> >>
> >> The photo of the bottom of the receiver area shows a Sawtek filter and
> >> other parts. At the bottom of the photo is C460, a feedthrough capacitor
> >> and that might be where the receiver output is but where my Tbolts are
> >> working I don't feel the need to look into whether you could connect
> >> the output of a seperate GPS receiver there to make it work.
> >>
> >> I do have one Tbolt that has no oscillator. I brought the EFC and 10Mhz
> >> connections to SMA connectors on the back so I can test other
> oscillators
> >> or GPSDOs that don't have an easy way to monitor of graph the stability
> >> of those units and using Lady Heather gives me a good way to compare the
> >> graphs to ones I'm used to. You might possibly be able to replace the
> >> built-in receiver but it might be easier to buy a working Thunderbolt.
> >>
> >>
> >> http://i906.photobucket.com/albums/ac262/rjb1998/GPS%
> 20top%201_zpslgxunnyw.jpg
> >>
> >> http://i906.photobucket.com/albums/ac262/rjb1998/GPS%
> 20bottom%201_zpschvruppt.jpg
> >> ___
> >> time-nuts mailing list -- time-nuts@febo.com
> >> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> >> and follow the instructions there.
> ___
> time-nuts mailing list -- time-nuts@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

[time-nuts] How a GPS Works

[Bryan _]

Interesting video


https://www.youtube.com/watch?v=6m0xGwkYYy0



-=Bryan=-
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Can Lady Heather set PC time directly from a TrimbleThunderbolt?

[Attila Kinali]

On Sat, 5 Aug 2017 13:01:56 +0200
Martin Burnicki  wrote:

> Chris Albertson wrote:
> > I'm not a fan of Meinberg because of the way they market freely
> > available software.
> 
> I'm sorry you feel this way.
> 
> We at Meinberg have supported the NTP project for many years, by
> donations of money and hardware, testing, submitting bug reports and
> patches. There've been also enhancements like the initial leap second
> handling code in the Windows port of ntpd, workarounds for limitations
> in Windows to increase the possible accuracy under Windows, etc.

I have to second Martin here. Meinberg made ntp on windows a thing.
Before them, it took a lot of effort to get it working (if you ever
got that far). Also, Meinberg is one of the few companies out there
who finance the development of ntp through the network time foundation. 

I also do not see how Meinberg "markets" ntp. If putting it on their
webpage, free of charge with lots of explanation what it is, where
it comes from and how to use it properly is marketing, then yes.
But then time-nuts is marketing Microsemi 5071s and Trimble Thunderbolts.


Attila Kinali
-- 
You know, the very powerful and the very stupid have one thing in common.
They don't alters their views to fit the facts, they alter the facts to
fit the views, which can be uncomfortable if you happen to be one of the
facts that needs altering.  -- The Doctor
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Can I haz an anti-hydrogen maser now?

[Poul-Henning Kamp]

In message <20170805130056.58880...@aluminium.mobile.teply.info>, Florian Teply
 writes:

>The obvious trick would be to choose their distance such that
>only their noise cancels...

But the good news is that if you mix their output, you would have
the worlds most precise DC signal :-)


-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

[time-nuts] Thunderbolt question

[Arthur Dent]

Pin 1= 0v
Pin 2= 0v
Pin 3= 0.749V
Pin 4= 4.892v
Pin 5= 0v
Pin 6= 3.417v

I’d say it would be an MMIC amp similar to this device. It

has the same pin-out so it is a possibility. The Amp In

my newer version is an 23 db gain device but 8-pin so I

Suspect your version may have similar specs. Here is a

Datasheet on the MGA-87563 6-pin device.



http://www.efo.ru/components/avago/catalog/files/pdf/AV01_0200EN.PDF
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Can I haz an anti-hydrogen maser now?

[Florian Teply]

The obvious trick would be to choose their distance such that
only their noise cancels...

SCNR,
Florian

Am Sat, 5 Aug 2017 01:09:00 +0100
schrieb Adrian Godwin :

> Don't put it anywhere near your hydrogen maser or they'll cancel each
> other out.
> 
> 
> On Sat, Aug 5, 2017 at 12:55 AM, Christopher Hoover
>  wrote:
> 
> > http://www.swansea.ac.uk/media-centre/latest-research/
> > firstobservationofthehyperfinesplittinginantihydrogen.php

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Can Lady Heather set PC time directly from a TrimbleThunderbolt?

[Martin Burnicki]

Chris,

Chris Albertson wrote:
> I'm not a fan of Meinberg because of the way they market freely
> available software.

I'm sorry you feel this way.

We at Meinberg have supported the NTP project for many years, by
donations of money and hardware, testing, submitting bug reports and
patches. There've been also enhancements like the initial leap second
handling code in the Windows port of ntpd, workarounds for limitations
in Windows to increase the possible accuracy under Windows, etc.

Quite some years ago there was no easy way to install ntpd under
Windows, so one of my colleagues had the idea to put a GUI setup program
together which makes installation under Windows as simple as possible
even for inexperienced users.

When we started this, we also discussed with the other NTP developers
and agreed that we would and should provide the installer via the
Meinberg download page, where we clearly say that the setup program
provides a precompiled version built from the public source code that is
available at ntp.org.

The installer is also free of charge, and there are no duties implied by
using it.

So once more, I feel sorry that you have such a bad feeling about this,
which has just been introduced to make NTP more popular even for users
who are not time nuts.

If you know how to do it you can still build your own binaries from the
original source code.

Martin

(who is biased since working at Meinberg)

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.