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Discussion of precise time and frequency measurement

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Brooks Shera's GPS standard or HP Z3801A??

DD
Dr. David Kirkby
Mon, Apr 25, 2005 9:35 AM

I was going to build the GPS reference by Brooks Shera

http://www.rt66.com/~shera/index_fs.htm

and have bought the PCB and started populating it (not much yet).

But now I am wondering if buying a used Z3801A might not be a better idea.

My thoughts are:

  1. Cost - the Z3801A will probably cost less than buying all the parts
    for Brook's Standard. This is especially so, with me in the UK, where
    shipping charges on lots of small items from the USA soon add up.

  2. Medium term stability - the double oven in the Z3801A might be more
    stable than an HP 18011A.

  3. Flexability - Brook's standard can be customised to whatever you want.

  4. Long term servicability - if one builds the standard oneself, one is
    far more likely to be able to debug it if things go wrong. One can buy a
    few of the chips, for spares, just in case one dies and becomes hard to
    get. The chips on the board are not that expensive.

  5. Jitter on GPS.

  6. If one needs to buy a manual on the Z3801A, that will add to its cost.

Any other thoughts ????

--
Dr. David Kirkby PhD CEng MIEE,
Senior Research Fellow,
Department of Medical Physics,
Mallet Place Engineering Building,
Gower St,
University College London,
London WC1E 6BT.

I was going to build the GPS reference by Brooks Shera http://www.rt66.com/~shera/index_fs.htm and have bought the PCB and started populating it (not much yet). But now I am wondering if buying a used Z3801A might not be a better idea. My thoughts are: 1) Cost - the Z3801A will probably cost less than buying all the parts for Brook's Standard. This is especially so, with me in the UK, where shipping charges on lots of small items from the USA soon add up. 2) Medium term stability - the double oven in the Z3801A might be more stable than an HP 18011A. 3) Flexability - Brook's standard can be customised to whatever you want. 4) Long term servicability - if one builds the standard oneself, one is far more likely to be able to debug it if things go wrong. One can buy a few of the chips, for spares, just in case one dies and becomes hard to get. The chips on the board are not that expensive. 5) Jitter on GPS. 6) If one needs to buy a manual on the Z3801A, that will add to its cost. Any other thoughts ???? -- Dr. David Kirkby PhD CEng MIEE, Senior Research Fellow, Department of Medical Physics, Mallet Place Engineering Building, Gower St, University College London, London WC1E 6BT.
MS
Mike Seguin
Mon, Apr 25, 2005 11:40 AM

----- Original Message -----
From: "Dr. David Kirkby" drkirkby@medphys.ucl.ac.uk
Subject: [time-nuts] Brooks Shera's GPS standard or HP Z3801A??

  1. If one needs to buy a manual on the Z3801A, that will add to its cost.

When I bought mine from BuyLegacy 3 years ago it came with a printed
manual... I have since found it as a pdf. I can send the pdf if you like.
It's 1MB.

73,
Mike, N1JEZ
"A closed mouth gathers no feet"

----- Original Message ----- From: "Dr. David Kirkby" <drkirkby@medphys.ucl.ac.uk> Subject: [time-nuts] Brooks Shera's GPS standard or HP Z3801A?? > 6) If one needs to buy a manual on the Z3801A, that will add to its cost. When I bought mine from BuyLegacy 3 years ago it came with a printed manual... I have since found it as a pdf. I can send the pdf if you like. It's 1MB. 73, Mike, N1JEZ "A closed mouth gathers no feet"
DD
Dr. David Kirkby
Mon, Apr 25, 2005 1:43 PM

Mike Seguin wrote:

----- Original Message -----
From: "Dr. David Kirkby" drkirkby@medphys.ucl.ac.uk
Subject: [time-nuts] Brooks Shera's GPS standard or HP Z3801A??

  1. If one needs to buy a manual on the Z3801A, that will add to its cost.

When I bought mine from BuyLegacy 3 years ago it came with a printed
manual... I have since found it as a pdf. I can send the pdf if you like.
It's 1MB.

Yes, if you could send the PDF, I would appreciate it. Should it be on a
web, and you recall where you got it from, I might as well download it
directly.

Please email to the original address I sent this from, NOT the list, as
I belive there's a limit of 128k on attachments, and few are going to
want it anyway.

--
Dr. David Kirkby PhD CEng MIEE,
Senior Research Fellow,
Department of Medical Physics,
Mallet Place Engineering Building,
Gower St,
University College London,
London WC1E 6BT.

Mike Seguin wrote: > ----- Original Message ----- > From: "Dr. David Kirkby" <drkirkby@medphys.ucl.ac.uk> > Subject: [time-nuts] Brooks Shera's GPS standard or HP Z3801A?? > > > >>6) If one needs to buy a manual on the Z3801A, that will add to its cost. > > > When I bought mine from BuyLegacy 3 years ago it came with a printed > manual... I have since found it as a pdf. I can send the pdf if you like. > It's 1MB. Yes, if you could send the PDF, I would appreciate it. Should it be on a web, and you recall where you got it from, I might as well download it directly. Please email to the original address I sent this from, NOT the list, as I belive there's a limit of 128k on attachments, and few are going to want it anyway. -- Dr. David Kirkby PhD CEng MIEE, Senior Research Fellow, Department of Medical Physics, Mallet Place Engineering Building, Gower St, University College London, London WC1E 6BT.
CH
Chuck Harris
Mon, Apr 25, 2005 3:09 PM

Just thought I would post a note on what is happening
with websites hosting HP/Agilent manuals.  It seems that
Agilent has decided to rein in on websites that are hosting
copies of HP/Agilent manuals.  They have sent "take-down" notices
to BAMA, and ebay, amoung others.  They seem to be most interested
in the sites that host low quality copies, or are profiting off of
CDs of copies.

There is some skuttlebutt that Agilent is going to put all of the
older manuals up as pdf's on their website...Let's hope that is
true.

But to those who are hosting HP/Agilent manuals, and copies of HP/
Agilent materials, they may be intouch.

-Chuck

Dr. David Kirkby wrote:

Mike Seguin wrote:

----- Original Message ----- From: "Dr. David Kirkby"
drkirkby@medphys.ucl.ac.uk
Subject: [time-nuts] Brooks Shera's GPS standard or HP Z3801A??

  1. If one needs to buy a manual on the Z3801A, that will add to its
    cost.

When I bought mine from BuyLegacy 3 years ago it came with a printed
manual... I have since found it as a pdf. I can send the pdf if you like.
It's 1MB.

Just thought I would post a note on what is happening with websites hosting HP/Agilent manuals. It seems that Agilent has decided to rein in on websites that are hosting copies of HP/Agilent manuals. They have sent "take-down" notices to BAMA, and ebay, amoung others. They seem to be most interested in the sites that host low quality copies, or are profiting off of CDs of copies. There is some skuttlebutt that Agilent is going to put all of the older manuals up as pdf's on their website...Let's hope that is true. But to those who are hosting HP/Agilent manuals, and copies of HP/ Agilent materials, they may be intouch. -Chuck Dr. David Kirkby wrote: > Mike Seguin wrote: > >> ----- Original Message ----- From: "Dr. David Kirkby" >> <drkirkby@medphys.ucl.ac.uk> >> Subject: [time-nuts] Brooks Shera's GPS standard or HP Z3801A?? >> >> >> >>> 6) If one needs to buy a manual on the Z3801A, that will add to its >>> cost. >> >> >> >> When I bought mine from BuyLegacy 3 years ago it came with a printed >> manual... I have since found it as a pdf. I can send the pdf if you like. >> It's 1MB. > >
DD
Dr. David Kirkby
Mon, Apr 25, 2005 3:18 PM

Chuck Harris wrote:

Just thought I would post a note on what is happening
with websites hosting HP/Agilent manuals.

I have received a definative statement from Agilent on this. I will NOT
post full details at this time, until I have received confirmation of
permission from Agilent.

But basically.

  1. I asked for permission to distribute manuals for free on the web.

  2. Was denied that, but they will grant me permission to distribute them
    for obsolete products by paper or CD  - even if I charge.

  3. I need to sign a document, return it to Agilent, and they will send
    me permission by a PDF file. I don't have to pay them anything.

  4. I have signed the document, returned it to Agilent by airmail, and
    will await their confirmation.

Sorry I am not willing to go into further details just as this minute.
But when I have received confirmation, I will post further details.

--
Dr. David Kirkby PhD CEng MIEE,
Senior Research Fellow,
Department of Medical Physics,
Mallet Place Engineering Building,
Gower St,
University College London,
London WC1E 6BT.

Chuck Harris wrote: > Just thought I would post a note on what is happening > with websites hosting HP/Agilent manuals. I have received a definative statement from Agilent on this. I will NOT post full details at this time, until I have received confirmation of permission from Agilent. But basically. 1) I asked for permission to distribute manuals for free on the web. 2) Was denied that, but they will grant me permission to distribute them for obsolete products by paper or CD - even if I charge. 3) I need to sign a document, return it to Agilent, and they will send me permission by a PDF file. I don't have to pay them anything. 4) I have signed the document, returned it to Agilent by airmail, and will await their confirmation. Sorry I am not willing to go into further details just as this minute. But when I have received confirmation, I will post further details. -- Dr. David Kirkby PhD CEng MIEE, Senior Research Fellow, Department of Medical Physics, Mallet Place Engineering Building, Gower St, University College London, London WC1E 6BT.
BH
Bill Hawkins
Mon, Apr 25, 2005 4:59 PM

Friends,

What cost-conscious modern organization is going to devote
resources to scanning obsolete manuals?

My devious mind thinks it is a way to dry up the competition
that Agilent has with recycled HP equipment. The more complicated
stuff, with microprocessor or logic gate arrays, is useless
without a manual. A 200CD oscillator is transparent to anyone
familiar with vacuum tubes.

And yet, we have a letter saying Manuals Plus can sell HP manuals.
Perhaps they have an arrangement that returns money to Agilent.
That would sound fair to an IP lawyer.

Bill Hawkins

-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com]On
Behalf Of Chuck Harris
Sent: Monday, April 25, 2005 10:10 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] HP/Agilent and manuals...

Just thought I would post a note on what is happening
with websites hosting HP/Agilent manuals.  It seems that
Agilent has decided to rein in on websites that are hosting
copies of HP/Agilent manuals.  They have sent "take-down" notices
to BAMA, and ebay, amoung others.  They seem to be most interested
in the sites that host low quality copies, or are profiting off of
CDs of copies.

There is some skuttlebutt that Agilent is going to put all of the
older manuals up as pdf's on their website...Let's hope that is
true.

But to those who are hosting HP/Agilent manuals, and copies of HP/
Agilent materials, they may be intouch.

-Chuck

Dr. David Kirkby wrote:

Mike Seguin wrote:

----- Original Message ----- From: "Dr. David Kirkby"
drkirkby@medphys.ucl.ac.uk
Subject: [time-nuts] Brooks Shera's GPS standard or HP Z3801A??

  1. If one needs to buy a manual on the Z3801A, that will add to its
    cost.

When I bought mine from BuyLegacy 3 years ago it came with a printed
manual... I have since found it as a pdf. I can send the pdf if you like.
It's 1MB.

Friends, What cost-conscious modern organization is going to devote resources to scanning obsolete manuals? My devious mind thinks it is a way to dry up the competition that Agilent has with recycled HP equipment. The more complicated stuff, with microprocessor or logic gate arrays, is useless without a manual. A 200CD oscillator is transparent to anyone familiar with vacuum tubes. And yet, we have a letter saying Manuals Plus can sell HP manuals. Perhaps they have an arrangement that returns money to Agilent. That would sound fair to an IP lawyer. Bill Hawkins -----Original Message----- From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com]On Behalf Of Chuck Harris Sent: Monday, April 25, 2005 10:10 AM To: Discussion of precise time and frequency measurement Subject: [time-nuts] HP/Agilent and manuals... Just thought I would post a note on what is happening with websites hosting HP/Agilent manuals. It seems that Agilent has decided to rein in on websites that are hosting copies of HP/Agilent manuals. They have sent "take-down" notices to BAMA, and ebay, amoung others. They seem to be most interested in the sites that host low quality copies, or are profiting off of CDs of copies. There is some skuttlebutt that Agilent is going to put all of the older manuals up as pdf's on their website...Let's hope that is true. But to those who are hosting HP/Agilent manuals, and copies of HP/ Agilent materials, they may be intouch. -Chuck Dr. David Kirkby wrote: > Mike Seguin wrote: > >> ----- Original Message ----- From: "Dr. David Kirkby" >> <drkirkby@medphys.ucl.ac.uk> >> Subject: [time-nuts] Brooks Shera's GPS standard or HP Z3801A?? >> >> >> >>> 6) If one needs to buy a manual on the Z3801A, that will add to its >>> cost. >> >> >> >> When I bought mine from BuyLegacy 3 years ago it came with a printed >> manual... I have since found it as a pdf. I can send the pdf if you like. >> It's 1MB. > > _______________________________________________ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
TV
Tom Van Baak
Mon, Apr 25, 2005 5:08 PM

This issue comes up a lot. If weren't for the glut of
surplus Z3801A I'm sure the situation would be very
different. Brooks Shera did a fine job with his project
and reached a wide audience with its QST publication.

If your goal is a turn-key 10 MHz frequency standard
with short-term stability under 1e-11 then a Z3801A
is a good solution.

If your goal is to build something yourself, to use parts
you have already, to learn as you go, and achieve
similar performance then use the Brooks Shera design.

The performace of either one is limited by the quality
of the particular oscillator inside which is why there is
always a drvie to find the best one.

The issue of GPS jitter is also related to the resolution
of the embedded TI counter you are using. There's little
point trying to lower the GPS receiver jitter, for example,
if your TI counter is the limiting factor.

If you're a time-nut you'll end up with both anyway so
that you can compare them; the only question is which
to get first. ;-)

/tvb

----- Original Message -----
From: "Dr. David Kirkby" drkirkby@medphys.ucl.ac.uk
To: "Discussion of precise time and frequency measurement"
time-nuts@febo.com
Sent: Monday, April 25, 2005 02:35
Subject: [time-nuts] Brooks Shera's GPS standard or HP Z3801A??

I was going to build the GPS reference by Brooks Shera

http://www.rt66.com/~shera/index_fs.htm

and have bought the PCB and started populating it (not much yet).

But now I am wondering if buying a used Z3801A might not be a better idea.

My thoughts are:

  1. Cost - the Z3801A will probably cost less than buying all the parts
    for Brook's Standard. This is especially so, with me in the UK, where
    shipping charges on lots of small items from the USA soon add up.

  2. Medium term stability - the double oven in the Z3801A might be more
    stable than an HP 18011A.

  3. Flexability - Brook's standard can be customised to whatever you want.

  4. Long term servicability - if one builds the standard oneself, one is
    far more likely to be able to debug it if things go wrong. One can buy a
    few of the chips, for spares, just in case one dies and becomes hard to
    get. The chips on the board are not that expensive.

  5. Jitter on GPS.

  6. If one needs to buy a manual on the Z3801A, that will add to its cost.

Any other thoughts ????

--
Dr. David Kirkby PhD CEng MIEE,
Senior Research Fellow,
Department of Medical Physics,
Mallet Place Engineering Building,
Gower St,
University College London,
London WC1E 6BT.

time-nuts mailing list
time-nuts@febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts

This issue comes up a lot. If weren't for the glut of surplus Z3801A I'm sure the situation would be very different. Brooks Shera did a fine job with his project and reached a wide audience with its QST publication. If your goal is a turn-key 10 MHz frequency standard with short-term stability under 1e-11 then a Z3801A is a good solution. If your goal is to build something yourself, to use parts you have already, to learn as you go, and achieve similar performance then use the Brooks Shera design. The performace of either one is limited by the quality of the particular oscillator inside which is why there is always a drvie to find the best one. The issue of GPS jitter is also related to the resolution of the embedded TI counter you are using. There's little point trying to lower the GPS receiver jitter, for example, if your TI counter is the limiting factor. If you're a time-nut you'll end up with both anyway so that you can compare them; the only question is which to get first. ;-) /tvb ----- Original Message ----- From: "Dr. David Kirkby" <drkirkby@medphys.ucl.ac.uk> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Monday, April 25, 2005 02:35 Subject: [time-nuts] Brooks Shera's GPS standard or HP Z3801A?? > I was going to build the GPS reference by Brooks Shera > > http://www.rt66.com/~shera/index_fs.htm > > and have bought the PCB and started populating it (not much yet). > > But now I am wondering if buying a used Z3801A might not be a better idea. > > My thoughts are: > > 1) Cost - the Z3801A will probably cost less than buying all the parts > for Brook's Standard. This is especially so, with me in the UK, where > shipping charges on lots of small items from the USA soon add up. > > 2) Medium term stability - the double oven in the Z3801A might be more > stable than an HP 18011A. > > 3) Flexability - Brook's standard can be customised to whatever you want. > > 4) Long term servicability - if one builds the standard oneself, one is > far more likely to be able to debug it if things go wrong. One can buy a > few of the chips, for spares, just in case one dies and becomes hard to > get. The chips on the board are not that expensive. > > 5) Jitter on GPS. > > 6) If one needs to buy a manual on the Z3801A, that will add to its cost. > > Any other thoughts ???? > > -- > Dr. David Kirkby PhD CEng MIEE, > Senior Research Fellow, > Department of Medical Physics, > Mallet Place Engineering Building, > Gower St, > University College London, > London WC1E 6BT. > > > _______________________________________________ > time-nuts mailing list > time-nuts@febo.com > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > >
PK
Poul-Henning Kamp
Mon, Apr 25, 2005 5:11 PM

In message 062101c549b9$68de3e60$aa15f204@computer, "Tom Van Baak" writes:

This issue comes up a lot. If weren't for the glut of
surplus Z3801A I'm sure the situation would be very
different. Brooks Shera did a fine job with his project
and reached a wide audience with its QST publication.

If your goal is a turn-key 10 MHz frequency standard
with short-term stability under 1e-11 then a Z3801A
is a good solution.

Don't forget that a PRS10 Rb from eBay and a Oncore M12+T from
synergy-gps.com would be both cheaper and more stable.

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@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.

In message <062101c549b9$68de3e60$aa15f204@computer>, "Tom Van Baak" writes: >This issue comes up a lot. If weren't for the glut of >surplus Z3801A I'm sure the situation would be very >different. Brooks Shera did a fine job with his project >and reached a wide audience with its QST publication. > >If your goal is a turn-key 10 MHz frequency standard >with short-term stability under 1e-11 then a Z3801A >is a good solution. Don't forget that a PRS10 Rb from eBay and a Oncore M12+T from synergy-gps.com would be both cheaper and more stable. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@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.
TV
Tom Van Baak
Mon, Apr 25, 2005 7:10 PM

Don't forget that a PRS10 Rb from eBay and a Oncore M12+T from
synergy-gps.com would be both cheaper and more stable.

Good point. Has someone posted a Z3801A vs.
PRS10/M12+ comparison? I have a lot of data
on the PRS10 but haven't put an M12+ to it yet.

/tvb

> Don't forget that a PRS10 Rb from eBay and a Oncore M12+T from > synergy-gps.com would be both cheaper and more stable. Good point. Has someone posted a Z3801A vs. PRS10/M12+ comparison? I have a lot of data on the PRS10 but haven't put an M12+ to it yet. /tvb
PK
Poul-Henning Kamp
Mon, Apr 25, 2005 7:47 PM

In message 000801c549ca$7c106d80$b20ff204@computer, "Tom Van Baak" writes:

Don't forget that a PRS10 Rb from eBay and a Oncore M12+T from
synergy-gps.com would be both cheaper and more stable.

Good point. Has someone posted a Z3801A vs.
PRS10/M12+ comparison? I have a lot of data
on the PRS10 but haven't put an M12+ to it yet.

I should add that with an UT+ the sawtooth has a tendency to
throw the PRS10s PLL off kilter, even with the 256 second
averager (because the sawtooth does not necessairly average
out to zero in that timeinterval).

Even then, the PRS10+M12+T is by far the best bang for the
buck I can think off.

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@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.

In message <000801c549ca$7c106d80$b20ff204@computer>, "Tom Van Baak" writes: >> Don't forget that a PRS10 Rb from eBay and a Oncore M12+T from >> synergy-gps.com would be both cheaper and more stable. > >Good point. Has someone posted a Z3801A vs. >PRS10/M12+ comparison? I have a lot of data >on the PRS10 but haven't put an M12+ to it yet. I should add that with an UT+ the sawtooth has a tendency to throw the PRS10s PLL off kilter, even with the 256 second averager (because the sawtooth does not necessairly average out to zero in that timeinterval). Even then, the PRS10+M12+T is by far the best bang for the buck I can think off. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@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.
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