Re: [time-nuts] HP E1938

[Richard Solomon]

Mention of the E1938 reminded me that I have a schematic that

measures 36" X 72" (yes, 3 feet by 6 feet) !! Talk about readability.


Also, somewhere, I still have one of them. I'll need to go find it and

try firing it up.


Now you got me going again ...


73, Dick, W1KSZ


Sent from Outlook

From: time-nuts  on behalf of Larry McDavid 

Sent: Saturday, April 15, 2017 10:42:40 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] HP E1938

Ok, so a standard DB 25-pin socket-contact connector will mate with the
on-board connector with the center hole and missing pins. That's good!

I now notice a comment on your webpages about this device in which you
mention a schematic. Do you have a schematic of this board? If so, can
you point to it or send me a copy.

I was unaware of the complete packaged unit on eBay; thanks for that.

Another poster mentioned the wiring of the connector on the full
instrument version power connector; is that pin-out and spec available?

Larry


On 4/15/2017 5:05 AM, Tom Van Baak wrote:
>> I purchased one of these HP E1938 OCXO recently on eBay but have not yet
>> received it.
>>
>> Is that special D-Submin connector a receptacle-shell, pin contact
>> version? Will a standard plug-shell, socket contact 25-pin D-Submin fit it?
>
> Hi,
>
> I'll cc the group here since we may get some useful comments.
>
> I'm not exactly sure what you mean. The E1938A oscillators that I've seen and 
> tested look like this:
>
> http://www.leapsecond.com/museum/e1938a/
>
> And those can be interfaced with a simple D-sub DB25 connector on the PCB. 
> For connections, see that page, or any number of postings about the E1938 in 
> the time-nuts archives.
>
> Note that on eBay there are at least three variations of E1938A oscillator. 
> The item#'s below are just random search picks (I have no affiliation with 
> any buyers or sellers) and I also know not all surplus refurbished surplus 
> recycled surplus stuff works. But we do this because when they did work, they 
> are sometimes totally amazing.
>
> 1) There's the bare "puck" alone, as in http://www.ebay.com/itm/290829077542 
> -- and I have no idea where one would start with that item since all the 
> support circuitry on the PCB would have to be re-created by hand.
>
> 2) There's the integrated PCB assembly, as in 
> http://www.ebay.com/itm/181043193416 -- which is more like what I tested.
>
> 3) There's the full instrument version, as in 
> http://www.ebay.com/itm/171293069062 -- which is most likely to work, or be 
> less hacked up, or dented, or salvaged, or rusted. It even has all the 
> connectors and power supplies, and GPS, etc.
>
> If any other time nuts have experience with each of these methods to obtain a 
> E1938 oscillator, please let us know.


--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)
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Re: [time-nuts] uncertainty calculations

[Hal Murray]

t...@radio.sent.com said:
> * You might have any possible phase relationship between the two
>   signals. If they are exactly related by a 10^7 ratio, it's possible
>   for the 1 PPS edges to exactly coincide with the 10 MHz edges.
>   Depending on the type of gating circuit, you will have jitter and
>   possibly metastability resolving whether which edge occured first. ...

> * To stay away from such problems, most precision counters add a small
>   amount of controlled jitter (phase modulation) to the clock.  ...

My experience with metastability is that it's really hard to make it happen.

Are the clock and data in a good lab setup really stable enough to make 
metastability a problem?

How much does the added jitter screw up measurements where it isn't needed?


-- 
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Re: [time-nuts] HP-59309A Clock counts only seconds

[Jeremy Nichols]

Update: The 4011s arrived in good condition. The sockets arrived today 
(I ordered a whole bunch with various numbers of machined pins as Tom 
Miller recommended). All the sockets were of the "good" kind except for 
the 14-pin sockets, which were the cheap kind in accord with Murphy's 
Law. :-(


Pause while I get the right kind of 14-pin socket.

Jeremy

On 4/4/2017 11:52 AM, Jeremy Nichols wrote:
Thanks, everyone, for your inputs. I've ordered some NOS 4011s (made 
by National Semi, mildly ironic since I used to work there) and some 
supposedly round pin sockets (the reviews were mixed—some folks got 
good stuff, some got junk).


I'll update the thread once I have everything here and installed.

Jeremy


On Mon, Apr 3, 2017 at 11:01 PM Tom Miller > wrote:


Also, you might install a high quality machined pin socket. Save the
non-replaceable PC board.

- Original Message -
From: "David C. Partridge" >
To: "'Discussion of precise time and frequency measurement'"
>
Sent: Monday, April 03, 2017 9:33 PM
Subject: Re: [time-nuts] HP-59309A Clock counts only seconds


> You can get a brand new CD4011BE from pretty much most suppliers
at about
> 15 cents that won't exhibit the problems of the earlier ones.
>
> Dave
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com
] On Behalf Of Jeremy
> Nichols
> Sent: 04 April 2017 00:44
> To: time-nuts@febo.com 
> Subject: [time-nuts] HP-59309A Clock counts only seconds
>
> I have a new-to-me HP-59309A HP-IB Digital Clock. The clock
works on both
> the internal crystal oscillator and on an external 10 MHz standard
> (GPSDO). However, it counts only to 60 seconds and then repeats
without
> updating the minutes digit. The TIME SET (FAST and SLOW)
push-buttons work
> but again, the count will not update minutes and hours, only
seconds. The
> DAY SET procedure works correctly for days and months. All the other
> switches and buttons do what they are supposed to do. Using my
10526T
> logic pulser I can force the minutes and hours counters to work.
> The power supply is in good condition (after replacement of a few
> components) and I see no other problems (yet).
>
> Tracing the clock signal through the logic circuitry brought me
to U3 on
> the A4 board. This (U3) is a 4011 quad 2-input NAND gate in a
14-pin DIP
> package. It "connects" the seconds counter to the minutes
counter and
> appears to have failed. One of the people on the email list
> > commented that the
4000 series CMOS
> chips have a known limited lifetime. Since these parts are no
longer in
> production, the writer expressed the concern that any parts I
might find
> to buy may be DOA.
>
> Before I go hunting for parts, I'd appreciate hearing from
anyone in the
> group who has experience with the 59309A Clock and/or the
4000-series CMOS
> family. In particular, are there modern equivalents to my 4011
chip? If
> the 4000's really do have a limited lifetime I'd rather use a
substitute.
>
> Jeremy, N6WFO
>
>
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Re: [time-nuts] HP E1938

[Bruce Griffiths]

More precisely the active EFC range is +1.25 to +3.75V with an absolute minimum 
of 0V and an absolute max of +5V.

At least this is the range that the pseudo differential AD7714 ADC inputs 
monitoring the EFC are configured for.

Bruce

> On 16 April 2017 at 14:57 Bruce Griffiths  wrote:
> 
> 
> 0 to +5V dc max, however only the 0 to 2.5V range appears measurable by 
> the AD7714 ADC on the PCB.
> 
> Increasing the EFC voltage decreases the capacitance in series with the 
> crystal requiring an increase in the inductance exhibited by the crystal 
> hence requiring a lower oscillator frequency.
> 
> Bruce
> 
> > > 
> > On 16 April 2017 at 13:01 Larry McDavid  wrote:
> > 
> > The units now available on eBay have various types of D-Subminiature
> > connectors and can be on either side of the board. I will have to 
> > wait
> > until my unit arrives to see what I get. It should be possible, if
> > necessary, to remove the connector and replace it with a more 
> > convenient
> > D-Submin connector on the desired side of the board.
> > 
> > I did not originally note the additional zip'd info available from 
> > that
> > eBay website but now have those files. Thanks for that link.
> > 
> > So far, I have not seen any spec for the EFC voltage and polarities 
> > used
> > in the "Integrated PWB." Anyone know that?
> > 
> > The "full instrument" version also available now on eBay is a 
> > complete
> > GPSDO but at $130 plus $80 shipping. I really don't need yet another
> > GPSDO but would use the integrated PWB assembly for a low ADEV
> > free-running 10 MHz source. I have a HP 10811D for that now but will
> > evaluate this new unit for performance.
> > 
> > Anyone have experience doing this and know the EFC requirements?
> > 
> > Larry
> > 
> > On 4/15/2017 4:01 PM, Richard (Rick) Karlquist wrote:
> > 
> > > > > 
> > > It's been 20 years, but I will try to recap what I remember
> > > about this connector. I believe there were 3 customers,
> > > and one of them required the DB connector with coax inserts
> > > for reasons of backward compatibility. I think this
> > > vendor was Motorola. We did not actually use the coax
> > > inserts, but left them blank and ran the RF, etc on
> > > ordinary pins. I believe you can make an ordinary male
> > > DB-25 mate with these insert versions by clipping off some
> > > of the pins that would be blocked by the female insert
> > > version. I vaguely remember that the other 2 vendors
> > > used gender changers or something. There might have
> > > an issue with the mating plane location being different
> > > for different customers.
> > > 
> > > I am sure that time-nuts, being talented at repurposing,
> > > will be able to think about this problem and come up with
> > > a simple solution to interfacing with these boards.
> > > No need to buy insert type connectors. I never had
> > > any trouble making cables that connected to these units
> > > using plain vanilla DB25's.
> > > 
> > > Rick N6RK
> > > 
> > > On 4/15/2017 10:42 AM, Larry McDavid wrote:
> > > 
> > > > > > > 
> > > > Ok, so a standard DB 25-pin socket-contact connector 
> > > > will mate with the
> > > > on-board connector with the center hole and missing 
> > > > pins. That's good!
> > > > 
> > > > I now notice a comment on your webpages about this 
> > > > device in which you
> > > > mention a schematic. Do you have a schematic of this 
> > > > board? If so, can
> > > > you point to it or send me a copy.
> > > > 
> > > > I was unaware of the complete packaged unit on eBay; 
> > > > thanks for that.
> > > > 
> > > > Another poster mentioned the wiring of the connector on 
> > > > the full
> > > > instrument version power connector; is that pin-out and 
> > > > spec available?
> > > > 
> > > > Larry
> > > > 
> > > > On 4/15/2017 5:05 AM, Tom Van Baak wrote:
> > > > 
> > > > > > > > > 
> > > > > > > > > > > 
> > > > > > I purchased one of these HP E1938 OCXO 
> > > > > > recently on eBay but have not
> > > > > > yet
> > > > > > received it.
> > > > > > 
> > > > > > Is that special D-Submin connector a 
> > > > > > receptacle-shell, pin contact
> > > > > > version? Will a standard plug-shell, socket 
> > > > > > 

Re: [time-nuts] HP E1938

[Bruce Griffiths]

0 to +5V dc max, however only the 0 to 2.5V range appears measurable by the 
AD7714 ADC on the PCB.

Increasing the EFC voltage decreases the capacitance in series with the crystal 
requiring an increase in the inductance exhibited by the crystal hence 
requiring a lower oscillator frequency.

Bruce

> 
> On 16 April 2017 at 13:01 Larry McDavid  wrote:
> 
> The units now available on eBay have various types of D-Subminiature
> connectors and can be on either side of the board. I will have to wait
> until my unit arrives to see what I get. It should be possible, if
> necessary, to remove the connector and replace it with a more convenient
> D-Submin connector on the desired side of the board.
> 
> I did not originally note the additional zip'd info available from that
> eBay website but now have those files. Thanks for that link.
> 
> So far, I have not seen any spec for the EFC voltage and polarities used
> in the "Integrated PWB." Anyone know that?
> 
> The "full instrument" version also available now on eBay is a complete
> GPSDO but at $130 plus $80 shipping. I really don't need yet another
> GPSDO but would use the integrated PWB assembly for a low ADEV
> free-running 10 MHz source. I have a HP 10811D for that now but will
> evaluate this new unit for performance.
> 
> Anyone have experience doing this and know the EFC requirements?
> 
> Larry
> 
> On 4/15/2017 4:01 PM, Richard (Rick) Karlquist wrote:
> 
> > > 
> > It's been 20 years, but I will try to recap what I remember
> > about this connector. I believe there were 3 customers,
> > and one of them required the DB connector with coax inserts
> > for reasons of backward compatibility. I think this
> > vendor was Motorola. We did not actually use the coax
> > inserts, but left them blank and ran the RF, etc on
> > ordinary pins. I believe you can make an ordinary male
> > DB-25 mate with these insert versions by clipping off some
> > of the pins that would be blocked by the female insert
> > version. I vaguely remember that the other 2 vendors
> > used gender changers or something. There might have
> > an issue with the mating plane location being different
> > for different customers.
> > 
> > I am sure that time-nuts, being talented at repurposing,
> > will be able to think about this problem and come up with
> > a simple solution to interfacing with these boards.
> > No need to buy insert type connectors. I never had
> > any trouble making cables that connected to these units
> > using plain vanilla DB25's.
> > 
> > Rick N6RK
> > 
> > On 4/15/2017 10:42 AM, Larry McDavid wrote:
> > 
> > > > > 
> > > Ok, so a standard DB 25-pin socket-contact connector will 
> > > mate with the
> > > on-board connector with the center hole and missing pins. 
> > > That's good!
> > > 
> > > I now notice a comment on your webpages about this device in 
> > > which you
> > > mention a schematic. Do you have a schematic of this board? 
> > > If so, can
> > > you point to it or send me a copy.
> > > 
> > > I was unaware of the complete packaged unit on eBay; thanks 
> > > for that.
> > > 
> > > Another poster mentioned the wiring of the connector on the 
> > > full
> > > instrument version power connector; is that pin-out and spec 
> > > available?
> > > 
> > > Larry
> > > 
> > > On 4/15/2017 5:05 AM, Tom Van Baak wrote:
> > > 
> > > > > > > 
> > > > > > > > > 
> > > > > I purchased one of these HP E1938 OCXO recently 
> > > > > on eBay but have not
> > > > > yet
> > > > > received it.
> > > > > 
> > > > > Is that special D-Submin connector a 
> > > > > receptacle-shell, pin contact
> > > > > version? Will a standard plug-shell, socket 
> > > > > contact 25-pin D-Submin
> > > > > fit it?
> > > > > 
> > > > > > > > > 
> > > > Hi,
> > > > 
> > > > I'll cc the group here since we may get some useful 
> > > > comments.
> > > > 
> > > > I'm not exactly sure what you mean. The E1938A 
> > > > oscillators that I've
> > > > seen and tested look like this:
> > > > 
> > > > http://www.leapsecond.com/museum/e1938a/
> > > > 
> > > > And those can be interfaced with a simple D-sub DB25 
> > > > connector on the
> > > > PCB. For connections, see that page, or any number of 
> > > > postings about
> > > > the E1938 in the time-nuts archives.
> > > > 
> > > > Note that on eBay 

Re: [time-nuts] uncertainty calculations

[Bill Byrom]

I believe that the problem is that the error in any one measurement is
not uniformly distributed in exactly that way. If you are trying to
count how many 10 MHz (100 ns interval) intervals occur between the 1
PPS edges in a period counter, you have to deal with the following?


* You might have any possible phase relationship between the two
  signals. If they are exactly related by a 10^7 ratio, it's possible
  for the 1 PPS edges to exactly coincide with the 10 MHz edges.
  Depending on the type of gating circuit, you will have jitter and
  possibly metastability resolving whether which edge occured first. The
  same thing happens on the end of the measured interval, but (depending
  on how it's set up) the propagation delays and metastability and
  jitter might be different. So you could get millions of sequential
  counts which were 1 count low, followed by millions of counts which
  were one count high, with no counts exactly at 10^7.


* To stay away from such problems, most precision counters add a small
  amount of controlled jitter (phase modulation) to the clock. When
  averaged over many measurements the effects of the two edges (gate and
  clock) lining up exactly are greatly reduced, since you are sliding
  one back and forth across the other with the modulation and the chance
  of metastability is small (assuming the signal being measured doesn't
  happen to match the phase modulation frequency).


* The metastability problem depends on how the edges are compared. Some
  traditional flip-flops and latches can be thought of as analog gain
  elements connected so that they tend to sit in state A or state B,
  which involve analog voltages and currents. If you graph the energy in
  the system, the energy is low in state A, rises to a peak halfway
  between A and B, and falls to a low value at state B. If the
  recognition of the timing edge occurs early enough the system remains
  in state A. If the timing is later the system is pushed toward the
  peak, but doesn't get over it and returns to state A. But if the
  timing is at the perfect location the system is balanced at the
  potential energy peak, and only random noise can push the system into
  a final state A or B over a significant length of time.


Sorry if this is considered obvious or trivial.

--

Bill Byrom N5BB







- Original message -

From: jimlux 

To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] uncertainty calculations

Date: Fri, 14 Apr 2017 08:49:07 -0700



On 4/14/17 8:37 AM, jimlux wrote:

> If one is counting an unknown 1pps source with a counter that
> runs at 10
> MHz (e.g. the error in any one measurement is uniformly
> distributed over
> 1 ppm) and you collect 100 samples,

> is the (1 sigma) measurement uncertainty 0.1ppm * sqrt(100)/sqrt(12)

>

> (standard deviation of a uniform distribution is 1/sqrt(12) )

>

> (assuming for the moment that both sources have no underlying

> variability - we're talking about the *measurement uncertainty*)

>



Oops..

0.1 ppm * 1/sqrt(N) * 1/sqrt(12)



That is, the standard  deviation goes down as sqrt(N)

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Re: [time-nuts] HP E1938

[Larry McDavid]

The units now available on eBay have various types of D-Subminiature 
connectors and can be on either side of the board. I will have to wait 
until my unit arrives to see what I get. It should be possible, if 
necessary, to remove the connector and replace it with a more convenient 
D-Submin connector on the desired side of the board.


I did not originally note the additional zip'd info available from that 
eBay website but now have those files. Thanks for that link.


So far, I have not seen any spec for the EFC voltage and polarities used 
in the "Integrated PWB." Anyone know that?


The "full instrument" version also available now on eBay is a complete 
GPSDO but at $130 plus $80 shipping. I really don't need yet another 
GPSDO but would use the integrated PWB assembly for a low ADEV 
free-running 10 MHz source. I have a HP 10811D for that now but will 
evaluate this new unit for performance.


Anyone have experience doing this and know the EFC requirements?

Larry


On 4/15/2017 4:01 PM, Richard (Rick) Karlquist wrote:

It's been 20 years, but I will try to recap what I remember
about this connector.  I believe there were 3 customers,
and one of them required the DB connector with coax inserts
for reasons of backward compatibility.  I think this
vendor was Motorola.  We did not actually use the coax
inserts, but left them blank and ran the RF, etc on
ordinary pins.  I believe you can make an ordinary male
DB-25 mate with these insert versions by clipping off some
of the pins that would be blocked by the female insert
version.  I vaguely remember that the other 2 vendors
used gender changers or something.  There might have
an issue with the mating plane location being different
for different customers.

I am sure that time-nuts, being talented at repurposing,
will be able to think about this problem and come up with
a simple solution to interfacing with these boards.
No need to buy insert type connectors.  I never had
any trouble making cables that connected to these units
using plain vanilla DB25's.

Rick N6RK

On 4/15/2017 10:42 AM, Larry McDavid wrote:

Ok, so a standard DB 25-pin socket-contact connector will mate with the
on-board connector with the center hole and missing pins. That's good!

I now notice a comment on your webpages about this device in which you
mention a schematic. Do you have a schematic of this board? If so, can
you point to it or send me a copy.

I was unaware of the complete packaged unit on eBay; thanks for that.

Another poster mentioned the wiring of the connector on the full
instrument version power connector; is that pin-out and spec available?

Larry


On 4/15/2017 5:05 AM, Tom Van Baak wrote:

I purchased one of these HP E1938 OCXO recently on eBay but have not
yet
received it.

Is that special D-Submin connector a receptacle-shell, pin contact
version? Will a standard plug-shell, socket contact 25-pin D-Submin
fit it?


Hi,

I'll cc the group here since we may get some useful comments.

I'm not exactly sure what you mean. The E1938A oscillators that I've
seen and tested look like this:

http://www.leapsecond.com/museum/e1938a/

And those can be interfaced with a simple D-sub DB25 connector on the
PCB. For connections, see that page, or any number of postings about
the E1938 in the time-nuts archives.

Note that on eBay there are at least three variations of E1938A
oscillator. The item#'s below are just random search picks (I have no
affiliation with any buyers or sellers) and I also know not all
surplus refurbished surplus recycled surplus stuff works. But we do
this because when they did work, they are sometimes totally amazing.

1) There's the bare "puck" alone, as in
http://www.ebay.com/itm/290829077542 -- and I have no idea where one
would start with that item since all the support circuitry on the PCB
would have to be re-created by hand.

2) There's the integrated PCB assembly, as in
http://www.ebay.com/itm/181043193416 -- which is more like what I
tested.

3) There's the full instrument version, as in
http://www.ebay.com/itm/171293069062 -- which is most likely to work,
or be less hacked up, or dented, or salvaged, or rusted. It even has
all the connectors and power supplies, and GPS, etc.

If any other time nuts have experience with each of these methods to
obtain a E1938 oscillator, please let us know.




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--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)
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[time-nuts] E1938A

[Skip Withrow]

Hello Tom,
There are two versions of the E1938A, one has a male DB-25 and one has a
female DB-25 (mounted on the opposite side of the board as the male).
Pinout and functions are the same between the two versions.  If your
hardware is expecting one type but all you have is the other an adapter
cable can always be made from a couple of connectors and ribbon cable (been
there, done that).
Regards,
Skip Withrow
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Re: [time-nuts] HP E1938

[Richard (Rick) Karlquist]

It's been 20 years, but I will try to recap what I remember
about this connector.  I believe there were 3 customers,
and one of them required the DB connector with coax inserts
for reasons of backward compatibility.  I think this
vendor was Motorola.  We did not actually use the coax
inserts, but left them blank and ran the RF, etc on
ordinary pins.  I believe you can make an ordinary male
DB-25 mate with these insert versions by clipping off some
of the pins that would be blocked by the female insert
version.  I vaguely remember that the other 2 vendors
used gender changers or something.  There might have
an issue with the mating plane location being different
for different customers.

I am sure that time-nuts, being talented at repurposing,
will be able to think about this problem and come up with
a simple solution to interfacing with these boards.
No need to buy insert type connectors.  I never had
any trouble making cables that connected to these units
using plain vanilla DB25's.

Rick N6RK

On 4/15/2017 10:42 AM, Larry McDavid wrote:

Ok, so a standard DB 25-pin socket-contact connector will mate with the
on-board connector with the center hole and missing pins. That's good!

I now notice a comment on your webpages about this device in which you
mention a schematic. Do you have a schematic of this board? If so, can
you point to it or send me a copy.

I was unaware of the complete packaged unit on eBay; thanks for that.

Another poster mentioned the wiring of the connector on the full
instrument version power connector; is that pin-out and spec available?

Larry


On 4/15/2017 5:05 AM, Tom Van Baak wrote:

I purchased one of these HP E1938 OCXO recently on eBay but have not yet
received it.

Is that special D-Submin connector a receptacle-shell, pin contact
version? Will a standard plug-shell, socket contact 25-pin D-Submin
fit it?


Hi,

I'll cc the group here since we may get some useful comments.

I'm not exactly sure what you mean. The E1938A oscillators that I've
seen and tested look like this:

http://www.leapsecond.com/museum/e1938a/

And those can be interfaced with a simple D-sub DB25 connector on the
PCB. For connections, see that page, or any number of postings about
the E1938 in the time-nuts archives.

Note that on eBay there are at least three variations of E1938A
oscillator. The item#'s below are just random search picks (I have no
affiliation with any buyers or sellers) and I also know not all
surplus refurbished surplus recycled surplus stuff works. But we do
this because when they did work, they are sometimes totally amazing.

1) There's the bare "puck" alone, as in
http://www.ebay.com/itm/290829077542 -- and I have no idea where one
would start with that item since all the support circuitry on the PCB
would have to be re-created by hand.

2) There's the integrated PCB assembly, as in
http://www.ebay.com/itm/181043193416 -- which is more like what I tested.

3) There's the full instrument version, as in
http://www.ebay.com/itm/171293069062 -- which is most likely to work,
or be less hacked up, or dented, or salvaged, or rusted. It even has
all the connectors and power supplies, and GPS, etc.

If any other time nuts have experience with each of these methods to
obtain a E1938 oscillator, please let us know.




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[time-nuts] Motorola T5829A Specifications

[Joe Hobart]

Does anyone know the aging and temperature specifications of a Motorola T5829A
"Ultra High Stability Oscillator"?

This is a 5 MHz standard containing an OCXO.  After a day of operation, the next
24 hour drift was 2.5E-9 lower, but change due to temperature variations is
unknown.  A nearby HP-105B showed very little change.

I need to determine a reasonable calibration interval.  Hopefully aging will
decrease with time.

Thanks,
Joe, W7LUX
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Re: [time-nuts] HP E1938

[Orin Eman]

Re: schematic.

There's a link on the second ebay auction page:

http://www.prc68.com/I/pdf/E1938pdfdocs.zip

On Sat, Apr 15, 2017 at 10:42 AM, Larry McDavid  wrote:

> Ok, so a standard DB 25-pin socket-contact connector will mate with the
> on-board connector with the center hole and missing pins. That's good!
>
> I now notice a comment on your webpages about this device in which you
> mention a schematic. Do you have a schematic of this board? If so, can you
> point to it or send me a copy.
>
> I was unaware of the complete packaged unit on eBay; thanks for that.
>
> Another poster mentioned the wiring of the connector on the full
> instrument version power connector; is that pin-out and spec available?
>
> Larry
>
>
> On 4/15/2017 5:05 AM, Tom Van Baak wrote:
>
>> I purchased one of these HP E1938 OCXO recently on eBay but have not yet
>>> received it.
>>>
>>> Is that special D-Submin connector a receptacle-shell, pin contact
>>> version? Will a standard plug-shell, socket contact 25-pin D-Submin fit
>>> it?
>>>
>>
>> Hi,
>>
>> I'll cc the group here since we may get some useful comments.
>>
>> I'm not exactly sure what you mean. The E1938A oscillators that I've seen
>> and tested look like this:
>>
>> http://www.leapsecond.com/museum/e1938a/
>>
>> And those can be interfaced with a simple D-sub DB25 connector on the
>> PCB. For connections, see that page, or any number of postings about the
>> E1938 in the time-nuts archives.
>>
>> Note that on eBay there are at least three variations of E1938A
>> oscillator. The item#'s below are just random search picks (I have no
>> affiliation with any buyers or sellers) and I also know not all surplus
>> refurbished surplus recycled surplus stuff works. But we do this because
>> when they did work, they are sometimes totally amazing.
>>
>> 1) There's the bare "puck" alone, as in http://www.ebay.com/itm/290829
>> 077542 -- and I have no idea where one would start with that item since
>> all the support circuitry on the PCB would have to be re-created by hand.
>>
>> 2) There's the integrated PCB assembly, as in
>> http://www.ebay.com/itm/181043193416 -- which is more like what I tested.
>>
>> 3) There's the full instrument version, as in
>> http://www.ebay.com/itm/171293069062 -- which is most likely to work, or
>> be less hacked up, or dented, or salvaged, or rusted. It even has all the
>> connectors and power supplies, and GPS, etc.
>>
>> If any other time nuts have experience with each of these methods to
>> obtain a E1938 oscillator, please let us know.
>>
>
>
> --
> Best wishes,
>
> Larry McDavid W6FUB
> Anaheim, California  (SE of Los Angeles, near Disneyland)
>
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> ailman/listinfo/time-nuts
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Re: [time-nuts] HP E1938

[Larry McDavid]

Ok, so a standard DB 25-pin socket-contact connector will mate with the 
on-board connector with the center hole and missing pins. That's good!


I now notice a comment on your webpages about this device in which you 
mention a schematic. Do you have a schematic of this board? If so, can 
you point to it or send me a copy.


I was unaware of the complete packaged unit on eBay; thanks for that.

Another poster mentioned the wiring of the connector on the full 
instrument version power connector; is that pin-out and spec available?


Larry


On 4/15/2017 5:05 AM, Tom Van Baak wrote:

I purchased one of these HP E1938 OCXO recently on eBay but have not yet
received it.

Is that special D-Submin connector a receptacle-shell, pin contact
version? Will a standard plug-shell, socket contact 25-pin D-Submin fit it?


Hi,

I'll cc the group here since we may get some useful comments.

I'm not exactly sure what you mean. The E1938A oscillators that I've seen and 
tested look like this:

http://www.leapsecond.com/museum/e1938a/

And those can be interfaced with a simple D-sub DB25 connector on the PCB. For 
connections, see that page, or any number of postings about the E1938 in the 
time-nuts archives.

Note that on eBay there are at least three variations of E1938A oscillator. The 
item#'s below are just random search picks (I have no affiliation with any 
buyers or sellers) and I also know not all surplus refurbished surplus recycled 
surplus stuff works. But we do this because when they did work, they are 
sometimes totally amazing.

1) There's the bare "puck" alone, as in http://www.ebay.com/itm/290829077542 -- 
and I have no idea where one would start with that item since all the support circuitry 
on the PCB would have to be re-created by hand.

2) There's the integrated PCB assembly, as in 
http://www.ebay.com/itm/181043193416 -- which is more like what I tested.

3) There's the full instrument version, as in 
http://www.ebay.com/itm/171293069062 -- which is most likely to work, or be 
less hacked up, or dented, or salvaged, or rusted. It even has all the 
connectors and power supplies, and GPS, etc.

If any other time nuts have experience with each of these methods to obtain a 
E1938 oscillator, please let us know.



--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)
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[time-nuts] datasheet info on Vectron VCXO

[R. Kuehn]

Hi,

I have a 500Mhz VCXO that I picked up a hamfest for free, but have had a
devil of a time finding anything at all about it. I've checked google,
ebay, and this list archive but can't find anything at all. I'd like to use
it for a GPSDO, frequency counter, or similar project in the future.

The unit is from  Vectron Industries Part No. CO 533ME, the unit measures
about 70mm x 45mm x 15mm with 6 pins, 2 of which are ground. It is still
attached to the a small pcb module but the silk-screen gives no hints about
the inputs/outputs. Also the board is multi-layer so I'm uncertain about
some of the connections with the passive components. In the second photo is
shown the back of the pcb module, I'm assuming that the oscillator output
pin is the one with the ring of through-hole vias?
Note that I have found a reference to a Vectron model CO-233ME, but they
are not at all the same units.

(front) http://imgur.com/k1BDMeu
(back) http://imgur.com/ATj8UY2

Thanks for any help!
Ralph
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Re: [time-nuts] NTGS50AA No Serial

[EB4APL]

I had a stupid problem with mine when doing some tests and I had the 
same symptoms and it took me several days of tests to realize the problem.


The original flat cable that goes to the auxiliary board with the panel 
lights and the RS-232 connector has the pins reversed so if you connect 
the pin one to pin one you still get some LEDs on but no comms. Connect 
it as per the attached photo.  If the list deletes the attachments, 
please ask me to send it directly.



El 15/04/2017 a las 13:11, Bryan _ escribió:

Have you tried different serial settings I wonder if the hard reset mucked 
things up. have a Nortel as well, never had a issue with a reset but try 
changing a few thing sup. It may need the unusual 19200,7,Odd and 1 stop bit 
setting.


If you try a terminal program do you at least see some garbage characters?

-=Bryan=-



From: time-nuts  on behalf of Ed Armstrong 

Sent: April 15, 2017 1:13 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] NTGS50AA No Serial

My NTGS50AA is suddenly lacking the ability to communicate. It's been
working fine for months, but I was trying a few things with my Raspberry
Pi NTP server.

Had GPSD accessing the NTGS50AA through a ch340 USB to serial adapter.
Found out Lady Heather displays much less info when connecting through
GPSD, so I went back to LH connecting directly to NTGS50AA through ch340
adapter on windows 7. Curiously, it was surveying, not in position lock.
So, I did a hard reset. Never heard from it since :(

If it's unplugged, all the lights behave as they should when you power
it up again. "Locked" light eventually comes on. PPS still works. Just
no serial. Even tried Trimble Studio with auto detect settings, no
connect here either. I've tried a second ch340 USB to serial adapter,
same deal. Any suggestions?

Thanks
Ed
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Enterprises
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time-nuts is a low volume, high SNR list for the discussion of precise time and 
frequency measurement and related topics. To see the collection of prior 
postings to ...



and follow the instructions there.
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Re: [time-nuts] NTGS50AA No Serial

[EB4APL]

I had a stupid problem with mine when doing some tests and I had the 
same symptoms and it took me several days of tests to realize the problem.


The original flat cable that goes to the auxiliary board with the panel 
lights and the RS-232 connector has the pins reversed so if you connect 
the pin one to pin one you still get some LEDs on but no comms. Connect 
it as per the attached photo.  If the list deletes the attachments, 
please ask me to send it directly.



El 15/04/2017 a las 13:11, Bryan _ escribió:

Have you tried different serial settings I wonder if the hard reset mucked 
things up. have a Nortel as well, never had a issue with a reset but try 
changing a few thing sup. It may need the unusual 19200,7,Odd and 1 stop bit 
setting.


If you try a terminal program do you at least see some garbage characters?

-=Bryan=-



From: time-nuts  on behalf of Ed Armstrong 

Sent: April 15, 2017 1:13 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] NTGS50AA No Serial

My NTGS50AA is suddenly lacking the ability to communicate. It's been
working fine for months, but I was trying a few things with my Raspberry
Pi NTP server.

Had GPSD accessing the NTGS50AA through a ch340 USB to serial adapter.
Found out Lady Heather displays much less info when connecting through
GPSD, so I went back to LH connecting directly to NTGS50AA through ch340
adapter on windows 7. Curiously, it was surveying, not in position lock.
So, I did a hard reset. Never heard from it since :(

If it's unplugged, all the lights behave as they should when you power
it up again. "Locked" light eventually comes on. PPS still works. Just
no serial. Even tried Trimble Studio with auto detect settings, no
connect here either. I've tried a second ch340 USB to serial adapter,
same deal. Any suggestions?

Thanks
Ed
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time-nuts is a low volume, high SNR list for the discussion of precise time and 
frequency measurement and related topics. To see the collection of prior 
postings to ...



and follow the instructions there.
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[time-nuts] Measuring coax temperature coefficient with a TICC

[Mark Sims]

I finally got around to using a TICC to measure the temperature coefficient of 
100 feet of generic RG-58 coax using a TICC.   The TICC was clocked by a HP 
5071A 10 MHz output.  The 1PPS output was connected to the input of the coax 
and the TICC chB input.  The TICC chA input was connected to the coax output 
via an inline terminator.   The TICC was set to "debug" mode  and Lady Heather 
plotted the chB-chA timestamp difference (hence the negative cable delay 
values).

The coax had been chilled down for 2 hours in a 5 degrees F in a freezer,  
connected to the TICC, and left to warm up in a 75 degree F room.   Over the 
10F to 70F temperature range (measured with an IR thermometer) the coax delay 
spanned around 300 ps... so figure around 5 ps per degree F (10 ps per degree 
C) for 100 feet of cable.

I'm adding currently adding the ability for Heather to use an external 
temperature sensor... ___
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Re: [time-nuts] HP E1938

[Bruce Griffiths]

Tom

#1 proved useful when this sub assembly failed (no 10MHz output) in my E1938A.

Someday I'll disassemble it to see what exactly failed. 

Also have #3 which works well when one figures out the connections on the PCB 
and the unusual backplane connector.


Bruce

> 
> On 16 April 2017 at 00:05 Tom Van Baak  wrote:
> 
> > > 
> > I purchased one of these HP E1938 OCXO recently on eBay but have 
> > not yet
> > received it.
> > 
> > Is that special D-Submin connector a receptacle-shell, pin contact
> > version? Will a standard plug-shell, socket contact 25-pin D-Submin 
> > fit it?
> > 
> > > 
> Hi,
> 
> I'll cc the group here since we may get some useful comments.
> 
> I'm not exactly sure what you mean. The E1938A oscillators that I've seen 
> and tested look like this:
> 
> http://www.leapsecond.com/museum/e1938a/
> 
> And those can be interfaced with a simple D-sub DB25 connector on the 
> PCB. For connections, see that page, or any number of postings about the 
> E1938 in the time-nuts archives.
> 
> Note that on eBay there are at least three variations of E1938A 
> oscillator. The item#'s below are just random search picks (I have no 
> affiliation with any buyers or sellers) and I also know not all surplus 
> refurbished surplus recycled surplus stuff works. But we do this because when 
> they did work, they are sometimes totally amazing.
> 
> 1) There's the bare "puck" alone, as in 
> http://www.ebay.com/itm/290829077542 -- and I have no idea where one would 
> start with that item since all the support circuitry on the PCB would have to 
> be re-created by hand.
> 
> 2) There's the integrated PCB assembly, as in 
> http://www.ebay.com/itm/181043193416 -- which is more like what I tested.
> 
> 3) There's the full instrument version, as in 
> http://www.ebay.com/itm/171293069062 -- which is most likely to work, or be 
> less hacked up, or dented, or salvaged, or rusted. It even has all the 
> connectors and power supplies, and GPS, etc.
> 
> If any other time nuts have experience with each of these methods to 
> obtain a E1938 oscillator, please let us know.
> 
> Thanks,
> /tvb
> 
> ___
> 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.
> 
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Re: [time-nuts] NTGS50AA No Serial

[Bryan _]

Have you tried different serial settings I wonder if the hard reset mucked 
things up. have a Nortel as well, never had a issue with a reset but try 
changing a few thing sup. It may need the unusual 19200,7,Odd and 1 stop bit 
setting.


If you try a terminal program do you at least see some garbage characters?

-=Bryan=-



From: time-nuts  on behalf of Ed Armstrong 

Sent: April 15, 2017 1:13 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] NTGS50AA No Serial

My NTGS50AA is suddenly lacking the ability to communicate. It's been
working fine for months, but I was trying a few things with my Raspberry
Pi NTP server.

Had GPSD accessing the NTGS50AA through a ch340 USB to serial adapter.
Found out Lady Heather displays much less info when connecting through
GPSD, so I went back to LH connecting directly to NTGS50AA through ch340
adapter on windows 7. Curiously, it was surveying, not in position lock.
So, I did a hard reset. Never heard from it since :(

If it's unplugged, all the lights behave as they should when you power
it up again. "Locked" light eventually comes on. PPS still works. Just
no serial. Even tried Trimble Studio with auto detect settings, no
connect here either. I've tried a second ch340 USB to serial adapter,
same deal. Any suggestions?

Thanks
Ed
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Enterprises
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time-nuts is a low volume, high SNR list for the discussion of precise time and 
frequency measurement and related topics. To see the collection of prior 
postings to ...



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Re: [time-nuts] HP E1938

[Tom Van Baak]

> I purchased one of these HP E1938 OCXO recently on eBay but have not yet 
> received it.
> 
> Is that special D-Submin connector a receptacle-shell, pin contact 
> version? Will a standard plug-shell, socket contact 25-pin D-Submin fit it?

Hi,

I'll cc the group here since we may get some useful comments.

I'm not exactly sure what you mean. The E1938A oscillators that I've seen and 
tested look like this:

http://www.leapsecond.com/museum/e1938a/

And those can be interfaced with a simple D-sub DB25 connector on the PCB. For 
connections, see that page, or any number of postings about the E1938 in the 
time-nuts archives.

Note that on eBay there are at least three variations of E1938A oscillator. The 
item#'s below are just random search picks (I have no affiliation with any 
buyers or sellers) and I also know not all surplus refurbished surplus recycled 
surplus stuff works. But we do this because when they did work, they are 
sometimes totally amazing.

1) There's the bare "puck" alone, as in http://www.ebay.com/itm/290829077542 -- 
and I have no idea where one would start with that item since all the support 
circuitry on the PCB would have to be re-created by hand.

2) There's the integrated PCB assembly, as in 
http://www.ebay.com/itm/181043193416 -- which is more like what I tested.

3) There's the full instrument version, as in 
http://www.ebay.com/itm/171293069062 -- which is most likely to work, or be 
less hacked up, or dented, or salvaged, or rusted. It even has all the 
connectors and power supplies, and GPS, etc.

If any other time nuts have experience with each of these methods to obtain a 
E1938 oscillator, please let us know.

Thanks,
/tvb


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[time-nuts] NTGS50AA No Serial

[Ed Armstrong]

My NTGS50AA is suddenly lacking the ability to communicate. It's been 
working fine for months, but I was trying a few things with my Raspberry 
Pi NTP server.


Had GPSD accessing the NTGS50AA through a ch340 USB to serial adapter. 
Found out Lady Heather displays much less info when connecting through 
GPSD, so I went back to LH connecting directly to NTGS50AA through ch340 
adapter on windows 7. Curiously, it was surveying, not in position lock. 
So, I did a hard reset. Never heard from it since :(


If it's unplugged, all the lights behave as they should when you power 
it up again. "Locked" light eventually comes on. PPS still works. Just 
no serial. Even tried Trimble Studio with auto detect settings, no 
connect here either. I've tried a second ch340 USB to serial adapter, 
same deal. Any suggestions?


Thanks
Ed
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