HP-5065a bought and finally working!
Dear Group,
I wish you well.
Do you recall a message and thread about a month ago with my concerns about buying a used / unknown condition HP-5065a rubidium frequency standard? I bit the bullet and bought it. Almost mint condition (cosmetically speaking) and with several operational issues.
Well, It took me several weeks to put it back to work. Several capacitors on several boards along with a couple of transistors and an IC were replaced. After that any being bored by the yellow light, it finally came off to allow a beautiful green lock condition light. I went through the necessary steps to tune it and calibrate it. Now, as I have been told recently. "You have been bitten by the Time Nuts bug." I am not complaining at all.
Now the technical issues if you kindly allow:
a. Does anybody have an HP-5065a manual for the latest versions? Mine (which I downloaded from the Internet) is intended for earlier versions. It seems I have one of the last produced units. I would kindly appreciate any help on this and I am willing to pay for time and expenses to anybody who could help. During the repair process I found several differences in the earlier versions design and had to figure out hoy mine works.
b. Is it possible to build a GPSDRb? I would like to know if it is reasonable to pursue the goal to discipline the 5065a with a TB which I also got recently.
c. I am waiting for the delivery of a recent purchase. An HP-59309a Digital Clock to go with the HP 5065a. How I wish I could find the optional LED integrated optional clock and 1PPS output. Is my purchase a good match for the 5065a? Any other suggestions to drive a clock?
d. I am waiting also for de delivery of an HP-105b mint condition quartz frequency standard. Would a second 59309a make sense to use it with this quartz standard? Or just saving it for a Cesium? Anybody willing to sell a spare, dust gathering, clean unit to me?
e. Any suggestions for software of lab equipment to measure my experiments like AD, jitter, phase comparisons, etc?
While I wait I am doing some experiments with a FE Rb standard to discipline an Adret synthesiser to output 32.768 KHz to directly drive a Nixie clock kit I just finished building.
Your comments are surely welcome. Thank you!
Kind regards,
Edgardo Molina
XE1XUS
Mexico
If it is a really good Rb standard, consider adjusting the
standard yourself by measuring the phase over several
days once the standard has warmed up and settled down.
A GPIB counter with phase measurement is useful for this.
--
Chuck Forsberg WA7KGX N2469R caf@omen.com www.omen.com
Developer of Industrial ZMODEM(Tm) for Embedded Applications
Omen Technology Inc "The High Reliability Software"
10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430
I think that it is the time for you to look at the TimePod: the TimePod can
help you with Allan Deviation and phase noise measurement, the next step
after clocks is measuring equipment and the TimePod is a sort of all-in-one
for time-nuts, its place is right after the bench yellow multimeter.
On Wed, Aug 22, 2012 at 9:03 AM, Chuck Forsberg WA7KGX N2469R
caf@omen.comwrote:
If it is a really good Rb standard, consider adjusting the
standard yourself by measuring the phase over several
days once the standard has warmed up and settled down.
A GPIB counter with phase measurement is useful for this.
--
Chuck Forsberg WA7KGX N2469R caf@omen.com www.omen.com
Developer of Industrial ZMODEM(Tm) for Embedded Applications
Omen Technology Inc "The High Reliability Software"
10255 NW Old Cornelius Pass Portland OR 97231 503-614-0430
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Edgardo,
Congrats on getting the 5065A up and operational. Make sure the A11 Board
(Temperature Controller) is all OK. Failure there can destroy the A12 RVFR
Assembly. There is a lot of 'expertise' on the list for this unit.
What is the serial number of your unit and what is the part number of the
manual you have?
I have a couple of manuals and I may also have the 'change sheets' that
updates the manual to your serial number. It may take me a while to chase
that down but if I have the 'change sheets', I can scan them and send them
to you.
I have not heard of anyone 'disciplining' the 5065A by GPS, other than by
hand from week to week. However, the 105B has a built in connection on the
back that is great for that purpose (negative slope, as I recall) and I have
done that using a Brooks Shera controller board and the 1 PPS from my TBolt.
It works quite well.
Joe
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Edgardo Molina
Sent: Wednesday, August 22, 2012 12:22 AM
To: time-nuts@febo.com
Subject: [time-nuts] HP-5065a bought and finally working!
Dear Group,
I wish you well.
Do you recall a message and thread about a month ago with my concerns about
buying a used / unknown condition HP-5065a rubidium frequency standard? I
bit the bullet and bought it. Almost mint condition (cosmetically speaking)
and with several operational issues.
Well, It took me several weeks to put it back to work. Several capacitors on
several boards along with a couple of transistors and an IC were replaced.
After that any being bored by the yellow light, it finally came off to allow
a beautiful green lock condition light. I went through the necessary steps
to tune it and calibrate it. Now, as I have been told recently. "You have
been bitten by the Time Nuts bug." I am not complaining at all.
Now the technical issues if you kindly allow:
a. Does anybody have an HP-5065a manual for the latest versions? Mine (which
I downloaded from the Internet) is intended for earlier versions. It seems I
have one of the last produced units. I would kindly appreciate any help on
this and I am willing to pay for time and expenses to anybody who could
help. During the repair process I found several differences in the earlier
versions design and had to figure out hoy mine works.
b. Is it possible to build a GPSDRb? I would like to know if it is
reasonable to pursue the goal to discipline the 5065a with a TB which I also
got recently.
c. I am waiting for the delivery of a recent purchase. An HP-59309a Digital
Clock to go with the HP 5065a. How I wish I could find the optional LED
integrated optional clock and 1PPS output. Is my purchase a good match for
the 5065a? Any other suggestions to drive a clock?
d. I am waiting also for de delivery of an HP-105b mint condition quartz
frequency standard. Would a second 59309a make sense to use it with this
quartz standard? Or just saving it for a Cesium? Anybody willing to sell a
spare, dust gathering, clean unit to me?
e. Any suggestions for software of lab equipment to measure my experiments
like AD, jitter, phase comparisons, etc?
While I wait I am doing some experiments with a FE Rb standard to discipline
an Adret synthesiser to output 32.768 KHz to directly drive a Nixie clock
kit I just finished building.
Your comments are surely welcome. Thank you!
Kind regards,
Edgardo Molina
XE1XUS
Mexico
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.
On 08/22/2012 01:22 AM, Edgardo Molina wrote:
b. Is it possible to build a GPSDRb? I would like to know if it is reasonable to pursue the goal to discipline the 5065a with a TB which I also got recently.
Some Rbs have a "C-field" input that can technically be used to
discipline it, but this is not the approach I am going to take with
mine. A Rb oscillator is internally an OCXO that is disciplined to the
Rb physics package, with the goal of holding a frequency over a long
period of time with the only variance coming from deficiencies in the
measurement circuitry. Using the C-field to discipline it is kind of
throwing out the long-term stability characteristics of the Rb and using
it as an expensive OCXO. It's more interesting to me as a holdover
source for a conventional GPSDO.
The design I'm thinking of is to have a separate microcontroller clocked
by the Rb that will generate a third pulse-per-second (the first two
being the raw one from GPS and the divided-down local oscillator). As
long as the GPS is locked the divider will not output pulses but will
monitor the pulses from the local oscillator and use it to count the
frequency of the Rb. Once lock is lost or holdover is manually engaged,
then it stops counting and starts outputting pulse-per-second based on
the last known average frequency it counted. The GPSDO would then
continue normal disciplining based on the Rb pulses until GPS lock
returns. Of course while locked the measured frequency would also be
reported so that the Rb could be calibrated in situ.
-- m. tharp
Hi
The problem you run into with this approach is that it is relatively high
jitter. You output "jumps" by what ever your microcontroller step time step
size is every so often. Since that's going to be 10's or possibly 100's of
ns, it's a major hit.
Bob
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Michael Tharp
Sent: Wednesday, August 22, 2012 10:47 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPSD-Rb
On 08/22/2012 01:22 AM, Edgardo Molina wrote:
b. Is it possible to build a GPSDRb? I would like to know if it is
reasonable to pursue the goal to discipline the 5065a with a TB which I also
got recently.
Some Rbs have a "C-field" input that can technically be used to
discipline it, but this is not the approach I am going to take with
mine. A Rb oscillator is internally an OCXO that is disciplined to the
Rb physics package, with the goal of holding a frequency over a long
period of time with the only variance coming from deficiencies in the
measurement circuitry. Using the C-field to discipline it is kind of
throwing out the long-term stability characteristics of the Rb and using
it as an expensive OCXO. It's more interesting to me as a holdover
source for a conventional GPSDO.
The design I'm thinking of is to have a separate microcontroller clocked
by the Rb that will generate a third pulse-per-second (the first two
being the raw one from GPS and the divided-down local oscillator). As
long as the GPS is locked the divider will not output pulses but will
monitor the pulses from the local oscillator and use it to count the
frequency of the Rb. Once lock is lost or holdover is manually engaged,
then it stops counting and starts outputting pulse-per-second based on
the last known average frequency it counted. The GPSDO would then
continue normal disciplining based on the Rb pulses until GPS lock
returns. Of course while locked the measured frequency would also be
reported so that the Rb could be calibrated in situ.
-- m. tharp
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.
On Wed, Aug 22, 2012 at 7:47 AM, Michael Tharp gxti@partiallystapled.comwrote:
The design I'm thinking of is to have a separate microcontroller clocked
by the Rb that will generate a third pulse-per-second
It is very hard to write a divers in software. You have to use assembly
language and you have to mmake sure that EVERY path in every branch is has
exactly the same number of clock cycles. And then you have to be lucky
that you can work out an exact integer division.
The above has been done but always the uP can't do anything else but the
divide down loop. If you need some other background task use a second uP
chip.
I think a better way to do holdover is to use a stable OCXO that is phas
locked to some timing source and then, in real time you might switch to the
"best" source. If one of your source is a 10MHz Rb then why divide that
down to 1Hz? Use the 10Mhz output to drive the OCXO.
I can't draw a diagram so I'l use even more words... The "final" OCXO has
10Mhz output and is controlled by a PLL. The PPL has two 10Mhz inputs
(references) it can choose from (1) the Rb and (2) a 10Mhz GPSDO. I think
you need a uP to control the switch and also likely to manage the loop
constants inside the PLL.
I've been thinging about the because I have a few GPSes and an Rb also.
That said this is not a high priority because in all the time I've been
doing this I've not once seen a need for holdover. GPS seems to be 100%
reliable.
What I really want is a portable standard. So rather then the above
I'mthinking about a GPS disiplined Rb. Then I can unplug the GPS and take
the Rb where it is needed.
Chris Albertson
Redondo Beach, California
Exactly. Every GPSRb works by adjusting the C-field: sort of let me (the
algorithm/GPS pair) calibrate your Rb for the long term (aging) variation
that every Rb has. The Rb is not good in the long term (100000 seconds),
not as good as a working and receiving GPS receiver. The Rb (as a whole)
is an expensive OCXO that has good short term stability, paired with a
disciplining algorithm and a GPS it becomes like a Cs (and maybe even
better in the short term).
On Wed, Aug 22, 2012 at 6:03 PM, Bob Camp lists@rtty.us wrote:
Hi
The problem you run into with this approach is that it is relatively high
jitter. You output "jumps" by what ever your microcontroller step time step
size is every so often. Since that's going to be 10's or possibly 100's of
ns, it's a major hit.
Bob
-----Original Message-----
From: time-nuts-bounces@febo.com [mailto:time-nuts-bounces@febo.com] On
Behalf Of Michael Tharp
Sent: Wednesday, August 22, 2012 10:47 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] GPSD-Rb
On 08/22/2012 01:22 AM, Edgardo Molina wrote:
b. Is it possible to build a GPSDRb? I would like to know if it is
reasonable to pursue the goal to discipline the 5065a with a TB which I
also
got recently.
Some Rbs have a "C-field" input that can technically be used to
discipline it, but this is not the approach I am going to take with
mine. A Rb oscillator is internally an OCXO that is disciplined to the
Rb physics package, with the goal of holding a frequency over a long
period of time with the only variance coming from deficiencies in the
measurement circuitry. Using the C-field to discipline it is kind of
throwing out the long-term stability characteristics of the Rb and using
it as an expensive OCXO. It's more interesting to me as a holdover
source for a conventional GPSDO.
The design I'm thinking of is to have a separate microcontroller clocked
by the Rb that will generate a third pulse-per-second (the first two
being the raw one from GPS and the divided-down local oscillator). As
long as the GPS is locked the divider will not output pulses but will
monitor the pulses from the local oscillator and use it to count the
frequency of the Rb. Once lock is lost or holdover is manually engaged,
then it stops counting and starts outputting pulse-per-second based on
the last known average frequency it counted. The GPSDO would then
continue normal disciplining based on the Rb pulses until GPS lock
returns. Of course while locked the measured frequency would also be
reported so that the Rb could be calibrated in situ.
-- m. tharp
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to
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On Wed, Aug 22, 2012 at 11:27 PM, Chris Albertson <albertson.chris@gmail.com
wrote:
It is very hard to write a divers in software. You have to use assembly
language and you have to mmake sure that EVERY path in every branch is has
exactly the same number of clock cycles. And then you have to be lucky
that you can work out an exact integer division.
It depends on what sort of processor you are using - that sort of approach
used to be
necessary when the low-cost MCUs were things like PICs that don't have
especially sophisticated on-chip timers, but even cheap devices now have
onchip
timer/counters that have reload and capture registers. Many of them also
have PLLs
on the die that are intended for clock generation but can often be abused
for other
purposes :)
Hi
If you run a processor with a PLL on it - be very careful. The jitter they add can be significant.
Bob
On Aug 22, 2012, at 11:08 PM, Peter Bell bell.peter@gmail.com wrote:
On Wed, Aug 22, 2012 at 11:27 PM, Chris Albertson <albertson.chris@gmail.com
wrote:
It is very hard to write a divers in software. You have to use assembly
language and you have to mmake sure that EVERY path in every branch is has
exactly the same number of clock cycles. And then you have to be lucky
that you can work out an exact integer division.
It depends on what sort of processor you are using - that sort of approach
used to be
necessary when the low-cost MCUs were things like PICs that don't have
especially sophisticated on-chip timers, but even cheap devices now have
onchip
timer/counters that have reload and capture registers. Many of them also
have PLLs
on the die that are intended for clock generation but can often be abused
for other
purposes :)
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To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.