Re: DOXCO from Z3801
I've been given a defunct Z3801 with a fully working ovened oscillator.
The rest of the GPSDO circuitry is just junk and will be chucked, but I
want to get the DOXCO running as a backup high stability reference here.
I've worked out the power connections for the oscillator and inner oven,
and have powered it up with +12V & +24V supplies. It's currently just
warmed up and is happily generating a nice sine at 10MHz, with +0.3V (at
the moment) t on the EFC.
I applied 24V to the outer oven earlier to see what happened, and measured
the thermistor resistance as it warmed, watching it fall from 110kΩat room
temp to 30kΩ where I stopped. I know the controller for the outer oven is
in external circuitry, but a brief web search failed to show a) what
temperature it should run at, To, and b) what the thermistor resistance
would be at that temperature, Ro.
Does anyone here know these figures off hand, or do I need to go to the
web and download the circuit and trace out the outer oven controller
details. I'll be doing my own controller circuitry, so just need To and
Ro.
Andy
www.g4jnt.com
Andy
For what you are doing I am not sure the outer ovens really needed. Its use
would have been for locations like Cel Towers and such that can be very
poorly heated if at all. I might guess you could put a temp probe in and
set it at some temp like 100 F and let it go. Or as I say not use it at all.
Others will have stronger opinions.
Regards
Paul
WB8TSL
On Wed, Dec 7, 2022 at 5:28 AM Andy Talbot via time-nuts <
time-nuts@lists.febo.com> wrote:
I've been given a defunct Z3801 with a fully working ovened oscillator.
The rest of the GPSDO circuitry is just junk and will be chucked, but I
want to get the DOXCO running as a backup high stability reference here.
I've worked out the power connections for the oscillator and inner oven,
and have powered it up with +12V & +24V supplies. It's currently just
warmed up and is happily generating a nice sine at 10MHz, with +0.3V (at
the moment) t on the EFC.
I applied 24V to the outer oven earlier to see what happened, and
measured
the thermistor resistance as it warmed, watching it fall from 110kΩat
room
temp to 30kΩ where I stopped. I know the controller for the outer oven
is
in external circuitry, but a brief web search failed to show a) what
temperature it should run at, To, and b) what the thermistor resistance
would be at that temperature, Ro.
Does anyone here know these figures off hand, or do I need to go to the
web and download the circuit and trace out the outer oven controller
details. I'll be doing my own controller circuitry, so just need To and
Ro.
Andy
www.g4jnt.com
time-nuts mailing list -- time-nuts@lists.febo.com
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Hi
Will your lab be running below freezing? If not, just ignore the outer heater and move on.
The main reason that heater exists is a very early requirement to have the reference operate
at (and quickly warm up from) -40C. The cell guys pretty much gave up on that idea after they
dug into all of the grubby details of the rest of the gear.
Bob
On Dec 7, 2022, at 4:38 AM, Andy Talbot via time-nuts time-nuts@lists.febo.com wrote:
I've been given a defunct Z3801 with a fully working ovened oscillator.
The rest of the GPSDO circuitry is just junk and will be chucked, but I
want to get the DOXCO running as a backup high stability reference here.
I've worked out the power connections for the oscillator and inner oven,
and have powered it up with +12V & +24V supplies. It's currently just
warmed up and is happily generating a nice sine at 10MHz, with +0.3V (at
the moment) t on the EFC.
I applied 24V to the outer oven earlier to see what happened, and measured
the thermistor resistance as it warmed, watching it fall from 110kΩat room
temp to 30kΩ where I stopped. I know the controller for the outer oven is
in external circuitry, but a brief web search failed to show a) what
temperature it should run at, To, and b) what the thermistor resistance
would be at that temperature, Ro.
Does anyone here know these figures off hand, or do I need to go to the
web and download the circuit and trace out the outer oven controller
details. I'll be doing my own controller circuitry, so just need To and
Ro.
Andy
www.g4jnt.com
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Ah, OK. It's working great on just the inner one at the moment
The temp is unlikely to drop below 15 to 16C - shack room temperature worst
case winter nights.
Andy
www.g4jnt.com
On Wed, 7 Dec 2022 at 14:07, Bob kb8tq kb8tq@n1k.org wrote:
Hi
Will your lab be running below freezing? If not, just ignore the outer
heater and move on.
The main reason that heater exists is a very early requirement to have the
reference operate
at (and quickly warm up from) -40C. The cell guys pretty much gave up on
that idea after they
dug into all of the grubby details of the rest of the gear.
Bob
On Dec 7, 2022, at 4:38 AM, Andy Talbot via time-nuts <
time-nuts@lists.febo.com> wrote:
I've been given a defunct Z3801 with a fully working ovened oscillator.
The rest of the GPSDO circuitry is just junk and will be chucked, but I
want to get the DOXCO running as a backup high stability reference here.
I've worked out the power connections for the oscillator and inner oven,
and have powered it up with +12V & +24V supplies. It's currently just
warmed up and is happily generating a nice sine at 10MHz, with +0.3V (at
the moment) t on the EFC.
I applied 24V to the outer oven earlier to see what happened, and
measured
the thermistor resistance as it warmed, watching it fall from 110kΩat
room
temp to 30kΩ where I stopped. I know the controller for the outer oven
is
in external circuitry, but a brief web search failed to show a) what
temperature it should run at, To, and b) what the thermistor resistance
would be at that temperature, Ro.
Does anyone here know these figures off hand, or do I need to go to the
web and download the circuit and trace out the outer oven controller
details. I'll be doing my own controller circuitry, so just need To
and
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Andy,
Here's a link to a description of the outer oven and its controller on the KO4BB manuals site.
However, on the link to the document containing the text, all of the images have gotten lost and are not visible.
Fortunately, I had downloaded the complete page and all the files, and put them all into a PDF for my own reference. I've attached it to this message. It contains an in-depth description of the outer oven and its controller circuitry, and I think it contains all the information you're after.
Enjoy!
DaveM
----- Original Message -----
From: "Time-Nuts" time-nuts@lists.febo.com
To: "Time-Nuts" time-nuts@lists.febo.com
Cc: "Andy Talbot" andy.g4jnt@gmail.com
Sent: Wednesday, December 7, 2022 3:38:54 AM
Subject: [time-nuts] Re: DOXCO from Z3801
I've been given a defunct Z3801 with a fully working ovened oscillator.
The rest of the GPSDO circuitry is just junk and will be chucked, but I
want to get the DOXCO running as a backup high stability reference here.
I've worked out the power connections for the oscillator and inner oven,
and have powered it up with +12V & +24V supplies. It's currently just
warmed up and is happily generating a nice sine at 10MHz, with +0.3V (at
the moment) t on the EFC.
I applied 24V to the outer oven earlier to see what happened, and measured
the thermistor resistance as it warmed, watching it fall from 110kΩat room
temp to 30kΩ where I stopped. I know the controller for the outer oven is
in external circuitry, but a brief web search failed to show a) what
temperature it should run at, To, and b) what the thermistor resistance
would be at that temperature, Ro.
Does anyone here know these figures off hand, or do I need to go to the
web and download the circuit and trace out the outer oven controller
details. I'll be doing my own controller circuitry, so just need To and
Ro.
Andy
www.g4jnt.com
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
I don't recall seeing that anyone ever reported the official temperature
setpoint for the outer oven. Most of the info on the Z3801A still
resides on realhamradio.com.
I found in my notes a paper printout of a webpage apparently put up
someone named Shegnauer, circa 2006, showing the schematic, and some
info and estimates for the temperature range, and a spice model of the
control system operation. It's a nice document. I tried to find it
online now, but it seems to have disappeared over the years. The same
link showed up in old messages on time nuts and other lists, but it
appears dead now. It must have been pretty well known, so it's likely
still floating around out there at some URL or in someone's files. If
you don't have it already, you should try to find it. I only have the
paper copy.
Anyway, it was suggested that the outer oven should run around 60-65 deg
C, while the thermistor is around 16.2 k ohms there. Personally, I
believe this is too high, and should be around 50-55 deg C or maybe a
bit more - right near the maximum ambient rating for the Z3801A,
neglecting any internal box temperature rise. If the performance specs
are relaxed toward the higher end of operating temperature range, then
the outer oven may not have to run so high. I don't recall, but think
that may be the case.
Ed
Hi!
Found original page at
https://web.archive.org/web/20050318020038/http://homepage.sunrise.ch/mysunrise/shegnauer/Z3801A/Outer%20Oven%20Controller/z3801a_outer_oven_description.htm
but the images are missing.
Edésio
On Wed, Dec 07, 2022 at 10:17:14AM -0800, ed breya via time-nuts wrote:
I don't recall seeing that anyone ever reported the official temperature
setpoint for the outer oven. Most of the info on the Z3801A still resides on
realhamradio.com.
I found in my notes a paper printout of a webpage apparently put up someone
named Shegnauer, circa 2006, showing the schematic, and some info and
estimates for the temperature range, and a spice model of the control system
operation. It's a nice document. I tried to find it online now, but it seems
to have disappeared over the years. The same link showed up in old messages
on time nuts and other lists, but it appears dead now. It must have been
pretty well known, so it's likely still floating around out there at some
URL or in someone's files. If you don't have it already, you should try to
find it. I only have the paper copy.
Anyway, it was suggested that the outer oven should run around 60-65 deg C,
while the thermistor is around 16.2 k ohms there. Personally, I believe this
is too high, and should be around 50-55 deg C or maybe a bit more - right
near the maximum ambient rating for the Z3801A, neglecting any internal box
temperature rise. If the performance specs are relaxed toward the higher end
of operating temperature range, then the outer oven may not have to run so
high. I don't recall, but think that may be the case.
Ed
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Try searching the Internet Archive for that old document whose links are now dead.
Sent from my iPhone
On Dec 7, 2022, at 11:29, ed breya via time-nuts time-nuts@lists.febo.com wrote:
I don't recall seeing that anyone ever reported the official temperature setpoint for the outer oven. Most of the info on the Z3801A still resides on realhamradio.com.
I found in my notes a paper printout of a webpage apparently put up someone named Shegnauer, circa 2006, showing the schematic, and some info and estimates for the temperature range, and a spice model of the control system operation. It's a nice document. I tried to find it online now, but it seems to have disappeared over the years. The same link showed up in old messages on time nuts and other lists, but it appears dead now. It must have been pretty well known, so it's likely still floating around out there at some URL or in someone's files. If you don't have it already, you should try to find it. I only have the paper copy.
Anyway, it was suggested that the outer oven should run around 60-65 deg C, while the thermistor is around 16.2 k ohms there. Personally, I believe this is too high, and should be around 50-55 deg C or maybe a bit more - right near the maximum ambient rating for the Z3801A, neglecting any internal box temperature rise. If the performance specs are relaxed toward the higher end of operating temperature range, then the outer oven may not have to run so high. I don't recall, but think that may be the case.
Ed
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Several of you are having trouble. Note that the document and all 4
images are on the k04bb manual site. Just follow the URL that DaveM
provided:
and note there are two entries. One is a html file and the other a
directory. In the directory are the 4 "missing" images.
Or, even simpler, just grab the PDF created and attached to the post by
DaveM an hour ago.
Note these files, including copies of the datasheets, are cached in
Stefan Hegnauer's time-nuts user page:
http://leapsecond.com/u/shegnauer/
A copy of his Z3801A power supply article survives here:
and the missing schematic for that was posted here:
https://febo.com/pipermail/time-nuts_lists.febo.com/2017-September/089331.html
and is also cached in the /u/shegnauer/ directory.
Hope that helps.
/tvb
On 12/7/2022 10:40 AM, Edesio Costa e Silva wrote:
Hi!
Found original page at
https://web.archive.org/web/20050318020038/http://homepage.sunrise.ch/mysunrise/shegnauer/Z3801A/Outer%20Oven%20Controller/z3801a_outer_oven_description.htm
but the images are missing.
Edésio
Hi
The idea of an unheated cell tower was indeed what they headed towards when this oven
was “designed”. Turns out there is a lot of hardware in a cell site that is very much not happy
at all when it gets below freezing. That killed the idea of the -40 degree cell tower on top of a
telephone pole dead. However it was to late for the initial version that HP came up with. They
stuck with the heater.
On a true double oven. The outer oven improves stability. It is set up along with the inner oven
and the design is optimized for both ovens. That’s not at all the case with this oven. It’s just a
warmup heater. It actually makes the stability of the device worse in most cases. Yes that sounds
crazy. For all the deep math and examples of just why this is true …. head over to Rick’s set
of papers. It’s all in there …..
Bob
On Dec 7, 2022, at 8:52 AM, paul swed via time-nuts time-nuts@lists.febo.com wrote:
Andy
For what you are doing I am not sure the outer ovens really needed. Its use
would have been for locations like Cel Towers and such that can be very
poorly heated if at all. I might guess you could put a temp probe in and
set it at some temp like 100 F and let it go. Or as I say not use it at all.
Others will have stronger opinions.
Regards
Paul
WB8TSL
On Wed, Dec 7, 2022 at 5:28 AM Andy Talbot via time-nuts <
time-nuts@lists.febo.com> wrote:
I've been given a defunct Z3801 with a fully working ovened oscillator.
The rest of the GPSDO circuitry is just junk and will be chucked, but I
want to get the DOXCO running as a backup high stability reference here.
I've worked out the power connections for the oscillator and inner oven,
and have powered it up with +12V & +24V supplies. It's currently just
warmed up and is happily generating a nice sine at 10MHz, with +0.3V (at
the moment) t on the EFC.
I applied 24V to the outer oven earlier to see what happened, and
measured
the thermistor resistance as it warmed, watching it fall from 110kΩat
room
temp to 30kΩ where I stopped. I know the controller for the outer oven
is
in external circuitry, but a brief web search failed to show a) what
temperature it should run at, To, and b) what the thermistor resistance
would be at that temperature, Ro.
Does anyone here know these figures off hand, or do I need to go to the
web and download the circuit and trace out the outer oven controller
details. I'll be doing my own controller circuitry, so just need To and
Ro.
Andy
www.g4jnt.com
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com