AD
Arthur Dent
Sat, Aug 22, 2015 3:19 PM
"Does anyone have any information or experience with this small
Trimble GPSDO?"
I had previously posted that what I thought these boards
were and how they might work and said I was waiting for 2
of these boards that I had ordered to arrive. Yesterday the
2 boards arrived in an Epacket from China. If you order
more than one board check them carefully on arrival because
the 2 I received were placed back-to-back with no padding
in between and a couple of the small SMD components on the
back side were partially ripped off the pc board. Fortunately
the damage was repairable and both boards are ok. What I found
was that there are at least 2 different versions of this GPSDO
and although both function the same, the location of some
of the parts differ.
First, there is the understandable language barrier and if
the sellers do have information that could help you get the
board up and running, it isn't included in the English
listings. Some of the info you can glean from looking at all
of the photos of the various units for sale on Ebay is just
from arrows on the photos telling where to connect power and
get the 10Mhz output. It took me a lot of trial and error plus
tracing out some of the runs to get to a point of where the
boards were working as intended.
The supply voltage required is stated to be 5.6 to 6VDC and
this goes to an LT1764A low dropout regulator set to 5VDC out
so my 'guess' is that 6VDC should be the minimum supply voltage
to make sure the regulator keeps working properly. With the
multicontact connector facing you you will see a 5A fuse near
the back right edge of the connector. I soldered the '+' supply
lead from my power supply (that puts out about 6.3VDC regulated)
to the left end of this fuse and the '-' supply lead to the ground
plane on the left of the connector. Using too high an input VDC
could cause the regulator to dissipate too much heat.
When the board is powered up with the antenna and the 10Mhz
output connected you will see no 10Mhz output. There are two
2-color LEDs on the board, on top of one version, and on the
bottom of the other version. One is the ALARM LED and the other
is the ACTIVITY LED. On power-up both light red then go out
(if all is well) then the ACT LED stays on solid green for maybe
10 minutes until the GPS receiver starts to track satellites. At
this point the ACT LED starts to flash a slow green and the 10Mhz
output is turned on. After a few more minutes when the board
achieves lock the ACT LED starts flashing green at a higher rate.
On the left front corner of the board is the 1 PPS connector.
To the right of that connector are 4 unpopulated holes for a
connector. I traced those out and found 2 went to a RS-232
chip that appears to be a different type depending on which of
the boards you receive. The left hole is ground (RS-232 pin 5
on the computer end), then the next hole is not connected, then
RS-232 pin 2, then pin 3 being the hole with the square index pad
on the right. Using a terminal emulator program and 57600 8N1N
I was able to communicate with the board. Typing '?' will give
you a long list of all the commands it will accept. For instance,
'STAT' and 'POSSTAT' are 2 of the commands that will give you
info on how the board is working. Typing *IDN? at the UCCM-P >
prompt returns 57964-60 for my board and POSSTAT shows up to 12
satellites can be tracked. The date code on my unit is 2009.
The board seems to work well but the OCXO runs pretty hot so it
probably isn't a double oven. The multicontact connector probably
has most of the functions and LED signals available but I couldn't
see using it so I'll get whatever signals I want directly off the
pc board.
-Arthur
"Does anyone have any information or experience with this small
Trimble GPSDO?"
I had previously posted that what I thought these boards
were and how they might work and said I was waiting for 2
of these boards that I had ordered to arrive. Yesterday the
2 boards arrived in an Epacket from China. If you order
more than one board check them carefully on arrival because
the 2 I received were placed back-to-back with no padding
in between and a couple of the small SMD components on the
back side were partially ripped off the pc board. Fortunately
the damage was repairable and both boards are ok. What I found
was that there are at least 2 different versions of this GPSDO
and although both function the same, the location of some
of the parts differ.
First, there is the understandable language barrier and if
the sellers do have information that could help you get the
board up and running, it isn't included in the English
listings. Some of the info you can glean from looking at all
of the photos of the various units for sale on Ebay is just
from arrows on the photos telling where to connect power and
get the 10Mhz output. It took me a lot of trial and error plus
tracing out some of the runs to get to a point of where the
boards were working as intended.
The supply voltage required is stated to be 5.6 to 6VDC and
this goes to an LT1764A low dropout regulator set to 5VDC out
so my 'guess' is that 6VDC should be the minimum supply voltage
to make sure the regulator keeps working properly. With the
multicontact connector facing you you will see a 5A fuse near
the back right edge of the connector. I soldered the '+' supply
lead from my power supply (that puts out about 6.3VDC regulated)
to the left end of this fuse and the '-' supply lead to the ground
plane on the left of the connector. Using too high an input VDC
could cause the regulator to dissipate too much heat.
When the board is powered up with the antenna and the 10Mhz
output connected you will see no 10Mhz output. There are two
2-color LEDs on the board, on top of one version, and on the
bottom of the other version. One is the ALARM LED and the other
is the ACTIVITY LED. On power-up both light red then go out
(if all is well) then the ACT LED stays on solid green for maybe
10 minutes until the GPS receiver starts to track satellites. At
this point the ACT LED starts to flash a slow green and the 10Mhz
output is turned on. After a few more minutes when the board
achieves lock the ACT LED starts flashing green at a higher rate.
On the left front corner of the board is the 1 PPS connector.
To the right of that connector are 4 unpopulated holes for a
connector. I traced those out and found 2 went to a RS-232
chip that appears to be a different type depending on which of
the boards you receive. The left hole is ground (RS-232 pin 5
on the computer end), then the next hole is not connected, then
RS-232 pin 2, then pin 3 being the hole with the square index pad
on the right. Using a terminal emulator program and 57600 8N1N
I was able to communicate with the board. Typing '?' will give
you a long list of all the commands it will accept. For instance,
'STAT' and 'POSSTAT' are 2 of the commands that will give you
info on how the board is working. Typing *IDN? at the UCCM-P >
prompt returns 57964-60 for my board and POSSTAT shows up to 12
satellites can be tracked. The date code on my unit is 2009.
The board seems to work well but the OCXO runs pretty hot so it
probably isn't a double oven. The multicontact connector probably
has most of the functions and LED signals available but I couldn't
see using it so I'll get whatever signals I want directly off the
pc board.
-Arthur
B
Bob
Sat, Aug 22, 2015 6:02 PM
Hi Arthur,
Thank you for this information. I have not received my board yet, I
probably still have a few weeks to go. The LT1764 will take up to 20V,
but I would never go to the edge. You could easily do 12V, the only
downside is the dissipation in the LT17654. Use a variable power supply
and raise the voltage slowly. Monitor the temperature with a
thermocouple, IR spot meter (radio shack had one for $10), or just use
your finger. If you can keep your finger on it comfortable for a long
period of time, the temp should be OK. The junction temp is rated for
125C.
Now on the flips side, my only concern is the regulator is not supplying
the oven power. Most Trimble OCXOs I see on Ebay are powered by +12.
When supplying only 6.5V the oven might not get up to temp producing
frequency instability and some erratic EFC stats.
See below, here is a 73090 OCXO (same as on some of those GPSDO boards)
powered by +12V. It's possible the regulator is meant to be powered
from +12V, supplying power to the digital logic and to the oscillator
portion of the OCXO. Then +12V directly supplies the oven.
http://www.ebay.com/itm/10-000000MHz-Trimble-Double-Oven-OCXO-Trimble-73090-Double-sinewave-15V-12V-/251883335405?hash=item3aa56aaeed
I will post my success and let everyone know how I make out. I
purchased this to have a backup for my Z3801 & Z3805. Both are on the
fritz, I will be post those trials and tribulations on a new thread.
Thanks so much for your response.
Bob
Hi Arthur,
Thank you for this information. I have not received my board yet, I
probably still have a few weeks to go. The LT1764 will take up to 20V,
but I would never go to the edge. You could easily do 12V, the only
downside is the dissipation in the LT17654. Use a variable power supply
and raise the voltage slowly. Monitor the temperature with a
thermocouple, IR spot meter (radio shack had one for $10), or just use
your finger. If you can keep your finger on it comfortable for a long
period of time, the temp should be OK. The junction temp is rated for
125C.
Now on the flips side, my only concern is the regulator is not supplying
the oven power. Most Trimble OCXOs I see on Ebay are powered by +12.
When supplying only 6.5V the oven might not get up to temp producing
frequency instability and some erratic EFC stats.
See below, here is a 73090 OCXO (same as on some of those GPSDO boards)
powered by +12V. It's possible the regulator is meant to be powered
from +12V, supplying power to the digital logic and to the oscillator
portion of the OCXO. Then +12V directly supplies the oven.
http://www.ebay.com/itm/10-000000MHz-Trimble-Double-Oven-OCXO-Trimble-73090-Double-sinewave-15V-12V-/251883335405?hash=item3aa56aaeed
I will post my success and let everyone know how I make out. I
purchased this to have a backup for my Z3801 & Z3805. Both are on the
fritz, I will be post those trials and tribulations on a new thread.
Thanks so much for your response.
Bob
BC
Bob Camp
Sat, Aug 22, 2015 7:29 PM
Hi
Great information !!!!!
On Aug 22, 2015, at 11:19 AM, Arthur Dent golgarfrincham@gmail.com wrote:
"Does anyone have any information or experience with this small
Trimble GPSDO?"
I had previously posted that what I thought these boards
were and how they might work and said I was waiting for 2
of these boards that I had ordered to arrive. Yesterday the
2 boards arrived in an Epacket from China. If you order
more than one board check them carefully on arrival because
the 2 I received were placed back-to-back with no padding
in between and a couple of the small SMD components on the
back side were partially ripped off the pc board. Fortunately
the damage was repairable and both boards are ok. What I found
was that there are at least 2 different versions of this GPSDO
and although both function the same, the location of some
of the parts differ.
First, there is the understandable language barrier and if
the sellers do have information that could help you get the
board up and running, it isn't included in the English
listings. Some of the info you can glean from looking at all
of the photos of the various units for sale on Ebay is just
from arrows on the photos telling where to connect power and
get the 10Mhz output. It took me a lot of trial and error plus
tracing out some of the runs to get to a point of where the
boards were working as intended.
The supply voltage required is stated to be 5.6 to 6VDC and
this goes to an LT1764A low dropout regulator set to 5VDC out
so my 'guess' is that 6VDC should be the minimum supply voltage
to make sure the regulator keeps working properly. With the
multicontact connector facing you you will see a 5A fuse near
the back right edge of the connector. I soldered the '+' supply
lead from my power supply (that puts out about 6.3VDC regulated)
to the left end of this fuse and the '-' supply lead to the ground
plane on the left of the connector. Using too high an input VDC
could cause the regulator to dissipate too much heat.
How much current does it pull at turn on? The regulator is only rated
to 3A so I would guess it’s less than that.
When the board is powered up with the antenna and the 10Mhz
output connected you will see no 10Mhz output. There are two
2-color LEDs on the board, on top of one version, and on the
bottom of the other version. One is the ALARM LED and the other
is the ACTIVITY LED. On power-up both light red then go out
(if all is well) then the ACT LED stays on solid green for maybe
10 minutes until the GPS receiver starts to track satellites. At
this point the ACT LED starts to flash a slow green and the 10Mhz
output is turned on. After a few more minutes when the board
achieves lock the ACT LED starts flashing green at a higher rate.
On the left front corner of the board is the 1 PPS connector.
To the right of that connector are 4 unpopulated holes for a
connector. I traced those out and found 2 went to a RS-232
chip that appears to be a different type depending on which of
the boards you receive. The left hole is ground (RS-232 pin 5
on the computer end), then the next hole is not connected, then
RS-232 pin 2, then pin 3 being the hole with the square index pad
on the right. Using a terminal emulator program and 57600 8N1N
I was able to communicate with the board. Typing '?' will give
you a long list of all the commands it will accept. For instance,
'STAT' and 'POSSTAT' are 2 of the commands that will give you
info on how the board is working. Typing *IDN? at the UCCM-P >
prompt returns 57964-60 for my board and POSSTAT shows up to 12
satellites can be tracked.
Time to get a few mods in on LH :)….
The date code on my unit is 2009.
The board seems to work well but the OCXO runs pretty hot so it
probably isn't a double oven.
I think it’s pretty safe to guess that a GPSDO designed well after SA
went off for good has a single oven rather than a double oven on it.
Bob
Hi
Great information !!!!!
> On Aug 22, 2015, at 11:19 AM, Arthur Dent <golgarfrincham@gmail.com> wrote:
>
> "Does anyone have any information or experience with this small
> Trimble GPSDO?"
>
> I had previously posted that what I thought these boards
> were and how they might work and said I was waiting for 2
> of these boards that I had ordered to arrive. Yesterday the
> 2 boards arrived in an Epacket from China. If you order
> more than one board check them carefully on arrival because
> the 2 I received were placed back-to-back with no padding
> in between and a couple of the small SMD components on the
> back side were partially ripped off the pc board. Fortunately
> the damage was repairable and both boards are ok. What I found
> was that there are at least 2 different versions of this GPSDO
> and although both function the same, the location of some
> of the parts differ.
>
> First, there is the understandable language barrier and if
> the sellers do have information that could help you get the
> board up and running, it isn't included in the English
> listings. Some of the info you can glean from looking at all
> of the photos of the various units for sale on Ebay is just
> from arrows on the photos telling where to connect power and
> get the 10Mhz output. It took me a lot of trial and error plus
> tracing out some of the runs to get to a point of where the
> boards were working as intended.
>
> The supply voltage required is stated to be 5.6 to 6VDC and
> this goes to an LT1764A low dropout regulator set to 5VDC out
> so my 'guess' is that 6VDC should be the minimum supply voltage
> to make sure the regulator keeps working properly. With the
> multicontact connector facing you you will see a 5A fuse near
> the back right edge of the connector. I soldered the '+' supply
> lead from my power supply (that puts out about 6.3VDC regulated)
> to the left end of this fuse and the '-' supply lead to the ground
> plane on the left of the connector. Using too high an input VDC
> could cause the regulator to dissipate too much heat.
How much current does it pull at turn on? The regulator is only rated
to 3A so I would *guess* it’s less than that.
>
> When the board is powered up with the antenna and the 10Mhz
> output connected you will see no 10Mhz output. There are two
> 2-color LEDs on the board, on top of one version, and on the
> bottom of the other version. One is the ALARM LED and the other
> is the ACTIVITY LED. On power-up both light red then go out
> (if all is well) then the ACT LED stays on solid green for maybe
> 10 minutes until the GPS receiver starts to track satellites. At
> this point the ACT LED starts to flash a slow green and the 10Mhz
> output is turned on. After a few more minutes when the board
> achieves lock the ACT LED starts flashing green at a higher rate.
>
> On the left front corner of the board is the 1 PPS connector.
> To the right of that connector are 4 unpopulated holes for a
> connector. I traced those out and found 2 went to a RS-232
There’s also this listing that shows an pair of 9 pins tacked on the
same board:
http://www.ebay.com/itm/Trimble-GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock-with-rs232-port-/261997391557?hash=item3d0042eec5
> chip that appears to be a different type depending on which of
> the boards you receive. The left hole is ground (RS-232 pin 5
> on the computer end), then the next hole is not connected, then
> RS-232 pin 2, then pin 3 being the hole with the square index pad
> on the right. Using a terminal emulator program and 57600 8N1N
> I was able to communicate with the board. Typing '?' will give
> you a long list of all the commands it will accept. For instance,
> 'STAT' and 'POSSTAT' are 2 of the commands that will give you
> info on how the board is working. Typing *IDN? at the UCCM-P >
> prompt returns 57964-60 for my board and POSSTAT shows up to 12
> satellites can be tracked.
Time to get a few mods in on LH :)….
> The date code on my unit is 2009.
> The board seems to work well but the OCXO runs pretty hot so it
> probably isn't a double oven.
I think it’s pretty safe to guess that a GPSDO designed well after SA
went off for good has a single oven rather than a double oven on it.
Bob
> The multicontact connector probably
> has most of the functions and LED signals available but I couldn't
> see using it so I'll get whatever signals I want directly off the
> pc board.
>
> -Arthur
> _______________________________________________
> 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.
BC
Bob Camp
Sat, Aug 22, 2015 11:32 PM
Hi
The gotcah (as many here have found out the hard way) is that the OCXO is indeed a +5V part and not a +12V unit. Apparently the internal Chinese market has them mis-labeld. That bleeds over into the listings you see on eBay. There are a lot of mistaken listings ….
Bob
On Aug 22, 2015, at 2:02 PM, Bob rbenward@verizon.net wrote:
Hi Arthur,
Thank you for this information. I have not received my board yet, I probably still have a few weeks to go. The LT1764 will take up to 20V, but I would never go to the edge. You could easily do 12V, the only downside is the dissipation in the LT17654. Use a variable power supply and raise the voltage slowly. Monitor the temperature with a thermocouple, IR spot meter (radio shack had one for $10), or just use your finger. If you can keep your finger on it comfortable for a long period of time, the temp should be OK. The junction temp is rated for 125C.
Now on the flips side, my only concern is the regulator is not supplying the oven power. Most Trimble OCXOs I see on Ebay are powered by +12. When supplying only 6.5V the oven might not get up to temp producing frequency instability and some erratic EFC stats.
See below, here is a 73090 OCXO (same as on some of those GPSDO boards) powered by +12V. It's possible the regulator is meant to be powered from +12V, supplying power to the digital logic and to the oscillator portion of the OCXO. Then +12V directly supplies the oven.
http://www.ebay.com/itm/10-000000MHz-Trimble-Double-Oven-OCXO-Trimble-73090-Double-sinewave-15V-12V-/251883335405?hash=item3aa56aaeed
I will post my success and let everyone know how I make out. I purchased this to have a backup for my Z3801 & Z3805. Both are on the fritz, I will be post those trials and tribulations on a new thread. Thanks so much for your response.
Bob
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.
Hi
The gotcah (as many here have found out the hard way) is that the OCXO is indeed a +5V part and not a +12V unit. Apparently the internal Chinese market has them mis-labeld. That bleeds over into the listings you see on eBay. There are a *lot* of mistaken listings ….
Bob
> On Aug 22, 2015, at 2:02 PM, Bob <rbenward@verizon.net> wrote:
>
> Hi Arthur,
> Thank you for this information. I have not received my board yet, I probably still have a few weeks to go. The LT1764 will take up to 20V, but I would never go to the edge. You could easily do 12V, the only downside is the dissipation in the LT17654. Use a variable power supply and raise the voltage slowly. Monitor the temperature with a thermocouple, IR spot meter (radio shack had one for $10), or just use your finger. If you can keep your finger on it comfortable for a long period of time, the temp should be OK. The junction temp is rated for 125C.
>
> Now on the flips side, my only concern is the regulator is not supplying the oven power. Most Trimble OCXOs I see on Ebay are powered by +12. When supplying only 6.5V the oven might not get up to temp producing frequency instability and some erratic EFC stats.
>
> See below, here is a 73090 OCXO (same as on some of those GPSDO boards) powered by +12V. It's possible the regulator is meant to be powered from +12V, supplying power to the digital logic and to the oscillator portion of the OCXO. Then +12V directly supplies the oven.
>
> http://www.ebay.com/itm/10-000000MHz-Trimble-Double-Oven-OCXO-Trimble-73090-Double-sinewave-15V-12V-/251883335405?hash=item3aa56aaeed
>
> I will post my success and let everyone know how I make out. I purchased this to have a backup for my Z3801 & Z3805. Both are on the fritz, I will be post those trials and tribulations on a new thread. Thanks so much for your response.
>
> Bob
> _______________________________________________
> 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.
A
Angus
Sun, Aug 23, 2015 12:29 PM
Hi Bob,
I got a Trimble 57963-80 last year and the 73090 OXCO and some other
parts on it are supplied with 5V from the LT1764A.
The DSP, FPGA, etc., also have various small regulators supplying
their supply voltages - one even has a dropper resistor in series.
These are connected to the main input supply, so raising it above what
it should be is probably not a good idea.
I thought at first that the LT1764A would be thermally connected to
the fixing hole beside it so that the heat could be removed, but it is
only connected to the copper on the top of board at that point - then
again, that may be the way it was mounted.
I did put a temp sensor on the 1764 to see how much it heated up
during warm up and when running, but neither looked close to being a
problem when run at 6V and room temperature.
At 6V, it took 2A during warm up and just over 1A when running at room
temp, but the warm up is fast.
When I got the board, someone had written on the OCXO with a marker
pen what the pins were, and the power was marked as 12V, and an EFC
voltage was also written on (about 0.2V from what I measured) which
was all a little weird.
It was listed as having been tested, but since the seller said that
they had no connection info, who tested it and how is anyone's
guess...
Angus.
On Sat, 22 Aug 2015 14:02:35 -0400, you wrote:
Hi Arthur,
Thank you for this information. I have not received my board yet, I
probably still have a few weeks to go. The LT1764 will take up to 20V,
but I would never go to the edge. You could easily do 12V, the only
downside is the dissipation in the LT17654. Use a variable power supply
and raise the voltage slowly. Monitor the temperature with a
thermocouple, IR spot meter (radio shack had one for $10), or just use
your finger. If you can keep your finger on it comfortable for a long
period of time, the temp should be OK. The junction temp is rated for
125C.
Now on the flips side, my only concern is the regulator is not supplying
the oven power. Most Trimble OCXOs I see on Ebay are powered by +12.
When supplying only 6.5V the oven might not get up to temp producing
frequency instability and some erratic EFC stats.
See below, here is a 73090 OCXO (same as on some of those GPSDO boards)
powered by +12V. It's possible the regulator is meant to be powered
from +12V, supplying power to the digital logic and to the oscillator
portion of the OCXO. Then +12V directly supplies the oven.
http://www.ebay.com/itm/10-000000MHz-Trimble-Double-Oven-OCXO-Trimble-73090-Double-sinewave-15V-12V-/251883335405?hash=item3aa56aaeed
I will post my success and let everyone know how I make out. I
purchased this to have a backup for my Z3801 & Z3805. Both are on the
fritz, I will be post those trials and tribulations on a new thread.
Thanks so much for your response.
Bob
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.
Hi Bob,
I got a Trimble 57963-80 last year and the 73090 OXCO and some other
parts on it are supplied with 5V from the LT1764A.
The DSP, FPGA, etc., also have various small regulators supplying
their supply voltages - one even has a dropper resistor in series.
These are connected to the main input supply, so raising it above what
it should be is probably not a good idea.
I thought at first that the LT1764A would be thermally connected to
the fixing hole beside it so that the heat could be removed, but it is
only connected to the copper on the top of board at that point - then
again, that may be the way it was mounted.
I did put a temp sensor on the 1764 to see how much it heated up
during warm up and when running, but neither looked close to being a
problem when run at 6V and room temperature.
At 6V, it took 2A during warm up and just over 1A when running at room
temp, but the warm up is fast.
When I got the board, someone had written on the OCXO with a marker
pen what the pins were, and the power was marked as 12V, and an EFC
voltage was also written on (about 0.2V from what I measured) which
was all a little weird.
It was listed as having been tested, but since the seller said that
they had no connection info, who tested it and how is anyone's
guess...
Angus.
On Sat, 22 Aug 2015 14:02:35 -0400, you wrote:
>Hi Arthur,
>Thank you for this information. I have not received my board yet, I
>probably still have a few weeks to go. The LT1764 will take up to 20V,
>but I would never go to the edge. You could easily do 12V, the only
>downside is the dissipation in the LT17654. Use a variable power supply
>and raise the voltage slowly. Monitor the temperature with a
>thermocouple, IR spot meter (radio shack had one for $10), or just use
>your finger. If you can keep your finger on it comfortable for a long
>period of time, the temp should be OK. The junction temp is rated for
>125C.
>Now on the flips side, my only concern is the regulator is not supplying
>the oven power. Most Trimble OCXOs I see on Ebay are powered by +12.
>When supplying only 6.5V the oven might not get up to temp producing
>frequency instability and some erratic EFC stats.
>
>See below, here is a 73090 OCXO (same as on some of those GPSDO boards)
>powered by +12V. It's possible the regulator is meant to be powered
>from +12V, supplying power to the digital logic and to the oscillator
>portion of the OCXO. Then +12V directly supplies the oven.
>
>http://www.ebay.com/itm/10-000000MHz-Trimble-Double-Oven-OCXO-Trimble-73090-Double-sinewave-15V-12V-/251883335405?hash=item3aa56aaeed
>
>I will post my success and let everyone know how I make out. I
>purchased this to have a backup for my Z3801 & Z3805. Both are on the
>fritz, I will be post those trials and tribulations on a new thread.
>Thanks so much for your response.
>
>Bob
>_______________________________________________
>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.
A
Angus
Sun, Aug 23, 2015 1:56 PM
On the left front corner of the board is the 1 PPS connector.
To the right of that connector are 4 unpopulated holes for a
connector. I traced those out and found 2 went to a RS-232
chip that appears to be a different type depending on which of
the boards you receive. The left hole is ground (RS-232 pin 5
on the computer end), then the next hole is not connected, then
RS-232 pin 2, then pin 3 being the hole with the square index pad
on the right. Using a terminal emulator program and 57600 8N1N
I was able to communicate with the board. Typing '?' will give
you a long list of all the commands it will accept. For instance,
'STAT' and 'POSSTAT' are 2 of the commands that will give you
info on how the board is working. Typing *IDN? at the UCCM-P >
prompt returns 57964-60 for my board and POSSTAT shows up to 12
satellites can be tracked. The date code on my unit is 2009.
The board seems to work well but the OCXO runs pretty hot so it
probably isn't a double oven. The multicontact connector probably
has most of the functions and LED signals available but I couldn't
see using it so I'll get whatever signals I want directly off the
pc board.
Hi Arthur,
That's interesting - I connected my one up to Trimble studio and
others, but got no joy - I never thought of just asking it :)
I went through the connections on the other pins, but most are just to
the FPGA or 0V. Most don't appear to be doing a lot - maybe they need
whatever is meant to be connected to this board to be connected before
they do anything.
There is another serial port which is the same baud rate but appears
to be binary, and prattles away every 2 seconds:
Pin 36 goes to Pin 4 of the UART (RX)
Pin 37 goes to Pin 8 of the UART (TX)
Pin 2 has binary data of about 64 bits at 1.6us/bit - looks like maybe
a timer or similar.
(Above pin numbers assume V+ is connected to pins 44-50 and are
hopefully correct, but always worth checking)
Angus.
>On the left front corner of the board is the 1 PPS connector.
>To the right of that connector are 4 unpopulated holes for a
>connector. I traced those out and found 2 went to a RS-232
>chip that appears to be a different type depending on which of
>the boards you receive. The left hole is ground (RS-232 pin 5
>on the computer end), then the next hole is not connected, then
>RS-232 pin 2, then pin 3 being the hole with the square index pad
>on the right. Using a terminal emulator program and 57600 8N1N
>I was able to communicate with the board. Typing '?' will give
>you a long list of all the commands it will accept. For instance,
>'STAT' and 'POSSTAT' are 2 of the commands that will give you
>info on how the board is working. Typing *IDN? at the UCCM-P >
>prompt returns 57964-60 for my board and POSSTAT shows up to 12
>satellites can be tracked. The date code on my unit is 2009.
>The board seems to work well but the OCXO runs pretty hot so it
>probably isn't a double oven. The multicontact connector probably
>has most of the functions and LED signals available but I couldn't
>see using it so I'll get whatever signals I want directly off the
>pc board.
Hi Arthur,
That's interesting - I connected my one up to Trimble studio and
others, but got no joy - I never thought of just asking it :)
I went through the connections on the other pins, but most are just to
the FPGA or 0V. Most don't appear to be doing a lot - maybe they need
whatever is meant to be connected to this board to be connected before
they do anything.
There is another serial port which is the same baud rate but appears
to be binary, and prattles away every 2 seconds:
Pin 36 goes to Pin 4 of the UART (RX)
Pin 37 goes to Pin 8 of the UART (TX)
Pin 2 has binary data of about 64 bits at 1.6us/bit - looks like maybe
a timer or similar.
(Above pin numbers assume V+ is connected to pins 44-50 and are
hopefully correct, but always worth checking)
Angus.
BB
Bob Benward
Mon, Aug 24, 2015 3:36 AM
Hi Angus,
Thanks for your reply. My original suspicion is the +6.5V rail. That needs
to come from somewhere, and you need headroom if it's an unregulated input.
Pumping 2A through a regulator like that is no easy feat. Although rated
for 3A, you need to keep the junction temperature below 125C. The part has a
30C/W thermal resistance (Tja) with a 1" square copper pad. So 6.5V and 3A
calculate as follows: (6.5V-5V)3A=4.5W. 4.5W30C/W=135C RISE, add that to
ambient, 25C, and you are 35C over max junction. In my world we have a 70C
ambient, and that leaves me (125C-70C)/30C/W=1.83W, or a maximum of
1.83W/1.5V=1.22A. Generally a tab mounted TO-220 (a D2Pak) can have a Tjc
(junction to case) or less than 1C/W. It's all the reest of the mounting
that piles on the thermal resistance.
The Trimble board has a top layer pad, some far side pad, and probably
multiple layer of ground plane over the rest of the board. The mounting
post is mostly likely part of the thermal resistance calculation. There is
also a time constant involved, it probably can't take the 2A forever, just
long enough to get the oven up to temp. I suspect they may have gotten the
thermal impedance down as low as 10C/W. I will test it with 12V and let
everyone know if I fry the board.
Bob
-----Original Message-----
From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Angus
Sent: Sunday, August 23, 2015 8:30 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Trimble GPS board
Hi Bob,
I got a Trimble 57963-80 last year and the 73090 OXCO and some other
parts on it are supplied with 5V from the LT1764A.
The DSP, FPGA, etc., also have various small regulators supplying their
voltages - one even has a dropper resistor in series.
These are connected to the main input supply, so raising it above what
should be is probably not a good idea.
I thought at first that the LT1764A would be thermally connected to the
fixing hole beside it so that the heat could be removed, but it is only
connected to the copper on the top of board at that point - then again,
may be the way it was mounted.
I did put a temp sensor on the 1764 to see how much it heated up during
warm up and when running, but neither looked close to being a problem
when run at 6V and room temperature.
At 6V, it took 2A during warm up and just over 1A when running at room
temp, but the warm up is fast.
When I got the board, someone had written on the OCXO with a marker pen
what the pins were, and the power was marked as 12V, and an EFC voltage
was also written on (about 0.2V from what I measured) which was all a
weird.
It was listed as having been tested, but since the seller said that they
connection info, who tested it and how is anyone's guess...
Angus.
On Sat, 22 Aug 2015 14:02:35 -0400, you wrote:
Hi Arthur,
Thank you for this information. I have not received my board yet, I
probably still have a few weeks to go. The LT1764 will take up to 20V,
but I would never go to the edge. You could easily do 12V, the only
downside is the dissipation in the LT17654. Use a variable power
supply and raise the voltage slowly. Monitor the temperature with a
thermocouple, IR spot meter (radio shack had one for $10), or just use
your finger. If you can keep your finger on it comfortable for a long
period of time, the temp should be OK. The junction temp is rated for
125C.
Now on the flips side, my only concern is the regulator is not
supplying the oven power. Most Trimble OCXOs I see on Ebay are powered
When supplying only 6.5V the oven might not get up to temp producing
frequency instability and some erratic EFC stats.
See below, here is a 73090 OCXO (same as on some of those GPSDO boards)
powered by +12V. It's possible the regulator is meant to be powered
from +12V, supplying power to the digital logic and to the oscillator
portion of the OCXO. Then +12V directly supplies the oven.
http://www.ebay.com/itm/10-000000MHz-Trimble-Double-Oven-OCXO-
3090-Double-sinewave-15V-12V-/251883335405?hash=item3aa56aaeed
I will post my success and let everyone know how I make out. I
purchased this to have a backup for my Z3801 & Z3805. Both are on the
fritz, I will be post those trials and tribulations on a new thread.
Thanks so much for your response.
Bob
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.
Hi Angus,
Thanks for your reply. My original suspicion is the +6.5V rail. That needs
to come from somewhere, and you need headroom if it's an unregulated input.
Pumping 2A through a regulator like that is no easy feat. Although rated
for 3A, you need to keep the junction temperature below 125C. The part has a
30C/W thermal resistance (Tja) with a 1" square copper pad. So 6.5V and 3A
calculate as follows: (6.5V-5V)*3A=4.5W. 4.5W*30C/W=135C RISE, add that to
ambient, 25C, and you are 35C over max junction. In my world we have a 70C
ambient, and that leaves me (125C-70C)/30C/W=1.83W, or a maximum of
1.83W/1.5V=1.22A. Generally a tab mounted TO-220 (a D2Pak) can have a Tjc
(junction to case) or less than 1C/W. It's all the reest of the mounting
that piles on the thermal resistance.
The Trimble board has a top layer pad, some far side pad, and probably
multiple layer of ground plane over the rest of the board. The mounting
post is mostly likely part of the thermal resistance calculation. There is
also a time constant involved, it probably can't take the 2A forever, just
long enough to get the oven up to temp. I suspect they may have gotten the
thermal impedance down as low as 10C/W. I will test it with 12V and let
everyone know if I fry the board.
Bob
>>> -----Original Message-----
>>> From: time-nuts [mailto:time-nuts-bounces@febo.com] On Behalf Of Angus
>>> Sent: Sunday, August 23, 2015 8:30 AM
>>> To: Discussion of precise time and frequency measurement
>>> Subject: Re: [time-nuts] Trimble GPS board
>>>
>>> Hi Bob,
>>>
>>> I got a Trimble 57963-80 last year and the 73090 OXCO and some other
>>> parts on it are supplied with 5V from the LT1764A.
>>>
>>> The DSP, FPGA, etc., also have various small regulators supplying their
supply
>>> voltages - one even has a dropper resistor in series.
>>> These are connected to the main input supply, so raising it above what
it
>>> should be is probably not a good idea.
>>>
>>> I thought at first that the LT1764A would be thermally connected to the
>>> fixing hole beside it so that the heat could be removed, but it is only
>>> connected to the copper on the top of board at that point - then again,
that
>>> may be the way it was mounted.
>>>
>>> I did put a temp sensor on the 1764 to see how much it heated up during
>>> warm up and when running, but neither looked close to being a problem
>>> when run at 6V and room temperature.
>>> At 6V, it took 2A during warm up and just over 1A when running at room
>>> temp, but the warm up is fast.
>>>
>>> When I got the board, someone had written on the OCXO with a marker pen
>>> what the pins were, and the power was marked as 12V, and an EFC voltage
>>> was also written on (about 0.2V from what I measured) which was all a
little
>>> weird.
>>>
>>> It was listed as having been tested, but since the seller said that they
had no
>>> connection info, who tested it and how is anyone's guess...
>>>
>>> Angus.
>>>
>>>
>>> On Sat, 22 Aug 2015 14:02:35 -0400, you wrote:
>>>
>>> >Hi Arthur,
>>> >Thank you for this information. I have not received my board yet, I
>>> >probably still have a few weeks to go. The LT1764 will take up to 20V,
>>> >but I would never go to the edge. You could easily do 12V, the only
>>> >downside is the dissipation in the LT17654. Use a variable power
>>> >supply and raise the voltage slowly. Monitor the temperature with a
>>> >thermocouple, IR spot meter (radio shack had one for $10), or just use
>>> >your finger. If you can keep your finger on it comfortable for a long
>>> >period of time, the temp should be OK. The junction temp is rated for
>>> >125C.
>>>
>>>
>>>
>>>
>>> >Now on the flips side, my only concern is the regulator is not
>>> >supplying the oven power. Most Trimble OCXOs I see on Ebay are powered
>>> by +12.
>>> >When supplying only 6.5V the oven might not get up to temp producing
>>> >frequency instability and some erratic EFC stats.
>>> >
>>> >See below, here is a 73090 OCXO (same as on some of those GPSDO boards)
>>> >powered by +12V. It's possible the regulator is meant to be powered
>>> >from +12V, supplying power to the digital logic and to the oscillator
>>> >portion of the OCXO. Then +12V directly supplies the oven.
>>> >
>>> >http://www.ebay.com/itm/10-000000MHz-Trimble-Double-Oven-OCXO-
>>> Trimble-7
>>> >3090-Double-sinewave-15V-12V-/251883335405?hash=item3aa56aaeed
>>> >
>>> >I will post my success and let everyone know how I make out. I
>>> >purchased this to have a backup for my Z3801 & Z3805. Both are on the
>>> >fritz, I will be post those trials and tribulations on a new thread.
>>> >Thanks so much for your response.
>>> >
>>> >Bob
>>> >_______________________________________________
>>> >time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
>>> >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> >and follow the instructions there.
>>> _______________________________________________
>>> time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> and follow the instructions there.
A
Angus
Fri, Aug 28, 2015 8:46 PM
On Sun, 23 Aug 2015 23:36:27 -0400, you wrote:
Hi Angus,
Thanks for your reply. My original suspicion is the +6.5V rail. That needs
to come from somewhere, and you need headroom if it's an unregulated input.
Pumping 2A through a regulator like that is no easy feat. Although rated
for 3A, you need to keep the junction temperature below 125C. The part has a
30C/W thermal resistance (Tja) with a 1" square copper pad. So 6.5V and 3A
calculate as follows: (6.5V-5V)3A=4.5W. 4.5W30C/W=135C RISE, add that to
ambient, 25C, and you are 35C over max junction. In my world we have a 70C
ambient, and that leaves me (125C-70C)/30C/W=1.83W, or a maximum of
1.83W/1.5V=1.22A. Generally a tab mounted TO-220 (a D2Pak) can have a Tjc
(junction to case) or less than 1C/W. It's all the reest of the mounting
that piles on the thermal resistance.
The Trimble board has a top layer pad, some far side pad, and probably
multiple layer of ground plane over the rest of the board. The mounting
post is mostly likely part of the thermal resistance calculation. There is
also a time constant involved, it probably can't take the 2A forever, just
long enough to get the oven up to temp. I suspect they may have gotten the
thermal impedance down as low as 10C/W. I will test it with 12V and let
everyone know if I fry the board.
Bob
Hi Bob,
There's not really any need for a 6V or so rail - a DC-DC converter
(and probably some filtering) can provide the right voltage just where
it's needed.
What looks like a Symmetricom variant is in listing #271483752431.
It does appear to have a DC-DC converter, etc., on the board.
Anyway, I dug out my Trimble to have a look at it, and I see that
there's a 10V tantalum capacitor on the input power, so it's certainly
not meant to run on 12V.
Angus.
On Sun, 23 Aug 2015 23:36:27 -0400, you wrote:
>Hi Angus,
>Thanks for your reply. My original suspicion is the +6.5V rail. That needs
>to come from somewhere, and you need headroom if it's an unregulated input.
>Pumping 2A through a regulator like that is no easy feat. Although rated
>for 3A, you need to keep the junction temperature below 125C. The part has a
>30C/W thermal resistance (Tja) with a 1" square copper pad. So 6.5V and 3A
>calculate as follows: (6.5V-5V)*3A=4.5W. 4.5W*30C/W=135C RISE, add that to
>ambient, 25C, and you are 35C over max junction. In my world we have a 70C
>ambient, and that leaves me (125C-70C)/30C/W=1.83W, or a maximum of
>1.83W/1.5V=1.22A. Generally a tab mounted TO-220 (a D2Pak) can have a Tjc
>(junction to case) or less than 1C/W. It's all the reest of the mounting
>that piles on the thermal resistance.
>
>The Trimble board has a top layer pad, some far side pad, and probably
>multiple layer of ground plane over the rest of the board. The mounting
>post is mostly likely part of the thermal resistance calculation. There is
>also a time constant involved, it probably can't take the 2A forever, just
>long enough to get the oven up to temp. I suspect they may have gotten the
>thermal impedance down as low as 10C/W. I will test it with 12V and let
>everyone know if I fry the board.
>
>Bob
>
Hi Bob,
There's not really any need for a 6V or so rail - a DC-DC converter
(and probably some filtering) can provide the right voltage just where
it's needed.
What looks like a Symmetricom variant is in listing #271483752431.
It does appear to have a DC-DC converter, etc., on the board.
Anyway, I dug out my Trimble to have a look at it, and I see that
there's a 10V tantalum capacitor on the input power, so it's certainly
not meant to run on 12V.
Angus.
BC
Bob Camp
Fri, Aug 28, 2015 11:36 PM
Hi Angus,
Thanks for your reply. My original suspicion is the +6.5V rail. That needs
to come from somewhere, and you need headroom if it's an unregulated input.
Pumping 2A through a regulator like that is no easy feat. Although rated
for 3A, you need to keep the junction temperature below 125C. The part has a
30C/W thermal resistance (Tja) with a 1" square copper pad. So 6.5V and 3A
calculate as follows: (6.5V-5V)3A=4.5W. 4.5W30C/W=135C RISE, add that to
ambient, 25C, and you are 35C over max junction. In my world we have a 70C
ambient, and that leaves me (125C-70C)/30C/W=1.83W, or a maximum of
1.83W/1.5V=1.22A. Generally a tab mounted TO-220 (a D2Pak) can have a Tjc
(junction to case) or less than 1C/W. It's all the reest of the mounting
that piles on the thermal resistance.
The Trimble board has a top layer pad, some far side pad, and probably
multiple layer of ground plane over the rest of the board. The mounting
post is mostly likely part of the thermal resistance calculation. There is
also a time constant involved, it probably can't take the 2A forever, just
long enough to get the oven up to temp. I suspect they may have gotten the
thermal impedance down as low as 10C/W. I will test it with 12V and let
everyone know if I fry the board.
Bob
Hi Bob,
There's not really any need for a 6V or so rail - a DC-DC converter
(and probably some filtering) can provide the right voltage just where
it's needed.
What looks like a Symmetricom variant is in listing #271483752431.
It does appear to have a DC-DC converter, etc., on the board.
Anyway, I dug out my Trimble to have a look at it, and I see that
there's a 10V tantalum capacitor on the input power, so it's certainly
not meant to run on 12V.
If they derated that cap 20%, it is not meant to run on anything over 8V. It’s
rare to see a voltage between 6.3 and 10 on those parts. Obviously 6.3 is to close
to run on a 6V line and get any decent MTBF.
Bob
HI
> On Aug 28, 2015, at 4:46 PM, Angus <not.again@btinternet.com> wrote:
>
> On Sun, 23 Aug 2015 23:36:27 -0400, you wrote:
>
>> Hi Angus,
>> Thanks for your reply. My original suspicion is the +6.5V rail. That needs
>> to come from somewhere, and you need headroom if it's an unregulated input.
>> Pumping 2A through a regulator like that is no easy feat. Although rated
>> for 3A, you need to keep the junction temperature below 125C. The part has a
>> 30C/W thermal resistance (Tja) with a 1" square copper pad. So 6.5V and 3A
>> calculate as follows: (6.5V-5V)*3A=4.5W. 4.5W*30C/W=135C RISE, add that to
>> ambient, 25C, and you are 35C over max junction. In my world we have a 70C
>> ambient, and that leaves me (125C-70C)/30C/W=1.83W, or a maximum of
>> 1.83W/1.5V=1.22A. Generally a tab mounted TO-220 (a D2Pak) can have a Tjc
>> (junction to case) or less than 1C/W. It's all the reest of the mounting
>> that piles on the thermal resistance.
>>
>> The Trimble board has a top layer pad, some far side pad, and probably
>> multiple layer of ground plane over the rest of the board. The mounting
>> post is mostly likely part of the thermal resistance calculation. There is
>> also a time constant involved, it probably can't take the 2A forever, just
>> long enough to get the oven up to temp. I suspect they may have gotten the
>> thermal impedance down as low as 10C/W. I will test it with 12V and let
>> everyone know if I fry the board.
>>
>> Bob
>>
>
> Hi Bob,
>
> There's not really any need for a 6V or so rail - a DC-DC converter
> (and probably some filtering) can provide the right voltage just where
> it's needed.
>
> What looks like a Symmetricom variant is in listing #271483752431.
> It does appear to have a DC-DC converter, etc., on the board.
>
> Anyway, I dug out my Trimble to have a look at it, and I see that
> there's a 10V tantalum capacitor on the input power, so it's certainly
> not meant to run on 12V.
If they derated that cap 20%, it is not meant to run on anything over 8V. It’s
rare to see a voltage between 6.3 and 10 on those parts. Obviously 6.3 is to close
to run on a 6V line and get any decent MTBF.
Bob
>
> Angus.
> _______________________________________________
> 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.
