After I purchased 4 of these he jacked his price up LOL
I really like these units, nice and small AND brand new except for the salvaged OCXO they are using.
They have 2 flavors, sine or square wave output so do a search on them.
One thing I read about these tho is that there is a slight bug in its firmware and they run just a touch on the slow side but its so minute that I cant measure it nor will it make any difference for me. I think its somere in the beginning of this thread ?
http://www.ebay.com/itm/HW-HUAWEI-GPS-DISCIPLINED-CLOCK-GPSDO-OSCILLATOR-Antenna-power-supply-/111716558224?hash=item1a02d36590
Wiss, Let us know how your new toy works when you get it
Are you sure these are the ones you bought? I've just noticed that there are now three different GPSDOs on ebay that all have this same aluminum+PCB case. The one you posted actually uses an Oscilloquartz 'Star 4' board. I found a datasheet on that, but no user manual. The second is the home-made one that appears to be running slightly slow. The third is a Trimble unit. I bought the bare Trimble unit from somewhere else and just powered it up yesterday. I can't find any data on it, but it uses a command set that is somewhat similar to the Z38xx series. It only took about 10 minutes from a cold start to figure out where it was and lock the oscillator! I didn't even have time to get the PC connected!
Ed
Is this the newer Trimble unit to which you are referring?
http://www.ebay.com/itm/Trimble-GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock-Antenna-power-/181810679481?hash=item2a54c2ceb9
Is this the newer Trimble unit to which you are referring?
http://www.ebay.com/itm/Trimble-GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock-Antenna-power-/181810679481?hash=item2a54c2ceb9
That's the one. It's also available as a bare board here:
http://www.ebay.com/itm/Trimble-GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock-/181777773438
Is this the newer Trimble unit to which you are referring?
http://www.ebay.com/itm/Trimble-GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock-Antenna-power-/181810679481?hash=item2a54c2ceb9That's the one. It's also available as a bare board here:
http://www.ebay.com/itm/Trimble-GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock-/181777773438
How have you (or have you) housed the bare board? I would worry about heat disappation if it is housed in that aluminum box shown on the eBay listing I posted. In the photos there, it looks like there is a second PCB underneath the Trimble PCB. I wonder what that is.
I've found one of those old Rockwell "Jupiter" GPS boards in a back drawer. Apparently it's good because it has a 10kHz GPS derived frequency standard that can be used in a PLL with a TXCO to give a GPS disciplined 10 MHz... http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm
Unfortunately I am not getting anything out of it on the RS232 pins (crappy non standard header doesn't help!). I think I have to set some pull ups and grounds correctly.
P.S. Hey, this makes 104 replies in this thread and over 3700 views! I guess somebody's interested in our little chat!
P.S. Hey, this makes 104 replies in this thread and over 3700 views! I guess somebody's interested in our little chat!
Yes indeed. I can't speak for others, but I've had great fun playing around with this Lucent unit this weekend. Thanks much for all your help!
The 10 KHz gives you the ability to use analog PLL techniques. That's what Miller did. If you only have 1 PPS to work with, you pretty much need to go to digital PLLs and microprocessors.
Non-standard header? The 'classic' board is the TU30 which has a 2x10 header on 0.1" centers. It doesn't get more standard than that. You must have a different model. Jupiter was a product line so there are multiple models. I think some of them have headers with 2 mm spacing. Consider yourself lucky. I've got a board that has a header on 0.05" centers.
Are you using something like a MAX232 to convert the signals from TTL to RS-232? If not, you might need to invert the signals. I've heard of people feeding TTL signals directly into a COM port, but I've never done it myself so I don't know the details.
The 10 KHz gives you the ability to use analog PLL techniques. That's what Miller did. If you only have 1 PPS to work with, you pretty much need to go to digital PLLs and microprocessors.
Non-standard header? The 'classic' board is the TU30 which has a 2x10 header on 0.1" centers. It doesn't get more standard than that. You must have a different model. Jupiter was a product line so there are multiple models. I think some of them have headers with 2 mm spacing. Consider yourself lucky. I've got a board that has a header on 0.05" centers.Indeed, mine are 0.07" - and it is the TU30 board, JUP8 V180 firmware, all the ICs are dated late 1999.QuoteAre you using something like a MAX232 to convert the signals from TTL to RS-232? If not, you might need to invert the signals. I've heard of people feeding TTL signals directly into a COM port, but I've never done it myself so I don't know the details.Yeah, I've used a CP2102 USB/UART. I've also had my 'scope on the RX and TX lines and there is nothing there.
Here is a summary of the info I've collected on the Lucent KS-24361 so far. Hopefully this saves someone from having to subject themselves to TimeNuts mailing list archives. By the way - see below for details on that continous output from connector J6 that I pasted earlier in the thread.
Useful Links
EEVBlog Thread (here):
https://www.eevblog.com/forum/testgear/economical-option-for-precision-frequency-reference/
Time Nuts thread with pinouts and other details:
http://permalink.gmane.org/gmane.comp.time.nuts/40898
Original Time Nuts thread:
https://www.febo.com/pipermail/time-nuts/2014-October/087274.html
J6 (RS422/1PPS) Pinout
1 - PPS+
3 - GND
4 - RX+
5 - TX+
6 - PPS-
7 - GND
8 - RX-
9 - TX-
All others not connected
J8 (Diagnostic) Pinout
3 - GND
4 - RX+
5 - TX+
7 - GND
8 - RX-
9 - TX-
All others not connected
Info on interfacing to PC using the Gearmo USB to RS-422 converter
Gearmo USB to RS-485/RS-422 Converter, model # US-485422.
Link to product on Gearmo.com: http://www.gearmo.com/shop/usb-to-rs485-rs422-converter-with-ftdi-chip/
Link to product on Amazon: http://www.amazon.com/gp/product/B005CPLOVW
The Gearmo uses an FTDI chip, and they have a download link to the FTDI drivers on their web site. You can also just grab the FTDI drivers from their web site (ftdichip.com). I believe the FTDI chip is RS232RL. It's also possible that the drivers can be installed via Windows Update
The Gearmo product comes with a little terminal board connected to a DB9-male connector. The terminal strip connections are labelled and match the names below (T/R+, RXD+, etc.). Note that the Gearmo documentation, and labels on the terminal strip, refer to "TXD" as "T/R".
Gearmo RTFG-u/REF0/1 J6 & J8
-------- ----------------
1 (T/R+) --> 4 (RX+)
2 (T/R-) --> 8 (RX-)
3 (RXD+) <-- 5 (TX+)
4 (RXD-) <-- 9 (TX-)
5 (GND) --- 7 (GND)
J6 Continuous Output
J6 starts up in a mode where it continuously emits time strings (see format below). You can switch it
into interactive mode by sending this command:
:ptim:tcod:cont 0
To switch back to continuous time mode, send this command:
:ptim:tcod:cont 1
Here is a sample output of J6 from my KS-24361 (REF 1):
:110100001842E03C7FA401AC
This string is a ':' character followed by 24 hex digits
character
(hex ascii) use values
----------- ------- ---------------------------------------------
0 ':' Line always starts with ':'
1 talker 0 = ref 0, 1 = ref 1
2 status 0 = active, 1 = inactive
3 (unused) 0
4 mode 0 = warmup, 1 = gps, 2 = holdover, 3 = fault
5 to 8 (unused) 0000
9,10 time hours in this mode
11 to 18 GPS time seconds since GPS start in 1980
19 to 22 Firmware Rom version
23,24 checksum
Use this site to convert GPS time (convert the number from hex to decimal first):
http://www.andrews.edu/~tzs/timeconv/timeconvert.php?
The sample output above translates to:
Talker=Ref 1
Status=Inactive
--
Mode=GPS
Hours in mode=0x18 (24)
GPS time = 0x42E03C7F (1121991807) -> 2015-07-27 00:23:10 UTC
ROM version = 0xA401
Checksum = 0xAC (Sum each byte (two hex digits) and take the low order byte of the result).
Some useful commands:
:SYST:STAT?
(Dumps useful status info)
:GPS:POS:SURV:PROG?
(Shows survey progress)
:GPS:INIT:DATE YYYY,MM,DD
:GPS:INIT:TIME HH,MM,SS
(Date and time in UTC)
:GPS:INIT:POS N|S,DD,MM,SS.SSS,W|E,DDD,MM,SS.SSS,AAA
(AAA is altitude above MSL in meters)
:DIAG:LOG:READ:ALL?
(Dumps log)
There's some other information that may be relevant to the Lucent RFTG units at these links:
http://www.prc68.com/I/KS-24361.html
http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=02_GPS_Timing
Does the GPS input of the unit happen to supply a DC bias voltage out for powering an external active antenna or must the antenna be powered externally if needed?
There's some other information that may be relevant to the Lucent RFTG units at these links:
http://www.prc68.com/I/KS-24361.html
http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=02_GPS_Timing
Does the GPS input of the unit happen to supply a DC bias voltage out for powering an external active antenna or must the antenna be powered externally if needed?
I am looking at the EFC and PPS graph in Z38XX. I think the PID loop that is controlling the EFC is not tuned very well. It looks massively underdamped. It's ashame we don't have access to the firmware, because that is so fixable.
If ths 15Mhz is created in the same way as the old one, you should be able yo bypass the the 15mhz filter as pass the 10mhz to the output amplifier.
I understand that the 10MHz 'test point' output is said to be jittery and perhaps due to an underdamped loop.
But is it confirmed that that remains to be the case even after the unit has stabilized with a good signal lock for several days or weeks so that everything 'settles down'?
How clean is the 'primary' 15MHz output, qualitatively or quantitatively?
As for a PCB for the 5MHz processing doubler and distribution amp, I could make some gerber files that would be compatible with OSHPark, Seeedstudio, elecrow, dirtypcbs, et. al. publically available in the near future if there is continued interest and I can get the CAD data on the particular parts involved in the publication.
If ths 15Mhz is created in the same way as the old one, you should be able yo bypass the the 15mhz filter as pass the 10mhz to the output amplifier.
I found a 10 Mhz sine signal that appears to be coming from a simple freq doubler which goes to a Schmitt trigger to get squared off that I think eventually comes out the 10 Mhz TP (J1). Think I will run that into some sort of driver and make that my 10 Mhz reference source rather than trying to filter the square wave.
If ths 15Mhz is created in the same way as the old one, you should be able yo bypass the the 15mhz filter as pass the 10mhz to the output amplifier.
I found a 10 Mhz sine signal that appears to be coming from a simple freq doubler which goes to a Schmitt trigger to get squared off that I think eventually comes out the 10 Mhz TP (J1). Think I will run that into some sort of driver and make that my 10 Mhz reference source rather than trying to filter the square wave.How "clean" is the sign wave? Can you hook it up to a SA and see what it looks like?
Received my GearMo today and it works great ! Turns out my old 422 converter took a dump. Also ordered a cheaper converter that worked 1 time, yup, it has the counterfeit FTDI chip.
So far the receiver sees 9 birds and tracks 8 of them as compared to 12 out of 15 with something that was made in this past century and with an indoor antenna lol
oh, the counterfeit FTDI works fine with the drivers that came with the unit on my Win XP machine but not Win 7. Guess you get what you pay for !
http://smile.amazon.com/gp/product/B00N9RCPAY?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00
Received my GearMo today and it works great ! Turns out my old 422 converter took a dump. Also ordered a cheaper converter that worked 1 time, yup, it has the counterfeit FTDI chip.
So far the receiver sees 9 birds and tracks 8 of them as compared to 12 out of 15 with something that was made in this past century and with an indoor antenna lol
oh, the counterfeit FTDI works fine with the drivers that came with the unit on my Win XP machine but not Win 7. Guess you get what you pay for !
http://smile.amazon.com/gp/product/B00N9RCPAY?psc=1&redirect=true&ref_=oh_aui_detailpage_o01_s00
Glad you got it all working. I made a proper DB9 cable for mine today, so no more terminal strip with wires hanging off it
I need to figure out how the DB9 power connection locks in. I read somewhere that the little pins (instead of screws) are called "slidelock". Have to see if I can get a connector with those.