A look at my Symmetricom GPSDO / 10MHz reference (OCXO + Furuno receiver)

[davebb]

Hi I got another display for my NMEA Display, This time I got it from this ebay seller and it came to the uk in 2 weeks 
http://www.ebay.co.uk/itm/12232-LCD-Dots-Matrix-Display-Module-122x32-Yellow-Green-LED-Backlight-New/221671035094?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20131017132637%26meid%3D97cf7a6697c74435b9cc233dd4320cbe%26pid%3D100033%26rk%3D2%26rkt%3D4%26sd%3D121111769872

Dave

[f1rmb]

Thanks for the URL Dave.

[davebb]

Thank you for redoing the HEX code

[davebb]

I have got a nice Hammond case I am going to try to cut out for the display with a jig-saw and mount the leds
and sockets,i am going to use a usb rather then a 9way D,
I see that the  Symmetricom GPSDO Board uses a few alarm leds,i only want to use 2 alarm leds ,
what is the best 2 to wire to,
Thanks Dave

[davebb]

 Hi Daniel
one thing is that after some time the fix LED goes out and stays out,is this normal?
when the fix led on the display board is on,i have un-plugged the ant and it goes off,reconnected it and then it comes back on,so that bit works fine it is only when its been on some time
Thanks Dave

[f1rmb]

Hi Daniel
one thing is that after some time the fix LED goes out and stays out,is this normal?
when the fix led on the display board is on,i have un-plugged the ant and it goes off,reconnected it and then it comes back on,so that bit works fine it is only when its been on some time
Thanks Dave

I think it's because the board switch off the survey mode. I'll take a look for this (I've already made some tweaks for this in the code, but since I don't use the display led, I didn't noticed that).

Cheers.

[davebb]

 Hi Daniel
ok,Thanks for the info
Thanks Dave

[Bryan]

Mine arrived today, board was in good condition with no damage. Enclosed in a bag with the same oily film as others have described. A good cleaning with some acetone and IPA it was time to test. Hooked it up to a 5v 3A supply and it starts up at 1.8a and makes quite a loud buzzing sound from the DC-DC converter. The singing disappears or goes above my hearing range after the OXCO starts to warm up. Noticed it began to quieten around 1amp. Once the OCXO had warmed up fully and attained a lock current draw was 830ma and the board quiet.

Pressing the MACT switch as others have pointed out and it is put into some type of holdover mode and the output is 10MHZ. I wonder if the 10MHZ when the MACT switch is the OXCO undisciplined or the last point in the disciplining from the receiver. The latter would be great. The 10Mhz output  shows nothing except for some slight ripple until locked. Once it locks (took about 2 hours) then the 10Mhz output comes to life with a sine wave at 3.4 vpp and 800mv 50ohm terminated. The 1pps output works as well.

I want to hook up the RS232 but thought I should seek some advice first so as not to risk damaging the board or the PC. I assume that the output pins are receiving and transmitting at TTL levels?. If so than I can not hook the pins up to the serial port on my computer with out level shifting?.  I have one of these RS232 to TTL boards. Would this be what I need to do. Although it doesn't have a BT? pin. Or can I just hook it straight into the serial port connector on the PC.

There is a console port (RS232 levels, and it's possible to tap into 3.3V signals before the level shifter chip, some cousin of MAX3232) which I connected to a DB9 port for diagnosis, I didn't make a hole for it yet since I'm not sure I'll keep it a DB9 or I'll put an integrated RS232-to-USB converter or even a small LCD with an arduino or similar, showing basic status information. But the LEDs are mostly enough.

GPSDO  PC

RX->TX
TX->RX
Gnd->Gnd
BT->??

[PA0PBZ]

The serial port on the board is at RS232 level, so you can hook it up to your pc directly (Just RX, TX and GND). I have no idea what BT is.

[Bryan]

Thanks, BT is the silkscreen label beside the pin on the GPSDO, or maybe it is RT for RST?

[PA0PBZ]

Thanks, BT is the silkscreen label beside the pin on the GPSDO, or maybe it is RT for RST?

Ok, I can't remember seeing that, but anyway leave it unconnected.

[guido]

Anybody got some recommendations on the power supplies? As the boost converter was broken on mine, i turned it around:

A mains to 12V 5A switcher (delta NL), with 5mVrms/20mVp-p ripple and 70mVrms/100mVp-p noise (BW=20MHz).
This will power the TXCO and an LM2676 based module (fabrimex) set for 5V (Ripple: 100mV @ nominal) It is 3.5A max, but i'll be using 1A or so (depending on the backlight of the huge lcd). This will power the UCCM PCB and my own electronics (pic, max232 and lcd). It's all based on parts i already have available.

I made a nice pcb to fit under the UCCM pcb. Same dimensions. I'm just wondering about the noise from the switchers affecting the 10MHz out. E.g. i could set both suppliers to a higher voltage output and add some low-drop regulators.

[Vgkid]

@ Bryan : On mine when unlocked( I have 2 units) one reads 9.99999991MHz, while the other reads 9.9999992MHz.so reasonably close to the correct frequency.
@ guido : the ocxo should use less than 1amp of current. Not sure of the draw on the 5v rails.
Though it shoud be able to be powered with a heatsinked ldo.

[guido]

The UCCD without boost convertor for the TCXO is some 200mA. The LCD backlight 220mA and the rest some 30mA. So adding some LDOs should be possible.

The TCXO is some 8W (ROX5242T2), so 0.67A when warming up (say 1A). Also do-able i guess.

The big question, will it be an improvement for the 10MHz output. Another option would be to filter the output

[guido]

Some pictures. This is how it arrived. I was lucky that all the connectors were there. The boost convertor is now removed as it was kaput.



The ongoing project. Here the micro is communicating to te UCCM and is putting the sync:ffom? answer on a small LCD.
On the breadboard a pic and max232. The other pcb is my pic programmer 



The current pcb design with only the switcher. My pcb software is acient, so i have to do my own 3D rendering But there are good reasons to keep using it. Nearly all parts are from the junk box.

[hs3]

I have seen several mentions about the boost converter being broken in these Symmetricom boards. I'm curious how did the broken boost converter behave? What happened when you tried to power on the board?

[Bryan]

Does anyone know if there is a command to change the Satellite signal strength parameters. In Lady Heather with my Nortel I can adjust the AMU value to pick up satellites that don't have a strong signal. I think the equivalent for these units is the sigvalue(). Unfortunately I am on the ground floor of a condo facing North. It is tough to see more than 2 or 3 birds in the sky with this unit. The survey took me a whole day. Fortunately the elevation mask is at 5 degrees (default)

[davebb]

Hi guido
are you going to post the diagram and hex code for this when your done developing all of this good stuff
Thanks Dave

[guido]

I could. But it requires a 4x40 display. Would be good if anyone has an opinion on my question (?).

[Bryan]

An interesting serial request is PTIME:TCODE? - this is not listed when you issue the ? help command, but is in other Symmetricom documentation.

Macbeth:

Do you have a link to the other Symmetricom documentation. Would be interested in other commands that this board can utilize.

[jackenhack]

I'm doing the finishing touches of my quick hack for getting status from my Trimble GPSDO (with the weird UCCM-P > prompt.) I'm using the front PPS output from one of the serial port to trigger an interrupt so I can synchronise the clock. I can then check the number of "ticks" and adjust everything synced to GPS time. Next up for implementation is to save the location after a survey and if the GPSDO resets, the controller automatically restores the coordinates from EEPROM. My version doesn't seem to store the survey data. Probably a unit where there was continuous power.

And naturally it dims the 7-segment LEDs at night and increases it in the morning. 
The cutout for the displays are really a botch job, but thankfully the box is dark so you have to get really close to see it.

[SHF]

Hi, all
Seeking connection assignment and everything in documentation (Schematics, assignment RS232 ...) for this motherboard :
http://www.ebay.de/itm/Used-SYMMETRICOM-UCCM-GPS-10MHz-Frequency-Time-Receiver-OCXO-/121761130751?hash=item1c598768ff:g:WZUAAOSw5ZBWF9jf

For info I would be grateful !
Greeting, Dieter

[davebb]

Hi read the 1st page and see the photos, all of the info is there
please ask again if your not shore
Dave

[davebb]

Hi Dieter , you may well have to fix it, but there are plenty of good photos on here
if it does not work the seller will tell you that he will send you another one, but he does not send it, you will have to put a clame  in with ebay, don't let me put you off as when they are working they work well
Dave

[ZigmundRat]

Could one or two of you guys please issue the DIAGnostic:LOG:READ:ALL? command and post the output? Maybe pastebin it if it's too long. My just received unit does not seem to be doing well, as all I receive is:

UCCM-P > DIAGnostic:LOG:READ:ALL?
Log status: 10 entries

L1:1980-01-06 00:07:11:Log cleared
L2:1980-01-06 00:07:11:SYST:PRESET performed
L3:1980-01-06 00:00:02:Power On [reset switch]
L4:1980-01-06 00:00:03:FPGA VCXO Alarm
L5:1980-01-06 00:00:03:OCXO Alarm
L6:1980-01-06 00:00:03:Funct Fail code: 00000208
L7:1980-01-06 00:00:03:Funct Fail OCXO curr: 201 mA
L8:1980-01-06 00:00:03:Funct Fail PDOP: 0.00
L9:1980-01-06 00:00:03:Funct Fail sat count: 0
L10:1980-01-06 00:00:03:Funct Fail TRAIM: 0 0
Command Complete

Status doesn't look too happy either:
UCCM-P > status

                 - UCCM Slot STATE -



1-1. #Now ACTIVE STATUS ---------------- [Alarm]
1-2. #Before ACTIVE STATUS ------------- [OCXO Warmup]
2-1. #Reference Clock Operation -------- [Not Used]
2-2. #Current Reference Type ----------- [LINK]
2-3. #Current Select Reference --------- [LINK0]
2-4. #Current Reference Status --------- [NOT SELECTED]
     #GPS STATUS ----------------------- [Unavailable]
     #Priority Level ------------------- [LINK > GPS]
     #ALARM STATUS
     #H/W FAIL ---------- [ 10MHZ ]
     #Bad Quality ------- [ LINK ]
3-1. PLL STATUS ------------------------ [Enable]
3-2. Current: PLL MODE ----------------- [OFFSET OBSERVATION MODE]
Command Complete

Unit is running off solid 5V supply, good 3.3v out of the regulator and 11.98v on the OCXO. EFC is almost 0 and stuck there though. No GPS fix either. How long did it take to establish an initial fix? Antenna is good (I moved it from another GPSDO).

Note that this is not my first GPSDO, and I have 5 others currently running.

Thanks!