Does anyone recognize this board, is it a gpsdo?

[Velund]

Programmed another command to other hotkey and removed foil from antenna... Polled it alternately  for status and number of sats with about 2 sec interval...

status;

STATUS=1,O,H;
info_track_sat;

INFO_TRACK_SAT=0;
status;

STATUS=1,O,H;
info_track_sat;

INFO_TRACK_SAT=1,
1,30;
status;

STATUS=1,O,H;
info_track_sat;

INFO_TRACK_SAT=2,
1,8,
2,30;
status;

STATUS=1,O,H;
info_track_sat;

INFO_TRACK_SAT=2,
1,8,
2,30;
status;

STATUS=1,O,H;
info_track_sat;

INFO_TRACK_SAT=2,
1,8,
2,30;
status;

STATUS=1,O,H;
info_track_sat;

INFO_TRACK_SAT=2,
1,8,
2,30;
status;

STATUS=1,O,H;
info_track_sat;

INFO_TRACK_SAT=4,
1,7,
2,8,
3,27,
4,30;
status;

STATUS=3,O,T;
info_track_sat;

INFO_TRACK_SAT=5,
1,7,
2,8,
3,27,
4,28,
5,30;
status;

STATUS=3,O,T;
info_track_sat;

INFO_TRACK_SAT=5,
1,7,
2,8,
3,27,
4,28,
5,30;
status;

STATUS=3,O,T;

[Velund]

Just for reference for someone who'll dare to make a fancy front panel status display for this module (or for a oscilloquartz board, or for both)... If I didn't start doing it myself using those $3 STM32 module and $3 1.8" SPI TFT LCD from eBay...

Responces from unit seening sats, in operational mode.

inv;

INV=NECGPS,057706,003xxx,00,057706,0172,,,6920N02442,0169;
conf;

CONF=0,0,A,+00:00,+0;
alarm;

ALARM=N;
gps_time;

GPS_TIME=1880,145528,01.07.15,00:00:00,00,17;
info_track_sat;

INFO_TRACK_SAT=6,
1,8,
2,11,
3,13,
4,15,
5,18,
6,19;
status;

STATUS=3,O,T;
temperature;

TEMPERATURE=+39.78;
type;

TYPE=4500,OEM_01;
atdc_status;

ATDC_STATUS=0,0;
hold_perf_status;

HOLD_PERF_STATUS=0;
info_vis_sat;

INFO_VIS_SAT=13,
1,5,12,228,18,2,
2,7,26,97,29,2,
3,8,21,40,42,2,
4,11,12,83,28,2,
5,13,65,268,16,2,
6,15,32,303,38,2,
7,17,13,159,21,2,
8,18,9,336,37,2,
9,19,9,160,20,2,
10,20,22,276,25,2,
11,27,1,18,15,2,
12,28,74,172,23,2,
13,30,57,98,26,2;

[Velund]

Tried all commands described in Oscilloquartz document in the following post:

https://www.eevblog.com/forum/testgear/bg7tbl-gpsdo-master-reference/msg740339/#msg740339

NEC board recognized all commands except one - 'tod_state;'

Not tried to set some parameters but checked that keywords is accepted (syntax error instead of unknown command response).

Manual switch to holdover mode works, may be useful to turn off disciplining during precise measurements.

Funny response to warm restart command:

restart(w);

OK(BUT NOT IMPLEMENTED);



Right after power-up seen status 'STATUS=0,A,I;' that quickly changed to 'STATUS=4,A,I;' and in a few minutes to 'STATUS=4,A,W;'...

From the abovementioned document:

STATUS=l,g,rm;<cr><lf>

l: LED's status:
l = 0 => OFF
l = 1 => Red
l = 2 => Red, blinking
l = 3 => Green
l = 4 => Green, blinking
l = 5 => Red-Green, alternate
l = 6 => Orange
l = 7 => Orange blinking

g: GPS status
g = A => GPS is in alarm
g = O => GPS is OK

rm: Real mode (I: Init, W: Warm-up, F: Fast, T: Tracked,
H: Holdover, S: Squelched)

[Velund]

Let it run for about 48 hours without interruptions - but response of 'hold_perf_status' command remained the same.

atdc_status;

ATDC_STATUS=0,0;
hold_perf_status;

HOLD_PERF_STATUS=0;

Looks like this commands is only for compatibility, and there is no real ATDC support.

[NivagSwerdna]

This thread seems to have gone quiet... I notice that some of these units have come onto ebay eBay auction: #182145209432 although the price seems to be 4x higher than before.

I'm quite interested by this device, particularly as the uBlox receiver has good performance.

How are you lucky (at a low price) owners doing?

[lukier]

This thread seems to have gone quiet... I notice that some of these units have come onto ebay eBay auction: #182145209432 although the price seems to be 4x higher than before.

Whoa, the seller copied my and grumpydoc posts verbatim (pinouts etc) in the description. No reference to either this thread or the respective authors. Not cool.

TBH the price is crazy for a spare, used, part from a base station. One can get Symmetricom GPSDO or BG7TBL for much less.

How are you lucky (at a low price) owners doing?

I haven't finished my Extron distribution amplifier + GPSDO + NTP server yet  I have all the parts, I've modded Extron to 50 ohms, but I still need to etch some accessory PCB and wire everything up. Maybe I'll finish that project this summer.

[NivagSwerdna]

TBH the price is crazy for a spare, used, part from a base station. One can get Symmetricom GPSDO or BG7TBL for much less.

I have a Symmetricom but this looks better, the spec of the PPS from the GPS receiver is certainly much better.  Shame about the price.

[grumpydoc]

Whoa, the seller copied my and grumpydoc posts verbatim (pinouts etc) in the description. No reference to either this thread or the respective authors. Not cool.

Indeed. Much more annoying from my point of view is the fact that he just scraped the list of links from my post which means that he's using my bandwidth for the OCXO datasheet. Lazily he could not even be bothered to check that the linked-to documents are still there.

TBH the price is crazy for a spare, used, part from a base station. One can get Symmetricom GPSDO or BG7TBL for much less.

While the Symmetricom units are around it is rather steep. However once those have dried up - and there are some suggestions that this is happening - it will be more achievable.

Look at what happened to the price of Rubidium units, dirt cheap for a while then the supply dried up and they quadrupled in price. Actually it looks like those have dropped a bit again and there are more on sale than the ast time I looked.

Almost tempted to pick up a spare.

[NivagSwerdna]

Almost tempted to pick up a spare.

I think US$199 is too much for me. I will keep an eye out in case more become available and the price goes down.  At around US$120 I would probably part with some cash.
I never intended to get a GPSDO and here I am looking at another one  It was a thread on this blog that got me started on this frequency nuts stuff 

[DimitriP]

199.00  Ha!   I needed a good laugh

[edpalmer42]

Almost tempted to pick up a spare.

I think US$199 is too much for me. I will keep an eye out in case more become available and the price goes down.  At around US$120 I would probably part with some cash.
I never intended to get a GPSDO and here I am looking at another one  It was a thread on this blog that got me started on this frequency nuts stuff 

Yeah, this stuff is addictive.  Guess how I know!     

Ed

[texaspyro]

There's another seller on Ebay for $129+$15 shipping.  I just ordered one:

http://www.ebay.com/itm/10MHz-GPS-Disciplined-Oscillator-GPSDO-/252610556561?hash=item3ad0c33291:g:ZLwAAOSw44BYFIlb

The commands that these speak are compatible with the Oscilloquartz Star-4 GPSDO (except at 115200 baud,  Star-4 is 9600 baud).   I now have Lady Heather working with the Star-4. hopefully it will also work with these...  that version (complete with New and Improved Documentation (tm)) should be out in a couple of weeks.

[texaspyro]

Lady Heather version 5.0 is now available for download from:
   http://www.ke5fx.com/heather/readme.htm

Many thanks to John Miles for hosting the distribution and his work on the Windows installer, PDF documentation file, readme file, and bring an all-around good guy.

Heather now has some proper user documentation.  Check the heather.pdf file and/or the comments in the first 3500+ lines of the heather.cpp file.  Heather can be compiled for Linux (including the Raspberry Pi) and macOS.  Download the heatherx11.zip file and check the readme.txt file for compilation instructions.

There are MANY new features in Heather.  One of the main ones is support for many new receiver types.  When Heather is started it defaults to attempting to automatically determine the receiver type.   You can bypass this and force the receiver type using the new "/rx..." command line options.  Some receiver types cannot be auto-detected.  Also many receivers power up speaking NMEA and you can enable their native binary language using the /rx commands.  Native binary mode gives better information and allows controlling the receiver configuration and settings.

Currently-supported receivers include:
Trimble Thunderbolt and Thunderbolt-E
Acron Zeit WWVB receiver
UCCM - Trimble / Symmetricom GPSDOs
DATUM STARLOC II GPSDO
NEC GPSDO (STAR-4 compatible)
GPSD interface
Jupiter-T (aka Zodiac)
Lucent KS24361 REF0/Z3811A (19200:8:N:1)
Motorola binary format
Generic NMEA receiver
Trimble Resolution T family with odd parity
Sirf binary
Generic Trimble TSIP binary
Ublox UBX binary
Venus mixed binary / NMEA
Nortel SCPI-compatible GPSDOs (NTWB, NTPX, etc.)
Z3801A and compatible SCPI GPSDOs
HP 5xxxx-style SCPI
Oscilloquartz STAR-4 (via the management interface)
NVS binary
PC system clock (no receiver)

After installing Heather, you should edit the heather.cfg file (or the PROPERTIES setting for the desktop icon) for your desired configuration.  Everybody should change the "/tz" option for their time zone... it comes set up for the US central time zone.  International uses should add a "/b..." command to set their daylight savings time information.   On Windows, you can press the "n" key and that will bring up NOTEPAD to edit the file.  For the changes to take effect you will need to re-start Heather (or do a "r heather.cfg" keyboard command).

[texaspyro]

There's another seller on Ebay for $129+$15 shipping.  I just ordered one:

http://www.ebay.com/itm/10MHz-GPS-Disciplined-Oscillator-GPSDO-/252610556561?hash=item3ad0c33291:g:ZLwAAOSw44BYFIlb

The commands that these speak are compatible with the Oscilloquartz Star-4 GPSDO (except at 115200 baud,  Star-4 is 9600 baud).   I now have Lady Heather working with the Star-4. hopefully it will also work with these...  that version (complete with New and Improved Documentation (tm)) should be out in a couple of weeks.

The first GPSDO that I got in was reporting a bad oscillator.  I sent him some information and links on how to talk to the device.  He sent a replacement unit (he actually sent two replacement units) and it is working properly. 

Lady Heather version 5 that can work with the NEC (and Oscilloquartz Star-4) GPSDOs has been released and is available on ke5fx.com  John has a Windows installer version and the X11 version for Linux or macOS. 

[texaspyro]

I had the NEC GPSDO running with Lady Heather to capture the leap second... the NEC didn't handle it well.  It reported the date as 30 Nov 2016 a couple of times and went into holdover mode.  I wonder if any WiMax systems in Japan crashed?

Log snipped attached...

[Ernie]

I just got my board, and powered up running very nicely also figure out the X2,X3,X4, and X5 LED. After about 3hrs the X5 LED blinking every 3rd sec. and X4 LED is ON.Seems to me that there is a long warming up period as mentioned before.
Nex week I am going to make an ADEV measurement to see the quality of the OCXO.
The X2 LED is still a question-mark....?
Any additional help appreciated.

[Pifke]

whats to do - to connect this board, to a pc with running lady heather soft. have got one for 46 €

is any shematic available

greetings 


@ Ernie same here - waiting for LED X5 at monent

[Pifke]

with the TI Datasheet i was confused .. Maxims Datasheet  shows me the right way , the max3243 is a ""newer"" max232.

[ilexprikle]

Help, I've just discovered this thread and hope somebody may be able to solve my problem.  I bought one of these NEC GPSDO PCBs when they were first put onto Ebay, when it arrived I didn't have time to get it going and when I looked at it recently it appears that there is a surface mount device missing near the 2R7 resistors see the photo below.  It looks like it may have dropped off in transit but I carefully looked through all the packing and couldn't find it. Does anyone know what this device is or can tell me the marking code on it?

The oscillator module appears to be ok and I'm really hoping I can get this board going.

Thanks
John

[Loddestuen]

On my board the part is marked "S G"

[ilexprikle]

Hi, Loddesteun, that's very helpful, thank you.  Initial info from the web suggests it might be a Toshiba PNP 2SA1162-GR which isn't difficult to replace.  I'll do a bit more checking and if nothing contradictory comes up, I'll replace it and do the big switch on.
Thanks again.
John

[SrS]

Does anyone know the type of connector used for Z2 & Z5? and maybe even where to get it in single quantities?
Or is everyone just soldering wires somewhere on the board to tap of signals?

They're still being sold on Ebay usually for more acceptable prices compared to the past.
Like: https://www.ebay.com/itm/NEC-EPSON-TOYOCOM-TCO-6920N-10MHz-GPS-Disciplined-Oscillator-GPSDO/254344933612
Or with different OCXO: https://www.ebay.com/itm/NEC-10MHz-GPS-Disciplined-Oscillator-GPSDO-GPS/263985049514

[eevjohn]

.
Many thanks to all the contributors in this thread who have helped with valuable information about the NEC board.
It has enabled my making up a successful GPSDO project.

I used that very same board ex China via eBay, added a box, two RS232 ports, and an RF amp to give 10 MHz “almost sine” output at +7dBm50.
It has a clear plastic top box so I could read the LEDs.

I have checked my GPSDO against another two GPS references and it works well.

Like any project of this type, and without an NEC board circuit, going from prototype to final with constant design change as you go, my GPSDO project is a little scattered and a bit messy inside.
I also broke quite a few design and construction rules, but the outcome is a working unit.

The RF Amp is an LNA PCB ex eBay with SPF51 MMIC type amp, with input and output coupling caps changed to 1000 pfd, and collector inductor changed to 1 mH approx.
This to modify the response “start” down from 50 MHz to below 1 MHz.
The caps are just soldered in parallel with the existing SMDs.

The RF Amp has the 400 mV PP LVDS 10 MHz differential signal as an input, after a 10 MHz LC filter, and produces an unbalanced 50 ohm output at a nominal level.
The Amp output level is set by slightly mis-tuning the filter output tuned circuit.

To take NEC PCB signals “off board” I just “isolated” them with 0.1 MF caps and sometimes with 100R resistors, or both C and R.
The MAX232 signals lines have 100R resistors as isolators to protect the NEC board drivers.
I didn’t use any board connectors on the NEC PCB, I just soldered directly to PCB or components.

Caution that the roughie circuits may not be exactly correct, and is more of a working conceptual record just for myself, but you will get the general idea.

My GPSDO 10 MHz powers up from cold at approx  -3 Hz and settles at 10 MHz after six hours, and best left for two days.
It shows “no alarms” after about three hours.

I use an eBay GPS antenna with +25 dB gain, and placed on my workshop inside window ledge.
The connection from NEC board SMB antenna socket to GPS Ant BNC is in RG316, and is DC connected for the GPS antenna amp.
My SMB “plug” is one “insert” from a 14 pin DIL IC socket.

The project requires 12 V DC at about 1.5 amps at power up, dropping to approx 300 mA after a while.
The unit may not start up correctly with a 1.0 A supply.

This NEC Board has no memory, so if there are any interruptions to DC supply, it goes through a whole power up sequence, and a whole 3 hour period before clearing any alarms (ie ALARM = N).

LEDs after 5 mins – X3 ON, X7 and X8 flash every 1 second.
LEDs after 3 hrs – X4 ON, X5 flashes every 5 secs, X7 and X8 flash together every 0.5 second.

The Terminal Dialog is similar to the Oscilloquartz STAR4+ Doc Spec, and attached is my collection of sample commands and actual replies via the “Service Port” on my NEC board.
The “Time Of Day” port outputs TOD data every second; no keyboard entry required.

A lot of the above has already been described in previous posts, but collated here.

Attached are some photos, Terminal Port Dialog, roughie interconnect circuits.

[Loddestuen]

Hi all,

I have had this board for some time now.. But I can not seem to get it to talk to my PC..

I'm a mechanical engineer, so bare with me.. I can read tech stuff, I have my own electronics hobby lab and i collect and repair vintage test equipment - mostly HP :-) So not all lost..

I have read this thread through 10 times, but I still cant figure out how to get the NEC board to talk to my PC (U-center or Lady Heather)

My PC has a real COM-port - soldered in.

But..
1) Where on the board do I connect which wires?
2) Do I need anything in between the board and the COM cable?
3) Do I need to change the COM port config in Windows (7) or in U-center / Lady Heather?

Please lent me a hand here..

Thanks,

Cheers from Denmark..

[Loddestuen]

In addition to the above out cry for help, I could add some info that might benefit other owners..

Its about the SINE OUT from the OCXO box..

OCXO direct output is only 1,25 V p-p

But the sine OUT at solder pad by mounting hole with respect to GND: 

2V p-p @1M ohm load with my scope.

Loading this OUTPUT with 50 Ohms results in 1V p-p - so I guess this output (if avalible at your PCB) is a 50 Ohms output..

The output (solderpads) are the ones with the yellow wires attached.