bg7tbl gpsdo master reference

[kj7e]

Comparing the Trimble vs my NEO-M8T modified BG7TBL GPSDO.  HP 53132A, 100 sec count, 100 count statistical mean average.  They tend to agree quite well, within 5uHz from 10MHz or <5x10^14

[haydenph]

I've had my BG7TBL GPSDO for a while, bought the distribution amp the other day and very happy with it.
Does anyone know if the issue with the frequency not being exactly on 10 MHz has been resolved in the later revisions?

[akumiszcza]

Yesterday I've received my BG7TBL GPSDO from China (aliexpress). The date on the case is 2019-08-03. During startup it is described as BG7TBL 20190123.

I did not open it yet.
Several things I've noticed:
* The screen sometimes stops. It happens sometimes during initialization of Lady Heater. The GPSDO works still, but in order to see the time and frequency on the lcd, I have to restart the device. When I touch the screen on the left side I hear some electric clicks.
* The GPSDO works well with u-center and Lady Heather. See attached screenshot of the satellite view Lady Heather (6.14). The GPS is connected via serial to USB converter for now.
* Was somebody able to configure the u-blox unit via u-center? When I try to send commands, it returns to the previous configuration instantly, but I can do hot/warm/cold reset with it (the lcd screen shows GPS NO FIX for a moment after this), so it seems there is a two-way connection. I would like to change the GNSS satellite configuration to see different satellite types (It's currently set to GPS only I guess – see attached settings, I would like to add GLONASS and/or Galileo).
* Is it possible to use PPS on RS232C to directly discipline NTP server? I guess the 1PPS signal is on the wrong pin of the serial port?

[akumiszcza]

Photos of the inside. Board date is 2019-01-07.

[akumiszcza]

Last post for now.

1. I was able to set it to my CET time and ppb by the command:
$GPGTC,2 CET  +0200T*$GPGTC,2 CET  +0200T*

2. I can confirm that whenever I run Lady Heather 6.14 with -rxu option (u-blox mode to see more data) the LCD screen stops, but the whole device continues to work. No such problem with u-center, or Lady Heather with -rx option (but then much less parameters visible).

[texaspyro]

-rxu configures the receiver for binary mode messages.  -rx uses NMEA (or whatever the receiver is configured for).  I suspect that the GPSDO firmware is not aware of binary mode messages.

[akumiszcza]

-rxu configures the receiver for binary mode messages.  -rx uses NMEA (or whatever the receiver is configured for).  I suspect that the GPSDO firmware is not aware of binary mode messages.

It seems only the LCD screen is affected. When I run Lady Heather with -rxu, the LCD stops updating, but Lady Heather shows all the info and everything updates continually. Then when I restart Lady Heather with -rxn (-rx in this situation would be the same as -rxu), the LCD starts working again. It's a pity, as u-blox mode gives much more info (Sawt, Accu, Frac, Dly, FW and HW info of the receiver, Antenna info, PPS (USRPPS), TDOP, NDOP, EDOP, EL, dBc, satellite states, leap second info). Two things differ, and I don't know why: "UTC offs" is 19 in u-blox, 18 in nmea and the altitude is about 30 meters higher in u-blox.

Unfortunately, I found out I cannot change satellite types – this GPSDO uses normal u-blox 7 series chip, which can work only with one type of satellites. Changing some other settings work (until reset).

[jonese]

I had the same issue with the LCD stopping, see my message a few posts back.  I found I had to provide additional grounding to the front and back "PCB panels" on the unit.  In my case, just touching the front or back portions of the unit could stop the LCD (the remainder of the unit continued to function).

Also, if you want it back without cold restarting it, just unplug the antenna for a few moments, the LCD will reset and come back.

[akumiszcza]

I had the same issue with the LCD stopping, see my message a few posts back.  I found I had to provide additional grounding to the front and back "PCB panels" on the unit.  In my case, just touching the front or back portions of the unit could stop the LCD (the remainder of the unit continued to function).

Also, if you want it back without cold restarting it, just unplug the antenna for a few moments, the LCD will reset and come back.

I've read your post before, but I don't think it's the same issue. I can stop and start the time at will by changing the data protocol. heather -rxu stops the screen, heather -rxn starts it again. In u-center I can switch protocols in Configure - Ports (PRT). "Protocol in" defaults to UBX+NMEA, "protocol out" is NMEA. If I change "protocol out" to UBX or even UBX+NMEA, the time on the screen stops. Unplugging the antenna does not change it. As texaspyro wrote, it must be that GPSDO does not understand binary mode internally.

[Switch80]

Good Evening together

I followed this Tread since a few Weeks and because i found the only Manual for the OSA OEM Star 4+ Board in this Thred, i thougt to Post here. (sorry its not BG7TBL, its amoj1010 )

A few Weeks ago i also got my Board from Ebay, and after some Trying i got it working and finally "Hold perf good" lit up on LH screen. 
I decited to dive a little deeper and try to understand How LH works with the Board, made some Improovements to the Interface Board an after some unsuccessfull tryings to comunicate whit the Board directly over Putty, i endede up using termite and it worked great. (you have to send ";<cr><lf>" after every command, and with Putty you have to send <cr><lf> in Binary. Termite lets you just choose to do this automaticly  )

But then i dived to deep.... 
There is a little not further documented command "download", so i gave it a try and hit Enter, what could happen?
The Board sput out the following:"OK;..UART Initialization OK...;..CFI Information OK...;..    FLASH Sector Erase OK...;..Please send SREC Image...;.."  *gulp*

OK, i had no Image Handy and i thougt it would downloading something, not uploading   

Because i was'nt into the Matter at this moment i tryed to exit the Update Mode with several Commands, no luck, at last i did a reset by powering the device off and on. I did many Firmwareupdates in my Life and never thougt this could be a Problem.
Normally you upload the Content, then CRC and Version check, and if you abort, back to Standartd settings. I even have a Dipswitch on my Graficcard to choose a secondary Firmware Storage if the first one crashes.

So far so Bad now, what Happen when you Power off a Xilinx Spartan 3A FPGA? He will loose his configuration! 
and the Cypress static Ram?  It is only "static" while powered on! 
But hey you got the Atmel Flash Memory, it holds Informations without Power! Yes thats true, but that was the one that sayd goodby first, you remember:"FLASH Sector Erase OK" 

i had a little Hope first, because it says Sector Erase, that the Inventors of the Board made a locked sector from which i could be able to boot again, i was Probing around some Time but no Luck, the Board is (probably) Dead 

So for Guys like me, dont even try to Type "download" and hit Enter

For all the other Pros around the Forum, if you are able to support me whith a Firmware File, or read out the Contents From the Flash, i will be willing to try out to rescue the Board and give you some Updates about the Process.
Anyone want to test something with the Board, or to Know something specific ist welcome, i will give my best, i consider the Board dead anyway...         

Thank you!

[EV]

What program are you using to send the command to the unit? I tried PuTTY 0.73 but did not work out how to send the command to serial port.

Now I have two BG7TBL LCD GPSDO's.  One with a blue background LCD model 2017-12-16 and a new one with a green lcd background model 2018-06-05.  I wanted to update the display on both to show ppb, found a few differences in the display programing command between them, also some information that's not in the very nicely but rouge translated v1.1 manual found here;
https://www.eevblog.com/forum/testgear/bg7tbl-gpsdo-master-reference/msg1912184/#msg1912184

This is whats in the book;
2. Display UTC Time, with Frequency Error in PPB (recommended)
$GPGTC,2 UTC +0000T*$GPGTC,2 GMT +0000T*

However, I found the 2017 unit accepted the code but gave the time an offset of tens of minutes, this was due to a missing 0 in the time parameter.  The correct code was;
$GPGTC,2 UTC +00000T*$GPGTC,2 UTC +00000T*

Also corrected the repeated "UTC".

The 2018 unit also would now say ERROR if the format was not perfect and needed the additional 0 in the string, the 2017 would accept the string but would not display the correct time.  Last, the code above with the proceeding + in the time parameter would cause the LCD display to literally display a "+" before the time.  To correct this, I replaced the + with an additional leading white-space as such;
$GPGTC,2 UTC  00000T*$GPGTC,2 UTC  00000T*

[EV]

I used Realterm program and it worked ok!

[BiggieJohn]

I just received a BG7TBL GPSDO from eBay, "US seller".  faceplate date is 2019-08-03, but the back side of the faceplate says 2018-06-05,
and the main board has a date  2019-01-07.  this is not a LCD version
OCXO is CTS 196-0017 with a mfg date or 2008 week 8. no info on GPS chip,
but on startup is spits out  this, so it seems to be a ublox UBX-M8030 fw 3.01

$GPTXT,01,01,02,u-blox AG - www.u-blox.com*50
$GPTXT,01,01,02,HW UBX-M8030 00080000*7E
$GPTXT,01,01,02,ROM CORE 3.01 (107888)*35
$GPTXT,01,01,02,FWVER=SPG 3.01*58
$GPTXT,01,01,02,PROTVER=18.00*0F
$GPTXT,01,01,02,GPS;GLO;GAL;BDS*69
$GPTXT,01,01,02,SBAS;IMES;QZSS*57
$GPTXT,01,01,02,GNSS OTP=GPS;GLO*29
$GPTXT,01,01,02,LLC=FFFFFFFF-FFFFFFFF-FFFFFFFF-FFFFFFFF-FFFFFFFD*31
$GPTXT,01,01,02,ANTSUPERV=AC SD PDoS SR*20
$GPTXT,01,01,02,ANTSTATUS=DONTKNOW*33
$GPTXT,01,01,02,PF=3FF*55

[BiggieJohn]

I also got a BG7TBL PLL_GPSDO, 2019-02-28 version.  This model appears to have an OCXO, isotemp model 131-261B with a data of 2012 week 12
no marking on GPS, but startup spits out Ublox UBX-G70XX rom 1.00 


$GPTXT,01,01,02,u-blox ag - www.u-blox.com*50
$GPTXT,01,01,02,HW  UBX-G70xx   00070000 FF7FFFFFo*69
$GPTXT,01,01,02,ROM CORE 1.00 (59842) Jun 27 2012 17:43:52*59
$GPTXT,01,01,02,PROTVER 14.00*1E
$GPTXT,01,01,02,ANTSUPERV=AC SD PDoS SR*20
$GPTXT,01,01,02,ANTSTATUS=DONTKNOW*33
$GPTXT,01,01,02,LLC FFFFFFFF-FFFFFFFF-FFFFFFFF-FFFFFFFF-FFFFFFFD*2C

[notfaded1]

I ordered one of the BG7TBL "Upgraded GPSDO GNSS Disciplined Oscillator Clock 10MHz +Antenna For GPS+GALILEO" from the original seller on ebay.  None of the sellers of this unit are in USA yet so I ordered from the first seller on ebay listing it in HK, China.  It says BG7TBL 2019-10-20 on the front.  Hopefully it won't take too many weeks to get here to the Arizona desert.  The new upgraded units can be ordered with two different SAT constellations configured.  GPS+GLAILEO just seemed like a combo I wanted to try.  I'm pretty sure you can change this.  I don't know anything about an upgraded manual or new commands.

Bill

[notfaded1]

Finally just got the shipping notice from China... they've been on holiday break and the Corona virus hasn't helped either.  I got the seller to add DHL shipping so it comes by air instead of slow boat from... you know the rest! 

[notfaded1]

Ok the GNSSDO arrived.  I plugged it in with it's cheap little antenna and before I could get the USB-serial cable hooked up it was locked and already on 12 SATS.  It literally locked in a few hundred seconds... I'll have to time it because it's the fastest locking GPS I've ever had or seen.  Also I hooked the 10MHz output to my 53131 port 1 and one of my Rb standards to port 2 and sampled Ratio port 1 -> port 2.

Bill

[notfaded1]

Here it is from the front...

[Electro Fan]

Ok the GNSSDO arrived.  I plugged it in with it's cheap little antenna and before I could get the USB-serial cable hooked up it was locked and already on 12 SATS.  It literally locked in a few hundred seconds... I'll have to time it because it's the fastest locking GPS I've ever had or seen.  Also I hooked the 10MHz output to my 53131 port 1 and one of my Rb standards to port 2 and sampled Ratio port 1 -> port 2.

Bill

Do you select whether it reports from GPS or Galileo or both?  Via the computer/what software?

Beyond the fast lock, how does the 10 MHz signal compare to your other GPSs?

Thx

[notfaded1]

Do you select whether it reports from GPS or Galileo or both?  Via the computer/what software?

Beyond the fast lock, how does the 10 MHz signal compare to your other GPSs?

Thx

I ordered it this way from HK.  It was the first listed "enhanced" GNSSDO from BG7TBL I could find with the later date on the front.  You can order it with different constellations set.  I chose US GPS and Galileo.  I'm guessing you can change the setting but it's not a switch or anything on the device and I'm sure probably not supported by them.  When I hook it to my 53131 as an external reference and check it against my two Rubidium standards it's 10MHz right on all the digits my 53131 can display.  I think maybe tomorrow I'm going to open it up and look what it's made of.  It would be neat if I can get more from lady heather than the default NMEA information but that's dependent on what inside right?  Here's what LH looks like after running a little while using the little cheap antenna it came with.

Bill

[notfaded1]

The next step is to hook it to my better GPS antenna... a plus +43db Symmetricom antenna.  I'm hoping with my Symmetricom 58536A I can safely run my symmetricom sync server that's higher voltage on port 1 powering my Symmetricom antenna and run the BG7TBL off port 2.  It's supposed to work that way... we'll see.  I've never mixed high and lower voltage GPS together on a splitter before. 

Bill

[notfaded1]

Update... the newer BG7TBL displays all the ublox info if you pass the flag to it.

Bill

[DaveR]

I also bought one of these, which arrived today (nine days from order to delivery).  It turned out to be very easy to change the GNSS system(s) it's originally set for - just use the Heather command "SG", or use U-Center to reconfigure it.  GPS + Galileo + Beidou also works well, as shown in the screenshots (all made using just the antenna it came with, indoors).

Regards,
Dave

[MegaVolt]

Tell the seller these new GPSDO

[Electro Fan]

Are you guys saying that although the units are advertised as supporting two systems you are actually getting 3 (GPS + Galileo + Beidou)?