Author Topic: bg7tbl gpsdo master reference  (Read 243913 times)

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Offline tardsat

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Re: bg7tbl gpsdo master reference
« Reply #500 on: February 07, 2018, 07:32:34 pm »
Leo Bodnar Units rock!  I have been using them non-stop and they are everything I could ever want (except maybe a little more flexibility on choosing the 2nd freq., but that may be my fault for not knowing how).  Their new mini is about $150 USD plus shipping.  I used USB to set mine up and from then on it runs on it's own off an old USB phone charger. 
 

Offline cdev

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Re: bg7tbl gpsdo master reference
« Reply #501 on: February 07, 2018, 07:40:12 pm »
The case on the newest bg7tbl GPSDO is IMHO, very nice looking. Solid.

I also am curious what manufacturer's oven is in there. Or maybe he is making his own?  Seems like it would make sense for him at this point.

--------

Also, I am curious about the Leo Bodnar unit

It uses a TCXO, right - not an OCXO??

But more accurate than the ones timing GPS's have internally?

Leo Bodnar Units rock!  I have been using them non-stop and they are everything I could ever want (except maybe a little more flexibility on choosing the 2nd freq.
« Last Edit: February 07, 2018, 07:48:34 pm by cdev »
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Offline kj7e

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Re: bg7tbl gpsdo master reference
« Reply #502 on: February 08, 2018, 12:14:08 am »
The case on the newest bg7tbl GPSDO is IMHO, very nice looking. Solid.

I also am curious what manufacturer's oven is in there. Or maybe he is making his own?  Seems like it would make sense for him at this point.


Guess I'll be the guinea pig, got one coming.  I'll post up some photos once it arrives.
 

Offline Dwaine

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Re: bg7tbl gpsdo master reference
« Reply #503 on: February 08, 2018, 05:06:07 am »
Hi Merv,

Your lady heather configuration should not show an ip address when you are connected via a COM port.
When the program is active type ? and you will see all of the startup commands available (a lot of them!), you can change the COM port by simply typing /4 in your case, that should clear things up.

Probably on windows?   The windows version has two icons to launch Lady Heather.  Most likely launched the one pre-configured for the IP connection.
 

Offline Diabolo

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Re: bg7tbl gpsdo master reference
« Reply #504 on: February 08, 2018, 05:37:56 pm »
Hello,

After verification, this new GPSDO - PLL bought $98 contains an OCXO, not a VCXO.
The metal case Ocxo becomes very hot after a few minutes of operation.
The deal is excellent !!



Regards,
Diabolo
« Last Edit: February 08, 2018, 06:52:17 pm by Diabolo »
 

Offline metrologist

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Re: bg7tbl gpsdo master reference
« Reply #505 on: February 08, 2018, 07:21:53 pm »
It looks like a #2 Phillips could help in this case>:D
 

Offline Diabolo

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Re: bg7tbl gpsdo master reference
« Reply #506 on: February 08, 2018, 07:44:15 pm »
Hello,

The case was opened on the post #495


Diabolo
 

Online beanflying

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Re: bg7tbl gpsdo master reference
« Reply #507 on: February 09, 2018, 08:25:23 am »
So many options and likely BS to filter on evilbay...

Anyone got one of these can confirm they have an amplifier to do the distribution or not?

https://www.ebay.com/itm/GPSDO-10MHz-GPS-Disciplined-Clock-3-sine-and-3-square-wave-2-1PPS-Send-GPS-ante/253375324294?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649



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Offline VK4GHZ

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Re: bg7tbl gpsdo master reference
« Reply #508 on: February 09, 2018, 11:08:49 am »
Hello,

New GPSDO 10 Mhz made in BG7TBL :
I bought this GPSDO 10 Mhz in aluminum box via EBay (or aliexpress) for +/- 98$  and I am very satisfied.
It can provide a square or sinusoidal wave by moving a component on the output.
Pins 14-15-16 Neo7 are open, but they can be arranged to vary the baud rate.

Edit : After verification, this new GPSDO - PLL bought $98 contains an OCXO, not a VCXO.
The metal case Ocxo becomes very hot after a few minutes of operation.
The deal is excellent !!

Diabolo
Thank you for the teardown.
Have you tried the RS-232 yet?

What, specifically, does it provide?
Assume NMEA packet?

Can you send commands to it?
If so, what can you configure?

TIA.
 

Offline Diabolo

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Re: bg7tbl gpsdo master reference
« Reply #509 on: February 09, 2018, 11:38:17 am »
Hello,

The GPSDO-PLL only gives access to NMEA received data, since the RX pin is not wired.
- https://www.eevblog.com/forum/testgear/new-gpsdo-bg7tbl/

Diabolo
« Last Edit: February 09, 2018, 11:42:59 am by Diabolo »
 

Offline pete99

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Re: bg7tbl gpsdo master reference
« Reply #510 on: February 10, 2018, 03:29:56 am »
Hi,
My unit looks the same.  Q1 inverted the RS-232 signal and no pc terminal program could read NMEA data.  The signal at R6 was normal, so had to pick it off there.  Q1 is supposed to be a voltage level translator.

Thanks fot the photos.
Steve
 

Offline cdev

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Re: bg7tbl gpsdo master reference
« Reply #511 on: February 10, 2018, 03:56:01 am »
Well, "the proof of the pudding is in the eating", but so very few of us have the equipment to do anything even remotely approaching testing of these devices.  ;)

To test them you need both a reference that is verifiably better than them, and a universal counter or similar, also of verifiable accuracy, locked to it!

Hello,

After verification, this new GPSDO - PLL bought $98 contains an OCXO, not a VCXO.
The metal case Ocxo becomes very hot after a few minutes of operation.
The deal is excellent !!



Regards,
Diabolo
"What the large print giveth, the small print taketh away."
 

Online beanflying

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Re: bg7tbl gpsdo master reference
« Reply #512 on: February 10, 2018, 07:06:50 am »
Part of the fun of 'nuttery' be it freq or volt is getting the best you can while |O Double the $$ for an extra decimal place.......

Think I will take a punt on what I posted a few back as it ticks the boxes for me in small compact with multiple outputs. I know a few good local amateurs with some additional test gear to test against.
Coffee, Food, R/C and electronics nerd in no particular order. Also CNC wannabe, 3D printer and Laser Cutter Junkie and just don't mention my TEA addiction....
 

Offline TheUnnamedNewbie

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Re: bg7tbl gpsdo master reference
« Reply #513 on: February 10, 2018, 09:31:12 am »
Anyone have any info on the oven that may be used on the latest BG7TBL GPSDO version 2017-12-15 with the LCD?  Also, is there a preferred seller someone can recommended?

looking at this guy right here;
https://www.ebay.com/itm/Latest-10MHZ-SINE-WAVE-Sinewave-GPS-DISCiPLINED-CLOCK-GPSDO-with-LCD-Display/202153437548?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

Would also like some more information on this one. I've been thinking about getting a rubidium oscillator but if I can get close with this unit that would also be nice.
The best part about magic is when it stops being magic and becomes science instead

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Offline Jörg

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Re: bg7tbl gpsdo master reference
« Reply #514 on: February 10, 2018, 12:36:07 pm »
A few pictures of my new BG7TBL GPSDO 2017-12-16.
 
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Offline jpb

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Re: bg7tbl gpsdo master reference
« Reply #515 on: February 10, 2018, 12:43:39 pm »
Well, "the proof of the pudding is in the eating", but so very few of us have the equipment to do anything even remotely approaching testing of these devices.  ;)

To test them you need both a reference that is verifiably better than them, and a universal counter or similar, also of verifiable accuracy, locked to it!

The other option is to buy two of them and test them against each other - or even get three of them and do a tri-cornered hat measurement. There are also methods that don't require a very expensive counter, though if you use the two mixer approach you do need an offset oscillator which may require say a DDS generator which are are not that cheap. The cheapest approach would be to use a phase comparitor (e.g. a mixer) and monitor the output voltage but I think this would require calibrating which may then require another signal source.
 

Offline jpb

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Re: bg7tbl gpsdo master reference
« Reply #516 on: February 10, 2018, 01:12:47 pm »
I just came across this article which contains measurements (a review) of the bg7tbl distribution amplifier and compares it to the G4HUPRF 8 channel distribution amplifier - I don't think it has been posted here before and it is worth a read:

http://www.reeve.com/Documents/Articles%20Papers/Reeve_10MHzDist.pdf
 
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Offline Jörg

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Re: bg7tbl gpsdo master reference
« Reply #517 on: February 10, 2018, 01:18:23 pm »
Still a few views on the last generation of the BG7TBL GPSDO.
Everything is fine also connect to PC with RS 232 cable. U-Center and Lady heaters work  easily with this device and the NMEA data is displayed in the software.
best regards
 
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Offline cdev

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Re: bg7tbl gpsdo master reference
« Reply #518 on: February 10, 2018, 02:51:22 pm »
UCenter can command the internal GPS!?

What does it enumerate as, what kind of ublox GPS chip is in there?

There is a banner when it first starts up, would you be able to capture it and paste it here?



Still a few views on the last generation of the BG7TBL GPSDO.
Everything is fine also connect to PC with RS 232 cable. U-Center and Lady heaters work  easily with this device and the NMEA data is displayed in the software.
best regards
« Last Edit: February 10, 2018, 03:05:24 pm by cdev »
"What the large print giveth, the small print taketh away."
 

Offline cdev

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Re: bg7tbl gpsdo master reference
« Reply #519 on: February 10, 2018, 03:09:35 pm »
WWV!

Beating a GPSDO against WWV will derive a beat frequency. That may be impossible to hear (way too low) but the difference might be possible to measure, removing the effect of the ionosphere somehow.. (averaging over 24 hrs repeatedly somehow? 24 hrs because the delay between WWV and your QTH should vary depending on height of ionosphere, seasonal also varies by time of day, also solar flare activity changes it..  Ionosphere may add several hundred km to 'distance' between QTH and WWV or similar time station, varying by aforementioned patterns, but also fairly unpredictable in short term. (DCF77 etc)

Easiest to measure would be to use the GPS to drive a DDS and set the DDS to a frequency approximately 1 KHz above or below WWV, then measure the audio beat frequency output. (difference) then take the average.

WWV is extremely stable as its derived from an atomic clock and I am sure sanity checked by multiple methods.
« Last Edit: February 10, 2018, 03:18:33 pm by cdev »
"What the large print giveth, the small print taketh away."
 

Offline 0xdeadbeef

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Re: bg7tbl gpsdo master reference
« Reply #520 on: February 10, 2018, 03:36:46 pm »
To test them you need both a reference that is verifiably better than them, and a universal counter or similar, also of verifiable accuracy, locked to it!
I would be more concerned about the short therm accuracy, i.e. phase jitter etc. Also the frequency regulation will most probably show some mid term oscillations depending on the design.
There are even GPSDO sold on eBay which don't even have an OCXO or at least a TCXO. So while a long term measurement would be most probably OK they could still be pointless as frequency normal.
Trying is the first step towards failure - Homer J. Simpson
 

Offline Jörg

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Re: bg7tbl gpsdo master reference
« Reply #521 on: February 10, 2018, 07:54:07 pm »
Quote
UCenter can command the internal GPS!?

What does it enumerate as, what kind of ublox GPS chip is in there?

There is a banner when it first starts up, would you be able to capture it and paste it here?



Still a few views on the last generation of the BG7TBL GPSDO.
Everything is fine also connect to PC with RS 232 cable. U-Center and Lady heaters work  easily with this device and the NMEA data is displayed in the software.
best regards


Hello.
No. I wrote U-Center can display the NMEA data. The U-blox neo 7m could not be controlled at the moment.

Another problem I have noticed yet.
On my two notebooks (with docking station) The GPSDO is misinterpreted as any pointing device.
The cursor jumps over the display and menus are activated indiscriminately.
Currently, the set up only works on my old Core2Duo tower.
 Jörg
« Last Edit: February 10, 2018, 07:56:01 pm by Jörg »
 
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Offline edpalmer42

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Re: bg7tbl gpsdo master reference
« Reply #522 on: February 10, 2018, 08:04:42 pm »
Any device that sends data to a Windows machine over a serial port can be misinterpreted as a serial mouse.  There are various ways to fix that, but they often don't work very well.  The best way to handle it is to disable the fake mouse in Device Manager.

Ed
 

Offline cdev

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Re: bg7tbl gpsdo master reference
« Reply #523 on: February 10, 2018, 08:22:33 pm »
When the power first comes up, what is the text that appears in the RS232 right at the beginning?


It might look something like this..

:40:45  $GNTXT,01,01,02,u-blox AG - www.u-blox.com*4E
19:40:45  $GNTXT,01,01,02,HW UBX-M80xx 00080000 *43
19:40:45  $GNTXT,01,01,02,ROM CORE 2.01 (75331) Oct 29 2013 13:28:17*4A
19:40:45  $GNTXT,01,01,02,PROTVER 15.00*01
19:40:45  $GNTXT,01,01,02,GNSS OTP:  GPS GLO, SEL:  GPS GLO*67
19:40:45  $GNTXT,01,01,02,ANTSUPERV=AC SD PDoS SR*3E
19:40:45  $GNTXT,01,01,02,ANTSTATUS=DONTKNOW*2D
19:40:45  $GNTXT,01,01,02,LLC FFFFFFFF-FFFFFFED-FFFFFFFF-FFFFFFFF-FFFFFF69*3E
19:40:45  $GNTXT,01,01,02,RF0 dev ok*04


Note that that particular output is from a questionable "M8N" board that I bought on ebay. A genuine M8N would have both ROM and flash firmware revisions displayed, not just one. My board appears to lack the EEPROM it is supposed to have.

Also, it may have an OXO, not a TCXO.. Which is another move to save a few pennies.. Its understandable, as I paid around $20 for my module, very little.

But I dont use it. If I was going to do it over I likely would just buy the factory fresh ones from places like cgshop which are sure to be genuine. But, the one I would need to buy for what I would want to do, the M8T, would cost ~$65-70. And I would need two of them.

Hello.
No. I wrote U-Center can display the NMEA data. The U-blox neo 7m could not be controlled at the moment.

Another problem I have noticed yet.
On my two notebooks (with docking station) The GPSDO is misinterpreted as any pointing device.
The cursor jumps over the display and menus are activated indiscriminately.
Currently, the set up only works on my old Core2Duo tower.
 Jörg
« Last Edit: February 10, 2018, 09:37:06 pm by cdev »
"What the large print giveth, the small print taketh away."
 

Offline Jörg

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Re: bg7tbl gpsdo master reference
« Reply #524 on: February 10, 2018, 09:24:43 pm »
Any device that sends data to a Windows machine over a serial port can be misinterpreted as a serial mouse.  There are various ways to fix that, but they often don't work very well.  The best way to handle it is to disable the fake mouse in Device Manager.

Ed


Thank you Ed.

I've been fighting for about half an hour with the crazy fake mouse.
In the end I won and it works now. Crazy!!

Thank you so much. Jörg
 


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