bg7tbl gpsdo master reference

[noreply]

Give links to buy new GPSDO

I bought my unit via amazon.co.uk (have piece of mind - if problem with unit or DOA - can return for full refund - no questions asked)

Just type-in ...

GPS Disciplined Oscillator GPS DISCIPLINED Clock

There may be more than one seller - go for the cheapest - or fastest delivery.

My unit cost GBP120

Good Luck 

[noreply]

I just got LH 6.14beta

Trying to run LH with BG7TBL 2020-03-02 GPSDO

LH reports 'no receiver' - after it goes through its default search

I'm using com4 - connection with GPSDO is good - data is flowing.

I think my GPSDO is using Ublox receiver - but not marked

Any suggestions or tests I should do to get LH to recognize the receiver?

Cheers

[Ringmodulator]

Hi,

use a simple terminalprogramm at 9600 Bd 8N1.
You should see the NMEA data comming in, if everything works OK.

You can use the ublox u-center software to check out the ublox fuctions.

With Lady Heather, specify the comport like starting with heather.exe /4 for com 4.

If it starts, it is in NMEA mode. With /rxu you can switch to the ublox mode.
Switch back with /rxn.

Be sure, to specify the correct comport, check in the system settings.

Regards
Chis

I just got LH 6.14beta

Trying to run LH with BG7TBL 2020-03-02 GPSDO

LH reports 'no receiver' - after it goes through its default search

I'm using com4 - connection with GPSDO is good - data is flowing.

I think my GPSDO is using Ublox receiver - but not marked

Any suggestions or tests I should do to get LH to recognize the receiver?

Cheers

[noreply]

Hi,

use a simple terminalprogramm at 9600 Bd 8N1.
You should see the NMEA data comming in, if everything works OK.

You can use the ublox u-center software to check out the ublox fuctions.

With Lady Heather, specify the comport like starting with heather.exe /4 for com 4.

If it starts, it is in NMEA mode. With /rxu you can switch to the ublox mode.
Switch back with /rxn.

Be sure, to specify the correct comport, check in the system settings.

Regards
Chis

Hey Chris - thanks for your help.

At least I was not going crazy.

Yeah - I'm getting data coming into the FT232 'dongle'

I configured my USB driver and set comport to COM1 with appropriate handshake - as you suggested - but the data I am receiving is gibberish - see screen cap picture.

I tried the obvious settings - different baud and handshake - but nothing sensible coming out of the GPSDO and into the computer.

At least I'm not doing the wrong thing - in principle - just need to find what went wrong.

1st stop is to get proper RS-232 cable and try - my parch wires 'work' - but obviously not 

If you can spot something I did wrong from the pics - than that's great - otherwise I will get proper interface.

I guess there is nothing I can set on the GPSDO side - and if it outputs data at the 9600 baud - then I am on the right track.

Thanks

Cheers

[Ringmodulator]

Hi,

you can start LH as heather.exe /1 /rxn
This switches my unit to NMEA mode.

For ublox mode, use heather.exe /1 /rxu

The /1 is for com 1.
In u-blox mode, the run led does not blink, but this is not an issue.
With the command /rxn, this can be restored.

I strongly suggest to try u-center from u-blox. It is on their homepage.
It will autodetect the port speed and mode, you just have to select the correct com port.

https://www.u-blox.com/en/product/u-center

Chris

[noreply]

Hey Chris,

Appreciate your quick response

I did some checking - and put an old HW flow control dongle I had onto the GPSDO RS232 output port - and notices that there are active RTS/CTS line activity.

I will try to wire this into my dongle - which can handle these signals - perhaps this will fix??

I will then certainly try u-blox

BTW - not directly relating to the above - I have purchased another 3 BG7TBL products

The 10MHz Distribution Amplifier,10MHz OCXO Frequency Standard,8 Port Output

The 1Hz-6GHz Frequency Counter.11digit/s@10MHz

and
 
The WB-SG1 signal generator 1hz-8ghz signal source broad band signal source with band - on - off modulation

Finally - I also got a LCD version of the GPSDO - it was below $100 - so I could not resist the bargain, but not sure if the Chinese supplier will ship when they realize its way less what others charge.

It was through Amazon - so if things go bad - will be able to get full refund.

If you want the links - let me know.

Well all of the above will keep me going for quite some time (pun unintended) whilst I explore this 'time' rabbit hole 

Cheers

[MegaVolt]

LCD version of the GPSDO - it was below $100

I'm curious. Give a link please. What is its date / version?

[noreply]

LCD version of the GPSDO - it was below $100

I'm curious. Give a link please. What is its date / version?

Sure, but be careful - the supplier sent me a message - that they wanted me to cancel the order - because the 'unit' was sold.

I did not - and Amazon confirmed it was shipped - so I will need to wait (snail mail) - to see indeed if it was shipped.

Maybe there was genuine misunderstanding - so will give +1 to supplier until otherwise.

I think the 2017-12-16 is the last revision - BG7TBL does not make this unit anymore??

PLEASE correct me if i'm wrong.

I believe there is a post in this thread - that details the programming of the LCD function.

https://www.amazon.co.uk/gp/product/B08D8TR4VW/

Good luck

Let me know if you manage to purchase and the system / supplier accepts the order

Cheers

[MegaVolt]

This item cannot be shipped to your selected delivery location. (((

[noreply]

This item cannot be shipped to your selected delivery location. (((

Hmm...

Maybe politics - Amazon has no problem - it must be the supplier - because this item is NOT fulfilled by Amazon directly.

So maybe China Post - has Problem with your location??

If you want check Aliexpress.com - maybe you can find same model for similar price - I just liked the 'safety' of using Amazon when buying from China directly - in case there are shipping problems.

My other order via Amazon - also from China was great service - the Supplier shipped quickly - I received in 9 days

Take Care my Friend 

[texaspyro]

Hi,

you can start LH as heather.exe /1 /rxn
This switches my unit to NMEA mode.

For ublox mode, use heather.exe /1 /rxu

The /1 is for com 1.

You should not have  to specify /rxn or /rxu.  If the unit is streaming data Heather should be able to auto identify the receiver type.

[Ringmodulator]

My unit BG7TBL 2019-10-20, in the default mode with the Run LED blilnking, LH without /r argument, starts in NMEA mode.
U-blox is is not auto-detected. What works for me is typing /rxu switching LH in ublox mode.

BTW: Is there a possibility in LH to display the estimated accuracy similar to the units with the integrated diplay option?

Hi,

you can start LH as heather.exe /1 /rxn
This switches my unit to NMEA mode.

For ublox mode, use heather.exe /1 /rxu

The /1 is for com 1.

You should not have  to specify /rxn or /rxu.  If the unit is streaming data Heather should be able to auto identify the receiver type.

[noreply]

Thanks to everyone who 'chimed-in' to help 

I managed to resolve MY problem which was related to my RS232 to USB interface cable

Long story short - it simply was not receiving the data correctly - and as a result - erroneous data prevented LH to identify the GPS receiver in the GPSDO - and subsequently not being able to function.

With a new AND WORKING cable - all is fine - I just had to specify the comport via /4 command (my device was on com4) LH fires up with NEMA receiver detected.

Is there a way to monitor the OCXO frequency drift of the GSPDO with respect to the received GPS reference with LH?

Not sure if this is possible with a NEMA receiver LH configuration.

Any feedback on this once again is most welcome.



Now I have another interesting problem.



I ordered a few more additional BG7TBL devices and received them today.

1. 10MHz OCXO frequency standard distribution amplifier 2019-09-13
2. FA-2 Precision Frequency counter
3. WB-SG1 Wideband Signal Generator (8GHz)

So I am about to enter even a bigger rabbit hole and might need more help from all of you who visit this thread.


First Question


The 10MHz OCXO distribution amplifier
- does anyone have a user manual?

I am puzzled by the RED led on the front which is labeled ALM

I can only assume this is similar to the ALM LED on the GPSDO ??

The operation of this - is to signal when the OCXO has stabilized or been conditioned by the GPS
When you switch-on the GPSDO for first time - the RED LED ALM is 'on' and this stays on for about 10 minutes - then it goes off (as expected)

On the 10MHz OCXO distribution amplifier - when powered-on the ALM LED is 'off' and it stays off no matter what happens.

Is this normal behavior?

Does it only go 'on' when there is some kind of failure ONLY??

Any input on this will be most welcome.



Second Question


The FA-2 Precision Frequency counter is capable of 11 digit resolution.

It has an external 10MHz reference

I presume (have not opened it up as yet) it has its own OCXO inside for the internal clock.

So any Frequency measurements it performs will be in relation to its internal clock

How can we then 'trust' the 11 digit resolution?

Is there some algorithmic technique used to get extra precision and not tied directly to the clock?

My concern is if I connect the GSPDO 10MHz reference to it - it will then report the GPSDO 10MHz frequency as 'perfect' because its using this as a refrence - I guess this is expected behavior.

So as I suspect - I WILL NOT be able to use the FA-2 to measure the GPSDO frequency deviation from true 10MHz

BUT

I will be able to measure ANYTHING else in reference to the assumed perfect 10MHz GPSDO clock.

Which is as expected - you cannot use yourself as a reference to check yourself ... you know what I mean (I hope).

Also, if someone knows of user manual - I am particular interested as to how to 'switch' on or off the LPF (displayed on front LCD display) - it is not responsive to any button sequences I tried. I assume you will be able to 'switch-on' the Low Pass Filter Function - not sure as to how this it to be applied and to what effect - presumably to 'clean-up' the signal where appropriate.

I found an existing thread on this device ...

https://www.eevblog.com/forum/metrology/bg7tbl-fa1-frequency-analyzer/

I guess I missed it the first time around



Third Question

Has anyone got the WB-SG1 Wideband Signal Generator (8GHz)?

If you do have it - have you got any 'tips' / suggestions / comments??




Thank you everyone - hope you find this post useful - please ask if you want me to do any testing
 

[Ringmodulator]

@noreply:

To your first question:
It is my understanding, that these 10MHz distibutors come in two versions. One with internal OCXO and the cheaper ones without internal TCXO.
The ALM LED is on, when neither an external 10MHz is detected, nor an internal OCXO is present. I dont own such a unit and this is, what I understood from the ebay descriptions.

To your second question:
You cant pull yourself out of the mud by grabbing your own hair.
If you want to evaluate the GPSDO, you need a better(!) reference to  compare it to.
The internal TCXO of the FA-2 is simply not suited for  this. The FA-2 can be calibrated against a GPSDO and then be used as a fairly accurate standalone unit.
It has to be recalibrated from time to time to take care of the aging of the internal OCXO.

Chris

[Ringmodulator]

...
The OCXO
- ALM led goes off
- temperature stability to be ok
- within 10 minutes 
- this sounds 'too good'
- I would have expected more time for the oscillator to be disciplined.
...

My understanding is, that the ALM LED goes off, as soon as the OCXO has reached its operating temperature.

Chris

Edit:

I did replace the OCXO in my unit with a Morion MV89A. It takes much longer for the ALM LED to go off.
This did make sense as this OCXO with its double oven is quite big and takes much longer to fully heat up.

But to sense this, there should have been a shunt resistor to detect the drop in current for the OCXO and it looks like there is none.
So it looks to be more likely, that the controller looks at the frequency of the OCXO in comparison with the 1pps signal and as soon as the OCXO frequency is below a certain theshold, it switches the ALM LED off.

Just guesswork.
Any better insights on this?

Chris

[pizzigri]

Sure, but be careful - the supplier sent me a message - that they wanted me to cancel the order - because the 'unit' was sold.

I did not - and Amazon confirmed it was shipped - so I will need to wait (snail mail) - to see indeed if it was shipped.

Maybe there was genuine misunderstanding - so will give +1 to supplier until otherwise.

I think the 2017-12-16 is the last revision - BG7TBL does not make this unit anymore??

PLEASE correct me if i'm wrong.

I believe there is a post in this thread - that details the programming of the LCD function.

https://www.amazon.co.uk/gp/product/B08D8TR4VW/

Good luck

Let me know if you manage to purchase and the system / supplier accepts the order

Cheers

OK, I managed to purchase it. It was not barred from delivery in Italy, but let's see... I'll post the results if eventually it does arrive!

[Electro Fan]

Interesting...

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6603695/

A couple excerpts below, more detail in the paper.

“This paper mainly contributes to the assessment of BDS-2, BDS-2/BDS-3, GPS, GLONASS, and Galileo PPP with the observations that were provided by the international Global Navigation Satellite System (GNSS) Monitoring and Assessment System (iGMAS).”

”Galileo has also made good progress in terms of the coverage and precise positioning. BDS and Galileo are basically at the same level as GPS and GLONASS, and they can be well applied to global precise positioning and other application.”

[Fennec]

You can try with Lady Heather or U-center to connect to the u-blox chip and see whats going on

It is NOT an UBlox Device, it is Chineese fake crap.

[Johnny B Good]

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

 Apologies but I simply couldn't resist - that's an issue best described as the microsoft ball(s up) intelli-mouse driver issue that has persisted ever since win2k through to win10. I did eventually track down a simple to run fix to disable this microsoft nonsense that had afflicted my (and almost everyone elses) usb to serial adapter drivers (FTDI and Prolific types) used to interface to U-blox  and other brands of GPS receiver modules relying on a built in serial to usb interface.

 Here's a link (probably the one I used - I can't recall for certain now) to an "MS Serial BallPoint Mouse Disabler"  <https://qpdownload.com/ms-serial-ballpoint-mouse-disabler/> for anyone else who might be experiencing the same problem or simply just want to guard against being caught out by this "MS mouse driver Balls up" issue in the future.

John

[Noy]

Does somebody already knows whats behind this "E-GPSDO bg7tbl"?
It looks like its another thing as PLL-GPSDO..
Grr cant copy Ali link here..

[Noy]

I also can buy it but the reviews / seller classification is realy bad. There are claims for item never arraived. And fake shop because it is too cheap and other things. Cancled my order..

This link was it:
https://www.amazon.co.uk/gp/product/B08D8TR4VW/

[noreply]

I also can buy it but the reviews / seller classification is realy bad. There are claims for item never arraived. And fake shop because it is too cheap and other things. Cancled my order..

This link was it:
https://www.amazon.co.uk/gp/product/B08D8TR4VW/

Interesting - that this is EXACTLY the SAME item and merchant I tried to purchase several months ago via Amazon - yes its a great price.

The Order was accepted and after a few days I got email from supplier telling me that this product is not good and that THEIR Supplier cannot supply - so they cannot ship to me and want to refund IN FULL.

I contacted Amazon - and told them what happened and did NOT want to cancel the order - because they have committed to this sale by virtue of advertising and NOT removing the product - even after they told me they cannot supply it.

Amazon contacted them and asked to TRY to honor the sale - apparently they cannot force the merchant to supply - BUT  CAN remove any future listings which are misleading.

In the end I simply gave up - because the merchant - did provide the FULL REFUND and I got another product from another (Also Amazon) supplier.

I suggest you contact Amazon - them them of your experience - and tell them this is NOT just you - the supplier STILL ADVERTISES the SAME product which they clearly cannot supply - Amazon can stop them from doing it further.

Anyway - thought I should share this feedback with you

Take Care

[pizzigri]

I also can buy it but the reviews / seller classification is realy bad. There are claims for item never arraived. And fake shop because it is too cheap and other things. Cancled my order..

This link was it:
https://www.amazon.co.uk/gp/product/B08D8TR4VW/

Interesting - that this is EXACTLY the SAME item and merchant I tried to purchase several months ago via Amazon - yes its a great price.

The Order was accepted and after a few days I got email from supplier telling me that this product is not good and that THEIR Supplier cannot supply - so they cannot ship to me and want to refund IN FULL.

I contacted Amazon - and told them what happened and did NOT want to cancel the order - because they have committed to this sale by virtue of advertising and NOT removing the product - even after they told me they cannot supply it.

Amazon contacted them and asked to TRY to honor the sale - apparently they cannot force the merchant to supply - BUT  CAN remove any future listings which are misleading.

In the end I simply gave up - because the merchant - did provide the FULL REFUND and I got another product from another (Also Amazon) supplier.

I suggest you contact Amazon - them them of your experience - and tell them this is NOT just you - the supplier STILL ADVERTISES the SAME product which they clearly cannot supply - Amazon can stop them from doing it further.

Anyway - thought I should share this feedback with you

Take Care

Ok, so I was in this band wagon as well... never received anything, contacted Amazon and worked until i got a higher up supervisor, and it seems, IT SEEMS - mind you - that the reason this and other similar ads for the GPSDO cannot get honored is because the seller has no clue what he is selling, and that he actually thinks the GPSDO is some sort of power inverter for car use - from 12V CC to 240V AC. And then, he cant get it at the price he advertised.
This makes some sort of sense, because if you read carefully the Amazon description, it acutally says:"...Pure Sine Wave Power Inverters Soft-start function AVR - Black".
Plus, I did not notice, but look at the "Customers also viewed these products" bar.
The Supervisor told me that Amazon allows sellers to make "mistakes" and he cannot hold him responsible for the advertisement, since it is correctly listed as a power inverter, as long as the seller refunds in full - which he did to me at least.

[Noy]

My E-GPSDO arrived today.
It is working but i still have to check how accurate.
I will try to measure it within the next days.
Attached some pictures from inside. PCB is marked with 10.1.2020 BG7TBL

GPS fix is only possible if i put the antenna outside (then within <30s (inside, behind my window there is no fix).

[Noy]

Hm wonder why the E-GPSDO should be more accurate than the PLL-GPSDO ?
Looks the same (even same PCB marking) except the ocxo number.
But its 7€ more expensive..