Author Topic: BG7TBL FA1 and FA2 frequency analyzers  (Read 7907 times)

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Offline texaspyro

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Re: BG7TBL FA1 and FA2 frequency analyzers
« Reply #100 on: November 05, 2019, 04:00:54 am »
So I can see all the 10 MHz counter readings scroll by in terminal mode on the PC (via USB connection).  I've turned off the FA-2 and entered the $E4040* command while the generator is outputting 10 MHz at 50 Ohms on Ch1 and then turned the FA-2 on but that didn't work.  What's the process for uploading the commands from the PC to the FA-2?  Thx

WTF?   How can one possibly expect it to accept commands or do anything when  it is powered off?    :palm:

You enter the $Exxxx commands while the counter is powered on and spewing measurement data.  Yes, the terminal display will look like confusing crap,  but the FA2 doesn't care.
 

Online Electro Fan

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Re: BG7TBL FA1 and FA2 frequency analyzers
« Reply #101 on: November 05, 2019, 04:09:11 am »
So looking at the manual and the commands:

select CH1=50R,input 10M 0dBm
$E4040*   

select CH1=50R,input 10M -20dBm
$E4141*

Just guessing but the process is to run the $E4040* command while the FA-2 is powered up and connected on Ch1 at 50 Ohms to a reliable generator outputting 10 MHz at 0 dBm?  Then save and exit?  Then repeat with $E4141*while the generator is running at -20 dBm?  Then save and exit? 

Save and exit might be $E2020* ?

Thanks

Not quite... the $Exxxx commands do the work and save the results.  So just connect the proper signal and issue the appropriate $Exxxx command.

So I can see all the 10 MHz counter readings scroll by in terminal mode on the PC (via USB connection).  I've turned off the FA-2 and entered the $E4040* command while the generator is outputting 10 MHz at 50 Ohms on Ch1 and then turned the FA-2 on but that didn't work.  What's the process for uploading the commands from the PC to the FA-2?  Thx

Edit:

Figured it out.... Seems to be working!  Thanks!!

Looks to now be within 0.1 dBm; fluctuates between 0.0 and 0.1 dBm of mirroring the generator settings for both 0 dBm and - 20 dBm.

On a scale of 1 to 10 that is about a 10. :)

For anyone else trying the process, a few details.

Connect the FA-2 on Ch1 at 50 Ohms to your generator outputting 10 MHz at 50 Ohms at 0 dBm.
Connect the FA-2 via a USB port.
Open a terminal program on your PC.
If it's working on the right com port you will see the 10 MHz counter readings scroll by.
Open MS Word and enter $E4040*
Save the file as a .txt file named E4040 (or some acceptable characters).
In the terminal program use the "send a text file" command to upload the E4040 text file.
You will see an acknowledgement of the calibration text file going by among the scrolling counter info in the terminal program.
Notice that the dBM reading on the FA-2 is now very close to 0 dBm.

Repeat the process at -20 dBm.

You should be good to go with not only pretty accurate frequency counting on the FA-2 but also pretty accurate dBm power readings.

BG7TBL Rocks!  and texasypro too!

EF
« Last Edit: November 05, 2019, 04:30:15 am by Electro Fan »
 
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Online Electro Fan

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Re: BG7TBL FA1 and FA2 frequency analyzers
« Reply #102 on: November 05, 2019, 04:40:15 am »
Happiness is test equipment where frequencies, amplitudes, and phases all read pretty closely across the gear.   :)
 

Offline texaspyro

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Re: BG7TBL FA1 and FA2 frequency analyzers
« Reply #103 on: November 05, 2019, 09:11:07 pm »
There is no need to send the $Exxxx commands from a text file.   You can enter them from the keyboard while the FA2 is spewing frequency readings.  Yes, it looks horrible and confusing but works just fine.

The next version of Lady Heather supports the FA2.  It has keyboard commands (in the "P" menu) for changing most of the device configuration options,  but I did not include the calibration commands (to minimize the chance of somebody accidentally screwing up their calibration).   But you can use the !u keyboard command that sends command strings to the FA2 in order to send the $Exxxx cal commands.
 

Offline edigi

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Re: BG7TBL FA1 and FA2 frequency analyzers
« Reply #104 on: November 06, 2019, 09:22:21 am »
My FA2 copy has probably some kind of beta SW as when I did the power measurement calibration it did not take any effect until a power cycle (btw. I was using Putty and right clicking sent the text to FA2 that I've copied earlier to clipboard; text is not echoed back though).

What was even stranger that at the end of the power measurement calibration I've noticed a huge change in its reference frequency (~120mHz; even retrace around the time when I replaced the relay switch was only a fraction of this), so I had to calibrate the frequency of the reference again. I simply don't have an explanation for this jump (maybe I've slightly knocked the box during the power measurement calibration or is this calibration also impacting the compensation voltage of the OCXO?).
 

Offline texaspyro

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Re: BG7TBL FA1 and FA2 frequency analyzers
« Reply #105 on: November 06, 2019, 04:25:13 pm »
You power cycled it...   could cause oscillator retrace error.
 

Offline neil

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Re: BG7TBL FA1 and FA2 frequency analyzers
« Reply #106 on: November 06, 2019, 08:00:54 pm »
Ebay has a bunch of different sellers with what appear to be the same FA2 device (photo's of some show a date code printed on the front panel after the BG7TBL name, others don't - significant?). And AliExpress and probably other sources also offer the device.

I'd like to get one, and so I'd appreciate vendor recommendations.  At this price point I'm not too concerned over the small price differences of the various sources, but more interested in quality and latest version.
 

Offline Diabolo

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Re: BG7TBL FA1 and FA2 frequency analyzers
« Reply #107 on: November 08, 2019, 01:00:23 pm »
Hello,

I bought my FA-2 from this seller. Quick expedition. The received FA-2 operates without defects or problems. I asked PSU EU version.
- https://fr.aliexpress.com/item/4000120075382.html?spm=a2g0s.9042311.0.0.1ec66c378LS7JX

Regards.
Diabolo
 


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