Topics

New build - setup / calibrartion question #calibration #ssb

Dean Souleles
 

Hi - 

Just completed my ubitx 5 build and it passed the first power on test (yay!).  The controls appear to work as intended.  CW sounds pretty good to my years.    SSB phone audio is garbled and difficult to understand.  The frequency display appears off as well.  When I tune WMV at 10.000 for example, I hear nothing.  When I dial in 10.002.100 or .200  get a nice clean tone (.200 is lower pitch).    I've read all the blogs / instructions on calibration and setup that I can find but they assume knowledge that I clearly don't have.   Is there a straightforward guide to follow?  What to do next?

Thanks,

Dean
KK4DAS

Neil Tolman
 

Dean asked:  "Is there a straightforward guide to follow?"  Yes please! I second that question!

Neil K1NBT


On Thursday, August 8, 2019, 11:10:57 PM EDT, Dean Souleles <dsouleles@...> wrote:


Hi - 

Just completed my ubitx 5 build and it passed the first power on test (yay!).  The controls appear to work as intended.  CW sounds pretty good to my years.    SSB phone audio is garbled and difficult to understand.  The frequency display appears off as well.  When I tune WMV at 10.000 for example, I hear nothing.  When I dial in 10.002.100 or .200  get a nice clean tone (.200 is lower pitch).    I've read all the blogs / instructions on calibration and setup that I can find but they assume knowledge that I clearly don't have.   Is there a straightforward guide to follow?  What to do next?

Thanks,

Dean
KK4DAS

Don - KM4UDX
 

Yes, I'm sorry the calibration and BFO process is such a muddle. Others here can help more, I'm sure.

In summary, all the various procedures and descriptions boil down to going into setup mode, adjusting the calibration #, saving it, then observing the current displayed freq vs the freq that you know you are listening to.  Repeat until the display freq matches the actual TX freq. Simple right? And adjusting the BFO process is also simple...tune to a known freq, and adjust the BFO in the setup menu until it sounds good, save the new setting. Repeat till you are happy. What? Excuse me? Hun? hhahaha. 

All that sounds easy, but it isn't, at least for me. How do I know what frequency WWV or CUV is? I mean they both take up a bit of bandwidth. Where exactly in the signal spread do I tune to? And depending on what the reference is sending, the signal spread can change like mad....e.g., a tone vs a voice. And what about the sidebands on voice? ahhhhh....help me.....Yeeks, what a mess. 

I ended up finding a sort of random signal on my SDR that looked like it was really narrow, on a simple frequency with a bunch of zeros, and it didn't change.  I figured it was really on that freq and used it as a reference. God help me if it was off. Because I wouldn't have a clue. With that sig, I did the above process.  For a newbie, this is totally obscure mess and felt like stumbling to success, in the dark, with a  blindfold on, and your shoelaces tied together. 

In my helplessness, I ended up going to a wise and kind mentor, who took pity on my youthful ignorance and general cluelessness.  He helped me get a grip on what we were trying to do. I pretend to understand. hahaha. But his help was totally essential for me to get anyplace.  For him, adjusting uBITX BFO  was a normal as milk on cereal: automatic and natural. For me, it was like...what? hahaha.

My budda like guru is the world renowned Dan W3BU. Who just happens to post about BFOing in this forum.  Here he wrote about using another radio while adjusting his uBITX.

https://groups.io/g/BITX20/message/70931

His post might help.  Feel free to ask him anything. I did. hahah.

If you are a visual type, here is a good youtube vid on uBITX BFOing.

https://youtu.be/sXJmAhpAjeI

At the end of the day, you'll just go into setup menu and tweak the calibration # until the freq display is close to where it should be.  If you use the memory manager, the process is much faster as you change the value in the MM, write it to the ubitx, and observe how much you improved or screwed things up.  And iterate your way to success.  But regardless of interface, the essential process is identical. 

Don
km4udx

Gordon Gibby
 

​All I do is tune to 10.00000000000 and then see what their TONES are.   should be 500 Hz or 600 Hz.

ANY waterfall will measure those very very very accurately.     FLDIGI, anythng.


Then calculalte the correction, apply it to the source code, recompile.

If you are using some product ccode, apply corrections until you get the tones to be perfect.

Should work.


Gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of Don - KM4UDX <dontAy155@...>
Sent: Friday, August 9, 2019 1:18 PM
To: BITX20@groups.io
Subject: Re: [BITX20] New build - setup / calibrartion question #calibration #ssb
 
Yes, I'm sorry the calibration and BFO process is such a muddle. Others here can help more, I'm sure.

In summary, all the various procedures and descriptions boil down to going into setup mode, adjusting the calibration #, saving it, then observing the current displayed freq vs the freq that you know you are listening to.  Repeat until the display freq matches the actual TX freq. Simple right? And adjusting the BFO process is also simple...tune to a known freq, and adjust the BFO in the setup menu until it sounds good, save the new setting. Repeat till you are happy. What? Excuse me? Hun? hhahaha. 

All that sounds easy, but it isn't, at least for me. How do I know what frequency WWV or CUV is? I mean they both take up a bit of bandwidth. Where exactly in the signal spread do I tune to? And depending on what the reference is sending, the signal spread can change like mad....e.g., a tone vs a voice. And what about the sidebands on voice? ahhhhh....help me.....Yeeks, what a mess. 

I ended up finding a sort of random signal on my SDR that looked like it was really narrow, on a simple frequency with a bunch of zeros, and it didn't change.  I figured it was really on that freq and used it as a reference. God help me if it was off. Because I wouldn't have a clue. With that sig, I did the above process.  For a newbie, this is totally obscure mess and felt like stumbling to success, in the dark, with a  blindfold on, and your shoelaces tied together. 

In my helplessness, I ended up going to a wise and kind mentor, who took pity on my youthful ignorance and general cluelessness.  He helped me get a grip on what we were trying to do. I pretend to understand. hahaha. But his help was totally essential for me to get anyplace.  For him, adjusting uBITX BFO  was a normal as milk on cereal: automatic and natural. For me, it was like...what? hahaha.

My budda like guru is the world renowned Dan W3BU. Who just happens to post about BFOing in this forum.  Here he wrote about using another radio while adjusting his uBITX.

https://groups.io/g/BITX20/message/70931

His post might help.  Feel free to ask him anything. I did. hahah.

If you are a visual type, here is a good youtube vid on uBITX BFOing.

https://youtu.be/sXJmAhpAjeI

At the end of the day, you'll just go into setup menu and tweak the calibration # until the freq display is close to where it should be.  If you use the memory manager, the process is much faster as you change the value in the MM, write it to the ubitx, and observe how much you improved or screwed things up.  And iterate your way to success.  But regardless of interface, the essential process is identical. 

Don
km4udx

Don - KM4UDX
 

Gordon, when you do this, do you have the uBITX under cat control so the uBTIX freq is controlled by and shown on the fldigi (for example) waterfall?

Gordon Gibby
 

​I just tune it.   With my hand.    


had to do the exact same thing for an ICOM 725 recently.   It is more complicated because there are TWO different frequency sources in the unit, so you have to first figure out which one is off.... in my case, the master oscillator (66 MHz) was correct, and the BFO oscillator was off.   


For the BITX, since ALL ferquencies come from ONE crystall.... far far easier.   


Gordon



From: BITX20@groups.io <BITX20@groups.io> on behalf of Don - KM4UDX <dontAy155@...>
Sent: Friday, August 9, 2019 1:30 PM
To: BITX20@groups.io
Subject: Re: [BITX20] New build - setup / calibrartion question #calibration #ssb
 
Gordon, when you do this, do you have the uBITX under cat control so the uBTIX freq is controlled by and shown on the fldigi (for example) waterfall?

Dean Souleles
 

Hi Gordon,

Thanks for the note.  Apologies for being dense. I did tune to 10.000 - no tone.  The tone is on 10.002.100 on my radio.  So first step - what do I change to get the frequency to display accurately?  Second,  after tuning to 10.002.100 I did use FLDIGI to look at the waterfall but I don't see anything that indicates the tone is 500 or 600 Hz.  I was using the speaker on the ubitx and the mic from my laptop - just audio to audio.  Do I need to direct connect the ubitx to the PC?  Perhaps I don't know how to setup the waterfall display in FLDIGI - but what I see looks nothing like what I have seen on web videos.  I set mode CW on FLDIGI and dialed  in 10.002.100 on the ubitx - nice clear tone.  Nothing on the waterfall display in FLDIGI looks like a 500 or 600 hz signal to me.  Perhaps I also don't understand how to setup FLDIGI.


I also don't understand what you mean by the following: 
"Then calculate the correction, apply it to the source code, recompile. If you are using some product ccode, apply corrections until you get the tones to be perfect."   

Dean
KK4DAS


 

Dean Souleles
 

Hi Don -

That is a helpful explanation.   I can definitely do the incremental trial and error method - just requires patience - but I also want to understand what I am doing.  I read Dan W3BU's post  - but I still don't quite understand that. He says something about using the "usual instructions to set the display"  Huh?  I think I get the idea about matching the frequencies between a sender and a receiver.  But beyond that - bang - head explodes.  

Dean

Gordon Gibby
 

Well guys, this is going to give you a good chance to begin to understand more and more about Radio!   

If you don’t hear the tone until you are tuned 2kHz off, then yes your radio is a fair bit out of calibration!!

First of all, make a direct electrical connection between your radio and your PC, use a capacitor, like 0.1 µF - 10 Micro farad to make the audio connection and you’ll have a much better signal to watch.  If that’s impossible for you, just keep using the microphone

Adjust settings of your FLDGI to provide its X axis in audio frequencies, not radio frequencies

Bingo!  Now you have an audio spectrum analyzer!!


Deep inside the uBitx code is a number that says what it thinks the crystals freq is.   It happens to be wrong.   If you know how to adjust the code you can fix it there;  if not you’ll need to use one of the calibration routine’s.   Expect  to have to do a good bit of thinking and experimentation to figure this out!  But you’ll be a better ham radio operator for having done the effort

Better than giving you some set of complicated instructions, is asking you to use your noggin to figure this out




On Aug 9, 2019, at 18:03, Dean Souleles <dsouleles@...> wrote:

Hi Don -

That is a helpful explanation.   I can definitely do the incremental trial and error method - just requires patience - but I also want to understand what I am doing.  I read Dan W3BU's post  - but I still don't quite understand that. He says something about using the "usual instructions to set the display"  Huh?  I think I get the idea about matching the frequencies between a sender and a receiver.  But beyond that - bang - head explodes.  

Dean

Don - KM4UDX
 

Q:   I did tune to 10.000 - no tone.  The tone is on 10.002.100 on my radio.  So first step - what do I change to get the frequency to display accurately?  

A:  when you tune to 10.002.1 you hear a signal on 10.000.0.  So your display freq is too high.   You need to shift the uBitx receiver down by 2.1k.  How? Change alignment # bit by bit until uBitx display freq equals 10mhz and sound is sounding there.  Go into setup, find the alignment value (sorry I forgot what the menu calls it), and add a negative 100, save it,  and retune. Are you closer or further off? Repeat as required. 

The discussion of using fldigi as a specterm analyzer is very clever, but too complicated for now.  One problem at a time, says me.  

Don - KM4UDX
 

Dear Mr. Gordon Libby. 

It pains me to say this, and I hate to admit it publicly, but you are exactly correct. Hahahah

Neverthelss, I for one, will take (and give) all the help I can get. My noggin is a wicked incomplete space.  A humble vessel ready for the wisdom of others.  

But, back to your observation, I humbly acknowledge your very good point.  Well said.

i slink back to the bench....


hahahah.

don
km4udx

Gordon Gibby
 

The fact that you have to turn into a higher frequency indicates the internals of the microbitX may be at too lower frequency but you will figure it out.  Try anything, it will either get better or worse.

Once you get it close, you can fiddle with the audio spectrum analyzer to get it within a couple of Hz. 

The crystal is not in an oven, so it’s going to move just a bit with temperature.

Every single one of them that I have seen is off, because the circuit does not provide exactly the capacitance they were cut for.   The oscillator is supposed to be around 20 MHz I believe and every single one I have seen is off by about 4 kHz




On Aug 10, 2019, at 15:18, Don - KM4UDX <dontAy155@...> wrote:

Dear Mr. Gordon Libby. 

It pains me to say this, and I hate to admit it publicly, but you are exactly correct. Hahahah

Neverthelss, I for one, will take (and give) all the help I can get. My noggin is a wicked incomplete space.  A humble vessel ready for the wisdom of others.  

But, back to your observation, I humbly acknowledge your very good point.  Well said.

i slink back to the bench....


hahahah.

don
km4udx

Don - KM4UDX
 

So there is a early draft users guide in the folders section with the following calibration steps. There may be better instructions in some other guide.  I am way too lazy to do a complete search. 

User Manual for KD8CEC uBITX software rev 1.061
https://groups.io/g/BITX20/attachment/45949/0/ug-toc2-rev0.52.pdf

If someone wants to make a youtube vid of the calibration procedure for a newbie, I would venmo them $10, or make a contribution to the foundation of their choice.

Note:  I have not tried these steps. I don't know if they work.  They seem unbelievably easy and straightforward. Which is why I would never try them. I would surly cause a warp in space time fabric with these 5 steps.
==============================

The uBITX reference oscillator on-board can be accurately calibrated using this menu.

The procedure is: 1. put the ubitx in USB mode

2. connect an antenna to the uBITX to listen WWV; alternatively connect a calibrated signal source at 10 MHz to the antenna input 

3. navigate the menus to get to the Set Calibration entry, and press the Function Sw. The uBITX will tune to 10,000,000 Hz, but the display will not show that.

4. rotate the encoder until you hear the zero beat

5. Carefully push the Function SW to save the calibration As a result of this process, uBITX frequencies will be within a few Hz of the dial setting.

For those who have access to a high resolution frequency counter, as an alternative to the above, you can: connect the uBITX to the counter via a pad of at least 20 db, and hold the CW key down while adjusting the uBITX encoder until you see on the frequency is exact. Then carefully push the Function SW to save the calibration.

Set the BFO

Set the BFO frequency used in USB and LSB. Rotate the encoder to vary the BFO frequency, then press the mic PTT switch to confirm. If you do not want to change the BFO frequency, press the function switch to abort.

Set CW RX BFO

Set the BFO frequency used in USB and LSB. Rotate the encoder to vary the BFO frequency, then press the mic PTT switch to confirm. If you do not want to change the BFO frequency, press the function switch to abort.

Change CW Tone

Set the CW sidetone frequency. Rotate the encoder to vary the CW sidetone frequency, then press the mic PTT switch to confirm. If you do not want to change the BFO frequency, press the function switch to abort


etc. etc. etc.