Date   
Re: Highlighting band selected

Arv Evans
 

Jeff

The BITX20 discussion group is a community of people with like interests 
and experiences.  Some are casual users of the equipment, and most are 
licensed ham radio operators who have technical talents as evidenced by 
their passing the ham radio exams.  The uBITX, and BITXxx, before uBITX 
were designed for the Ham radio community.  Most of the members of this 
discussion group are here to discuss mods, operating, and camaraderie.
As of today there are 7871 members of the group, most of which are 
satisfied with their uBITX, BITX40, or earlier BITX20 units.  BITX units 
have evolved over time, usually involving on-line discussions and suggestions.

The people on this group are willing to help with problems, but that requires 
working with these helpers.  If one just powers up a new uBITX and starts 
pushing buttons without understanding what it might do, then problems may
occur.  If you look at the block diagram, and then at the schematic, you will 
see that the uBITX is not a simple circuit.  It is the result of several years of 
design, testing, re-design, and more testing by those with experience in 
this work.

uBITX boards are "factory tested" before they are shipped.  It is unlikely 
that a defective uBITX board was overlooked and shipped without testing.  
The tests performed at HFSignals have been listed earlier on this group.  
The tests performed could be listed again but probably would not mean 
much unless the owner takes the effort to understand how the radio works.

Now, some "remote guessing" at what might be the problem.  
  • Others have suggested that the BFO adjustment could be off. 
    That is the most likely problem...and could have been reset by
    yourself when initially trying to operate the rig.  We do need 
    you to perform the BFO alignment procedures before we go 
    further.  To do this you need to understand the concepts of 
    "zero-beat" and "offset".  Picture the IF filter as an open door
    that allows only passband frequency signals to go through.
    Unless the incoming signal mixing with the tuning oscillator 
    is heterodyned to inside the filter passband, you will not be
    receiving the desired signals.  Once the desired signal is  
    passing through the IF filter, it is again heterodyned to audio
    by mixing that signal with the BFO. 

    On transmit this process is reversed with audio plus BFO
    (balanced for Suppressed Carrier DSB generation) and
    presented to the IF filter which slices off the sideband that
    falls outside the filter passband.  Note that if your BFO is
    misaligned so that both sideband fall inside the filter
    passband, you will be transmitting both sidebands, or what
    is known as Suppressed Carrier AM.

  • The next but unlikely possibility is that one of the balanced
    demodulator diodes was installed backwards at the factory.
    We can test for that if you are willing, but first we need to 
    know that the BFO is adjusted properly.  Without that any 
    tests might be counter-productive.

  • Highly unlikely is that the IF transformer feeding the detector 
    has been mis-wired or mis-connected at the factory.  This 
    would have been caught at testing time, but we will not rule 
    it out as a last resort.  

  • Least possible possibility is that your crystal filter is not filtering 
    properly.  That would have been caught during factory testing.
And, please remember that the members of this group who volunteer 
their time to help you with your uBITX are not employees of HFSignals 
and do not get paid for their time.  The BITX phenomena started as 
an idea on an aircraft flight between New York and India.  It was initially 
built by individuals from junkbox parts.  Then one ham started offering 
bags of parts (no PCB) for building your own BITX transceiver.  And, 
the rest is history.  Group support is rather unique among manufacturing 
of technical products, but is not unheard of.  It has worked well for the 
uBITX and for the group.

Yes, a long email, but it may help to understand the idea of Group support 
and of the uBITX itself.

Arv  K7HKL
_._


On Thu, May 28, 2020 at 8:57 AM Jeff Debes <jeff.debes@...> wrote:
Bill, Tony,

Thanks for the advice.
To be clear: I have a confirmed QSO where the op copied me on LSB and USB with out me changing any settings.
 Is that still a possible symptom for misaligned BFO?
If so fine. I will try again at home with a PC.
I want to say that the kit is sold as a working board, &  the buyer is trusting that it is working, that it was tested properly. What if it is not? That will happen.
Documentation clarity for engineers is one matter, and appears to be simple enough, for casual builders it may need to differ.
A support group such as this is fine for resolving many issues , but it should not be the only recourse.
Why do so many users come back here to ask questions? ( the documentation is not adequate?)
Personally, I’m used to building non-digital circuits/radios.   There is operability simplicity , excellent ease of use,  and clarity in analog radio circuits.
Anyway
Thanks everyone for the advice. I will try the suggestions.

Jeff
> On May 28, 2020, at 9:25 AM, Bill Cromwell <wrcromwell@...> wrote:
>
> Hi,
>
> I have to agree with Tony and the others on this. A misaligned BFO will produce the same symptoms on *ANY* radio like this one (includeing those with four figure price tags). I have worked on a few for other hams and the BFO way way far off on the ones with these symptoms.
>
> If you are unable to get it working you might find somebody on here to get it going for you. I think you should try to get it working yourself. I did not find any deficiencies in the instructions.
>
> 73,
>
> Bill  KU8H
>
>> On 5/28/20 8:27 AM, Tony Vandenborn wrote:
>> Jeff
>> When you study the uBITX block diagram, and understand it, you can clearly see it is rather impossible that your radio receives/transmits both sidebands same time. You really have to align the BFO and master oscillator frequencies, your kit is not defective!
>> Tony
>> Op do 28 mei 2020 om 14:18 schreef Jeff Debes <jeff.debes@... <mailto:jeff.debes@...>>:
>>    Ok Stephen,
>>    I will think about trying it.
>>    I used to do a small bit or arduino programming but that is not
>>    something i want to get back into.
>>    Right now though I need to know why my radio only works as double
>>    sideband. I don’t think its an alignment problem,  I  have doubts
>>    that tuning will cure the issue.
>>    I hope someone has ideas on what might be wrong else I might want to
>>    return this unit to HD Sigs as defective.
>>    Jeff
>>>    On May 28, 2020, at 7:28 AM, Stephen KO4CVU
>>>    <goinfishin1952@... <mailto:goinfishin1952@...>> wrote:
>>>
>>>    Jeff, I can vouch for Reed’s software. It makes a great
>>>    improvement in the operation and control of the touchscreen.
>>>    Downloading and installing It was my first experience working with
>>>    an Arduino Nano, (although I did have some experience with
>>>    programmable logic controllers years ago.) If I can do it, it must
>>>    not be too hard! :) I will be happy to share my notes about the
>>>    process with you, if you’d like them.
>>    --     *jeff.debes@... <mailto:jeff.debes@...>*
>
> --
> bark less - wag more
>
>
>


--
*jeff.debes@...*



Re: Turn of BFO mod

ajparent1/kb1gmx <kb1gmx@...>
 

Jeff,

No, no and no.

Reasons the filter is less than 2.5Khz wide so even with a diode detector it would
sound really muddy.  AM really wants AGC, no got.   FM wants a wider filter as
well though its mostly a 10M thing.

Or you can tune in the AM and zero beat the carrier and listen to AM.
The digital VFO is stable enough to stay within a few HZ for days.

Allison
---------------------------------
No direct email, it goes to bit bucket due address harvesting in groups.IO

Re: New V6 CW tone frequency

Evan Hand
 

I would recommend that all check calibration, as there have been a lot of reports of issues.  None of the 3 boards that I bought were calibrated accurately from the factory. 

Ashhar Farhan has made it fairly simple for the version 6 boards.  The video instructions are here:
https://www.youtube.com/watch?v=t6LGXhS4_O8
with the BFO tuning aid here:
https://www.hfsignals.com/index.php/bfo-tuning-aid/

The above should be done as the first step in solving sensitivity, power, transmission distortion, or selectivity issues.  The basic steps are the same for all boards, the details of how to get to the calibration and for the version 5 board the fact that stock software transmits a 10 MHz carrier for the calibration.  The BFO adjustment is the same.
73
Evan
AC9TU

Re: New V6 CW tone frequency

Dale Parfitt
 

It certainly sounds as though you need to calibrate  the BFO.  As is signals, are on the edge of the crystal filter.

When mine arrived sidebands were reversed. Calibrating the BFO fixed it instantly.

 

Dale W4OP

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of rskarka@...
Sent: Thursday, May 28, 2020 7:06 AM
To: bitx20@groups.io; robert.skarka@...
Subject: [BITX20] New V6 CW tone frequency

 

Yesterday I received my new uBITX v6 full kit and assembled it. After a short function check (could hear some CW and FT8 signals), I installed CEC firmware and Nextion display. Everything worked right out of the box, but later I noticed, that when I tune to CW signals, the audio tone is very high. When I tune the HF for strongest audio signal, the audio tone is around 5khz, and when I change the frequency to get the tone lower, the signal disappears before getting down to the range of 1kHz.

For testing, I tuned to a strong CW station in LSB, USB, CWL and CWU. The highest volume for each mode was approximately:

 

7029 kHz LSB

7033 kHz CWL

7023 kHz CWU

7025 kHz USB

 

With SSB modes I can tune the tone frequency down, but also the signal is stronger at higher frequencies than 800Hz

 

 

So far, I didn't do any calibration, and right after uploading the CEC firmware, I downloaded the eeprom data with the ubitx manager software.

Could this be a frequency or bfo calibration issue? Im not sure, because it is mostly a problem in CW modes, and I thought the boards come calibrated from the factory.

 

Should I go back to the stock fw and display to run the calibration procedure of the V6 firmware with the web spectrum analyzer tool?

 

Something else to check? I have an HP/Agilent Oscilloscope, but the last calibration of that was 2003, so not sure how accurate the frequency counter of that is.

 

Thanks for help,

 

Robert

Re: Highlighting band selected

Arv Evans
 

Jeff

Until you have tried the alignment procedure there is no way we can know 
if you have a real problem, or if you just have not performed the alignment 
process.  We would like to help you, but you have to work with us.  What 
have you tried thus far?  What were the results of performing the alignment 
process?

Arv
_._


On Thu, May 28, 2020 at 6:18 AM Jeff Debes <jeff.debes@...> wrote:
Ok Stephen,
I will think about trying it.
I used to do a small bit or arduino programming but that is not something i want to get back into.
Right now though I need to know why my radio only works as double sideband. I don’t think its an alignment problem,  I  have doubts that tuning will cure the issue.  
I hope someone has ideas on what might be wrong else I might want to return this unit to HD Sigs as defective.
Jeff


On May 28, 2020, at 7:28 AM, Stephen KO4CVU <goinfishin1952@...> wrote:

Jeff, I can vouch for Reed’s software. It makes a great improvement in the operation and control of the touchscreen. Downloading and installing It was my first experience working with an Arduino Nano, (although I did have some experience with programmable logic controllers years ago.) If I can do it, it must not be too hard! :) I will be happy to share my notes about the process with you, if you’d like them.

--
jeff.debes@...

Re: Both sidebands present on receive or transmit? V6

Arv Evans
 

Jeff

Have you tried to do the necessary adjustments?  

Arv
_._


On Thu, May 28, 2020 at 5:28 AM Jeff Debes <jeff.debes@...> wrote:
It really seems that this radio is  working as double sideband  transmit and receive.
Not sure that adjustments will
fix this.


--
*jeff.debes@...*



Re: Turn of BFO mod

Arv Evans
 

Jeff

This is an SSB radio.  It requires the BFO to heterodyne the IF frequency to audio.

It might be possible to convert it to an AM radio by building a non-SSB detector to 
connect ahead of the heterodyne style detector circuit.  Why stop at AM?  Might 
also be interesting to add an FM style IF section and FM detector!

Another possibility is something like the rather old "Q-5'er" which would be an AM 
receiver tuned to the IF frequency and connected ahead of the SSB detector.
This might work, or might be plagued with BFO leak-through, unless the BFO were 
set way off the IF frequency or even turned off for AM mode.

All desires for the SSB transceiver to do something that it was not designed to do 
may be possible, and many on this group have dome some of these mods.  What 
is required to successfully modify the original circuit and original software is a good 
knowledge of how the system actually works, and how to design suitable 
modifications.

Arv
_._


On Thu, May 28, 2020 at 5:28 AM Jeff Debes <jeff.debes@...> wrote:
Is there a way/mod  to turn off the bfo to listen to AM signals?


--
*jeff.debes@...*



Re: UK Import Charges

howard winwood G4GPF
 

they are! but not exempt to vat. vat goes on postage too.

On 28 May 2020, at 16:10, Mark GØNMY <mark.g0nmy@...> wrote:

I always thought Amateur radio parts were exempt form import duty??

 

New V6 CW tone frequency

rskarka@...
 

Yesterday I received my new uBITX v6 full kit and assembled it. After a short function check (could hear some CW and FT8 signals), I installed CEC firmware and Nextion display. Everything worked right out of the box, but later I noticed, that when I tune to CW signals, the audio tone is very high. When I tune the HF for strongest audio signal, the audio tone is around 5khz, and when I change the frequency to get the tone lower, the signal disappears before getting down to the range of 1kHz.
For testing, I tuned to a strong CW station in LSB, USB, CWL and CWU. The highest volume for each mode was approximately:

7029 kHz LSB
7033 kHz CWL
7023 kHz CWU
7025 kHz USB

With SSB modes I can tune the tone frequency down, but also the signal is stronger at higher frequencies than 800Hz.


So far, I didn't do any calibration, and right after uploading the CEC firmware, I downloaded the eeprom data with the ubitx manager software.
Could this be a frequency or bfo calibration issue? Im not sure, because it is mostly a problem in CW modes, and I thought the boards come calibrated from the factory.

Should I go back to the stock fw and display to run the calibration procedure of the V6 firmware with the web spectrum analyzer tool?

Something else to check? I have an HP/Agilent Oscilloscope, but the last calibration of that was 2003, so not sure how accurate the frequency counter of that is.

Thanks for help,

Robert

Re: Bitx V6 Modifications

Jhard356@...
 

Stephen
Thanks for your reply. What microphone with pre-amp would you recommend? 
Jody


On May 28, 2020, at 12:57 PM, Stephen KO4CVU <goinfishin1952@...> wrote:

First, read the “uBITX Power and Gain Issues” topic in the Wiki for more information. Don’t expect the same power output on 10 meters as you might get on 80 meters.
Second, go ahead NOW and order a microphone with a pre-amp if you intend to communicate via phone/SSB. You will also need a stereo plug to install on the new microphone cord, if you buy one.
Third, after turning on the unit and familiarizing yourself with the factory Arduino sketch, download and install Reed’s latest sketch. You will really appreciate his improvements.
Fourth, spend a LOT of time watching Arhhan’s video about how to adjust the VFO and BFO. You may need to check these adjustments on the radio you receive. It has taken me a number of adjustment attempts to get close to usable settings.

Re: Not getting daily digests

_Dave_ AD0B
 

Yes mine and a local friend noticed the same thing , no overnight digests since about a week ago. 
I was able to get it back when I switched to full featured digest.
--
73
Dave
ADOB
Raduino bracket and Ham_Made_Keys

Re: Turn of BFO mod

Evan Hand
 

Maybe a diode detector (like an RF probe) between CW-1 pin 1 and TP 20 might work to receive.  The selectivity is then defined by the 45 MHz roofing filter, which is 15 kHz wide.  You would need to turn off the BFO.  It would require a switching circuit for the diode to be able to back to SSB/CW with the crystal filter.

Just speculation on my part.

73
Evan
AC9TU

Re: Turn of BFO mod

Curt
 

Jeff

we get the framework of your question - its in relation to BFO action on 'ancient' typically general conversion receivers, that lacked a proper product detector. 

an AM signal off course is 2X or more wider than SSB, especially if we want more spectrum into our headphones.  the 2nd xtal filter is too narrow for AM signals - for both sidebands to pass through.  but some may have added a product detector after the first 45 MHz xtal filter.  try a search engine to see who has reported results adding an envelope detector -- uBITX envelope detector or AM detection.  BTW, an envelope detector is pretty much a simple diode - but it has to have appropriate gain in front of it (but it might not take much for huge 41m AM signals.  others add a SDR at 45 MHz that would also be a good AM receiver. 

I appreciate your inquisitiveness.  Too easy for us to miss context of your question, not presuming product detector behavior.

73 curt

Re: Turn of BFO mod

Reed N
 

I described how to skip the BFO stage, but didn't put any thought into if it would actually work for AM. It may actually be that the audio mixing stage ended up becoming the BFO, sans filter, or perhaps there would be no output at all, like you speculate.


Reed

Re: Not getting daily digests

Marko Barovic
 

I'd try checking if they somehow ended up in Spam. Sometimes that happens to me with just random subscription emails like YouTube.

Cheers,
Marko

On Thu, 28 May 2020, 8:01 PM AGØH <kmilr1@q.com> wrote:
I haven't been getting the 'daily digest' from this group for over a week.  I've gone into my subscription settings and found nothing has changed:  the daily digest option is still checked.  I rechecked it again and hit the 'save' button.  
Unfortunately, nothing has changed.  
How do I 're-activate' it?
Keith-AGØH

Re: Turn of BFO mod

Dale Parfitt
 

Hi Reed,

I cannot see how a signal  will be present at the output of the product detector if you remove the BFO signal. Isn’t that equivalent to multiplying by zero (0)? And then any residual that  does remain (extremely low level) would require an envelope detector for AM demod.

 

Dale W4OP

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Jeff Debes
Sent: Thursday, May 28, 2020 1:52 PM
To: BITX20@groups.io
Subject: Re: [BITX20] Turn of BFO mod

 

Thank you Reed , you’re always very helpful!



On May 28, 2020, at 12:14 PM, Reed N <greenkid336600+groupsio@...> wrote:


You should be able to listen to AM even with the BFO. However, if you want to get rid of it completely for some reason, you'll need to jumper C211 to C40 to remove the BFO crystal filter stage, then modify the code to get the correct mixing products on the audio side. I don't think I'd recommend this.


Reed


--
jeff.debes@...

Not getting daily digests

AGØH
 

I haven't been getting the 'daily digest' from this group for over a week.  I've gone into my subscription settings and found nothing has changed:  the daily digest option is still checked.  I rechecked it again and hit the 'save' button.  
Unfortunately, nothing has changed.  
How do I 're-activate' it?
Keith-AGØH

Re: uBitX assembled: bit of a challenge with alignment/bfo adj - Volume/switch knob fix

Jeff Debes
 

Great explanation Arv! 
Thanks!


On May 28, 2020, at 1:55 PM, Arv Evans <arvid.evans@...> wrote:


Dan

It seems that a number of new users of uBITX are not familiar with the "zero-beat" 
process, and not familiar with BFO offset relative to crystal filter bandwidth.  

If doing a zero-beat and your BFO is not properly aligned then the received signal 
will not be placed properly inside the filter passband.  This Allows the opposite 
sideband to be heard over top of the zero-beat.  

Technical info..... When setting the BFO frequency relative to received frequency, 
the BFO should be set approximately 12 db down one side of the crystal filter 
skirt.  Which skirt is determined by which sideband is going through the filter.
You have a DSB signal prior to the filter and setting the BFO 12 db down the 
filter skirt further reduces the unwanted sideband.  Doing this also rolls-off low
frequency audio tones to make your sideband signal more efficient.
The uBITX assembly instructions do include a block diagram that should make 
this easier to understand.  

Arv
_._


On Wed, May 27, 2020 at 10:14 PM <pulco.ant@...> wrote:
Hello. Got my full kit (board v6.2 / firmware v6.1) the other day and assembled it this morning.Easy as pie.

I managed to puzzle out (I think) how to get into alignment: hold tuning knob in while powering up. The screen calibrate _everytime_ is annoying. Zerobeating is challenging because there is a second hetrodyne that becomes audible and climbs in frequency *just* as I'm approaching zerobeat. So far, when I tune WWV afterwards, the display read 10,000.05, and I've done it a number of times. Setting the BFO - what's that about? I used an audio spectrum analyzer as 1 post suggested, but - is that all there is to it?

Volume/switch knob: I dealt with that by grinding down about 3/32" of the knob from the radio side of the knob. This allows that setscrew to move further down the switch shaft and it gets much better purchase on the shaft.It just doesn't have the same flare now as the tuning knob.

Please ring in with suggestions.

Thanks and 73
--
Dan D'Eon
AG7GM


--
jeff.debes@...

Re: Bitx V6 Modifications

Stephen KO4CVU
 

First, read the “uBITX Power and Gain Issues” topic in the Wiki for more information. Don’t expect the same power output on 10 meters as you might get on 80 meters.
Second, go ahead NOW and order a microphone with a pre-amp if you intend to communicate via phone/SSB. You will also need a stereo plug to install on the new microphone cord, if you buy one.
Third, after turning on the unit and familiarizing yourself with the factory Arduino sketch, download and install Reed’s latest sketch. You will really appreciate his improvements.
Fourth, spend a LOT of time watching Arhhan’s video about how to adjust the VFO and BFO. You may need to check these adjustments on the radio you receive. It has taken me a number of adjustment attempts to get close to usable settings.

Re: uBitX assembled: bit of a challenge with alignment/bfo adj - Volume/switch knob fix

Arv Evans
 

Dan

It seems that a number of new users of uBITX are not familiar with the "zero-beat" 
process, and not familiar with BFO offset relative to crystal filter bandwidth.  

If doing a zero-beat and your BFO is not properly aligned then the received signal 
will not be placed properly inside the filter passband.  This Allows the opposite 
sideband to be heard over top of the zero-beat.  

Technical info..... When setting the BFO frequency relative to received frequency, 
the BFO should be set approximately 12 db down one side of the crystal filter 
skirt.  Which skirt is determined by which sideband is going through the filter.
You have a DSB signal prior to the filter and setting the BFO 12 db down the 
filter skirt further reduces the unwanted sideband.  Doing this also rolls-off low
frequency audio tones to make your sideband signal more efficient.
The uBITX assembly instructions do include a block diagram that should make 
this easier to understand.  

Arv
_._


On Wed, May 27, 2020 at 10:14 PM <pulco.ant@...> wrote:
Hello. Got my full kit (board v6.2 / firmware v6.1) the other day and assembled it this morning.Easy as pie.

I managed to puzzle out (I think) how to get into alignment: hold tuning knob in while powering up. The screen calibrate _everytime_ is annoying. Zerobeating is challenging because there is a second hetrodyne that becomes audible and climbs in frequency *just* as I'm approaching zerobeat. So far, when I tune WWV afterwards, the display read 10,000.05, and I've done it a number of times. Setting the BFO - what's that about? I used an audio spectrum analyzer as 1 post suggested, but - is that all there is to it?

Volume/switch knob: I dealt with that by grinding down about 3/32" of the knob from the radio side of the knob. This allows that setscrew to move further down the switch shaft and it gets much better purchase on the shaft.It just doesn't have the same flare now as the tuning knob.

Please ring in with suggestions.

Thanks and 73
--
Dan D'Eon
AG7GM