Re: Highlighting band selected

Jeff Debes

Thanks, I have not performed alignment in the way that is described. Consider then it is not aligned. 
Shortly I will return to my home QTH where I have all the resources needed,  and then I will follow the alignment procedure  as precisely as possible. 
Thank you for your follow up.

On May 28, 2020, at 5:45 PM, Arv Evans <arvid.evans@...> wrote:


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.
Thanks everyone for the advice. I will try the suggestions.

> 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



Join to automatically receive all group messages.