uBitx #ubitx


SUNIL A R
 

Hi, 
      Iam buying a ubitx ver 4.3 , its alll trifilar coil (All the RF transfomers are 8-10 trifilar turns on FT37-43) winding is not twisted. Please eplane diffrent between twisted winding and no twisted winding, 
Which is better. And one more thing u bitx frequency 1.25khz drift from actual frequency
(eg: in shortwave AM band 7.42MHz,  uBitx tune 7.418.75MHz). How can correct it ? 
kindly please give me the frequency and all other setting procedure
                                                               TU.  73
 
 
                                                                              Tu 73 


Curt
 

Sunil

Nice to see your message. I am thinking the twisting is to make the behavior of the 3 windings more uniform (exact with each other). Hard to say exactly how much it matters, perhaps Farhan knows.

In tuning a AM signal on 40m, you are hearing the lower sideband (lsb). The passband of the v4 ubitx is nicely narrow. I would evaluate how well it is receiving ssb signals, if the BFO is not well adjusted it could make the frequency error higher. 1.25 kHz seems high that maybe bfo might be off calibration. Listen to more signals and try only small adjustments each time. Find ubitx alignment or adjustment at hfsignals website. BFO calibration is easy, frequency adjustment is a bit difficult. 

One comment, if you do CW, when perfectly calibrated the cw frequency can be 700 Hz off, because the display is shared between ssb and cw.

Be patient in working this, I enjoy using this rig.

73 Curt


Jerry Gaffke
 

Twisting the wires on the transformers helps ensure all three wires see identical magnetic fields.
This could improve the balance of the diode mixers at T1,2,3,4,7, and thus help reject
unwanted signals from getting through the mixer.  (Google "doubly balanced mixer".)  
But so long as all three windings look equally tight and well spaced, I doubt there is an issue
with windings that are not twisted. 

I can't think of any particular reason why twisting would matter in the transformers
used for the power amp at T8,9,10,11.


MVS Sarma
 

Hi Sunil Jee,
 Please take a close up shot of any single  trifilar wound trafo that you feel is not twisted. Your photo is not clear.

To the best of my knowledge, HF signals  did not change the policy to untwisted trifilar transformers.
regards
sarma
 vu3zmv
 


On Wed, Feb 20, 2019 at 8:27 AM Jerry Gaffke via Groups.Io <jgaffke=yahoo.com@groups.io> wrote:
Twisting the wires on the transformers helps ensure all three wires see identical magnetic fields.
This could improve the balance of the diode mixers at T1,2,3,4,7, and thus help reject
unwanted signals from getting through the mixer.  (Google "doubly balanced mixer".)  
But so long as all three windings look equally tight and well spaced, I doubt there is an issue
with windings that are not twisted. 

I can't think of any particular reason why twisting would matter in the transformers
used for the power amp at T8,9,10,11.


Evan Hand
 

The best way that I have found to tune the uBitx is to use a free audio spectrum analyzer software with a mic providing the input. First set the uBitx so that there is only noise on the speaker and then adjust the BFO to center the "noise" signal between 500 and 3000 hz on the analyzer.  I would then go back to a known frequency standard (Like WWV in the US) and adjust the frequency readout by zero beating to the know standard.  The way to adjust the BFO and Frequency displayed is documented on the HF Signals web site.  I just use the audio analyzer in place of a weak SSB signal, and do the BFO first.

Link to free Audio Analyzer software:
http://www.techmind.org/audio/specanaly.html

73
Evan
AC9TU


SUNIL A R
 

Tu for the response 73...


SUNIL A R
 

Tu for the response 73....


SUNIL A R
 

Tu for the response 73....


SUNIL A R
 

Tu for the response 73....


SUNIL A R
 

Tu for the response 73....


Vic WA4THR
 

The frequency calibration procedure in v4.3 software is different than earlier versions. You need another receiver capable of listening on 10mhz. With the uBitX connected to a dummy load, go into the calibration mode and the rig will start transmitting a CW carrier. Adjust the tuning knob until the carrier is right on 10mHz in the second receiver. It may help to switch between USB and LSB in the second receiver to be sure the signal is centered between them. With the frequency calibrated, you can then tune in a SSB signal and adjust the BFO for the best sound.

=Vic=


SUNIL A R
 

Ok  , and one more - how can save  after calibration ,
just encoder botten press  and exit
or any other method   
                                                Tu 73...


Jim Strohm
 

Jerry Sevick W2FMI (SK) didn't note that twisted or untwisted wires in transmission-line transformers made a difference, but since he usually wound his transformers with #14 or larger wire, and used certain insulation and/or tape thicknesses on each wire to establish the characteristic impedance of the lines he made, it was easier NOT to twist.

Since we usually use very fine wires --say, #26 -- it's much easier when winding to prepare a length of neatly and uniformly twisted x-filar line.  The actual pitch of the twist has little effect on the characteristic impedance of the line until you get into a tight enough pitch that it begins to stretch the wire and/or deform the insulating enamel. 

The direction of the pitch doesn't matter either, but if you twist a 6-foot (2 meter) length of x-filar wire, all the transformers you wind from it will have the same pitch and direction except maybe the last few inches on each end.

Electrically, twisting won't make much of a difference.  Physically, twisting makes it vastly simpler to wind and control turns count.

And all your toroids look prettier when you're done.

73
Jim N6OTQ

>

From: Jerry Gaffke
Date: Tue, 19 Feb 2019 18:57:31 PST

Twisting the wires on the transformers helps ensure all three wires see identical magnetic fields.
This could improve the balance of the diode mixers at T1,2,3,4,7, and thus help reject
unwanted signals from getting through the mixer.  (Google "doubly balanced mixer".)  
But so long as all three windings look equally tight and well spaced, I doubt there is an issue
with windings that are not twisted. 


iz oos
 

Jim, I had bought the W2FMI book and I re-read it many times. His analysis is on transmission lines transformers (current and voltage ones), not on conventional transformers. You may not apply his findings on other types of transformers. Are the ubitx voltage transmission line transformers?


Il 20/feb/2019 15:36, "Jim Strohm" <jim.strohm@...> ha scritto:
Jerry Sevick W2FMI (SK) didn't note that twisted or untwisted wires in transmission-line transformers made a difference, but since he usually wound his transformers with #14 or larger wire, and used certain insulation and/or tape thicknesses on each wire to establish the characteristic impedance of the lines he made, it was easier NOT to twist.

Since we usually use very fine wires --say, #26 -- it's much easier when winding to prepare a length of neatly and uniformly twisted x-filar line.  The actual pitch of the twist has little effect on the characteristic impedance of the line until you get into a tight enough pitch that it begins to stretch the wire and/or deform the insulating enamel. 

The direction of the pitch doesn't matter either, but if you twist a 6-foot (2 meter) length of x-filar wire, all the transformers you wind from it will have the same pitch and direction except maybe the last few inches on each end.

Electrically, twisting won't make much of a difference.  Physically, twisting makes it vastly simpler to wind and control turns count.

And all your toroids look prettier when you're done.

73
Jim N6OTQ

>

From: Jerry Gaffke
Date: Tue, 19 Feb 2019 18:57:31 PST

Twisting the wires on the transformers helps ensure all three wires see identical magnetic fields.
This could improve the balance of the diode mixers at T1,2,3,4,7, and thus help reject
unwanted signals from getting through the mixer.  (Google "doubly balanced mixer".)  
But so long as all three windings look equally tight and well spaced, I doubt there is an issue
with windings that are not twisted. 


N2MS
 

Vic,

I finally found this as the V4.3 documentation is not clear. Thanks for this explanation. Once I have set the calibration how do I save it?

Mike N2MS


Evan Hand
 

Mick and Vic,

I have v4, v5, and v6 units.  The stock software on the uBitx v4 can be calibrated using this procedure:
https://petetest2017.files.wordpress.com/2019/01/micro-bitx-calibration-instructions.pdf

It is the v5 software that transmits a carrier on 10MHz for calibration.  I quickly replaced the stock software of the v5 with the KD8CEC software because I was worried that it would transmit when not connected to an antenna set for 10MHz (intended to work with a 50ohm dummy load).

73
Evan
AC9TU


N2MS
 

Evan,

Thanks for the clarification. Whem my unit powers up it shows V4.3 but transmits the carrier in the setup calibration mode. Is there another way to determine the firmware?

Mike N2MS

On 11/22/2022 2:30 PM Evan Hand <elhandjr@...> wrote:


Mick and Vic,

I have v4, v5, and v6 units. The stock software on the uBitx v4 can be calibrated using this procedure:
https://petetest2017.files.wordpress.com/2019/01/micro-bitx-calibration-instructions.pdf

It is the v5 software that transmits a carrier on 10MHz for calibration. I quickly replaced the stock software of the v5 with the KD8CEC software because I was worried that it would transmit when not connected to an antenna set for 10MHz (intended to work with a 50ohm dummy load).

73
Evan
AC9TU
_._,_._,_


Evan Hand
 

I looked in the Github archive for v4.3, and Vic is correct; the latest version does send a 10MHz carrier out of the antenna port.  It was not that way originally for the two units I purchased in late 2018.

I recommend going to the KD8CED software, as it does not transmit to set calibration.  It is done the same as described in the PDF.

The KD8CEC software for the v3 and v4 uBitx is available here:
https://github.com/phdlee/ubitx/releases/tag/v1.20

You will need to either download and compile the Arduino sketch with the correct options or use Xloader to load the correct Hex file from the zip file folder for UBITXV345.  Let me know what you would like to do. 

The easiest would be to use the installed software and have a frequency counter or another radio to adjust the calibration.  The BFO is best set using the BFO Tuning Aid here:
https://www.hfsignals.com/index.php/bfo-tuning-aid/

73
Evan
AC9TU


Vic WA4THR
 

Hello, Mike. It has been quite some time, but I think you press the tuning encoder to save the calibration. Good idea to write it down beforehand, too. You can have a simple dummy load with a few resistors to get 50 ohms for this procedure.

Once calibrated, upgrading to the KD8CEC software should be easy and it will find the calibration stored on the Arduino...or you can switch sooner and use its procedure to calibrate. The CEC software has several advantages and also a memory manager program that allows you to directly set calibration values.

=Vic=


ajparent1/kb1gmx
 

SUNIL,

Twisted wires on the core are closer coupled and more uniform, helps to have that.
By closer coupled the coupling from from any one wire to the other two is  then
assured to be as possible to 1.  Having that be predictable is critical to circuit
design and uniformity.

The untwisted(yellow cores with added color) in the picture are not transformers
those are inductors of some specific value.

Hope that clears up what you are seeing.


Allison
------------------
Please use the forum, offline and private will go to bit bucket.