I set the??set up the tuning and BFO on the V6.?as per the video link by Ashar Farhan shared here?
Now i have a question does calibration on 1 wavelength (40m)? helps out for all the wavelengths in ubitx v6.
VU2KTW

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I'm having audio feedback during transmit through my external speaker on 20m only on ubitx v6? I hear my voice (distorted) on the receive side when transmitting on 20m band.?
Thanks,

My Ubitx 4 is off frequency a bit. The QSO I was tuning @ 7.185.000 on my commercial Xcvr was 7.183.700 on the uBitx 4.
My question is which way should I move the VFO to match them? I have the CEC memory manager or could I just move the VFO with the zero beat menu item?

Thanks in advance
Scot?
WB7AVU

Hi Rene,

It sounds like your BFO is not calibrated.? Have you done that yet?? I think these radios are not calibrated before they are shipped -- it is left up to the user.

There is a weblink here to assist with that:

https://www.hfsignals.com/index.php/bfo-tuning-aid/

73,


Mark

Hello everyone, i am a new uBitx user, I have built uBitx v5 and loaded CEC firmware for Nextion 3.2 inch display. Moreover, I have incorporated a second Arduino Nano to use it as a . I have gone through Ian's (KD8CEC) instructions to enable I2C S-meter and so on and what I see on the display is according to those instructions. The question is: Do I have to calibrate the I2C S-meter in some way, e.g. using a signal generator and applying -73 dBm (S9) to the antenna port of the uBitx? Has any of you done such a thing before?
73, George, SV1DEQ

Hi,

Thank you to all those who responded with kind words of encouragement.

I am attaching the draft design for initial review and comments.

Some notes;
1. There are two connectors, one that sits on the board and the other
that is attached to the PCB. I haven't got a nomenclature for these
yet.
2. The RF Preamp is being kept as a provision for future expansion
3. The RF Preamp and the CW filter will be switched via separate SMD 12V relays

Apols if the circuit diagram seems all over the place, I put it in an
order that I thought was correct. The reader may have to flip between
pages to check connectivity.

LEDs are placed on each daughter-board to show if the board is active
or not. One side of the board will have the RX section and the other
will have the TX section.

I am planning to make the base board on a 100mm x 100mm board but this
seems like a tall order at the moment.

What are people's thoughts on using a double line right angle pin
connector:
I understand that rigidity might be at stake here, but other
connectors that can be used to fix the board, might cost more?

For the adventurous reader - A brief writeup of the design follows:
Stage 1: A J310 RF Preamp has been introduced. This design is
available here: . The RF Preamp
will be switched in only on receive mode and will be in the RX RF
Chain. Care will need to be taken to ensure that the break-before-make
is established with microcontroller (uC) control to ensure that stray
TX RF does not leak into the switching circuitry. It may also be
possible to bring the switching control to the front panel instead of
using a uC.


Stage 2: The first TIA stage has been broken down into a single
section and has been terminated using pinouts. This will allow for a
small SMD board to be utilised to host the RX chain and the TX chain.
This board is meant to be a plugin version and allows for any
prototype TIA circuitry to be implemented in this section. The actual
board size is estimated to be 1.5" square and has the RX chain on one
side and the TX chain on the other side. A Red/Green LED is provided
on each side to indicate if VRX or VTX is powered on. Additionally
each board also has a ferrite bead/choke/inductor on the VTX, VRX and
the GND lines to prevent spurious RF/uC hash from passing through.


Stage B - Baseboard: The Baseboard contains all components that are
not on the daughtercards, this includes all coils, mixer (ADE-1+),
Xtal filter, and the Audio Amplifier. These base components are not
expected to change frequently.

Stage 3: This is the second TIA stage and and follows exactly the same
concept of Stage 2. See note above.

Stage 4: I decided to try a new AGC RF+AF and the schematic for this
stage has been taken from the JackAL AGC addon that has been presented
on the forum.


Note: All components are SMD (1206) with the exception of the large
transistors and the XTAL filter.


Stage 5: The CW filter is taken from here:
Which was earlier taken
from QRP Notebook by the late Doug DEMaw W1FB. This is also in SMD and
will be either switched by a relay or a front panel switch. I may be
able to get some more info on the theory of operation later


Stage 6: The AF Amplifier chosen is a discrete design and has been
proven in use earlier. This replaces the LM386 and/or the TDA2822

Stage 7: The QEX ladder filter design has been kept the same, but is
now based on a modular board. At the time, it was thought that varicap
diodes could be added to the filter, but this was later removed as it
was thought that there could be impedance mismatched. Instead of
varying the bandwidth of the filter, it was also thought that an
Active CW filter would be a better approach. Passband filtering may
also be achieved by changing the LO2 frequency and this is left to the
experimenter.

Stage 8: A post filter amplifier has been added to compensate for the
low signal level in the RF chain. The gain of this stage may have to
be adjusted and this is left to the experimenter. This stage will also
be built on a daughtercard.

Stage 9: A Mic speech processor and Preamp has been added. This has
been designed by KPS Kang

Best 73

Ravi/M0RVI

On Tue, 10 Mar 2020 at 10:13, Ravi Miranda via Groups.Io
<ravimiranda@...> wrote:

Hi Jonathan,

Thank you for the information and link. Excellent work and nice documentation.

I will continue to work on my design and share it with the group.
Best 73,

Ravi/M0RVI

On Mon, 9 Mar 2020 at 14:29, Jonathan Kayne, KM4CFT <jzkmath@...> wrote:

Ravi,
I am also working on a modular uBitx project which puts all the modules in their own PCBs. I have posted all the project files on my AMP lab project page and you are more than welcome to modify or use as you wish.
I made them using KiCad.



Regards,
-Jonathan Kayne, KM4CFT

--
I'm here to add more value to the world than I'm using up.

--
I'm here to add more value to the world than I'm using up.

No problems with my antennas or my radio, works fine now. Thanks anyway.

Joel
N6ALT

Sounds like it could be fun, though the stock uBitx does not qualify as QRP on the lower HF bands.? You would have to adjust the drive down to be a true QRP (5 watts or under) radio.? Easy to do on my Icom, have to open the case to do so on the uBitx.

FWIW
73
Evan
AC9TU

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?

Since extending our big loop antenna, have had to turn on attenuation? to prevent the Audio signals from over-driving the audio.? Even without the attenuation on there is hardly any noise except for signals.?

Just saying::: that perhaps instead of looking for more amplification maybe your antenna system may need to be worked on.
--
73
Dave

Hi Malcom,

Thank you for sharing your schematic for the unit. Will check the junk box for parts before ordering parts, or possibly David's kit. I'll check your QST lead for further information. Thank you again for your helpful response. Still have the main, and BFO to calibrate. Have had no joy without test equipment, frustration reigns!

73,
Wes/KH2EE

--

Hi David,
I went to website and watched the utube video. Nice unit in operation. Have spot in panel next to the headphone jack for the led. Thank you for suggesting this option.?
Have never done any SMD construction, would probably have to go with ready made.
73,
Wes/KH2EE

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Great option!! ?Thanks for sharing

I have the QRP-Labs VFO kit on my Bitx40 from day one and it works very well.? I've set it up to calibrate withe a GPS 1PPS and all is good.

Bob, W1EXZ

One thing that really appealed to me about the MS51 when I read Tom's first post was its potential as an I/O expander for something like an ESP32. What makes it attractive for that are the I2C and SPI interfaces. And since they are so low cost and readily available directly from nuvoTon it is feasible to use them for something as simple as interfacing just a button and/or LED as well as the other applications that Tom has suggested.

I found lots of TSSOP 20 to DIP adapter boards available on Aliexpress for about 8 cents each to help get around the SMT issue.?