Date   
Built V4 uBitx for sale

chuckr@hostu.org
 

For Sale: HFSignals uBitx V4 bult transceiver. Has KD8CEC V 1.1 software and Nextion 3.5 screen. In custom case with speaker and cooling fan for finals.
Mods: Moved 5 volt regulator to case, also has second 5 volt regular to the 12 volt fan, quite running and keeps finals cool. Power out varies a small amount from 14 watts at 3.7mhz, 10 at 7.2mhz, 12 at 14.2mhz etc. Second arduino for Sig meter etc. and 4 spare finals included. Will post pics on ( http://hostu.org/ubitx ) just click on each pic. Will accept best reasonable offer. Shipping will be added based on your zip and payment will be by paypal only. Please note the board has a minior repair from bad bias pot and both bias pots and finals have been replaced. Unit is is working order (ssb needs work adjustments ] but you will need to do some final finishing work and adjustment yourself. When making an offer please know you will need to replace the 3.5 in. Nextion Enhanced Screen as there is a crack near the top ( 24.99 at banggood ). It does not stopping the radio from working but does interfere with some menu functions. Cat connection works ok for some basic needs. Questions and offers to ubitx@...    paypal email sales@....

bangood link for nextion screen     https://www.banggood.com/3_5-Inch-Nextion-Enhanced-HMI-Intelligent-Smart-USART-UART-Serial-Touch-TFT-LCD-Module-Display-Panel-p-1188732.html?rmmds=search&cur_warehouse=CN

Re: Built V4 uBitx for sale

chuckr@hostu.org
 

pics and email     ubitx at hostu.org         and   paypal add      sales at hostu.org

Re: Complainers?

Brian L. Davis
 

http://www.kitsandparts.com/index.php
If you look at a specific torroid you will find that you can select the value you want and it will tell you how many turns and the approximate length of wire needed.  Sounds like what you would like to see.

73,
Brian, WA5RDG

Re: LPF kit for ubitx v3

Mike Short
 

Break them up and remove pins one at a time. They are too cheap to risk lifted runs, etc on the board.

Re: Complainers?

M0OOZ
 

Very useful webpage - I use this all the time. It also gives you the Z @ any particular frequency

73
Geoffrey David Cowne M0OOZ


On Sun, 10 Feb 2019 at 22:40, Brian L. Davis <brianldavis@...> wrote:
http://www.kitsandparts.com/index.php
If you look at a specific torroid you will find that you can select the value you want and it will tell you how many turns and the approximate length of wire needed.  Sounds like what you would like to see.

73,
Brian, WA5RDG

Re: Tuning clicks on bitx40 #bitx40help

Billy Shepherd <dis60cd@...>
 

Any luck? I’m using probably the same kit and the clicks are extremely annoying. 

Re: uBitx V4 Audio extremely quiet and other needed mods#ubitx

alphamale@...
 

Ok, so we got the rig on a service monitor this weekend.. After using the service monitor to align the radio (the procedure used from the hfsignals website did get it close, and the one suggested by Evan got even closer) I was able to inject a signal at 29.7 MHz and at 1.0 MHz and using a audio spectrum analyzer on the output from the ubitx I was able to fine tune the alignment so that a 1KHz test tone put into the injected signal came out of the ubitx as a 1KHz tone, at the exact dial frequency of the signal. Evan's alignment procedure did get me within about 500 on the number needed for the BFO setting to accomplish this, so thanks for that Evan.

Here is what I found on the service monitor:
With a signal input of -45 dbm, the ubitx has plenty of audio, and can actually overdrive the audio amplifier chain if turned up too much. -45 dbm is equivalent of 30db over S9, or S9+30 signal. This is close to what we get from the AM radio station that is only about 4 miles away, volume from the test signal and the radio station are about the same at this level.

With a signal input of -70 dbm the ubitx made enough audio with the volume turned clear up that we could hear the test tone, but it was quiet. -70 dbm should be an S9 signal of 50 uV, so I would have expected much louder signal. It was, however a very clear signal.

With an input of -100dbm (around S4 on the scale, or 1.6 uV) the signal was present, but barely audible to our ears.

With an input of -120 dbm (0.2uV or S1 on the scale) we could not hear the signal out of the speaker, however the spectrum analyzer could still detect it's presence.

My Conclusion: The ubitx has a very sensitive receiver, and it works very well even at the lower signal input levels, but the amount of amplification in the AF stage is inadequate if the signal is below about S7 in strength.

We tested on four different V4 ubitx boards that were built within the last week, and got the same results on three of the four. The fourth one was just a little louder than the other three, not much, but enough we could tell a difference.

Ashhar, hopefully this extra information is helpful to you. Do my boards appear to be operating properly, in which case we may just need to add an audio amplifier and AGC circuit to make them easier to use, or does it look like these are not functioning as designed? Do these results look similar to what others are seeing with this board? For what it is worth, the V3 board one of our guys has is about 2 to 3 times louder than any of the V4 boards.

I am not opposed to adding an audio amplifier if that is the correct solution to the perceived problem with the audio, but I would like to know that it is the best course of action before I proceed. I dislike fixing problems with a tourniquet when a bandage would have sufficed, if you know what I mean.

Thank you everyone for the kind assistance you have offered here.

Erik Larson - AD7OV

Winding toroids

 

Hi,

I've found the calculator on toroids.info to be very accurate -- so much that I rarely measure after winding anymore.  They  quote a quite generous length of wire to use (even considering the 1" leads) so I usually subtract an inch or so.

No need to re-wind if you loose count. As long as you have a cell phone or other digital camera, just take a picture and then zoom in on it.  It becomes very easy to count if you do that.

How I wind: first put the wire through the center, gather the ends, and pull them taut.  Now wind one half of the windings, and then the other.  This way you only have to deal with one half the length of wire at a time (instead of threading the entire length through for the beginning turns).

73,


Mark -- N7EKU/VE3

Re: Spurs/Harmonics fixes for v4 based on v5 board design?

Evan Hand
 

Going back to a previous topic: tools to check on uBitx emissions

I finally had time this past weekend to do some more playing with the SDRPlay RSP2 and the uBitx.  After a lot of testing in trying to clear up my confusion on why my step attenuator that I bought did not step down the RSP2 measurements correctly, I ultimately worked out that there is compression of the signal probably caused by the AGC function of the RSP2, or the software.  When I kept the signal below -55 DBm, a step change in the attenuator matched a change in the measured signal.  As I got closer to the -55 DBm level, the step decreased.  I then checked against my RF Explorer and verified that the RSP2 was not reporting accurately unless the input was below the -55 DBm.

I then went on to check the harmonics on CW using both the RF Explorer and the RSP2: again, as long as the input was below -55 DBm for the RSP2, the results matched.  I then went on to test the rig on SSB trying to use my two tone generator that I built from an article by DK7IH (was posted prior in this thread).  Did not work as expected, as I could not get clear two frequency spikes on the RSP2.  I then ran a number of tests on the generator, and found that the tones were not the same as the ARRL standard, and that there were a lot of "extra" tones depending on the balance/level setting.  Final result of the testing is that the rig is not compliant on CW, however it IS compliant for 40 meters SSB.  Will go on to test the rest of the bands next weekend.

Turns out that the tone generator software that runs on a PC has a very clean signal, at least from my backup laptop.  Tested it through the free audio spectrum analyzer listed prior as well, and was able to set the 700 and 1700 hz tones that did not have any other garbage.  Built a cable to connect the output of the laptop to the input on the uBitx with a slide switch to turn on the PTT signal.

All this confirms to me that 
1 - I still need to work on my construction and testing techniques, and more importantly 
2 - need to verify test equipment and procedures regardless of where they come from.
3 - Could not have verified the RSP2 levels without the RF Explorer (needed a third device to break the tie between the step attenuator and the RSP2).

If anyone else is trying the SDRPlay series of SDR radios as a signal analyzer, would you please share your experiences so that we all can learn more?

As always, the above are my interpretations of my experiences, yours may be different.

73
Evan
AC9TU 

Re: Black rectangles - Bitx40 hardware or software problem?

Michael Mitchell <mitchellmichaelh@...>
 

I have 10 years experience in a manufacturing environment using these displays. Don't waste time thinking you can fix the display , how much is your time worth. Just replace it. We had 50 % failure rate with cheap displays. 

Re: uBitx V4 Audio extremely quiet and other needed mods#ubitx

Curt
 

Erik

you can imagine your 4 rigs there, and your nice data gathering, describe the audio output.  I find audio is adequate in headphones - using speakers perhaps greater difference of opinion may abound.  please note that v4 uses a simple pair of transistors for the audio output, perhaps with less max power output than the previous (and upcoming) versions that use an IC.  I confess for CW work I need audio filtering anyway, so I use a NESCAF - that works nicely for SSB also -- this includes a LM386 output stage to drive my headphones.  I guess the speaker isn't finding much use in my operating. 

BTW I installed the sidetone mod described at the K3PZN website.  This one is configured to route such that it isn't impacted by the volume setting.  its a cut trace, a 1meg resistor in my case and a piece of wire. 

If your builders want more robust audio inside the box - I am suspicious a search here will provide some ideas.  Also check ubitx.net to see what is posted, but I find content isn't any better vetted than what is here. 

73 Curt

Re: uBitx V4 Audio extremely quiet and other needed mods#ubitx

Ashhar Farhan
 

The v4 audio amp was meant for comfortable headphones listening. You can add an LM386 amplifier or even a TDA2003 in place of this for more gain. Without the agc, it is best to add the gain after the volume control

- f

On Mon 11 Feb, 2019, 7:29 AM Curt via Groups.Io <wb8yyy=yahoo.com@groups.io wrote:
Erik

you can imagine your 4 rigs there, and your nice data gathering, describe the audio output.  I find audio is adequate in headphones - using speakers perhaps greater difference of opinion may abound.  please note that v4 uses a simple pair of transistors for the audio output, perhaps with less max power output than the previous (and upcoming) versions that use an IC.  I confess for CW work I need audio filtering anyway, so I use a NESCAF - that works nicely for SSB also -- this includes a LM386 output stage to drive my headphones.  I guess the speaker isn't finding much use in my operating. 

BTW I installed the sidetone mod described at the K3PZN website.  This one is configured to route such that it isn't impacted by the volume setting.  its a cut trace, a 1meg resistor in my case and a piece of wire. 

If your builders want more robust audio inside the box - I am suspicious a search here will provide some ideas.  Also check ubitx.net to see what is posted, but I find content isn't any better vetted than what is here. 

73 Curt

Re: Tuning clicks on bitx40 #bitx40help

 

Using a 2 cap one resistor rc filter pretty much takes care of the clicks. Did it to mine and works great 
--
David

 N8DAH
Kit-Projects.com

Shop is open!

Re: Tuning clicks on bitx40 #bitx40help

James Lynes
 

On my spare Raduino that I am using on a DC receiver, I added a diode and 4 parallel 150 ohm 1/4 watt resistors in front of the 5v regulator. Also added a bypass cap and electrolytic cap.

This helped but did not eliminate the clicks.

Interestingly, when I was running from a 9v battery,  the clicks would get worse when the voltage dropped. At this point the display washed out to illegible. 

James

Re: Spurs/Harmonics fixes for v4 based on v5 board design?

Jerry Gaffke
 

You should be able to turn off AGC on the SDRPlay stuff.
If not, might be time to move to a different software package.


On Sun, Feb 10, 2019 at 04:41 PM, Evan Hand wrote:
I ultimately worked out that there is compression of the signal probably caused by the AGC function of the RSP2, or the software. 

Re: uBitx V4 Audio extremely quiet and other needed mods#ubitx

pat griffin
 

FWW
I have a v3 and somehow using wspr I managed to damage U1 which is a TDA2822M audio amp. The output is now very low. The TDA is a stereo amp and the other channel is unused so I may use that. In the meantime, I have wired in a nice little 386 amp on a small board that is available from marlin p Jones mpja.com item number 31805 m1 for $3.95. It works great and has plenty of output
73
Pat AA4PG


On Feb 10, 2019, at 8:12 PM, Ashhar Farhan <farhanbox@...> wrote:

The v4 audio amp was meant for comfortable headphones listening. You can add an LM386 amplifier or even a TDA2003 in place of this for more gain. Without the agc, it is best to add the gain after the volume control

- f

On Mon 11 Feb, 2019, 7:29 AM Curt via Groups.Io <wb8yyy=yahoo.com@groups.io wrote:
Erik

you can imagine your 4 rigs there, and your nice data gathering, describe the audio output.  I find audio is adequate in headphones - using speakers perhaps greater difference of opinion may abound.  please note that v4 uses a simple pair of transistors for the audio output, perhaps with less max power output than the previous (and upcoming) versions that use an IC.  I confess for CW work I need audio filtering anyway, so I use a NESCAF - that works nicely for SSB also -- this includes a LM386 output stage to drive my headphones.  I guess the speaker isn't finding much use in my operating. 

BTW I installed the sidetone mod described at the K3PZN website.  This one is configured to route such that it isn't impacted by the volume setting.  its a cut trace, a 1meg resistor in my case and a piece of wire. 

If your builders want more robust audio inside the box - I am suspicious a search here will provide some ideas.  Also check ubitx.net to see what is posted, but I find content isn't any better vetted than what is here. 

73 Curt

Re: No TX #ubitx

Ted
 

Being there's already a thread on the subject, here's another one. 

New (to me) V3 board, virgin in the kit box. Tested all functions for a good hour or so, kind of getting a good base-line of where it is, as new. The output on 80, 40, 30, and 20 all showing 20 watts or so on CW key if the meter in my tuner is to be believed. 

L5 and L7 swapped for shielded SMT's and all levels still fine. Added CW level adjustment and side tone volume adjustment (both, trimmers). TX still fine, but intentionally reduced to around 10w as measured on 80 & 40. All still fine.

To this point, things are so good that it's almost boring but in a good way. The next thing I know, the TX has disappeared.  The display shows that TX should be TX'ing and the relays closing solidly.  Having been through this with a V4 board a few weeks ago, I started at Q20 and ran through the whole voltage measurement list with the PTT/mike keyed as directed. Every solitary transistor point measures right where it should be; TX current rises from 23mA to 64mA as opposed to 2+ Amps. The MRF510's do not heat up.

What's interesting is that, with this board hooked up to an antenna and a nearby rig hooked up to another, key down on CW produces a weak but recognizable note on the redundant radio - though, it's continuous for as long as the relays are closed ad not switching on/off with key down as if CW were actually working.

Again, that signal is audible but not loud. When the uBitx gets switched to a dummy load, the other radio hears nothing.  Bearing in mind that I've read this thread, I've wiggled the torroids but have not yet checked them for continuity. A length of wire touched to C80 produces no received CW note on the othe radio.

Anyone want to take a stab some of the possibilities other that some curse upon my work bench?

Tnx,

Ted
K3RTA

Re: No TX #ubitx

 

Ted,

Your finals are blown. Check if you have TX 5V at the output of regulator, if yes
then replace IRF510s.

Raj

At 11/02/2019, you wrote:
Being there's already a thread on the subject, here's another one.

New (to me) V3 board, virgin in the kit box. Tested all functions for a good hour or so, kind of getting a good base-line of where it is, as new. The output on 80, 40, 30, and 20 all showing 20 watts or so on CW key if the meter in my tuner is to be believed.

L5 and L7 swapped for shielded SMT's and all levels still fine. Added CW level adjustment and side tone volume adjustment (both, trimmers). TX still fine, but intentionally reduced to around 10w as measured on 80 & 40. All still fine.

To this point, things are so good that it's almost boring but in a good way. The next thing I know, the TX has disappeared. The display shows that TX should be TX'ing and the relays closing solidly. Having been through this with a V4 board a few weeks ago, I started at Q20 and ran through the whole voltage measurement list with the PTT/mike keyed as directed. Every solitary transistor point measures right where it should be; TX current rises from 23mA to 64mA as opposed to 2+ Amps. The MRF510's do not heat up.

What's interesting is that, with this board hooked up to an antenna and a nearby rig hooked up to another, key down on CW produces a weak but recognizable note on the redundant radio - though, it's continuous for as long as the relays are closed ad not switching on/off with key down as if CW were actually working.

Again, that signal is audible but not loud. When the uBitx gets switched to a dummy load, the other radio hears nothing. Bearing in mind that I've read this thread, I've wiggled the torroids but have not yet checked them for continuity. A length of wire touched to C80 produces no received CW note on the othe radio.

Anyone want to take a stab some of the possibilities other that some curse upon my work bench?

Tnx,

Ted

Re: uBitx V4 Audio extremely quiet and other needed mods#ubitx

alphamale@...
 

Thanks Ashhar for confirming that the audio amp is what is needed if we are going to use a speaker. I agree that now the volume is adequate using a set of headphones. My original problem was solved by properly aligning the receiver.

I was comparing to a V3 board that one of the other members already had and it's greater output of audio made me wonder if we had done something wrong in building this one. I did not realize that the v4 was designed to have lower audio output than the v3 board. I had assumed that the discrete amp had been designed to replace the IC within the same specs.

Thanks to everyone here for the help and the ideas. This is a wonderful little radio for experimenting with, and we now know exactly what to expect as we build them in our group.

Erik Larson - AD7OV

Re: No TX #ubitx

Jerry Gaffke
 

Not terribly weird you hear a signal with the key up.
When transmitting, the Si5351's clk2 is at the transmit freq, clk0 and clk1 are shut down.
Clk2 goes into the mixer at D1,D2, it is the mixer that gets unbalanced by your key to enable a transmission.

Since this all happens after L5,L7, that mod should have nothing to do with it.
And clearly, the sidetone volume adjustment should not matter much.

But very curious about just what this "CW level adjustment" is, I'd check that mod carefully.
Maybe short across it somehow, see if that helps.

Jerry



On Sun, Feb 10, 2019 at 08:02 PM, Ted wrote:
Being there's already a thread on the subject, here's another one. 

New (to me) V3 board, virgin in the kit box. Tested all functions for a good hour or so, kind of getting a good base-line of where it is, as new. The output on 80, 40, 30, and 20 all showing 20 watts or so on CW key if the meter in my tuner is to be believed. 

L5 and L7 swapped for shielded SMT's and all levels still fine. Added CW level adjustment and side tone volume adjustment (both, trimmers). TX still fine, but intentionally reduced to around 10w as measured on 80 & 40. All still fine.

To this point, things are so good that it's almost boring but in a good way. The next thing I know, the TX has disappeared.  The display shows that TX should be TX'ing and the relays closing solidly.  Having been through this with a V4 board a few weeks ago, I started at Q20 and ran through the whole voltage measurement list with the PTT/mike keyed as directed. Every solitary transistor point measures right where it should be; TX current rises from 23mA to 64mA as opposed to 2+ Amps. The MRF510's do not heat up.

What's interesting is that, with this board hooked up to an antenna and a nearby rig hooked up to another, key down on CW produces a weak but recognizable note on the redundant radio - though, it's continuous for as long as the relays are closed ad not switching on/off with key down as if CW were actually working.

Again, that signal is audible but not loud. When the uBitx gets switched to a dummy load, the other radio hears nothing.  Bearing in mind that I've read this thread, I've wiggled the torroids but have not yet checked them for continuity. A length of wire touched to C80 produces no received CW note on the othe radio.

Anyone want to take a stab some of the possibilities other that some curse upon my work bench?

Tnx,