zBitx alternative board...
Hello, we don't even know when it will start shipping, and we all want to rewrite the design from scratch.
I'm in, too.
Do you think it would be possible to change the raspberry for another more powerful board? Would it be worth it? Could it be to play with Freedv with more guarantees of success? Would it be compatible with the PI pico's screen management?
Would everything have to be recompiled or would it work directly on another arm chip?
I've seen this board (RADXA) that offers more memory, and more processor speed, and also USB-c connectors.
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Re: sBitx v3 - original application gives high power, wsjtx up to 2W only
I have now switched from USB to DIGI and there is no difference, I use the previous settings. I read the output power on an external Daiwa CN-801Type H meter, because the built-in meter cannot be adjusted. (When I received the device, it behaved strangely for a long time, then I realized that one of the output power measuring diodes was faulty. The 1N60 diodes selected in pairs show the value shown in the picture for a 20 W output. The value is the same up to about 5 Watts, then it gradually differs.) Since I have v2, I had to set the scale value per band by using the default and changing the value, restarting and taking measurements, which was a long process.
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Gyula HA3HZ
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Re: sBitx v3 - original application gives high power, wsjtx up to 2W only
Wojtek,
I haven't been doing much radio lately and it didn't show up, but there must have been some modification, because so far the wsjt-x and jtdx transmit slider didn't affect the transmit power.
I just checked and it showed up, the slider position affects the output power. The change is probably related to hamlib.
The state I have set (sBitx v2) differs from the description referenced in point 6 (I think it's the original state, no one maintains the page).
The wsjt-x (2.7.1-rc8) setup looks like this:
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With this setting and gradually raising the slider, I see the 20 watt output power, unlike before, now the slider is at 50%.
This setting may probably be different if your output power scale value is different on the given band.
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Gyula HA3HZ
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Re: sBitx v3 - original application gives high power, wsjtx up to 2W only
You can get real-time help on our Discord server.. ?
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-JJ
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Re: Trying to update firmware in ubitx6.1
#v6
Thanks for posting a solution! Now the next time we b?rk one, we can find this.
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-- J R Parrick (K0TBS).
Si vis pacem, para bellum!.
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Re: sBitx v3 - original application gives high power, wsjtx up to 2W only
I run WSJTx on my DE which has the hardware upgrades. I used to just leave the slider up all the way and control the power out with the Drive Setting. But I recently upgraded and updated to the newest 64 bit image and 4.4 software. I now find that the slider has a large impact on the power output and I leave it at about 60% of max. I also am running in digi mode now versus USB as that is what defaulted with the upgrade. You might try upgrading.if you haven't already done so.
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Re: sBitx v3 - original application gives high power, wsjtx up to 2W only
I have this problem as well. Using either wstjx or fldigi, I get a max of ~3 W out(*) with the power sliders at maximum.
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I am no longer alone in the universe.
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(*) DRIVE set to 63 to get 10 W out on CW results in 1.3 W at the autotuner.
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Re: sBitx v3 - original application gives high power, wsjtx up to 2W only
I set the mode to USB in the sbitx application and the maximum power is still 2W.
The slider in wsjtx still controlls the power.
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73,
Wojtek
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Re: sBitx v3 - original application gives high power, wsjtx up to 2W only
Wojtek,
Set it to USB and you can set the output power with the Drive value. The wsjtx slider does not work with sbitx, the Drive is the determining factor.
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Gyula HA3HZ
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sBitx v3 - original application gives high power, wsjtx up to 2W only
Hi,
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Due to the problems with non-standard callsigns, I have decided to use wsjtx.
I have updated sbitx with the `update` script.
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I start it via VNC.
- I installed tigervnc on my sBitx
- I log in to my sBitx via: `ssh pi@... -L5907:localhost:5907`
- In another console on PC I run: `vncviewer :7`
- Then in the vnc session in a terminal I run:`killall sbitx; cd ~/sbitx; sleep 1; ./sbitx`
- In another console I run `export DISPLAY=:7 ; wsjtx`
- The wsjtx is configured as described here:
- I set Digital mode in the sbitx and FT8 in wsjtx.
The result is that I can see the received FT8 messages, I can transmit, but the power is limited to 2W (as reported by sbitx).
I can control the power with the slider in the wsjtx window. The power is proportional to the slider position, but the upper position gives 2W.
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When running only the original sbitx application, I can control power up to 20W and higher.
What is the reason of that problem and how can I cure it?
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73,
Wojtek
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Yes, it can be quite confusing. It's also possible that an errant hot wire from a bench psu touched somewhere. I had to step back from this one for a while, because I was beginning to get frustrated and we know where that can go! So I decided
to work on assembling a K9HZ 20w pa board that I will probably drive with my Lime mini 2. I also have a radioberry 2 that I am working on getting configured properly. So with the three different projects going at once, I can always move to another when I start
getting frustrated and tired of one.
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-------- Original message --------
From: "Gordon Gibby KX4Z via groups.io" <docvacuumtubes@...>
Date: 3/14/25 6:41 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Sounds like another case where something is screwy.
I don’t think you could blow D7 unless you had reverse polarity power.
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so there may be a mislabeling or a screw circuit board here. Or maybe just a mistake in figuring out where things are blown.
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but all of these combined to make it extremely difficult to figure out what the heck is going in very carefully measure and look and pride and think and compare figure out what really is blown and what isn’t and where it is really connected and where it
isn’t!!
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we’ve already seen one example where this unit was wired differently from everybody else. ??
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gordon Kx4z?
-- Mike - K8MCB?
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Re: uBITX v6 Low Audio - Back at it again
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Sounds like another case where something is screwy.
I don’t think you could blow D7 unless you had reverse polarity power.
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so there may be a mislabeling or a screw circuit board here. Or maybe just a mistake in figuring out where things are blown.
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but all of these combined to make it extremely difficult to figure out what the heck is going in very carefully measure and look and pride and think and compare figure out what really is blown and what isn’t and where it is really connected and where it isn’t!!
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we’ve already seen one example where this unit was wired differently from everybody else. ??
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gordon Kx4z?
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Mike,
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D7 is for reverse polarity protection.? It should not blow unless the power is connected wrong.??
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I had trouble adjusting the bias on my DE sbitx.? The TR switching was not working correctly, allowing the amp to enter sustained oscillation.? The amp does not amplify until the bias is close to correct and the oscillation begins.
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I would verify that both sections of the TR switching (Q9, Q28, Q29, and associated transistors).
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73
Evan
AC9TU
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So, everything is still switching, but...when I was attempting to adjust the bias, which was about 800mA in receive, and about 1.2A with PTT engaged, in USB, 40m drive at 1 mic at 0. When I began to adjust cw from the full ccw position, the
pot didn't do anything until over half a turn, and immediately jumped to 3-5A, and proceeded to pop D7.
?If it's not one thing, it's another!!! Anyway, both D30 and D31 are both OK, dropping about .6v each. Aside from checking Q28 and the 2 finals, what else could be the issue, other than the likely blown pot for the bias?
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-------- Original message --------
From: "Evan Hand via groups.io" <elhandjr@...>
Date: 3/14/25 2:00 PM (GMT-05:00)
Subject: Re: [BITX20] reviving my sbitx v3
Mike,
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As Gordon points out, there is most likely a problem with the receiver TR switch.? As with the transmitter switching, verify the operation of Q28.
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You can also try removing the RF from the circuit with a low drive setting.? Set it up as shown on the voltage measurement sheet.
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If Q28 turns on and off with the PTT signal, then look at the diodes themselves.? You should be able to check the diode in the circuit without power.
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It is good you found this before being forced to replace another set of finals and other components.
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73
Evan
AC9TU
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-- Mike - K8MCB?
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That’s the ham radio spirit!! Congrats !!
Gordon kx4z
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On Mar 14, 2025, at 14:43, Praba Karan via groups.io <vu3dxr@...> wrote:
? Found a cure for this defect. I have disabled existing LM386 audio amp and used TDA2822 amp module. I took audio input from IC socket pin 3 without any surgery. Now audio is good. The only issue is slightly lower audio level and yet to find ?space for audio module inside cabinet.
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Found a cure for this defect. I have disabled existing LM386 audio amp and used TDA2822 amp module. I took audio input from IC socket pin 3 without any surgery. Now audio is good. The only issue is slightly lower audio level and yet to find ?space for audio module inside cabinet.
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Mike,
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As Gordon points out, there is most likely a problem with the receiver TR switch.? As with the transmitter switching, verify the operation of Q28.
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You can also try removing the RF from the circuit with a low drive setting.? Set it up as shown on the voltage measurement sheet.
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If Q28 turns on and off with the PTT signal, then look at the diodes themselves.? You should be able to check the diode in the circuit without power.
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It is good you found this before being forced to replace another set of finals and other components.
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73
Evan
AC9TU
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They should be back biased by the high-voltage supply. Either it’s not working or there might be a problem around Q 28, haul out the voltmeter meter and start looking at voltages in receive and in transmit and figure out what’s going on.
Study the schematic to understand how the switching works
Good luck!!!
Gordon kx4z
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On Mar 14, 2025, at 11:49, Michael Bales via groups.io <mikebales73@...> wrote:
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Evan, doing a once over before setting the PA bias, I noticed that I am getting excessive heating of D30, D31 upon Tx. I still have output from the finals. It could be heating elsewhere as well, but I didn't want to leave it on Tx any longer than needed until
I can id the problem.?
Mike
From:[email protected] on behalf of Evan Hand via groups.io
Sent:?Thursday, March 13, 2025 10:25 PM
To:[email protected]
Subject:?Re: [BITX20] reviving my sbitx v3
To be clear, both the receiver and the transmitter use that mixer.? It translates the signal from the 40MHz IF frequency to the operating frequency in both directions.
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73
Evan
AC9TU
-- Mike - K8MCB?
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Evan, doing a once over before setting the PA bias, I noticed that I am getting excessive heating of D30, D31 upon Tx. I still have output from the finals. It could be heating elsewhere as well, but I didn't want to leave it on Tx any longer than needed until
I can id the problem.?
Mike
toggle quoted message
Show quoted text
From:[email protected] on behalf of Evan Hand via groups.io
Sent:?Thursday, March 13, 2025 10:25 PM
To:[email protected]
Subject:?Re: [BITX20] reviving my sbitx v3
To be clear, both the receiver and the transmitter use that mixer.? It translates the signal from the 40MHz IF frequency to the operating frequency in both directions.
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73
Evan
AC9TU
-- Mike - K8MCB?
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EB3AM Jordi
HA3HZ
J R Parrick (K?TBS)
W6LKB