Re: sBitx-DE Schematics with most recent mod 2 kit
#sBitx
Thank you, Allison.? I will try to work out the issue from these.
73
Evan
AC9TU
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Re: sBitx-DE Schematics with most recent mod 2 kit
#sBitx
Until the docs are improved what I have may match or are at least close.
NOTE sBitx_main_v2.pdf shows diode switched LPF. NOt implements but the RX/TX
switch may match the little board or be close.? The other was an earlier proposed
and again likely close but not exact.
That may help.
?
--
Allison
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Please use the forum, offline and private will go to bit bucket.
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sBitx-DE Schematics with most recent mod 2 kit
#sBitx
Some background:
I applied both upgrade/modification kits to my sBitx.? This was after having blown the finals and the transmitter keying section (Q9 and Q10 with the added 2n7000) after the first software-based T/R fix.? I replaced the transistors and added the mods.? I also updated the software with a git pull on my second Raspberry Pi 4.? It started up without any apparent issue.? I was connected to a dummy load, so I did not test the receiver, though it did appear to be working with the dummy load.? I was able to set the bias per the upgrade instructions.? I turned it off (I forgot to shut down the software first) and the next day went back to continue working on it.
The power was first measured at 15 watts, then dropped to 2.5 watts.? It started to draw an excessive current, and I could not turn off the transmitter.? Now anytime I key the transmitter, I get the 2.5 watts out, high current draw, and have to power off to stop it.?
Suggestions on where to look are welcomed.? Since it seems to start in receive mode OK, I assume there is an issue with the T/R board.
What I need are the schematics of the T/R board.? The main board schematics in the upgrade document do not have the details of the T/R board.? It is hard to diagnose without the schematics.?
Any help is appreciated.
73
Evan
AC9TU
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Hi All I've had an uBITX v6 for a couple of years now, at first I used it without modifications, but after a while I started modding it. 1) Increased mic gain to avoid shouting at the microphone 2) Allison KB1GMX's mod for driver and pre-driver stages to enable more power at higher bands. 3) Changed stock heat sinks for bigger ones Also, In the last months, I have put together a small board to enable some extra capabilities.
- CW audio filter using Op Amps
- LM567 tone detector to center CW signals in the filter's passband
- VK3YE's automatic volume control using LED/LDR
 I tested the board and then mounted it inside the uBITX using a 3D printed support. I've added to the front panel a LED for the tone detection and two switches to enable/disable CW filter, and to enable/disable AVC.     I tested the tone detector and CW filter, and they are working as expected. The AVC can attenuate strong signals, when a weak signal is present, I don't perceive any audio distortion. However, when I receive a strong signal, the LED shines and the attenuation kicks in. The signal is attenuated, but a high frequency noise is generated, like a whistle or hissing sound. I tried increasing capacitor sizes (C2 and C3 in schematic) without luck, I also moved the wires to check if there is some sort of coupling, but that didn't solve anything. I sense the signal from VOL-H and then LDR is connected in parallel with VOL-M. The LDR has 200k ohms dark resistance and drops to a few ohms when the LED is at max strength. After some tests, the noise also appears if I attenuate the signal illuminating the LDR using a flashlight, so It doesn't seem to be related to the LED circuit. Any clues or suggestions? Maybe I need to try a different photo resistor?
Any suggestions for this issue or for the other mods are welcome. Thanks LU2HES
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Re: V5 Locks up on CW transmit 17m and above
I have also found that the location of the cable harness to the mainboard and Raduino measures a lot. If I ran them high, immediately behind the Nextion, even with volume turned to minimum, I would hear a loud screech on boot. (Interestingly, if I turned the volume up a couple notches, the screech would go away. When i tucked the wiring harness down below the Nextion, all was good. I haven't done a lot of TX on the uBITX, so cant confirm that your TX lockup will not happen.
73
Mark
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AJ6CU
KD8CEC 2.0, Nextion Screens,? and open source uBITX Raduino boards for Arduino IOT, BLE, RP2040, Teensy 4.0, and Raspberry Pi Pico
https://github.com/aj6cu
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Re: #sbitx upgrade kit 2 is on the way
#sBitx
Gordon and others, The WATTS control is uncalibrated. I am pushing a new version soo? that will have the corrected drive levels, until then use an external power/swr meter to keep the output below 40 watts on all bands. - f
My notes on how my upgrade went, some suggestions for potentially making it easier, including links to Farhan's excellent instructions for the TR upgrade, and link for the switching regulator upgrade (which I hadn't yet done) are:
73,
Gordon KX4Z
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Re: #sbitx upgrade kit 2 is on the way
#sBitx
My notes on how my upgrade went, some suggestions for potentially making it easier, including links to Farhan's excellent instructions for the TR upgrade, and link for the switching regulator upgrade (which I hadn't yet done) are:
73,
Gordon KX4Z
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Re: #sbitx upgrade kit 2 is on the way
#sBitx
Got both the switching regulator and the T/R switch upgrades done.? ?Discovered a few items along the way.? ?
Broke the pad on the switching regulator output while reassembling -- no power to the PI.? ?Ran the Pi from separate supply until dissassembled the entire thing AGAIN and found the broken connection, effected a repair.? ?First time I have pushed the PTT on this fantastic rig.? ?I had great fun tuning the lower and upper filter points while listening to CW on 80 meters!? ?
Soon I'll list some hints and notes on goofs I made, photos.? ?
The upgrade two instructions:? ?
I would have to admit considerable trepidation on the SMD parts!!!? ? Delighted that it is all back together and apparently working.? ?Fantastic learning tool.
Gordon KX4Z
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Re: V5 Locks up on CW transmit 17m and above
Interesting. I had a similar problem with my uBitx v6 and a Nextion screen. Mine is 5¡±, and the upper bands would lock up in transmit with no side tone. It would stop only by cycling the power. I must have fixed it by simply moving around some of the cables because it resolved without doing anything else, and I never found the cause. Along similar lines I solved the Nextion noise whine from suggestions here. It¡¯s audible even when the audio is turned way down. Apparently it¡¯s from the Nextion backlight which is minimized by increasing the brightness to 100% but is still annoying. The noise was completely eliminated by putting a 2.5 mH choke in series with the red Vcc power line to the Nextion. I used a FT-114-43 toroid. 70 turns of #22 gauge wire was recommended but I was able to wind a few more turns than that, and my meter showed 3.5 mH. I also put a small 1000 ¦ÌF 16 V electrolytic across to ground for good measure. I also used RG178 in the audio lines.
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Re: V5 Locks up on CW transmit 17m and above
After a lot of experimenting I have figured the rf is coming from the Nextion display.? If I tune to the band I want, then disconnect the display I can key the radio and I have a side tone.? I have shortened the leads from the display to the arduino and added ft50-43 toroids to the tx and rx lines of the display.? It has helped some, I can get it to work properly on 17m and occasionally on 15m.? 12m and 10m are still a write off as far as cw. I'll have to figure that out yet.
Spencer VA3SPN
?
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Re: #sbitx Little Transmit RF After Mod Kit
#sBitx
Anthony, You need a tweaked version of the sbitx. I am pushing it out in 12 hours. This new year business is very distracting :-D - f
I've performed the mod and I'm somewhat baffled as I cannot get much RF output power.
Here are the results of a test with the rig in CW mode, power set to 15 watts.? All measurements are taken from ground, with RF measurements done using an oscilloscope and DC measurements done with a voltmeter:
Q11 collector: 1.2 V pk-pk
Q12 & Q13 Collectors: 12.4 V pk-pk
Q14 & Q15 Collectors: 11.2 V pk-pk
Q18 Pin 1: 3.6 V DC? & 7.2 Vpk-pk RF
Q18 Pin 2: 12 V
Q19 Pin 1: 3.6 V DC & 6.8 V pk-pk RF
Q19 Pin 2:?12 V
PA-OUT (T8 Output) 12.4 V pk-pk? (About 0.37 W)
The rig has been dormant for quite awhile as I was waiting for the mod kit to arrive.? ?I couldn't recall if Q18 and Q19 were blown from testing months ago, so I went ahead and replaced them with the transistors from the mod kits, so these are new components.? This is unlikely?to be relevant but I'm using the stock sbitx code from GitHub, and the transmit sequencing mod was removed so the Q9 / Q10 circuit is back to its original state (I obviously have?+12V on R10, R49, and R77 at transmit).
Any ideas?? It's like Q18 and Q19 just don't want to work....
73 Goody K3NG
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#sbitx Little Transmit RF After Mod Kit
#sBitx
I've performed the mod and I'm somewhat baffled as I cannot get much RF output power.
Here are the results of a test with the rig in CW mode, power set to 15 watts.? All measurements are taken from ground, with RF measurements done using an oscilloscope and DC measurements done with a voltmeter:
Q11 collector: 1.2 V pk-pk
Q12 & Q13 Collectors: 12.4 V pk-pk
Q14 & Q15 Collectors: 11.2 V pk-pk
Q18 Pin 1: 3.6 V DC? & 7.2 Vpk-pk RF
Q18 Pin 2: 12 V
Q19 Pin 1: 3.6 V DC & 6.8 V pk-pk RF
Q19 Pin 2:?12 V
PA-OUT (T8 Output) 12.4 V pk-pk? (About 0.37 W)
The rig has been dormant for quite awhile as I was waiting for the mod kit to arrive.? ?I couldn't recall if Q18 and Q19 were blown from testing months ago, so I went ahead and replaced them with the transistors from the mod kits, so these are new components.? This is unlikely?to be relevant but I'm using the stock sbitx code from GitHub, and the transmit sequencing mod was removed so the Q9 / Q10 circuit is back to its original state (I obviously have?+12V on R10, R49, and R77 at transmit).
Any ideas?? It's like Q18 and Q19 just don't want to work....
73 Goody K3NG
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Hello
We at HFSignals are working to get the next version of the sBitx released soon. However with the testing going on we will be making the announcement once we have successfully tested sBitx V2. Do write to us at sales@... and we will include your name in our mailing list.
Regards,
Thomas
hello, i have seen people ask when the sbitx will be available again without any definite answers .I would be interested in a kit myself as i have a pi and a display
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--
Support@...
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Re: sBitx - I just got an envelope of parts...
The address I gave is older the manal has been updated many times
so keep an eye there for improvements.
Use the one Lou Ki5Fty gave for the most current.
Also if you want the history and look back use the web interface as
then you can see what was missed.
--
Allison
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Please use the forum, offline and private will go to bit bucket.
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Re: sBitx - I just got an envelope of parts...
Obviously you have not paid attention to what going on and why.
At this point have you even tried to do anything with your Sbitx?
The manual is at:
https://docs.google.com/document/d/1jWkgISG9JqwB1tDC3_ONAGIGfjSqxmNEtBxnI8Dyjyg/edit
Allison
------------------
Please use the forum, offline and private will go to bit bucket.
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Re: sBitx - I just got an envelope of parts...
Yes, that is the second upgrade to the developers edition to fix oscillations?on the PA, change tr switching to diodes and add a realtime clock for the pi.? Here are the instructions:
On Sat, Dec 31, 2022 at 4:52 PM Ken N2VIP < ken@...> wrote: I was driving home from a ham breakfast gathering, and something got me to thinking about my sBitx. When I got home, I saw I got an envelope full of various components, with no explanation or instructions.
What are the parts for? Where is the info on what to do with them? A quick review of hfsignals website didn't give me any answers.
Thanks in advance, if there was an email thread on this I missed it...
Ken, N2VIP
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Re: Modified sBitx received, ???
Got my upgrade kit today - great way to start the new year tomorrow, modifying a radio!? Thanks Ashhar and HFSignals,? great customer service!? And thanks to everyone in the group that diagnosed the problems, engineered the fixes and explained everything along the way. I have learned a lot from?y'all!
73 and Happy New Year!
Oh.? I didn't know fully modded new units were being shipped.? Sorry.
For all those installing the mod, it appears that the previous TX sequencing mod or the original unmodified Q10 circuit needs to be in place.? I'm not getting final PA bias with the TX sequencing mod out and the Q10 back to stock, however I'm still not getting RF.? Still troubleshooting....
On Sat, Dec 31, 2022 at 5:56 PM Joel Caulkins/N6ALT < caulktel@...> wrote: Anthony,
I don't know, all I do know is the radio that just arrived is what will be the final release to the public, (not the developers addition). It's very clean inside and doesn't looked hacked up or anything, I can see where the driver MOSFETs were supposed to go but have never been supplied on mine. There is new daughter card that is sticking up on the left front side of the PCB, I'm guessing it's the diode switching board, I just don't know because I never looked into the inside until today. Farhan would know better what it shipped with.
Joel
N6ALT
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Re: Modified sBitx received, ???
Oh.? I didn't know fully modded new units were being shipped.? Sorry.
For all those installing the mod, it appears that the previous TX sequencing mod or the original unmodified Q10 circuit needs to be in place.? I'm not getting final PA bias with the TX sequencing mod out and the Q10 back to stock, however I'm still not getting RF.? Still troubleshooting....
On Sat, Dec 31, 2022 at 5:56 PM Joel Caulkins/N6ALT < caulktel@...> wrote: Anthony,
I don't know, all I do know is the radio that just arrived is what will be the final release to the public, (not the developers addition). It's very clean inside and doesn't looked hacked up or anything, I can see where the driver MOSFETs were supposed to go but have never been supplied on mine. There is new daughter card that is sticking up on the left front side of the PCB, I'm guessing it's the diode switching board, I just don't know because I never looked into the inside until today. Farhan would know better what it shipped with.
Joel
N6ALT
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Re: Modified sBitx received, ???
Anthony,
I don't know, all I do know is the radio that just arrived is what will be the final release to the public, (not the developers addition). It's very clean inside and doesn't looked hacked up or anything, I can see where the driver MOSFETs were supposed to go but have never been supplied on mine. There is new daughter card that is sticking up on the left front side of the PCB, I'm guessing it's the diode switching board, I just don't know because I never looked into the inside until today. Farhan would know better what it shipped with.
Joel
N6ALT
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sBitx - I just got an envelope of parts...
I was driving home from a ham breakfast gathering, and something got me to thinking about my sBitx. When I got home, I saw I got an envelope full of various components, with no explanation or instructions.
What are the parts for? Where is the info on what to do with them? A quick review of hfsignals website didn't give me any answers.
Thanks in advance, if there was an email thread on this I missed it...
Ken, N2VIP
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Agustin - LU2HES
John Terrell, N6LN
Joel Caulkins/N6ALT