Re: Known issues on uBITX r4
#ubitx
You may just get by with a 2 amp supply, but I would go with at least one rated for 3 or 4 amps. It is always to have a few more amps than needed so the supply runs cool.?
On Fri, Jun 29, 2018 at 12:59 PM, hirosmb JAZZ <hirosmb@...> wrote: Thanks, R.E.
Yes, I read about the power supply in different thread.
If I am correct, ubitx works properly with 12V 2A power supply, right?
Let me at first carefully find the one at AKIHABARA where is a famous place to buy those electric parts and devices in TOKYO.
Actually I am going to AKIHABARA tomorrow to buy some other necessary items coz I already ordered my ubitx. :)
Many thanks for your advice!
// hiro, JJ1FXF
2018/06/30 0:29¡¢R. E. Klaus via Groups.Io < reklaus@...> ¤Î¥á©`¥ë: The new audio amp in the V4 uBITS is a very common design in inexpensive audio equipment for many years. It could be sensitive to power supply voltage levels and if you are using it at below its design supply voltage it may not have enough bias current resulting in crossover distortion. The 2 solutions would be to make sure you have the proper minimum voltage applied or re-bias the outputs...add a third diode, or use a potentiometer in place of the diodes so the bias can be adjusted. In higher power systems, the 2 diodes would be in physical contact with the output transistors and would self adjust the bias as the transistors heat up to reduce the chance of thermal runaway.??
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Sprinkle 0.1 ufd capacitors from supply lines to ground. They¡¯re cheap, and they¡¯re great!
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On Jun 29, 2018, at 13:17, Mark M <junquemaile@...> wrote:
The issue discussed in the 'RFI from uBitx TX after AGC and other mods installed' thread appears to be caused by RF getting into the 12v supply and from there into the 5v supply that feeds the AGC board (the ND6T/K5BCQ kit). At least that appears to be the issue on mine. I thought I'd start another thread to talk about that.
I have the ubitx in a case from amateurradiokits.in. The power comes in thru a plug in the rear panel at the right of the panel (looking at it from the front), thru a fuse and then thru three wires twisted together along the rear panel to the connector on the board at the far left. There's also a polarity protect diode across the supply. The power connector is right next to the antenna connector and the supply wires run past the final transistors and .
I'm running the ubitx on 13.8v from an Astron 20A power supply, The testing was done feeding a Heathkit Cantenna dummy load.
So, any suggestions on how to fix this would be appreciated. Don mentioned heavier supply wires and capacitor at the input. I thought I'd try re-routing the supply wires inside case to get them away from the RF section. Moving the power connector to the other end of the rear panel would make the run much shorter. Other than that, I don't know. RF hardware is not my forte (I'm mostly a software guy).
Thanks.... Mark AA7TA
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The issue discussed in the 'RFI from uBitx TX after AGC and other mods installed' thread appears to be caused by RF getting into the 12v supply and from there into the 5v supply that feeds the AGC board (the ND6T/K5BCQ kit). At least that appears to be the issue on mine. I thought I'd start another thread to talk about that.
I have the ubitx in a case from amateurradiokits.in. The power comes in thru a plug in the rear panel at the right of the panel (looking at it from the front), thru a fuse and then thru three wires twisted together along the rear panel to the connector on the board at the far left. There's also a polarity protect diode across the supply. The power connector is right next to the antenna connector and the supply wires run past the final transistors and .
I'm running the ubitx on 13.8v from an Astron 20A power supply, The testing was done feeding a Heathkit Cantenna dummy load.
So, any suggestions on how to fix this would be appreciated. Don mentioned heavier supply wires and capacitor at the input. I thought I'd try re-routing the supply wires inside case to get them away from the RF section. Moving the power connector to the other end of the rear panel would make the run much shorter. Other than that, I don't know. RF hardware is not my forte (I'm mostly a software guy).
Thanks.... Mark AA7TA
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Re: A Breadboard Technique for the uBITX
The photo is of a 5" touch screen (resistive) display (7" is an option) and the processor is the Teensy 3.6. Al (AC8GY) and I are working to finish the JackAl board for everything. I posted a desciption of the JackAl features a few days ago. The AGC (both audio and IF) requires a "non-standard" attachment to the board, but everything else works through the existing connectors. We hope t have the Beta boards going out next week.
Jack, W8TEE
On Friday, June 29, 2018, 12:51:38 PM EDT, Jon Titus, KZ1G <tituskz1g@...> wrote:
Very nice, Jack.? Have you described your setup?? I'm interested in the type of display and processor board, and the software.
--
Jon Titus, KZ1G
Herriman, UT USA
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Re: Known issues on uBITX r4
#ubitx
Thanks, R.E.
Yes, I read about the power supply in different thread.
If I am correct, ubitx works properly with 12V 2A power supply, right?
Let me at first carefully find the one at AKIHABARA where is a famous place to buy those electric parts and devices in TOKYO.
Actually I am going to AKIHABARA tomorrow to buy some other necessary items coz I already ordered my ubitx. :)
Many thanks for your advice!
// hiro, JJ1FXF
2018/06/30 0:29¡¢R. E. Klaus via Groups.Io < reklaus@...&²µ³Ù;¤Î¥á©`¥ë:
toggle quoted message
Show quoted text
The new audio amp in the V4 uBITS is a very common design in inexpensive audio equipment for many years. It could be sensitive to power supply voltage levels and if you are using it at below its design supply voltage it may not have enough bias current resulting in crossover distortion. The 2 solutions would be to make sure you have the proper minimum voltage applied or re-bias the outputs...add a third diode, or use a potentiometer in place of the diodes so the bias can be adjusted. In higher power systems, the 2 diodes would be in physical contact with the output transistors and would self adjust the bias as the transistors heat up to reduce the chance of thermal runaway.??
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Re: A Breadboard Technique for the uBITX
I haven't experienced any noise problems.? I still must shorten some wires and think about a final mounting arrangement.
--
Jon Titus, KZ1G
Herriman, UT USA
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Re: A Breadboard Technique for the uBITX
Very nice, Jack.? Have you described your setup?? I'm interested in the type of display and processor board, and the software.
--
Jon Titus, KZ1G
Herriman, UT USA
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Re: A Breadboard Technique for the uBITX
I used a plastic cutting board and some pieces of single sided copper clad board mounted with "L" brackets as a temporary "enclosure" to mount
the board and controls ?so that I can play with mods and figure out what controls and switches I really need,?before I start cutting and drilling a permanent enclosure.?
This photo is a about a week or two old as I already have my 2.8" Nextion Display attached and mounted.?
I learned my lesson with the BITX40, I packaged it a little too early and ended up struggling a bit to find space to add extra switches to take advantage of new features as more software mods appeared.
Cheers
Michael VE3WMB?
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Re: Known issues on uBITX r4
#ubitx
Arv,
Appreciated for your comments and pointers ?of details.
Certainly let me try some mods you advised after I set up my ubitx as it is.
I am not a hardware guy and so need a little more time to understand your advice.
However, it¡¯s a very good opportunity for me to know more about hardware and ubitx for sure.
Thanks a lot. I will come back to this topic when my ubitx is ready to be modified.
// hiro, JJ1FXF
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Hiro
The distortion issue seems to be more related to audio level and impedance and quality of the
attached speaker.?? Layout of the uBITX-4 audio output section allows one to make changes
like changing the idling current of the NPN-PNP output pair and adding negative feedback.? The two emitter resistors can be shorted to give more output current, but be careful that audio level does not overheat the output pair.? Adding a resistor for negative feedback could improve linearity. /g/BITX20/topic/4104436?p=,,,20,0,0,0::,,,0,0,0,4104436Arv
_._
On Thu, Jun 28, 2018 at 11:59 PM hirosmb JAZZ < hirosmb@...> wrote: Do all of the v4 have this distortion issue? Or ?only for the certain lots?
Thanks, Andy.
Ur videos helped me to understand what the distortion issue is like.
// hiro, JJ1FXF
2018/06/29 14:47¡¢Andy V. Borisenko via Groups.Io < rw9rn@...&²µ³Ù;¤Î¥á©`¥ë: I have ?v4.
big problems with sound.
if you bypass the built-in audio amplifier, then you can use it.
for example, a video from my uBitx v4
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Re: Easy, Inexpensive Cooling Fan, Excelway Case
Nice...any more pictures??
Jack, W8TEE
On Friday, June 29, 2018, 11:32:58 AM EDT, Vince Loschiavo <vince320@...> wrote:
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Re: Known issues on uBITX r4
#ubitx
Yes, Bill.
As far as I know, the distortion issue comes up with only v4 ubitx, however it¡¯s just a matter of degree.
I already placed my order with DHL, while taking a train back home today! :)
I also plan to use CEC firmware which I already modified a bit to limit the frequencies to TX in accordance with Japanese regulation.
I compiled the modified firmware which successfully runs on my Arduino UNO now.
Also I ordered a Nextion LCD at eBay which presents really lovely UI/UX.
I don¡¯t think I can sleep properly tonite coz I¡¯m so much excited. :)
Thank you, all of you here who share all the information of ubitx, such a wonderful rig!
// hiro, JJ1FXF
2018/06/30 0:21¡¢Bill Cromwell <wrcromwell@...&²µ³Ù;¤Î¥á©`¥ë:
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Hi,
I have V3 with a socketed audio chip labeled as Feb 2018. It worked right out of the box - as advertised. I have not had to make *any* mods at all. I do expect to install the CEC software but that is only to get some options I would like to have for CW. I am already using it for CW. I do not have distirtion, I can tune in SSB and AM stations and they are clear. Lucky me?
Wait until you have actually used your radio to decide if you 'need' mods. Most of the mods I see described are optional and only for the owners perefernces - like my plans to install the CEC software. There will be no hardware changes to mine.
73,
Bill KU8H
On 06/29/2018 12:35 AM, Mvs Sarma wrote:
There are few members who reported the good functioning of Audio amplifier.
we need to check whether the element is wrong in design or some pieces
went out with distorted output.
Regards
MVS Sarma
On Fri, Jun 29, 2018 at 9:44 AM, hirosmb JAZZ <hirosmb@...
<mailto:hirosmb@...>> wrote:
Jack,
Thanks for ur quick reply.
I read some articles of mods, but couldn¡¯t recognize which are
necessary mods for uBITX r4 board.
Does the r4 board still need to be fixed for the distortion issue?
// hiro
--
bark less - wag more
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Good rundown on warnings.
Fortunately we haven't had a new idealistic programmer decide to set the?-Werror complier flag yet. That was great fun unleashed at the worst possible moment.
Tom, wb6b
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Hi raj,
again many thanks for your kindleness and help.
?I am appriciate this very much and Hope?for succesful repair.
?
When my bitx was still working I developed a combination of agc and rx muting?to prevent
the switching cracks complete.
you are interested .?
73, elmar
Gesendet:?Freitag, 29. Juni 2018 um 17:47 Uhr
Von:?"Raj vu2zap" <rajendrakumargg@...>
An:[email protected]
Betreff:?Re: [BITX20] Bitx 40arduino
Elmar,
Change the nano on the raduino and reprogram.
Raj
At 29-06-18, you wrote:
Hello raj,
I am very glad to See your fast response.
sorry to say I killed my Raduino by myself.
Build the bitx in a new case and wiring one of the normally unused cables to the 12 Volt rail.
Now I am very angry? about myself ,hi.
Not very famili?r with digital Equipment ?looking for any Solution.
vy73 -Elmar-Dl2qa g qrp 3231
?
?
Gesendet: Freitag, 29. Juni 2018 um 16:39 Uhr Von: "Raj vu2zap" <rajendrakumargg@...> An: [email protected] Betreff: [BITX20] Bitx 40arduino
Elmar, Tell us what is the problem. Raj At 29-06-18, you wrote: >Hello, >my arduino board is defect. >how i can buy a new one..? >I would be very thankful for any help. >with Kind regards >elmar?dl2qa@...
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Re: RFI from uBitx TX after AGC and other mods installed
Don,
Just checked, feedback is affected by level of volume control.
More with higher volume, quits with volume all the?way down,?mike
unplugged, or plugged in, also with?audio coming from the computer for FT8.
?Can't get to the scope right now that will have to wait until later.?
The gain pot is mounted to the front aluminum panel with a grounding lug on the
shaft.? Paint was?removed from the panel for all grounding points. All
grounds from the AGC board go to that gounding lug and then a ground wire is run
to the front corner of the uBitx board mounting/grounding hole.? Actually
the 13.8V-20V input voltage goes through a 12 volt heat sinked?regulator
mounted to the back panel (uBitx supply)?and grounded there and to the back
corner of the main board. It is bypassed on both the input and output per the
data sheet.?Will check later regarding scoping the 12volt supply to the
board at the regulator.? I run the 13.8V-20V? prior to the regulator
directly to the finals depending on?required power output.?Also might
mention I have a computer fan hooked to the vaiable?input voltage with a
47ohm 5 watt resistor in series.? The fan runs all the time but never at
full power even at 18V. It gives me a variable fan speed, variable noise, low at
13.6V and faster, little louder,?at higher voltages, hince more cooling for
higher voltages on the finals. Have not seen or heard any noise/hash problems
with the fan and the finals always run cool.?Adds about?150 ma to the
total current which would not be good for portable use but okay on my linear
supply.?
?
73,Rick
KN4AIE
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Rick, Yes, having insufficient filtering will allow all sorts of
problems. At this point, a few of those experiencing these problems are finding
that those signals are getting through to the 5 volt supply from the main 12
volt input. It would be worthwhile to track it down and cure it there since that
lets it in to everything. The subsequent recommendation toward
shorting the AGC bias to ground was to facilitate the multi-hang time delays
afforded by K5BCQs kit. Yes, removing the 5 volt bias to the amplifier will open
that path and reduce the effect but notice that the 5 volt input is well
bypassed on the AGC board which means that there must be considerable
interference coming in onto whatever that 5 volts supplies. Does turning the
volume control all the way down affect it? If not, then it might be coming in on
the 12 volt supply. Another possibility is that the volume control ground
side has enough resistance that we are getting ground-loop effects. Try an
additional grounding from the cold end of that potentiometer. I am a big
believer in single-point grounding whenever possible. Efforts toward achieving
that often are fruitful. 73, Don
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Re: Known issues on uBITX r4
#ubitx
Hiro
The distortion issue seems to be more related to audio level and impedance and quality of the
attached speaker.?? Layout of the uBITX-4 audio output section allows one to make changes
like changing the idling current of the NPN-PNP output pair and adding negative feedback.? The two emitter resistors can be shorted to give more output current, but be careful that audio level does not overheat the output pair.? Adding a resistor for negative feedback could improve linearity. /g/BITX20/topic/4104436?p=,,,20,0,0,0::,,,0,0,0,4104436Arv
_._
On Thu, Jun 28, 2018 at 11:59 PM hirosmb JAZZ < hirosmb@...> wrote: Do all of the v4 have this distortion issue? Or ?only for the certain lots?
Thanks, Andy.
Ur videos helped me to understand what the distortion issue is like.
// hiro, JJ1FXF
2018/06/29 14:47¡¢Andy V. Borisenko via Groups.Io < rw9rn@...&²µ³Ù;¤Î¥á©`¥ë: I have ?v4.
big problems with sound.
if you bypass the built-in audio amplifier, then you can use it.
for example, a video from my uBitx v4
|
Elmar,
Change the nano on the raduino and reprogram.
Raj
At 29-06-18, you wrote:
toggle quoted message
Show quoted text
Hello raj,
I am very glad to See your fast response.
sorry to say I killed my Raduino by myself.
Build the bitx in a new case and wiring one of the normally unused cables
to the 12 Volt rail.
Now I am very angry? about myself ,hi.
Not very famili?r with digital Equipment ?looking for any Solution.
vy73 -Elmar-Dl2qa g qrp 3231
?
?
Gesendet: Freitag, 29. Juni 2018 um 16:39 Uhr Von:
"Raj vu2zap" <rajendrakumargg@...> An:
[email protected] Betreff: [BITX20] Bitx 40arduino
Elmar, Tell us what is the problem. Raj At 29-06-18, you wrote:
>Hello, >my arduino board is defect. >how i can buy a new one..?
>I would be very thankful for any help. >with Kind regards
>elmar?dl2qa@...
|
Re: Known issues on uBITX r4
#ubitx
Hiro, JJ1FXF
It is easy to build your own copy of the uBITX-4 audio section to experiment with.? You will
need two 2N3904 and one 2N3906 and assorted resistors and? capacitors.? This will let you
play with the same audio section and work up changes if you find them necessary.?
While the uBITX is not modular, the circuit sub-sections are isolated enough to allow parts
to be constructed as stand-alone modules.? This lets builders work on upgrades and
modifications without hacking into their uBITX boards.? Once a suitable modification has
been designed, built, and tested it can then be applied to a working uBITX with more chance
of success.?
Arv? K7HKL
_._
On Thu, Jun 28, 2018 at 11:46 PM hirosmb JAZZ < hirosmb@...> wrote: IC. I¡¯ll pay my attention to this distorted audio issue for a while.
Any other known hardware problems on uBITX r4, the latest board?
Many thanks, MVS.
// hiro
There are few members who reported? the good functioning of Audio amplifier. ?we need to check whether the element is wrong in design or some pieces went? out with distorted output.
|
Re: Easy, Inexpensive Cooling Fan, Excelway Case
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Re: RFI from uBitx TX after AGC and other mods installed
Rick,
Yes, having insufficient filtering will allow all sorts of problems. At this point, a few of those experiencing these problems are finding that those signals are getting through to the 5 volt supply from the main 12 volt input. It would be worthwhile to track it down and cure it there since that lets it in to everything.
The subsequent recommendation toward shorting the AGC bias to ground was to facilitate the multi-hang time delays afforded by K5BCQs kit. Yes, removing the 5 volt bias to the amplifier will open that path and reduce the effect but notice that the 5 volt input is well bypassed on the AGC board which means that there must be considerable interference coming in onto whatever that 5 volts supplies. Does turning the volume control all the way down affect it? If not, then it might be coming in on the 12 volt supply.
Another possibility is that the volume control ground side has enough resistance that we are getting ground-loop effects. Try an additional grounding from the cold end of that potentiometer. I am a big believer in single-point grounding whenever possible. Efforts toward achieving that often are fruitful.
73, Don
|
Re: Known issues on uBITX r4
#ubitx
The new audio amp in the V4 uBITS is a very common design in inexpensive audio equipment for many years. It could be sensitive to power supply voltage levels and if you are using it at below its design supply voltage it may not have enough bias current resulting in crossover distortion. The 2 solutions would be to make sure you have the proper minimum voltage applied or re-bias the outputs...add a third diode, or use a potentiometer in place of the diodes so the bias can be adjusted. In higher power systems, the 2 diodes would be in physical contact with the output transistors and would self adjust the bias as the transistors heat up to reduce the chance of thermal runaway.??
|
Raj vu2zap
Vince N2AIE
Don, ND6T