Date   
Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

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



2018/06/30 0:59、Arv Evans <arvid.evans@...>のメール:

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.

https://en.wikipedia.org/wiki/Push%E2%80%93pull_output

http://mircwiring.blogspot.com/2017/03/simple-complementary-push-pull-power.html

https://groups.io/g/BITX20/topic/4104436?p=,,,20,0,0,0::,,,0,0,0,4104436

Arv
_._


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@...>のメール:

I have  v4.
big problems with sound.
if you bypass the built-in audio amplifier, then you can use it.

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 

Re: A Breadboard Technique for the uBITX

Jon Titus, KZ1G <tituskz1g@...>
 

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

Re: A Breadboard Technique for the uBITX

Jon Titus, KZ1G <tituskz1g@...>
 

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

Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

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@...>のメール:

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.  

Re: A Breadboard Technique for the uBITX

Jack, W8TEE
 

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

RF in 12v Supply

Mark M
 

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

Re: RF in 12v Supply

Gordon Gibby <ggibby@...>
 

Sprinkle 0.1 ufd capacitors from supply lines to ground. They’re cheap, and they’re great!

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



Re: Known issues on uBITX r4 #ubitx

Ralph Mowery
 

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@...>のメール:

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.  


Re: RF in 12v Supply

Lawrence Galea
 

Try RG58 for the supply.


On Fri, Jun 29, 2018 at 7:17 PM, 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





Re: RF in 12v Supply

Lawrence Galea
 

That's apart from Gordon's suggestion

On Fri, Jun 29, 2018 at 7:20 PM, Lawrence Galea <9h1avlaw@...> wrote:
Try RG58 for the supply.


On Fri, Jun 29, 2018 at 7:17 PM, 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






Re: RF in 12v Supply

Gordon Gibby <ggibby@...>
 

Make sure the ground is a healthy healthy healthy connection as well, either a chassis or some pretty thick wires and lots of them, arrange so they all connect at some point called single point ground.  


On Jun 29, 2018, at 13:21, Lawrence Galea <9h1avlaw@...> wrote:

That's apart from Gordon's suggestion

On Fri, Jun 29, 2018 at 7:20 PM, Lawrence Galea <9h1avlaw@...> wrote:
Try RG58 for the supply.


On Fri, Jun 29, 2018 at 7:17 PM, 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






Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

IC.


Is the one like above OK?

Thanks in advance, Ralph.

// hiro, JJ1FXF



2018/06/30 2:19、Ralph Mowery <rmowery42@...>のメール:

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@...>のメール:

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.  


Re: RFI from uBitx TX after AGC and other mods installed

Lawrence Galea
 

Those two daughter boards especially with those long wires are a sure way of inviting RF pickup especially being so near the LPFs relays.
It could be that the boards are picking RF directly by being so near the LPFs relays.
Have you tried shifting them to the front and using shielded cables for all connections?

On Thu, Jun 28, 2018 at 4:33 PM, alans77 via Groups.Io <alans77@...> wrote:
Hi Don: In an effort to eliminate the RF getting back into the audio amp I replaced the TX RF output twisted pair between the uBitx board and my PL259 with coax also switched to coax wrapped 5 turns around a 120-43 core between the volume control and the AGC board. I still hear my voice loud and clear from the speaker on 80 and 40M. I am going to look for an easy way to to mute the amp or speaker.


Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

Ah, ubitx.net says “5 Amps should suffice”.

// hiro, JJ1FXF



2018/06/30 2:33、hirosmb JAZZ <hirosmb@...>のメール:

IC.


Is the one like above OK?

Thanks in advance, Ralph.

// hiro, JJ1FXF



2018/06/30 2:19、Ralph Mowery <rmowery42@...>のメール:

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@...>のメール:

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.  


Re: Running on a Jump Box

Gwen Patton
 

You misunderstand me, Ralph. I don't WANT it to act the same. If I wanted that, I'd just run it directly from the jump box. But I don't want it to run away in RF, as at that level it can damage my tuner. I want it to run at 5-10 watts, not 18-20! I can control it with the amperage, and since the fuse is a 2A inline, I don't want it to run more than that. So I'm certainly not going to set it to 3A unless I want to toast marshmallows on my tuner.

Re: RFI from uBitx TX after AGC and other mods installed

Don, ND6T
 

Seems like the problem is coming from the 5 volt lead. I am hesitant to try more than 10uF from it to ground due to the charging surge. It already has 2uF when the AGC is connected. What about some ferrite beads on that lead? Lawrence, others tried moving the boards without effect. Additionally, this seems to be audio!?! Interesting. Hey Rick, cool idea with the fan! An audible voltage indicator, too! -Don

Re: RF in 12v Supply

Arv Evans
 

0.1 mfd across the power leads at the power supply and again at the uBITX power
connector.  It could be that RF is modulating the 12V power lead and that causing
RF in the power supply regulator.  Bypassing the DC power at the power supply
should stop that if it is the problem. 

Arv
_._


On Fri, Jun 29, 2018 at 11:20 AM Lawrence Galea <9h1avlaw@...> wrote:
Try RG58 for the supply.


On Fri, Jun 29, 2018 at 7:17 PM, 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





Re: Known issues on uBITX r4 #ubitx

Arvo W0VRA
 

On Fri, Jun 29, 2018 at 10:19 am, Ralph Mowery wrote:
You may just get by with a 2 amp supply...
My 2A supply will not work the µBITX on 80M.  The supply trips out on overcurrent.  It works well on 40M and above.

Re: A Breadboard Technique for the uBITX

Dennis Yancey <bigbluedry@...>
 

Have any pricing done on them yet?