Date   
Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

WONDERFUL!!

This is the mod I certainly will do at first after setting up my ubitx.

Again, many thanks, Andy.


// hiro, JJ1FXF



2018/06/29 22:45、hirosmb JAZZ <hirosmb@...>のメール:

Andy,

Tons of thanks to you.

ARIGATO!

// hiro, JJ1FXF



2018/06/29 22:38、Andy V. Borisenko via Groups.Io <rw9rn@...>のメール:

Hiro, special for you
sound bypassing the built-in amplifier v.4
https://www.youtube.com/watch?v=PsB6_HeeToc&feature=youtu.be

Bitx 40–arduino

dl2qa@...
 

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: Running on a Jump Box

Ralph Mowery
 

You should not set the current limit to a lower limit than what the device needs.  Probably what is going on is that when you have the current set for 1.5 amps and the rig really needs say 2 amps , the 12.5 volts cuts back to 10 or 11 volts so the output drops way off.  That is not the way to run it.  Then when you go to the jump box the voltage will not cut back.

Set your bench supply to about 3 amps and the same voltage as the jump box and they will probably act the same.

de ku4pt


On Fri, Jun 29, 2018 at 9:06 AM, Gwen Patton <ardrhi@...> wrote:
Yesterday, I set up a separate antenna for the uBitX on my front porch, to test battery operations, potentially to use the rig in the field. The antenna I set up was not ideal, and my Elecraft T1 ATU would not tune it. But now I'm not so sure. I was powering the uBitX from a Stanley automotive jump and power box, the kind that has a lighter-type socket on the front, and automotive battery clamps on the back for jumping a car. The voltage is 13.7v, not a lot higher than what I was putting into it on the bench, which was 12.5v, but the available amperage was of course much higher -- this is a BIG jump box that I purchased for jump-starting my wheelchair van in an emergency.

I haven't measured the available amperage on the lighter socket, but I suspect it's much higher than the 1.5A I limited my bench power supply to giving. The bench supply has been set to 12.5v @ 1.5A, and with those settings I get almost exactly 5W out on both 40 and 20m into a big dummy load (the MFJ paint can model). But when I power it from the battery box, I get well over 5w, around 20 watts from whistling into the mike. The key gives a very high output power as well. It may be that it was too much output power for the tuner to handle, and it wouldn't such a strong signal.

My bench supply takes 19vdc in from a switching supply that gives 19v @ 3.5A, and allows the user to set a buck-boosted output between 0 and 18v, with commensurate amperage. The DC in socket I installed is the same size as the one on the uBitX, and most of my other projects, as I thought ahead to powering them. I just tested connecting the jump box to the bench supply, and the bench supply to the uBitX, and can keep the higher power from the battery from overpowering the radio. I'm going to order an extra bench supply module -- cheap on Ebay -- and install it permanently on the back of the uBitX to give me controllable flexibility in the output power. Running the uBitX at 12.5v @ 1A limit brings the output power into the dummy down to 2w.

Is there a point below which I might damage the radio from running it too low? Has anyone else had similar experience with too much amperage?

I'm going to rethink the speaker I have mounted in the case, as it doesn't have enough oomph to make it worthwhile. Or, I may add a small audio amp for the speaker. I have several in my junque box. Listening with a pair of headphones sounds great. I'm having no trouble with the audio on phones, just on speaker, and the incoming signals sound good. If nothing else, I have a 10w musical instrument amp from Monoprice on its way. I was going to use it for amplifying my harmonica, but I can use it for this without difficulty. It's a battery-powered model, so I'll be able to take it into the field as well.

I have some antenna kits on the way, including the multi-band antenna on the QRPGuys site and the parts for a "flimsy" W3EDP antenna on the way (I didn't have a 4:1 unun on hand; that's on order as well), and will report my results with them. I'm starting with a Sotabeams 40m end-fed with their "Pico Tuner", which I will be building today.

Gwen NG3P

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
elmar­dl2qa@...

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

Rick Price
 

Don,
I too am hearing the audio in the speaker during transmission.  I noticed it first when transmitting digital using FT8, in fact at times the transmitter went into ocillations with the feedback. I could not figure out what had changed while using FT8. I had installed the on off switch per your original instructions and found with it off the ocillations and the feedback went away. I usually have the agc turned off and only have it on when listening to a net with some very strong signals. After reading several posts on this issue I went back and tried it again and sure enough when transmitting voice or FT8 I hear it in my speaker audio until I turn AGC off.
I have the AGC board mounted on the back of the RF Gain pot and RG-174 to and from the header on the uBitx board. All volume control and mic jacks are RG-174 back to the main board. Again not a problem for me as I keep the AGC off most of the time, but interesting.   I have noticed earlier when having mike problems that when transmitting rf does show on the scope looking at the 5 volt supply from the Radino. I was using the 5 volt supply to power a mike amp. I haven't looked at the 12Vsupply.  Your AGC on off suggestion from an earlier posted set of installation instructions follows.
 
"If you want to add a switch to shut off the AGC, do so at the audio input.  I would sugest a singlepole double-throw switch with the connection to C1 at the center, ground to one side, and the other to the hot side of the volume control.  If power is removed from this circuit Q2 will not be biased "on" and will reduce signal levels significantly."
 
Rick KN4AIE

Re: Bitx 40arduino

Elmar Völler <dl2qa@...>
 

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 familiär 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: BITX20@groups.io
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 >elmar­dl2qa@...

Re: Known issues on uBITX r4 #ubitx

Bill Cromwell
 

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

Re: Easy, Inexpensive Cooling Fan, Excelway Case

Vince Loschiavo
 

Arvo,
Nice catch...I'm going to move the fan supply to same spot.
Thanks
Vince
N2AIE

Re: A Breadboard Technique for the uBITX

Bo Barry <wn4ghv@...>
 

Nice! Sure beats the days of drilling and filing of steel cabinets. Bo W4GHV since '54

Re: Known issues on uBITX r4 #ubitx

R. E. Klaus
 

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

Don, ND6T
 

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: Easy, Inexpensive Cooling Fan, Excelway Case

Vince Loschiavo
 

Re: Known issues on uBITX r4 #ubitx

Arv Evans
 

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


2018/06/29 13:35、Mvs Sarma <mvssarma@...>のメール:

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@...> 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



2018/06/29 12:38、Jack Purdum via Groups.Io <jjpurdum@...>のメール:

Most of the mods that have been made are summarized at: ubitx.net

Jack, W8TEE

On Thursday, June 28, 2018, 11:31:43 PM EDT, <hirosmb@...> wrote:


Hi, all.

I’m really new to uBITX and planning to place my order to hfsignals.com very soon.

Then please share its known hardware issues of uBITX r4 that I need to modify or solder.

Thanks in advance and hope to QSO with my uBITX soon.

// hiro, JJ1FXF


Re: 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 familiär 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: BITX20@groups.io 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 >elmar­dl2qa@...

Re: Known issues on uBITX r4 #ubitx

Arv Evans
 

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: RFI from uBitx TX after AGC and other mods installed

Rick Price
 

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



From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Don, ND6T via Groups.Io
Sent: Friday, June 29, 2018 11:30 AM
To: BITX20@groups.io
Subject: Re: [BITX20] 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: Bitx 40arduino

Elmar Völler <dl2qa@...>
 

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: BITX20@groups.io
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 familiär 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: BITX20@groups.io 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 >elmar­dl2qa@...

Re: Compiler warnings

Tom, wb6b
 

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

Re: Known issues on uBITX r4 #ubitx

hirosmb JAZZ <hirosmb@...>
 

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@...>のメール:

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


Re: Easy, Inexpensive Cooling Fan, Excelway Case

Jack, W8TEE
 

Nice...any more pictures??

Jack, W8TEE

On Friday, June 29, 2018, 11:32:58 AM EDT, Vince Loschiavo <vince320@...> wrote: