Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
Mike,
Could you do a voltage test around the audio amp and report ? Volume =
0.
Q71/72/73 CBE
Raj
At 14/06/2018, you wrote:
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I have completed the uBitx and
calibrated both frequency and BFO. The sensitivity appears OK. However
audio has a strange crispy / semi-distorted sound to it.
I read the post from W3JDR
? about biasing Q70 more strongly, however that only reduced the
gain somewhat but didnt seem to help the crispy / semi distorted sound.
I have tried several headsets and a speaker. Same issue.
Anyone have any hints to what may be done to achieve better audio and get
rid of that distortion effect?
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So if I get some light from a bulb it is putting out RF but still not getting contacts.? What else could the problem be?? Do I need to buy a new board?
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Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
Q70 appears to be the bottleneck with its extremely high gain try reducing R51 to 1k5 and R50 100k-150k. See? what works best.
Rahul VU3WJM
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Re: Ubitx and Sherwood rx tests
Which variation?? Everyone builds theirs differently.
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Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
Some more testing results:
I attached an external high quality Hi-Fi type NAD linear audio amplifier via an electrolytic capacitor (for DC blocking). On that NAD amp. the audio is no longer distorted. I have a feeling that the final amp of uBitx V4 has a flaw in it.....
As far as I know, is the most common way of biasing a push pull amplifier to avoid crossover distortion:
To me it looks like there is a problem in the final amp ...
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Gilles,
It is because you have soldered a 4.7K resistor across two pins of the Raduino wires blue and green.
Suggest you do it across the back of the Raduino board!
Please see the wiring diagram/instructions.
Raj
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At 16/06/2018, you wrote: I just finished my uBitx. At the start, the display lights up with "CW 7.150.00" and the speaker only transmits Beep Beep Bip !! Ancune possible action with the encoder (Push button or rotation).
Someone has an idea because I have not found anything on the forum that can allow me to move forward. The audio level can be adjusted with the potentiometer.
Thanks for your help
Gilles - F1BFU
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I just finished my uBitx. At the start, the display lights up with "CW 7.150.00" and the speaker only transmits Beep Beep Bip !! Ancune possible action with the encoder (Push button or rotation).
Someone has an idea because I have not found anything on the forum that can allow me to move forward. The audio level can be adjusted with the potentiometer.
Thanks for your help
Gilles - F1BFU
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Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
I have used an oscilloscope and a signal generator to more tests regarding the audio distortion. I have followed the signal thru the audio chain after the last mixer when appying a known clean and weak signal on the input so no front end or mixer overload ocurs. Everything looks clean on the oscilloscope until the output of final two transistors. The signal on the output of Q71 looks fine. On the output of Q72/ Q73 the signal is distorted around the zero crossing. /g/BITX20/photo/59179/3?p=Name,,,20,1,0,0I wonder, is the biasing actually correctly done? Should it have been like this instead? /g/BITX20/photo/59179/0?p=Name,,,20,1,0,0
Here is the distorted signal out of the amp (blue trace, note different Y axis scale). The red trace is the signal earlier in the audio chain. /g/BITX20/photo/59179/1?p=Name,,,20,1,0,0Pls post your comments.
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Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
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Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
Disregard S57DX and listen later in the recording. Pls listen to the CW signal later in the recording. This is a weak signal. Even the very weak signals barely detectable sounds distorted.
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Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
i was thinking the same thing.? Should try other signals, NOT during a contest.
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I am glad you got it in the end. Nice perseverance. Lucky for me it was the encoder that was at issue in my uBitX. Now, I have a spare Raduino from Mike Hagen's shop that when I find the time I may turn into a signal generator for the fiddle shop.? I also found a Telefunken am/fm-stereo/sw/turntable model for $40?at a thrift store. The console is cosmetically an A minus and electronically a B plus. The only thing that seems to be an issue are the volume and tone controls that are, in a sense, stuck at a constant output. If it's as simple as replacing two potentiometer's and perhaps recapping the receiver it was one heck of a fantastic deal. Even as is, its a marvel.
Update on the Saga of the lifeless encoder...
I have been chasing encoder issues for a couple of weeks now. We have tried everything, almost. I even ordered the good Bourn encoders in two flavors, they got here and no help. The CEC software would not respond to the encoder to change the frequence for love or money. It would allow menu selection and sub menu selection but not frequency.
To make a long story short, I found the problem and have a fix for it... get a NEW NANO.
After breadbording a UNO and LCD and KY-040, loaded the software and it worked as it should. awesome. So, I laid the two NANOs that I had been using to find the issue aside and stole one from another project. It worked flawlessly... first time, every time..
Moral of the story, when you think you have done everything, there is always something else to do.
Moral #2, keep plenty of NANOs around... lol.
PTL for that solution. I can only give Him credit.
Now I can resume getting my uBitx on the air..
Thanks to everyone for their assistance, advice and encouragement.
--
72 and God bless
KD4EPG
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Re: Can't get my uBitX to transmit CW on the Dial frequency
I was a bit harsh in that last post.
Anyways, I'll just assume this exchange is resolved.
Though there has been more than a little confusion around here
regarding the display frequency during CW operations.
Worth more discussion.
Jerry
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On Fri, Jun 15, 2018 at 07:43 pm, Tim Gorman wrote:
Jerry,
Not always totally clear what you are talking about, but my best
guess was that you thought moving the BFO was all that was needed to
receive CW instead of SSB.
Nope, the original poster was talking about CWL and CWU, not SSB. My
response was to his original comment.
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Exciting times in the uBITx world
We are at an exciting time in the uBITx world ...
Version 4 uBITx main board in production
The Version 4 board of the uBITx
() is now in full
production.? This fixes several problems with the v3 board
including removing the audio pop? going between RX and TX (and
vice-versa), providing more even power out on the higher bands,
and replacement of the troublesome TDA2822 chip with a 2N3904
transistor audio line-up to keep things simple.
KD8CEC about to to release firmware to support Nextion screens
Ian Lee KD8CEC will shortly launch a new version of CEC firmware
that will interface with Nextion displays.? There is an article
() on
with a link to a Youtube video from Ian that is
bound to get you pretty excited about his forthcoming release.? I
am suggesting you should consider buying a Nextion touchscreen
display now before the other 6000 uBITx owners decide they all
NEED one.?? They mayu sell out pretty quick!
Ian's Nextion feature does not require a processor upgrade.? An
otherwise unmodified board (although an s-meter would be
desirable) only requires a 2.4" or 2.8" Nextion display and a
microSD card to get it going.? You simply download a software
upgrade to the Raduino and one for the Nextion (for saving to a
microSD card) and you will be away.?? There are easy connections
to the Raduino too, with the connector supplied with the Nextion.
BITeensio board and software now available
We also have the? announcement of the BITeensio board
availability from W0EB ().?
This uses a Teensy 3.5 or 3.6.? Software to support the new
processor is available to download from the W0EB website.
JackAl Board imminent
Finally, we are also eagerly awaiting the launch of the JackAl
board () from W8TEE and
team. This also uses a touchscreen display along with a Teensy 3.6
processor.? Digital audio processing and other new features will
be welcomed by constructors.
Yes indeed, an exciting time.?? Check out all of the latest
developments at ubitx.net
73 Mike ZL1AXG
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Re: Can't get my uBitX to transmit CW on the Dial frequency
Jerry, Not always totally clear what you are talking about, but my best
guess was that you thought moving the BFO was all that was needed to
receive CW instead of SSB. Nope, the original poster was talking about CWL and CWU, not SSB. My response was to his original comment. tim ab0wr
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I've been plugging away steadily at my uBitX, as I've had the time and energy. I bought the case from Banggood and the 3d printed end plates. I liked the inexpensive case, but after it was already on its way I felt a little twinge about the shielding. I priced copper tape, but decided against it, and got what is proving to be a very nice alternative.
I bought a spray can of MX Chemicals' "Super Shield" conductive nickel coating. I put several very thin coats on the insides of the case and the end plates, after masking the places I didn't want the coating with painters' tape. Any loose excess was easily brushed and knocked off, and the rest seems perfectly content to stay attached to the plastic (the can said it was compatible with ABS, and that's what the case is made of). If I have doubts, I can get a can of clear-coat and seal it, but I don't think it's necessary.
Now that I have the case, I need to go through the few steps I'd already done and shorten some of the connector wires. I found that I'd left them too long, and want to cut down on the noise. I also want to go back over the headphone jack and wire it so I can put a speaker in the lid of the case that'll get deactivated when a headphone is plugged in. I don't plan on using this rig with my Bencher paddle, so I'll leave it wired for a straight key and use the nice one I got from cwmorse.us. (I used to have an antique Navy straight key, but I have no idea where it's hiding.) In the meantime, I'm brushing up on my code -- I haven't used it very much.
I've got several QRP rigs of different vintages, from the SW Labs 20-meter CW rig to the W8TEE/K2ZIA rig from QST, and an SDR I backed that works quite well, HobbyPCB's RS-HFIQ rig, that I primarily use for digital modes. I'd taken a breather from amateur radio for a while, and lately I've wandered back to it, glad to do something constructive with my time rather than playing video games or watching daytime TV (shudder). I became disabled in 2006, and need something to keep me active, or things start getting depressing indeed.
I'm glad to have projects such as this one to work on, and I'm looking forward to getting it on the air!
Gwen, NG3P
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Re: Can't get my uBitX to transmit CW on the Dial frequency
Hmmm.
OK, if we are now talking about moving the BFO to the other side of the 12mhz
crystal filter when switching between lower and upper sindband operation,
we can just agree and stop the discussion.
I was responding to this from post 52029:
> If you are working CW at 7030 then why should you have to set the
> receive frequency to 7.029.300? That just means you need to know
> whether you are in CWL or CWU and do math in your head to know what
> frequency you are actually listening to!
>
> Why not just shift the BFO so the receive frequency can remain showing
> 7030 and you still get your 700hz tone?
Not always totally clear what you are talking about, but my best guess was that
you thought moving the BFO was all that was needed to receive CW instead of SSB.
That could indeed be done in such a way that the CW carrier would create a 700 hz
audio tone, and the LCD display would correctly show the frequency of that carrier.
But I was pointing out that the carrier would be blocked by the 12mhz crystal filter,
and thus just moving the BFO is not optimal.? The rig should do the 700 hz addition
to determine the carrier frequency to be displayed in the LCD, not my head.
I've got other uses for that.
Jerry, KE7ER
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On Fri, Jun 15, 2018 at 03:12 pm, Tim Gorman wrote:
Jerry,
On Fri, 15 Jun 2018 11:54:42 -0700
"Jerry Gaffke via Groups.Io" <jgaffke@...> wrote:
Tim,
I'm not convinced. you can't just move the BFO to receive CW.
That's not what is being discussed.
Assume you are receiving an upper sideband phone signal at your 7030
mhz. The crystal filter is only allowing through that upper sideband
energy between roughly 7030.500 khz and 7032.500 khz, any residual
carrier from the transmitter is further suppressed by our 12mhz
crystal filter.
We are talking about changing from CWL to CWU, not from SSB to CW.
Now, assume that remote transmitter switches to a CW transmission at
7030 khz. We are now only interested in the carrier at 7030 khz, but
the crystal filter is not allowing that carrier through.? Does not
matter where we place the bfo, there is simply no signal to hear.
(Assuming our filter is perfect).
The remote transmitter is already sending CW. There is no switching
involved.
The solution is to special case the reception of a CW signal.
When receiving in upper sideband mode, we should have the receiver
tuned for a frequency 700 hz lower than that displayed in the LCD.
And when receiving in upper sideband mode, we should have the
receiver tuned for a frequency 700 hz higher than that displayed in
the LCD. The BFO can stay where it was for SSB phone reception.
We aren't talking about using USB and LSB to receive CW, we are talking
about using the CW mode to receive CW. Since it is a carrier we can
receive either on the upper side of the carrier or on the lower side of
the carrier.
But there is no reason to have to tune to a different indicated
frequency for receive. Just adjust your vfo or your bfo and leave the
indicated receive frequency the same as the transmit frequency. I used
to ue the adjustable BFO in my old RME-4350 to move from one side of
the CW signal to the other to avoid interference.
tim ab0wr
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Re: New rig, current to finals does not go up when transmitting (was Need help)
It is always wise to get a piece of equipment working before any mods.? Same as working with a commercial rig that you want to convert to the ham bands.? get it working correctly where it is suppose to be? and then do the mods. ?de ku4pt
On Fri, Jun 15, 2018 at 6:10 PM, <hotrod541@...> wrote: Thanks to both of you for your replys. I checked the radio today, when you key on cw the amp reading is .189A to 2.59 A on key down.? I get a little over 10 watts out.? It looks like it may be the mike so I pulled a old mike from the junk box and I stripped it down and will install the element that came with the radio. I will see if that corrects the problem. I am trying to get the radio to work correctly before I try any mods.? Thanks again.
Buddy3223
KJ4ZSI
_._,_.
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Re: uBitx has a bit too crispy / semi-distorted audio even on low signal levels
#ubitx
#ubitx-help
Are you comparing? the uBITX signal quality with that from another receiver?
I could be wrong but S57DX sounds like a typical highly processed signal.
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Update on the Saga of the lifeless encoder...
I have been chasing encoder issues for a couple of weeks now. We have tried everything, almost. I even ordered the good Bourn encoders in two flavors, they got here and no help. The CEC software would not respond to the encoder to change the frequence for love or money. It would allow menu selection and sub menu selection but not frequency.
To make a long story short, I found the problem and have a fix for it... get a NEW NANO.
After breadbording a UNO and LCD and KY-040, loaded the software and it worked as it should. awesome. So, I laid the two NANOs that I had been using to find the issue aside and stole one from another project. It worked flawlessly... first time, every time..
Moral of the story, when you think you have done everything, there is always something else to do.
Moral #2, keep plenty of NANOs around... lol.
PTL for that solution. I can only give Him credit.
Now I can resume getting my uBitx on the air..
Thanks to everyone for their assistance, advice and encouragement.
--
72 and God bless
KD4EPG
|
Raj vu2zap
Gwen Patton