Date   
Re: uBITX + Teensy audio interface - ground loops (?), RX/TX audio bleed? #teensy #ubitx

Rob French (KC4UPR)
 

Evan, thanks for the input.

Regarding the feedback into the headphones... that totally makes sense.  I will try the dummy load test.  My breadboard is a bit of a spider's nest, and even has a couple of wires floating in space at the moment (the mic input to the Teensy, which I don't actually have hooked up yet, since I'm using USB audio for my transmit audio).  I also noticed that moving my hand in various places around the system seems to impact the sound of the feedback audio--muffle it, change the tone a little, change the amount of hum, etc. 

I'm using a laptop computer.

I don't understand how I'd be missing a connection to ground, however.  USB carries a connection to ground, so the Teensy (and the Teensy side of the audio transformers) should be referenced to the same ground as the computer, via the USB cable, right?

I wonder if I should try switching USB ports?

Re: uBITX + Teensy audio interface - ground loops (?), RX/TX audio bleed? #teensy #ubitx

Evan Hand
 

I believe that there is a grounding issue, though not a "loop".  When you have only the Teensy connected, there is not a reference to ground on the computer, so you get the hum.  This would be irrespective of the transformers.  When you connect the Raduino, you get the ground from the uBITX.

I would be curious if you are using a laptop or a desktop computer?

On the other issue, feedback into the uBITX headphones, I have had that issue, along with distortion in transmitted audio.  For me it was traced to RF getting back into the uBITX along the coax shield and the mic input.  I solved that with snap on ferrites at the entrance of the coax to the shack.  This is a trait of the uBITX as the audio is not completely muted to allow for the side tone in CW mode, at least that is what I surmized, as grounding that input removed the issue as well.  Since you are bread boarding, the total audio system could be an antenna feeding back into the uBITX.  Ferrites on the audio lines might help if you determine that it is RF causing the issue.  Try transmitting into a good dummy load that would have minimal radiated RF.  If the tx distortion goes away, then RF is the issue.

Above are just some ideas to try.

73
Evan
AC9TU

Re: uBITX + Teensy audio interface - ground loops (?), RX/TX audio bleed? #teensy #ubitx

Rob French (KC4UPR)
 

An additional note, I am powering the Teensy currently via USB.  My intent eventually is to power it off 5V internal to the uBITX.  So I don't know if that will help, or hurt.  (I'd like to end up with a single USB port, with the Teensy being both a USB Audio and a USB Serial device, and passing through CAT to the Raduino.)

uBITX + Teensy audio interface - ground loops (?), RX/TX audio bleed? #teensy #ubitx

Rob French (KC4UPR)
 

Alright!

So, I've put together a rudimentary audio interface and DSP filter using a Teensy 3.2 and the Teensy audio board.  Currently, it's on a breadboard.  I have three 1:1 audio transformers to interface the Teensy to the uBITX:

RX audio: Vol-H => 1:1 => Teensy audio in (L) => (DSP processing) => Teensy audio out (L) => 1:1 => high-side of volume pot
TX audio: Mic => preamp => Teensy audio in (R) => (DSP processing) => Teensy audio out (R) => 1:1 => 10uF blocking cap => uBITX mic in

(I actually haven't hooked up the mic/preamp yet, but I'm actually using USB audio.)

So that's the other piece--I've put together a sketch for the Teensy that allows switching between audio inputs/outputs, enabling/disabling filters, etc.  So I've been doing FT8, and the Teensy sketch actually takes USB audio in, and sends that to the Teensy audio out (R) for transmit.  Likewise, I take the audio in (L) and send that to the computer via the Teensy USB audio.

So, it IS working... I've just made a few FT8 contacts with my terrible attic antenna, and they seem like about what I've been getting when I was using a simple USB audio adaptor.  I will eventually need to do some kind of assessment of the transmitted audio, make sure that's up to snuff (especially make sure I'm not transmitting noise/hum).

Which brings me to my issues:

(1) When I just have the Teensy plugged into the computer via USB, I get terrible hum.  Nearly unusable.  But, when I also plug in the Raduino to the computer via USB for CAT control, the hum goes away!  So I'm guessing this is some kind of ground loop caused by the USB cables and the computer??? Why would it go away when I plug in the second USB device?  And why aren't my transformers "protecting" me from the hum?  As far as I can tell, the ground between Teensy and the computer is isolated from the input and output audio grounds.  (That said, I will note that for ease of use on my breadboard, the uBITX side of the transformers are all tied together, both the input transformers and the output... maybe that's an issue?)

(2) Whenever I transmit, I also get the transmitted audio in my uBITX headphones.  So, I'm FAIRLY certain I've got my sketch configured to use the left channel for all RX audio, and the right channel for all TX audio.  Likewise, I tell WSJTX to do input on the right channel, and output on the left channel.  This transmitted audio also has pretty significant hum on it.  I'm wondering if it's coupling between the left and right channel output transformers?  (They're about an inch apart.)  It is pretty loud... I wouldn't expect that if it were coupled, but I'm really not smart on this.  

Thanks,
Rob KC4UPR

(FYI, I've attached the audio layout of my sketch.  As noted, L channel is always intended to be RX, and R channel is always intended to be TX.  I use the rxAudioMixer and txAudioMixer as switches to select which input to pass through.  I probably need to eliminate some paths that I put in when I was testing the sketch... e.g. there will never be RX audio input coming from the PC, nor should there ever be TX audio output going to the PC (unless I want to do it for monitoring).  The txAudioSwitch and rxAudioSwitch are used to determine if I send unfiltered audio to the PC, or filter it first.)

Re: V5 firmware calibration

vk6qa
 

Hi Maurice

Sounds like you up and running, do you have a ant for 80M? where is your QTH?

 

73’s

Keith

VK6QA

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Maurice Bersan via Groups.Io
Sent: Friday, 4 October 2019 5:41 AM
To: BITX20@groups.io
Subject: Re: [BITX20] V5 firmware calibration

 

Thanks Evan, couldn't be much clearer than that

Cheers

Maurice

 




Avast logo

This email has been checked for viruses by Avast antivirus software.
www.avast.com


Re: V5 firmware calibration

Maurice Bersan
 

Thanks Evan, couldn't be much clearer than that
Cheers
Maurice

Re: V5 firmware calibration

Evan Hand
 

It has been a while since I did the calibration of my v5, so please check and record changes as they are made.

1 - You will need a dummy load for the calibration of the stock v5 as it transmits a 10MHz signal in the calibration process.
2 - You need a calibrated receiving device capable of receiving the 10 MHz signal.  This can be another receiver that you know to be accurate, or a frequency counter.  I used my Icom IC-7300 to calibrate mine.  It also worked with an inexpensive frequency counter connected to a short piece of wire.
3 - The process is then to put the uBITX in the calibration mode using the encoder, and adjusting until you have a zero beat on the receiver, or the correct frequency on the frequency counter.
4 - Press the encoder when the frequency is correct, and then power cycle the uBITX to use the new value.
5 - I used a free PC audio spectrum analyzer software with a mic to adjust the BFO.  Tune to a clear, static only frequency on the uBITX, and then adjust the BFO until the spectrum is sentered between 500 and 2500 Hz.

I would suggest waiting for one of the experts in this group for more, or better, explanation of the process.

73
Evan
AC9TU

V5 firmware calibration

Maurice Bersan
 

I got my UBITX V5 up and running today but I find the displayed dial frequency is off. Can someone help out with a step by step calibration setting guide for the V5?I can only find a guide for the earlier version firmware which appears to be different. By the way WWV is a no show around here so I can't use it for calibration.
Thankful for any help.
Cheers

Re: Adjustments using uBITx Memory Manager

Vic WA4THR
 

I believe the default is still that the KD8CEC software shifts the transmit signal on CW, rather than the receive, so that is what you are seeing. A provision the the Memory manager program is there to correct that, though. Just select "Shift Display Frequency on CWL, CWU Mode" as shown below. Now your transmit signal will be on the display frequency as it should be, but your receive will be offset so you can hear replies on the same frequency.
=Vic=

Adjustments using uBITx Memory Manager

hickmodawg@...
 

Hello from CA!

I’m running the CEC Ver. 1.200 Firmware in my uBITx Ver. 5 radio.

I successfully adjusted the Master Calibration using uBITx Memory Manager until  I ‘zero-beat’ WWV at 10 MHz.

Thanks Ian for the great program!

 

But, in 40 meters, in CWU mode, when my LCD says 7.050 MHz, my transmitted signal peaks at 7.050.69.  Should I adjust this?

In CWU mode, when I zero-beat a received 7050 MHz signal my LCD shows 7.050 (of course, since it's zero-beat, I cant hear it)

 

In CWL, when my LCD says 7050, my transmitted signal peaks at 7.049.08

In CWL, when I zero-beat a received 7050 signal, my LCD says 7.050.19

 

I have attached a screen-shot of the settings on my radio that I have been adjusting using uBITx Memory Manager.

Can anyone give me advice on which settings I should change to operate properly and how to do it?  I think I'm getting closer but in CWU, I transmit on 705, I'm a little off and then I to adjust RIT way down in order to hear them come back to me. 
Thanks for the help so far.  I’m learning and making progress!

 

73,

Martin, AJ6CL

Re: ubitx with Icom SM-6 desk mic

Marsh Parker
 

No, no changes are required.  I am using an SM-8. Hook Icom pin 1 to MIC violet, pin 5 to PTT orange (Raduino) and pins 6,7 to GND. Leave internal MIC controls alone.
Marsh NC7V

Re: #bitx40 - My Bitx40 tunes from 7400 to 7500 approx. #bitx40

Allard PE1NWL
 

Hi Alejandro,

Which firmware version do you have on your Raduino?
(the version number which is shown on the LCD at power on)

73 Allard PE1NWL

On Wed, October 2, 2019 16:42, lu1dla@... wrote:
Hi,
I'm LU1DLA, Alejandro from Argentina.
Yesterday I finished the assembly of Bitx40 with Rarduino. I'm very happy.
I have a problem. My Bitx40 tunes from 7400 to 7500 approx...

*Can someone tell me where the problem may be?*

*Can I set a potentiometer of a range other than 10K?

Thanks! 73*

-=-=-=-=-=-=-=-=-=-=-=-

Re: #bitx40 - My Bitx40 tunes from 7400 to 7500 approx. #bitx40

MVS Sarma
 

Pleasectry tuning to ww  station' original freq  abd try to adjust bfo to get the signal.

This rougly helps.

On Wed, 2 Oct 2019, 8:19 pm Mvs Sarma, <mvssarma@...> wrote:
The vfo offset should be antenna frequency- crystal ladder frequency.

The bfo should be crystal ladder center freq +2.8  or 3khz
 Please check. 



On Wed, 2 Oct 2019, 8:12 pm , <lu1dla@...> wrote:
Hi,
I'm LU1DLA, Alejandro from Argentina.
Yesterday I finished the assembly of Bitx40 with Rarduino. I'm very happy.
I have a problem. My Bitx40 tunes from 7400 to 7500 approx...
 
Can someone tell me where the problem may be?
 
Can I set a potentiometer of a range other than 10K?

Thanks! 73

Re: #bitx40 - My Bitx40 tunes from 7400 to 7500 approx. #bitx40

MVS Sarma
 

The vfo offset should be antenna frequency- crystal ladder frequency.

The bfo should be crystal ladder center freq +2.8  or 3khz
 Please check. 



On Wed, 2 Oct 2019, 8:12 pm , <lu1dla@...> wrote:
Hi,
I'm LU1DLA, Alejandro from Argentina.
Yesterday I finished the assembly of Bitx40 with Rarduino. I'm very happy.
I have a problem. My Bitx40 tunes from 7400 to 7500 approx...
 
Can someone tell me where the problem may be?
 
Can I set a potentiometer of a range other than 10K?

Thanks! 73

#bitx40 - My Bitx40 tunes from 7400 to 7500 approx. #bitx40

lu1dla@...
 

Hi,
I'm LU1DLA, Alejandro from Argentina.
Yesterday I finished the assembly of Bitx40 with Rarduino. I'm very happy.
I have a problem. My Bitx40 tunes from 7400 to 7500 approx...
 
Can someone tell me where the problem may be?
 
Can I set a potentiometer of a range other than 10K?

Thanks! 73

Re: V5 id

Maurice Bersan
 

Ok will do. Thanks Keith. Actually just went through dwellingup with the motorcycle group this morning. 

On 2 Oct 2019 7:35 a.m., vk6qa <vk6qa@...> wrote:

Hi Maurice

It would more than likely be a V5 if you have just purchased it from India.

You have just purchased a great little radio and I hope you have as much fun as I have with both my V4 and V5 radio’s.

If you would like , when you get it up and running  drop me an email and we can organize a sked on 80M to check it out.

 I often come up on 3600kHz around 0710 hrs but if I am not on air I am sure that the other boys on the net would welcome you .

vk6qa@...

Dwellingup

 

73’s

Keith

 

 

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Vk6hly via Groups.Io
Sent: Tuesday, 1 October 2019 6:00 PM
To: BITX20@groups.io
Subject: [BITX20] V5 id

 

Hi and thanks for the ad to the group.
I just received my ubitx only after 5 days and that includes the weekend. And I live remote southwest Western Australia...no complaint there.
One question tho, how can I tell if my board is V5? I can't find any version I'd on it anywhere.....or will it be v5 because it's new delivery?
Cheers
Maurice


Virus-free. www.avast.com

Re: WTB 680nH Inductors #parts

Dale Hardin
 

Ha! After two tries I finally got uH instead of uF.  I think it has to do with old age.  Dale

On Tue, Oct 1, 2019 at 5:23 PM Dale Hardin via Groups.Io <joe.dale.hardin=gmail.com@groups.io> wrote:
Hello all,
Anyone have any of the inductors like Raj ordered from ebay they would like to sell? I really don't need 300 at a time from the ebay seller.  BTW, as of this date, the ebay seller has sold 21,300 of these parts.  Got 10 to spare?  Please contact me privately.
Dale
--
Dale Hardin, KS4NS
Elberta, AL



--
Dale Hardin
24750 State St. Unit 487
Elberta, AL 36530
251-597-9256

--
Dale Hardin, KS4NS
Elberta, AL

Re: V5 id

vk6qa
 

Hi Maurice

It would more than likely be a V5 if you have just purchased it from India.

You have just purchased a great little radio and I hope you have as much fun as I have with both my V4 and V5 radio’s.

If you would like , when you get it up and running  drop me an email and we can organize a sked on 80M to check it out.

 I often come up on 3600kHz around 0710 hrs but if I am not on air I am sure that the other boys on the net would welcome you .

vk6qa@...

Dwellingup

 

73’s

Keith

 

 

 

 

From: BITX20@groups.io [mailto:BITX20@groups.io] On Behalf Of Vk6hly via Groups.Io
Sent: Tuesday, 1 October 2019 6:00 PM
To: BITX20@groups.io
Subject: [BITX20] V5 id

 

Hi and thanks for the ad to the group.
I just received my ubitx only after 5 days and that includes the weekend. And I live remote southwest Western Australia...no complaint there.
One question tho, how can I tell if my board is V5? I can't find any version I'd on it anywhere.....or will it be v5 because it's new delivery?
Cheers
Maurice


Virus-free. www.avast.com

WTB 680nH Inductors #parts

Dale Hardin
 

Hello all,
Anyone have any of the inductors like Raj ordered from ebay they would like to sell? I really don't need 300 at a time from the ebay seller.  BTW, as of this date, the ebay seller has sold 21,300 of these parts.  Got 10 to spare?  Please contact me privately.
Dale
--
Dale Hardin, KS4NS
Elberta, AL

Looknig for ND6T bitx click-fix PCB

John Scherer
 

Anyone have a spair ND6T design, click-fix PCB they would part with?  Let me know

--
John - N0CTL