Joel,
I would like to suggest that you read the Drok converter discussion on the keithsdr forum.
Just a small note. You put it in the v2 box and at the same time blocked the possibility of ventilation inside the box.
I just want to say that you have not placed the converter in the best place.
Of course, if you also cool the current large heatsink with an external fan, it also creates a suction from the box.
These are just the insights of an outside observer. Please don't take this as a big problem.
--
Gyula HA3HZ

Hello ...

Hours and Hours went into this so far, mostly due to my IGNORANCE and stuff I have forgotten or never learned about either digital signal processing.....or the C language (about which I know just enough to be dangerous)

I now have a working transmitter system where I can independently set, using the same command-line techniques one uses to set the "sidetone" etc,?

static int basscutfreq? ? at any 50-hz interval from 100 to 1000 (default 100) -- frequencies below this setting in the transmitted voice will be cut by 20dB
static int treblefreq? ? at any 50Hz interval from 1000 to 4000 (default 4000);? frequencies above this will be amplified by "trebleboost"
static int trebleboost? voltage multipler coefficient from 1 (0dB) to 20 (huge dB)? ? 2 is like 6dB
static int noise? ? ? ? ? ?unusual scale, from 0 to 3000.? ?Power of noise is proportional to the square of this number.? ? 0 is none; 3000 is overwhelming to normal speech into the microphone.? ?The noise signature didn't turn out as nice as I would have liked; in the frequency domain it is flat with some linear phase shifts (rand() did not work out)? and in the time domain it looks like an impulse function that decays rapidly as an exponentially decaying sinewave.
The noise sounds like ignition or power line noise to a fair degree.....best thatt I could do.? ?But that is plenty good enough to test intelligibility in the face of of noise!!

I went from creating the noise in the frequency domain to doing it in the time domain -- where I got GREAT RANDOM NOISE....but it was then subjected to the same treble boost and would wreck the experimental goals....so I had to go back to frequency domain.

Experimental Method
The students will have to work on the experimental procedure now that I have the software.? ?
Basically, they will attempt to prove that in the setting of significant noise, accuracy of copy is greater with more boost to the high end, and cut to the low end.? ?Exactly how they do that.....will depend on how cagey they are!? ?That is science!!

The sBitx platform provided a fantastic resource for creating the signals.? ?I used my V2 to create the transmissions, added about 50-60 dB attenuation in line,, kept the drive to about 11-14%, and used a DE as the receiver.? ? There are periodic problems where the codec in the DE goes south, but I got a LOT done anyway.

Available for Others
When we get this a little farther along, I can package up all the source code in a zip and make available.? ?There may not be other teachers as wacky as me, and with students as willing as my PreCalc students, but we are going to make a try at it!

And in the process I learned a lot about the user interface.....which will help me with some other things I want to get done with this radio.....
Gordon KX4Z

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Hi Dan;

Change the mode to CW, reduce the SIDETONE level, then go back to FT8.

73; Steve, N3SB

Gents,

???? While playing around on FT8 with the DE V3. When transmitting I hear an extremely loud tone. Is everything ok? How do I stop it?

Dan KD3CEU

?

I originally sent this to Rafael, but he suggested I re-post to the group, as others may have the same question.

I downloaded the .IMG file you mentioned onto the computer I am presently using.? This one runs Windows.? I will be transferring it to my other computer, which runs Linux Mint, and unzipping it. When I have done that, I will have some further questions.? I would like to see a 128 GB or larger card in the sBIT at the end of it all, along with some other useful software. The sBIT presently has a 32 GB card in it, and a 8 GB Pi.? It was acquired second hand from an amateur who had to give up the hobby for medical reasons.? I haven't had it on the air yet, and won't be until I can operate portable under reasonable weather conditions. I do have the official Pi keyboard and mouse and will be using them.? I won't be using the on-screen keyboard, and not sure if I will use the touch screen.

Gerry Sherman

Sent by the Windows 11 Thunderbird

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Hi Barry, no I haven't tried that yet, I only just saw your post regarding the .1 cap today, that would be a good fix alright and I might try that on my DE. The "Beefy" regulator that I used has the exact same specifications as the one that comes in the radio, it's 12V to 5V at 3 amps max but the CONVERSION EFFICIENCY is over 95% which makes it run pretty cool and the shielding and filtering makes it RF quiet. My V3 used to get pretty warm over on the left side of the radio because of the Mini 360 regulator, now it runs stone cold on that side. All in all, I think it's a improvement.

Joel
N6ALT

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I have been fighting bad band noise on all of my sBitx's from the DE to my V2 and V3, finally decided and set out to find another solution. I researched the most quite Buck converter that the RC and Drone users are using and they mostly agree that this is the best one,? I tried it in my V3 and found it works great with no rf noise that I can see anywhere and the general noise floor is much lower than before and the best part, it runs cool to the touch after 5 hours. I'm now going to install one in my DE now. YMMV.

Joel
N6ALT

Bob, I do have a noise floor on 40 meters, but by other radios are not affected the same as the BitX40. I would like to take the radio out of the shack and operate somewhere portable. unfortunately nasty weather the last few days has precluded that idea.
Randy
K5UTM

Steve
I'm using a Talent Cell 12v battery pack. the battery does provide an additional 5v USB connection.
Randy
K5UTM

Evan,?
Yes my Bixx40 dies have the Raduino board. I did watch closely during boot up and I'm getting a uncalibrated VFO error message. in checking the tuning for example I'm finding a station that should be at 185.0 khz needs to be tuned to 185.3 khz. I checked the assembly manual and recalibrating the vfo is not real clear to me. Hopefully? I I can figure it out and recalibrate the Radiuno, and maybe the noise problem will disappear.?

In a pinch, you can just download a free audio spectrum analyzer onto your phone or tablet. No need for connections, just “audio couple” between speaker on uBitx and microphone on phone. As said by Evan, get the “hump” between 2-300hz and (on mine, due to filter width) 3000hz.

I would pay closer attention to getting the BFO tuned such that your low audio frequency edge is at least 200hz, but not more than 300hz away from the dial/carrier frequency. The high-frequency audio end of the passband probably varies from rig to rig.

If you have FLDIGI installed and configured, you could always just use the waterfall. Tune BFO so white noise represented by light blue speckles starts at 2-300Hz.?

—Tim NC0Q

Hi Randy,

I do not have a Bitx40.? I have six uBiTx from v4 on.? When I saw this type of issue that could not be traced to the power supply, it was the BFO.? Do you have a way to verify that the BFO is working and at the correct frequency?? Does your Bitx40 use the Raduino board also used on the uBiTx?

Just some suggestions
73
Evan
AC9TU

Hi Randy;

Can you provide more details about the 12 volt power cell you are using?

Does it by chance include a USB power port, or support other output voltages beside 12 Volts?

73; Steve, N3SB

I found your design pretty much spot on. Of course there was the usual off by 0.5mm stuff. But that goes with the territory when you are manually recreating a design. The only issues I remembered was that the V3 Kit's button was slightly larger than the design and that the pho/mike/keyers plugs were off 1mm one way or the other horizontally. Pretty minor stuff! I figured your design saved me probably at least 3 days in the cycle of measuring, printing, correcting, repeat...? With a box the size of the sbitx case, it takes 5 hours tor print with a .6 nozzle!

73
Mark

--
AJ6CU/7
KD8CEC 2.0, Nextion Screens,? and open source uBITX Raduino boards for Arduino IOT, BLE, RP2040, Teensy 4.0, and Raspberry Pi Pico
https://github.com/aj6cu