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Hi all -

I now have the Attiny hooked up to the directional coupler and in the circuit. On key down I read about 1.5V on the VFWD pad of the coupler, but the screen still reflects 0 power and SWR 1.0. ?As others have mentioned I also noticed that VFWD and VREF going in to the ATTiny85 are reversed. I enabled debug print of the VFWD and VREF vales as read in the Pi - they are always -1.

Anyone else have this issue?

And per my earlier post can anyone let me know what board manager you are using for the AtTiny85?

73,
Dean
KK4DAS

ps.: Until now, jtdx had a high input signal in receiving sBitx, but now I can't set it so low that it doesn't overcontrol it.
Then the audio error message appears, which appears again and again every time you switch to a broadcast.
--
Gyula HA3HZ

Thank you for sharing your experience. A few things I will probably try. We are having a heat wave at the moment, it was 45C in the car before we left. At the age of 73, I already have a hard time bearing the heat.
--
Gyula HA3HZ

On Sun, Jul 14, 2024 at 10:01 AM, Mike - KD4MM wrote:

Hahaha.... I made them for you, Dean! Not my best idea, but OK.

Credit must go where credit is due - they work!

It was type 43 material for the ferrites.
Being a ham I have a lot of different sized ferrite cores, beads etc.
The shielding of the 22 pin 150mm DPI/DSI (display) ribbon did help.

The real issue was the input DC power cable to the display panel.
It was already twisted but not enough for effective common mode reject.
The DPI/DSI ribbon even being shielded was still radiating into/onto the DC power cable.
Twisting the DC power cable further helped.
I installed another LP filter on the DC input to the display board plus two 43 ferrites. This definitely eliminates the DPI/DSI ribbon cable coupling noise.

Still when reassembling the front panel try and keep the DPI/DSI cable away from the display DC power cable. I know they are very close but do your best.

Now able to run the IF level up to high levels(over 70) without internal RFI wiping out the receiver. Running about 55-60 now on IF level verses 15-20 before.
Big improvements in overall S/N.

Also installed ferrite on the main DC input line to the board.

Ferrite on 5v Dc-Dc converter output.

Still have a couple of birdies in LSB on all bands. It’s in the audio passband which makes it sound like a carrier.
I’ll take a closer look at these as it appears to be coming from the Pi4 which I attempted to shield with a cover on the exposed area. More analysis needed.

I hope anyone with a V3 who is experiencing these issues will use this data to make your SBITX perform like it was intended.

Hopefully HFsignals will take a good look at these effective solutions. Possibly incorporate some or all. Cost is minimal.
$20 in parts, 2 hours labor if your old like me. 63 yo…

These modifications are documented. Before and after videos and pictures.

If and when I make progress on attenuating the leftover birdies I’ll inform the group.

JES,
?I entered digital mode as usual and started JTDX and then cqrlog on an external hdmi monitor. JTDX has a higher entry level, so I adjusted IF=0 Audio=0. The surprise came when I selected it for broadcasting, because the mode on the radio immediately changed to USB and only the PTT was switched on, there was no audio. So something is wrong.
The installation is now done by cloning. and I saw that there was a change in sbitx_sound.c, so I left everything in the origin state.
--
Gyula HA3HZ

On Sun, Jul 14, 2024 at 06:14 AM, JJ - W9JES wrote:

I will have to make a video of these exciting changes to show you how to use them!

I look forward to this.

Joel
N6ALT

That worked, thanks for all yours and others hard work.

Joel
N6ALT

try

cd sbitx
git stash
./update

Hi JJ,

When trying to do the update i get the following error:

Your local changes to the following files would be overwritten by merge:

Please commit your changes or stash them before you merge.
Aborting...

Any idea whats causing this?

Joel
N6ALT

Hahaha.... I made them for you, Dean! Not my best idea, but OK.

All -


v3.027 is now available!

Changes:
AM Mode..
TX EQ..
QRO..
SSB Power Calibration..
Hamlib fixes and functional improvements..
and all sorts of other great things! I will have to make a video of these exciting changes to show you how to use them!

You can update from terminal with:

cd sbitx
./update





Join our Discord server for assistance, issues, or discussion..

I want to extend my deep gratitude to the development team for their countless hours into adding features to this release. Thank you W2JON, KF7YDU, and N1QM. Also want to thank Farhan for the AM mode building blocks.



-JJ

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?

I'm glad you were able to solve the noise problem.
Returning to my question, I did not want to influence your answer, so my question was not clear.
was that he attached a conductive layer with glue, which he then insulated with a foil insulator, so that the conductive layer does not cause a short circuit elsewhere. The point is that it was not grounded anywhere, so it created EMI protection.
The person was satisfied with this solution.
Currently, they make a 15 pin to 22 pin flexible cable with EMI protection for the RPi5, but this is not good for us for the RPi4.

I route the power cable through an FT140-43 type ferrite ring. The cable has a cross-section of 2x2.5 mm2 and I made 6 turns on the ferrite ring just before the power connector of the sBitx. You can see a photo of this in my previous message.

One addition: if you use an external keyboard, you can take a screenshot of the keyboard by pressing the Prtscr button. You can find the image as date_time_screen_size_scrot.png in the RPi home folder.

If you are an active radio user, you may need to dissipate the heat produced by the device. Since I use the device a lot, I put a lot of emphasis on this.
In half a year, I made 4800 QSOs in digital modes, so I cool the heatsink from the outside and the RPi from the inside with a fan. Currently, the external temperature here is permanently above 40C, the CPU temperature starts at 38C when switched on and reaches 58C during continuous use. The critical temperature is 80C, but there is no need to worry, because the built-in protection then comes into play and regulates the speed and usage.
Thank you for answering my request. I wish you successful use and lots of joy.
--
Gyula HA3HZ

On Sun, Jul 14, 2024 at 08:44 AM, Smeden wrote:

Btw. Do you know of anyone that have succeed in using a faster ADC + modified LP to create a "wider" bandscope?

No-one has made it work with a different codec to my knowledge. The Pi Hat is not available commercially. Farhan made them as a one off run to hand-out after his talk at Hamventrion. My original build with the separate codec board worked but it is a cleaner build with the Hat.

Another member here posted gerbers for a different version of the hat - I haven't looked at it. /g/BITX20/message/112593

I agree with the modular approach - my analog circuit is very different from the Farhan's version. I lifted bits and pieces of his circuit - the SI5351 buffer amps and the audio amp in particular. I used his LPF values but I made the LPF relay switched rather than diode switched. When I get around to it I would like to post a module by module discussion on my blog. I don't have the desire to do a full end-to-end schematic as others have asked for, but I don't mind taking it a board at a time. The plus side is its is good documentation for me!

73,
Dean
KK4DAS

Thanks for sharing your experience here.

I will try to make a similar "homebrew" sBitx variant. My goal is not to scratch-build a 1:1 copy, but to make it modular and tweak the different stages if possible. ( Or take "shortcuts" like using a multi-band BPF I allready have. )

Right now I'm having some trouble finding this "Pi HAT" w. WM8731 or compatible CODEC.

All my searching effort leads me to the same "Audio Codec Board - PROTO" that you used in your previous setup.The smarter Pi HAT alternative is nowhere to be found. :/

Btw. Do you know of anyone that have succeed in using a faster ADC + modified LP to create a "wider" bandscope?

73,NielsOZ9NS

On Sun, Jul 14, 2024 at 06:34 AM, Karl Heinz Kremer, K5KHK wrote:

What are these blue holders for your boards? They look 3D printed. Is there an existing design?

Yes - they are 3d printed - don't recall where I got the design. Happy to send you the STL - send an email to KK4DAS gmail.

73,

Dean
KK4DAS

Thank you for sharing your steps and progress!


-JJ

After 2x 3.5mm ferrite beads on Pi4 display power leads. Shielded DPI/DSI cable too. Just a couple of birdies now.
Excellent results.

On Sun, Jul 14, 2024 at 05:16 AM, Kb4yho wrote:

I found using my Oscope noise on the power cable going to the display board.

Appears DSI/DPI ribbon cable coupling RFI onto unshielded power cable.

I could actually move the front panel away from the board and the RFI was almost gone.
I put a 2x 3.5mm ferrite bead on the power cable. RFI noise has been attenuated greatly. It’s no longer audible.
Now just some birdies. I’ll deal with them.
So successful troubleshooting.

Took awhile to track down.
Fairly simple fix.

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