Hi, no I haven't done anything with the pi pico zero. Looks kind of neat though, if I needed something with a smaller form factor, it looks like a much easier option than building a custom rp2040 board, certainly something worth considering.

Thanks for the answer. If I have interested you, I am waiting for a video where you tested "pi Pico zero" in the near future.​@@101Things-ds8tc

Thanks! Good question! Simplistically, the class E amplifier is configured to deliver 5W with a 12V supply, so I think it would look like about 29 ohm load to the class D amplifier.

@@101Things-ds8tc haha, yeah, that makes sense! Thanks!

Thanks! Yes, there's lots of potential I think...

You’re welcome 😊

Ah yes, I used the 2.4 inch version... Good luck with your build.

@101Things-ds8tc i guess this comment will help others, but I ordered the 2.8" screen, because it is shown in the video. :(

We could look at providing an alternative front panel to accommodate the 2.8inch screen. I think it could work with a bit of fiddling...

@101Things-ds8tc Or you could edit the video to add a note that the 2.4" is required, not the 2.8" shown... I didn't read the BOM before ordering, because of this video.

I have blurred it out in the video. I can add a 2.8 inch version of the front panel too if there is any interest.

Cool! Thanks very much for the feedback. 3dB steps is slightly more difficult, but should be possible. 6dB steps uses powers of 2, so all the manipulation can be done with shifts. 3dB steps would need shifts and multiplies. The 100uF capacitor is a DC blocking capacitor and determines the bass response. It forms a high-pass filter with the headphone (e.g. 32 ohm), so has a cutoff frequency of about 50Hz). Substituting a 22uF capacitor would give a cutoff of about 200Hz, so would block out more bass frequencies. This would be fine for voice signals though. If you use an amplifier, this would have an input impedance in the 10k or more, so would let through everything above 1Hz. The 100ohm resistor and 470nF capacitor form a low-pass filter. This determines the trebble response, these value give a cutoff of 3.3kHz. Decreasing either the resistor of capacitor would increase the cutoff frequency, but would allow through more PWM ripple. There isn't much to be gained from increasing the cutoff frequency because the DSP filters don't let through much above 3kHz in any case. The values I have used are good choices for voice reception, but it would be possible to make some tweaks to improve reception of music (within the limits of what an AM channel can achieve). Cheers Jon

@@101Things-ds8tc What 470n?? At 00:09 the layout shows a 100uf, 100r & 104 cap??? Should the 104 be a 470nf?

Ah yes, there is an inconsistency between the coloured schematic in the video and the more traditional schematic on the documentation page. I actually used 100n in the build and it works fine, it would have a cutoff of 15kHz, but should still attenuate the PWM ripple by about 30dB. 470nF would probably be better having a cutoff closer to 3kHz giving about 40dB attenuation of PWM ripple.

Glad you like it!

Probably not that difficult, it's a very similar idea. One issue might be that the resolution of the images is much higher, so not sure how good they would look on a small TFT.

Glad you liked it!

Cool, best of luck!

That would be cool. I think it should work OK with an FM receiver, and it should be fairly easy to add PD120 support.

Yes cool idea, definitely doable I think! 👍

Thanks, glad you enjoyed it!

Wow, that was quick! Thanks 👍

Yes, I think so I kept that in mind when I designed it, planning to give it a go when I get a moment.

Thanks!

Thanks!! PD120 should be trivial to implement, but I would need to downscale the image to fit on the screen.

Yes, that's pretty cool. I must give it a try sometime!

¡Gracias!

Thanks, much appreciated 👍

Thank you too!

Thanks!

Thanks, much appreciated 👍

Thank you! Cheers!

I did some research on this project, there's boards on pcbway for it and I think it's a full transceiver

Díky! Navrhl jsem jej jako opakovaně použitelný modul, takže by měl být snadno integrovatelný do stávajícího přijímače. Může přijímat nezpracovaný zvuk nebo IQ signál.

Thanks, will do!

Thank you too!

Thank you! Cheers!

Thanks!

Thanks, working on it!

Thanks, much appreciated. Always happy to answer any questions you might have, and you can always raise an issue in GitHub.

Thanks, that's very much appreciated!

Cool, glad you like it!

Awesome, thank you!

Cool, sounds interesting!

Happy to help! Can you tell me a bit more about the problem - how far have you managed to get? You could try using the pre-compiled version first and see if that works?

@@101Things-ds8tc Hi dear! Tnx for the prompt answer. I'm a newbee on pico family. I get receiver working with pico 1 so I could test the functionality. Yesterday i got my brand new pi2 so I try to make it work. As a result is 1) cant open the file....(where the picorx is) or 2) missing partition table. I usually clone the project on github, dowload on github desk top and finally I open it with visual studio. I see all the pico rx files, i go further with run on usb, i see it running, but ends with nothing. code -4 or cant open the file or again no partition table. Thanks a lot for your help,

Ok, have you tried using the pre-compiled uf2 file? Do you still have the same issue?

Yes. Nothing.

@@101Things-ds8tc I mean I dont have similar problems with other projects, so I dont think this is the problem.But never be sure! What do you suggest? Did you use VSC for charging the program? I did by passing thought Github desktop as usual. With pico1 no similar issue.

Not sure exactly, the mirror is the most expensive part. The aluminium profiles aren't too expensive, and you can spend as much or as little as you like on the other optics. All in, I don't think you would save much over a commercial dobsonian, there seems to be some very reasonable models available.

@@101Things-ds8tc is the aptura ad6 a good one

I don't have any personal experience, but it seems like a good spec for the price and you would be hard pressed to build one for less.

Sure, there is the original picorx design it was based on, you can find that here: github.com/dawsonjon/PicoRX/tree/master/PCB/pico_rx. It doesn't have all the latest tweaks though. You could try this one by Jim Reagans: github.com/JimReagans/PICO-RX or this one by F4GOH: github.com/f4goh/SDR-PICO.

@101Things-ds8tc Nice. I'll have a look. Been following the project for a while, but with the USB audio and the FFT waterful.

I’m not saying any are difficult to source. They just aren’t overnight or second-day available. I’m ruined by modern availability expectations. We used to wait for parts from across the continent and it took 3-5 days just to get boxed and shipped, then a few more days. It often took 3 weeks, and we LIKED it.

I feel your pain 😭

Brilliant, thanks so much!

Thanks that's great! I think we have most of the features you listed already, but we are still adding new features all the time. Extending the frequency range might be possible with an overclock, or by using another mixer/down converter. A few people have reported success recieving VHF and UHF this way.

Yes, that wouldn't suprise me. Actually all the AGC modes respond quickly to an increase in power, but the time it takes to increase the gain when the power decreases changes significantly. It probably makes sense to use manual gain control to turn the loop then switch the AGC back on.

The magnitude axis of the spectrum scope is scaled dynamically depending on the signal strength. The horizontal dotted lines are spaced at 40dB intervals and to give an indication of the magnitude scaling. The lines get closer together when strong signals are present.

@101Things-ds8tc ok I see thanks 👍

Hi, good question! The ADC on the pi-pico needs a voltage between 0v and 3.3v (unlike a sound card which can accept negative voltages), so it does need a DC bias to work properly. With 3.3v devices, the DC bias at the input to the analog mux is mid rail and this conveniently passes through the QSD giving the required DC bias at the ADC input. If you add a 100nF DC blocking capacitor between the op-amp and the ADC, it will remove the DC bias, and will need to be added back in using a biasing network between the capacitor and the ADC. (The uSDX does precisely this, using a blocking capacitor to remove the DC bias and then adding the DC bias back in again. This is so that they can exploit the ability to change the ADC reference voltage to implement a simple gain control mechanism, as the ADC reference changes, so does the bias. The Pico ADC doesn't have this feature.) Overall, I think adding a potential divider between the op-amp and the ADC is a simpler (and safer) option, because it can reduce the DC bias from 2.5v to say 1.5v as well as reducing voltage swing (which might happen if the op-amp saturates) from 5v to 3v, respecting the limits of the ADC input. Kind regards Jon

Hi, I have added the squelch delay to the TFT branch now, feel free to give it a try... Your JBL GO project sounds very interesting, would love to see a picture! I have other plans for the spare ADC channel, but I have added a "shortcut" to make it easier to adjust the squelch settings, just hold the "back" button and the encoder button, then turn the encoder... Hope that helps!

@101Things-ds8tc Thank you very much.

I'm using GitHub actions to automate the build, and that's where the link should take you. Under "actions" you should see a number of builds, if you click on the latest one you should see 3 downloadable .zip files which contain the .uf2 files. Just pick the one that matches your Pico version....

Thanks so much, glad you found it useful!

I'm not using WiFi or Bluetooth at the moment, but I guess they could be useful in future versions of the project. I have builds to support either the risc-v or arm cores. They both give very similar performance with the current software.

Yes, sure, it's got the bandwidth and has good noise performance. It's a 5v device though, so you will probably have to adapt the circuit to run the op-amp from 5v rather than 3.3v.

of course you can. did you run with pico2?

@@antoniobertezzolo6307 I bought a pico 2 and , i install Python , but still not run the code

Thanks, glad you like it!

@@101Things-ds8tc love it