Voice tx as transceiver with AM modulation [$85]

[AleyRobotics]

Voice tx as real transeiver with FM works great! Is it possible voice tx as real transeiver with AM modulation?

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[iz2fly]

Hi @Brumi-2021 I did a short test with Nightly Release 220920 night, only listening and transmitting without tools, in RX mode no problem in FM and USB mode, the audio in USB mode is also very good. In TX mode the signal is a bit distorted. I am using the AK4951 audio codec. I had another Portapack (now broken unfortunately )and it was better, maybe it had another audio codec. See audio test without modulation on my website. With this Portapack in USB mode, pressing the PTT produces an annoying background noise. Thanks.

[Brumi-2021]

Hi @iz2fly No , that nightly release that you tested , (is from 20th of sept) and I think it has not integrated the mic Automatic volume Level Control for the AK4951 Audio code that I released several months ago , but I updated yesterday as a PR (combining it with new Boost control feature in the WM8731 Audio codec).

You can download it from my last post of issue #683 or let me add also here the same link https://github.com/eried/portapack-mayhem/files/9690624/portapack-h1_h2-mayhem_WM_mic_boost_and_AK_ALC.zip

you will recognise in the menu that top ALC option (in AK4951 users). It is a kind of digital mic compressor , and I also played there in some option with the audio BW .

Or that BOOST option in the WM8731 users

73,

[iz2fly]

Hi @Brumi-2021. Perfect, I tried the 840da4c6 relase, very good modulation (ALC-OFF-12KHz). Now for us ham radio it is enough to block the TX frequency with the RX frequency. We hope to have it soon. Thank you very much.

[Brumi-2021]

Hi @iz2fly , And did you try all the other ALC GUI options ? One easy way to test them, Is to set up AUTO vox PTT control (TX Activation = AUTO) , reduce the vox control threshold (LVL) to <15 (example) and then , when talking to the Mic, you will activate the TX vox control , and from that TX time , you can easily change all the ALC GUI options , and you will hear in your closer receiver in real time the sound effect . (But in the high dB gain options you will need to use headphones to avoid mic sound coupling ) With that ALC feature , you can pick up all the ambient room sound, even from many meters distance , but protecting in some margin the peak overmodulation , I think , not perfect , but I found it quite nice and attractive feature .
I mainly added it , trying to protect and minimize any TX overmodulation and neightbour channel harmonics generation . Let me know if you followed me Cheers , 73

[gullradriel]

Hello. I'm not in favor of locking tx and Rx frequencies. A lot of repeaters are not using the same tx and rx freq, and I think it's better to have the possibility to choose instead of having a locked one. Maybe adding two buttons to set 'tx from rx' and 'rx from tx' freq could do the trick.

[Brumi-2021]

Hello @GullCode , thanks for your post . I fully agree with you . Maybe , as you suggested , a good compromise would be a new button to communize TX/Rx Freq YES/NO but before continuing with it , I want to see the progress and merge of the latest PR . Combined (ALC-ak/ BOOST-wm) #717 Step by step Cheers

[iz2fly]

Hi @Brumi-2021. 840da4c6 relase. I have tried with two different microphones, the best setting is: GAIN: 47 (Amp: 0, still broken) Mode: USB or FM MIC-GAIN: x1 ALC -9dB-6KHz or MIC-GAIN: x1.5 / x2 ALC -12dB-6KHz. or MIC-GAIN: x1.5 / x2 ALC OFF-12KHz. In TX mode the screen turns off. I have tried various TX Activation settings, it does not work, it turns on but does not turn off by itself. In AUTO mode, Audio RX listening does not work. Maybe you need to test away from the radio, tests to do. Cheers

[gullradriel]

@iz2fly Tx is turning the screen off because 'Stealth Mode' mode is enabled on your portapack. Check the icon on the top bar on the screen, there should be kind of a man with a hat in green, tap it to turn it grey. TX should now keep the screen on.

[Brumi-2021]

Yes , , @GullCode advanced my answer https://github.com/eried/portapack-mayhem/wiki/title-bar That icon , green means stealth mode activated , black screen when TX

[iz2fly]

Already done

[iz2fly]

Hi @GullCode, thanks for your suggestions, just one button is enough for me, RX = TX, Yes or No. (See my previous photo) I almost always use the USB mode and in USB, LSB, DSB mode there are no radio repeaters, during radio connections you often have to change frequency even of only 10 or 100 Hz, this is very complicated if you need to change two frequencies. Two different frequencies are rarely used, sometimes the RX frequency is slightly different because one of the radios is not working properly. I have already made connections with HackRf-One also in 5GHz in USB mode (100Km). I'm sorry not to be useful for software development, I can only verify that it works correctly. Thank you for your patient work. Cheers

[Brumi-2021]

Hi @iz2fly , thanks for your test . As you can see , with ALC in AK4951 platform we will have more options and tools , to adjust a correct modulation and avoid Mic distortion and harmonics.

Pls keep testing , and enjoying about it . Did you also realise that selecting high ALC gain , you can pick up all surround room sounds ? I think ALC is working quite well . And always we can select ALC OFF , disabling ALC block , same as previous fw settings . Now it is pending to get also some other feedback with WM8731 platform . Cheers

[Brumi-2021]

Hi , @iz2fly , In your last evaluation , you had activated the "stealth mode" . Now that you restored it to off . Can you pls make a deeper check about ALC (mic Auto Volume Level control options , and report inside the annexed PR #717 ? Several colleagues confirmed it in WM8731 platform . Now pending more user check in AK4951 Platform If possible check different GUI ALC options with different MOD types FM/AM/SSB/DSB and confirm that the new feature works well , without any side effect .

Thanks in advance . 73 ,

[Brumi-2021]

Hi , aside the bounty issue , To reduce the real open issues , I think that original issue (AM Voice in TX) can be close it. Cheers ,

[gullradriel]

I agree. You fixed it. See with @eried for that bounty thing, I'm closing the issue as asked.

[Brumi-2021]

Hi @gullradriel , thanks for closing it . No I did not add AM , nor excellent SSB feature with Hilbert Transform (that one written by @strijar ) . All those jobs were done by several great developers !!!

I just studied it and made many small improvements about SSB level and also recovered the lost CTCSS , and the roger beep , and added audio ALC / BOOST control in both Audio codec AK4951/WM8731 to minimise the ADC mic saturation and harmonics reduction .

So I do not claim at all for the bounty , this belongs to other prior members . They can talk directly with Eried.

Cheers

[gullradriel]

Well, overall you all did a good job, you included :-) The bounty job is for @eried to solve, so I'm cool X-D

[iz2fly]

Thank you all, great work! It could be completed by blocking the RX frequency with TX, it seems to me that this option is already in the code, this way it can be used as a ham radio.

[Brumi-2021]

Hi @iz2fly , pls check tomorrow's nightly binary , I hope , it will have included that PR #871 (or comming soon) And evaluate it , I think is Ok .

73,

[iz2fly]

Hi @Brumi-2021 Hurray! F: TX=RX, that would be more understandable to me, but that's totally fine. A thousand thanks. Perfect job! 73

[Brumi-2021]

Hi @iz2fly , I was waiting your reply !!! I knew that you would like it 😉

did you already test it in some QSO ? I tested it just locally , and it seems all ok , I could not see any side effect .but if you find anything let me know.

You already requested me several times 😃 , first , when I was recovering CTCSS and Roger beep ... , and recently again ... to be honest I feel much complex and difficult to program with independent freq control . And I feel specially useful if you use 2m repeaters area with some clear freq delta , from input / output ,... , but anyway , now we can choose ...

As you said the code is well structured , and I believed that originally was designed with this common freq, so the code had some clues about how to implement it partially ... the rest, test and debug ...

Enjoy many nice QSO’s and DX’s

73 ,

[iz2fly]

Ciao, @Brumi-2021. Now I'm at rest due to illness, the modulation in SSB mode seems excellent to me, when I'll recover I'll try to make some QSOs. Thanks again.