Fwd: Operating CW with GNURadio

Accidentally sent my reply only to Marcus.

---------- Forwarded message ---------
From: Albin Stigö <albin.stigo@gmail.com>
Date: Wed, Dec 24, 2025, 13:19
Subject: Re: Operating CW with GNURadio
To: Marcus Müller <mmueller@gnuradio.org>

You can connect the paddle to a keyer and then connect the keyer output to line in. Then you can use an audio input block + Hilbert transformer to get a baseband cw signal. You will probably have to shift it and maybe upsample too.

Happy holidays,

Albin 

On Wed, Dec 24, 2025, 13:06 Marcus Müller <mmueller@gnuradio.org> wrote:

Hi Mati!

Do you already have a way of connecting your paddle to your computer? That's the hardest
part here, and how you do it will define how you implement the software (i.e., GNU Radio)
side of this.

 > ¿Its there any way to manipulate the SDR from the paddle and tx to send dits and dats?

With GNU Radio, **you** are implementing the SDR, and only the RF samples are sent to the
RF frontend (e.g. via network or USB). I'm worried you're having a radio device that's
something different and doesn't fit into that. What is the "TX-capable SDR" you have, and
how does one interface it with GNU Radio?


Best regards,
Marcus

On 2025-12-23 5:45 PM, lu9cbl@gmail.com wrote:
> Hi to all! i want to operate CW with an TX-capable SDR with GNU Radio, but i want to use
> it with a physical CW doble paddle.
>
> ¿Its there any way to manipulate the SDR from the paddle and tx to send dits and dats?
>
> ¿Any idea if its possible?
>
>
> Thanks to All
>
> Mati LU4BA (Ex LU9CBL)
>
>

Re: Operating CW with GNURadio

Hi Mati! For my part, I have tried several solutions, but in the end it all boils down to two possibilities: - use Barry KV4FV's gr-morse-code-gen (there are several examples on the net) - sending the sidetone of a "physical" keyer as TX modulation (as is done for FT8 digital modulations, etc.). At this point, it will no longer be A1A but A2A; in practice, nothing really changes. Other solutions suffer from various defects (latency, loss of characters, etc.). My TRX SDR [https://sourceforge.net/projects/urtx/], not yet updated to the latest version (lazy me...), may be of help to you. I use it for traffic on QO100, mainly in CW considering my "magical" 500mW. I would like to take this opportunity to wish you and the mailing list a happy holiday season. de I3VFJ, Vittorio fingerprint: `fb5f492a54e016c632c933d3ee4b7e38203c79ca` Inviato con la posta elettronica sicura Proton Mail. martedì 23 dicembre 2025 17:48, lu9cbl@gmail.com <lu9cbl@gmail.com> ha scritto: > Hi to all! i want to operate CW with an TX-capable SDR with GNU Radio, > but i want to use it with a physical CW doble paddle. > > ¿Its there any way to manipulate the SDR from the paddle and tx to send > dits and dats? > > ¿Any idea if its possible? > > > Thanks to All > > Mati LU4BA (Ex LU9CBL)

Re: Operating CW with GNURadio

Hi Mati!

Do you already have a way of connecting your paddle to your computer? That's the hardest
part here, and how you do it will define how you implement the software (i.e., GNU Radio)
side of this.

> ¿Its there any way to manipulate the SDR from the paddle and tx to send dits and dats?

With GNU Radio, **you** are implementing the SDR, and only the RF samples are sent to the
RF frontend (e.g. via network or USB). I'm worried you're having a radio device that's
something different and doesn't fit into that. What is the "TX-capable SDR" you have, and
how does one interface it with GNU Radio?


Best regards,
Marcus

On 2025-12-23 5:45 PM, lu9cbl@gmail.com wrote:
> Hi to all! i want to operate CW with an TX-capable SDR with GNU Radio, but i want to use
> it with a physical CW doble paddle.
>
> ¿Its there any way to manipulate the SDR from the paddle and tx to send dits and dats?
>
> ¿Any idea if its possible?
>
>
> Thanks to All
>
> Mati LU4BA (Ex LU9CBL)
>
>

Re: Operating CW with GNURadio

If the paddles use a 3.5mm jack as audio input then you can probably do it. Maybe take a look at gr-morse-code-gen as well 

S. Aditya Arun Kumar

On Tue, Dec 23, 2025, 11:06 PM lu9cbl@gmail.com <lu9cbl@gmail.com> wrote:

Hi to all! i want to operate CW with an TX-capable SDR with GNU Radio,
but i want to use it with a physical CW doble paddle.

¿Its there any way to manipulate the SDR from the paddle and tx to send
dits and dats?

¿Any idea if its possible?


Thanks to All

Mati LU4BA (Ex LU9CBL)

Operating CW with GNURadio

Hi to all! i want to operate CW with an TX-capable SDR with GNU Radio,
but i want to use it with a physical CW doble paddle.

¿Its there any way to manipulate the SDR from the paddle and tx to send
dits and dats?

¿Any idea if its possible?


Thanks to All

Mati LU4BA (Ex LU9CBL)

Questions about suitable hardware for testing.

Hi.
I want to test some OOT Gnuradio modules with actual hardware.
I have looked at these, as they support transmitting and receiving
simultaneously.

GeekRF One PlutoSDR
PLUTO+ AD9363
B220 Mini AD9361
LibreSDR B210 Mini
AIDOSDR A3 (16-bit ADC/DAC)
So, what should I choose?

DUC/DDC CH0: Frequency Shift (Hz) Error

Hello, 

Not sure if this is a bug or I'm doing something wrong (probably the latter).

I'm on ubuntu using GNU Radio 3.10.9.2 (Python 3.12.3)

I have the following blocks (all RFNoC):
RX Radio -> DDC -> DUC->TX Radio

I try to use the frequency shift on DUC or DDC and get the following error:

[RFNoC Stream Controller] Error starting stream: RfnocError: ResolveError: Attempting to overwrite property `freq@USER:0' with a new value after it was locked!
[ERROR] [RFNOC::GRAPH::DETAIL] 0/DDC#1: RfnocError: ResolveError: Attempting to overwrite property `freq@USER:0' with a new value after it was locked!

RuntimeError: RfnocError: ResolveError: Attempting to overwrite property `freq@USER:0' with a new value after it was locked!

Please let me know what additional information you need. Thank you in advance.

***I also have a question about why my TX/RX does not activate in this setup. I'm trying to receive a signal, shift it with an offset, and transmit it out as soon as possible. I'll submit that later with more details but it's probably a config issue (btw DUC/DDC are both needed since that's how the SEP points in FPGA image for the X410 SDR come configured). Flowgraph launches if I just set offset to 0, but TX and RX lights remain off.