VOR signal reception

[Muhammad Anas]

Dear GNU Radio Community,

I am working on VOR signal reception using the USRP N210 in GNU Radio
Companion. I am encountering an issue with signal reception after applying
a low pass filter at 200 Hz. The desired 90 Hz, 130 Hz, and 150 Hz signals
are not visible in the frequency spectrum. Instead, a 40 Hz signal
dominates, and the 90 Hz signal appears suddenly with low gain and then
disappears.

Project Details:

   - Daughterboard: WBX (default)
   - Antenna: VERT900 (TX/RX)
   - Modulation: Message signals of 90 Hz and 120 Hz are modulated on a
   1.02 kHz subcarrier and then further modulated on a 1.1 GHz carrier.

This modulated signal is transmitted from a signal generator using the same
antenna and received by the USRP N210 in GRC. The signal spectrums are
attached.

Could you please help me identify any potential issues or missing steps in
my setup?

Thank you for your assistance.

Best regards,

Muhammad Anas

AMPLITUDE (GAIN) Comaprison/ Editor issues

[Muhammad Anas]

Dear GNU Radio Community,

I hope this message finds you well. Currently, I am engaged in a project
involving amplitude difference(gain difference) of 130 Hz and 150 Hz signal
in frequency spectrum through GNU Radio Companion, utilizing the QT GUI
Frequency Sink block.

I am seeking guidance on a specific requirements: Is there any easy way to
do the amplitude difference of any two signal's gain values and show their
difference value result as a message output during runtime. I am doing this
on Windows 10, and I have also issues in writing code and using the python
embedded block, when I want to change the editor to VS code or any other
editor(pre-installed editors) , there is no option of VS code editor in the
choice options and when I select the notepad.exe then it does not open that
editor. Could you please help me how to use this block and write and
configure python code in Windows 10.

Your insights or suggestions on achieving this would be immensely valuable
to my project.

Thank you sincerely for your assistance.

Best regards,

Muhammad Anas

Re: Making a VLF SSB receiver

[Marcus Müller]

Hi Julian,

the audio source is set to a sample rate of 48 kHz. So, you're either already 
bandpass-subsampling and forgot to mention, or you can't represent frequencies higher than 
24 kHz with your digitizer in this setting. Can't tell you which – your physical setup 
isn't part of your flowgraph :)


So, please do specify your question a bit more: What's your digitizing system, which rates 
do you plan to work at, and show spectra (using the screenshot functionality of your OS) 
of what you get, and if possible, a sketch of what you want.


Best regards,
Marcus

On 19.07.24 15:46, Julian Aranguren wrote:

Hi everyone !

Long story short, in the context of a broader project I am attempting to recreate on 
GNUradio an SSB receiver for VLF, meant to function with an ultrasonic hydrophone. The 
goal here is to demodulate everything between 20 and 40khz (or higher, with a similar 
bandwidth) down to between 0 and 20. Basically the same as a bat detector or a 
surface-diver communication device.


A few colleagues and I made a flowgraph by copying and adapting the SSB receiver from the 
GNUradio tutorial (https://wiki.gnuradio.org/index.php/Simulation_example:_Single_Sideband_transceiver#The_Weaver_method_of_SSB_demodulation ). It works, but it doesn't really do what we exactly want and we are struggling to get it to work that way, as we're unfamiliar with some of the GNUradio terminology and online tutorials tend to be unclear.


How would you change the flowgraph to work the way we seek to ? I noticed in particular 
that this version has a fine tuning option which we believe to be superfluous (with a 
17.5khz carrier), and a 16khz carrier.


Thanks a lot !

Re: AMPLITUDE (GAIN) Comaprison/ Editor issues

[Steve Hageman]

Hello Muhammad - As for the editor selection issue, please see this post.

https://lists.gnu.org/archive/html/discuss-gnuradio/2024-07/msg4.html

As for the amplitude comparison. I would use the FFT block and then use an 
embedded python block to find the difference between the FFT bins in question.

https://wiki.gnuradio.org/index.php/FFT

You should be able to either output this as a Tag or a Message, or just an 
array of the difference value (brute force, but easy to implement and deal with 
downstream).

Hope this helps

From: discuss-gnuradio-bounces+steve.hageman=outlook@gnu.org 
 on behalf of 
Muhammad Anas 
Sent: Monday, July 22, 2024 3:49 AM
To: discuss-gnuradio@gnu.org 
Subject: AMPLITUDE (GAIN) Comaprison/ Editor issues


Dear GNU Radio Community,

I hope this message finds you well. Currently, I am engaged in a project 
involving amplitude difference(gain difference) of 130 Hz and 150 Hz signal in 
frequency spectrum through GNU Radio Companion, utilizing the QT GUI Frequency 
Sink block.

I am seeking guidance on a specific requirements: Is there any easy way to do 
the amplitude difference of any two signal's gain values and show their 
difference value result as a message output during runtime. I am doing this on 
Windows 10, and I have also issues in writing code and using the python 
embedded block, when I want to change the editor to VS code or any other 
editor(pre-installed editors) , there is no option of VS code editor in the 
choice options and when I select the notepad.exe then it does not open that 
editor. Could you please help me how to use this block and write and configure 
python code in Windows 10.

Your insights or suggestions on achieving this would be immensely valuable to 
my project.

Thank you sincerely for your assistance.

Best regards,

Muhammad Anas

Re: Editor issues

[Steve Hageman]

Hello Muhammad - It just dawned on me that you may not know the external 
editor 'fix' for windows.


My previous email gave directions for how top find the "config.conf" 
file. Once you find this you can edit the line that says: "editor = " to 
something like this,


editor = C:\Users\steve\AppData\Local\Programs\Microsoft VS Code\code.exe

The path above is for my Win10 system and my VS Code location - you juts 
need to specify your VS Code install path.


Reference documentation,

https://wiki.gnuradio.org/index.php/Embedded_Python_Block#To_specify_a_default_editor_in_Windows