Optimize the signal i received.

[Eelco]

Hi, i was able to decode the message transmitted by SAQ 24-12-2024 (saq twente) and i also used my own receiver (saq opname).
In the noise there is a signal but it is not good enough to decode with the gerke-decoder.
Is it possible to improve the recorded signal in a way the gerke-decoder could decode the transmission?
I have made the recording with audacity and the recording is named saq opname.aup3 and can be downloaded here.
https://edegraaff.stackstorage.com/s/bMNytHyRwB9rFEGC
I am curious if the recording could be improved and how.

Regards
Eelco de PD1EG
More about the SAQ project at my blog https://www.fishfreak.org/sdr/

• This topic was modified 5 months, 1 week ago by Eelco.
• This topic was modified 5 months, 1 week ago by Eelco. Reason: Improve text

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[rich.g.williams]

I ran through your “saq opname” files and there is no sign of the SAQ CW at 17,200Hz running it through Audacity just confirmed there is nothing.

You might have more success with a big vertical loop with the plane of the loop pointing towards SAQ. Both end wires need to be terminated at the receiver and one end also Earthed.

Hope that helps.

[Eelco]

Hi Rich, thanks for the tips. I will give it another try next time. I will add the earth as extra and see if it improves the signal. Ther is a lot QRN here so maybe i would even search for a better location during the transmittion.
Regards Eelco.

[rich.g.williams]

PS I just had a look at your project file “saq opname.aup3” and unfortunately I can’t see any valid VLF there setting the waveform to spectral view. Looks like something has gone wrong and you are not recording VLF, should be frequencies up to about 21KHz. The spectral view should show several VLF stations with SAQ at 17.2KHZ but I don’t see any VLF stations in your file on the spectral view.

Rich

[rich.g.williams]

Hi Eelco.

Suggest you can have a look at Listen to SAQ Its on this site its on “SAQ in the ether” then “Listen to SAQ” and scroll down to the title “Reception using an audio editor”

It shows how you can setup Audacity’s filter curve to pass a very narrow band of frequencies around 17.2 KHz then it shows how to shift the pitch right down to 750 Hz. Then you can hear the morse code.

Then save the audio file and try it with the gerke-decoder.

Hope that helps,

Rich

• This reply was modified 5 months, 1 week ago by rich.g.williams.

[Eelco]

Hi, you’re right, I have done this with my previous recording, I will give it a try.

• This reply was modified 5 months ago by AlexanderSAQ.
• This reply was modified 5 months ago by AlexanderSAQ.

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