dsc

AIS, Navtex, DSC
Brijill
Posts: 10
Joined: Thu Jul 13, 2023 6:50 am

dsc

Post by Brijill »

Hi. I have sdrangel v 7.15.0 running on my Linux Ubuntu laptop. I tried all day yesterday to decode dsc on various frequencies with no luck at all. I'm using an airspy hf dongle, which does not show a mode option in sdrangel. Can you confirm that the dsc demodulator actually chooses usb mode. And also do I have to correct the dial frequency for usb, or use the published frequency ie 8414.5 KHz. I've tried both, with and without correction of -1.5KHz with no success. Incidentally the ft8 demodulator works with published frequency of 14.074 MHz ok. Is there a way to upload spots to pskreporter by the way. Many thanks for sdrangel, which for the most part works very well. Best Regards 73 Brijill
srcejon
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Location: London
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Re: dsc

Post by srcejon »

For DSC, you should just need to use the published frequency. What can you see in the spectrum window? Perhaps post a screenshot.

As far as I know, uploading to pskreporter isn't supported yet.
Brijill
Posts: 10
Joined: Thu Jul 13, 2023 6:50 am

Re: dsc

Post by Brijill »

Thanks for the reply..Here is a screenshot with frequency of 8414.5 KHz. I've tried -1.5 KHz with no results either. I know the antenna is ok as I can receive other sigs ok. Puzzled!..Oh great!. Now how do I put a screenshot on here?. My brain hurts. Never mind, I'll keep taking the tablets and probably fall off the wagon and; horror!. Buy another Windows machine instead. Come back YaDD I love you! lol
srcejon
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Joined: Thu Jan 19, 2023 2:30 pm
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Re: dsc

Post by srcejon »

Select attachments tab, then add files. File shouldn't be biggerthan 2MB.
Brijill
Posts: 10
Joined: Thu Jul 13, 2023 6:50 am

Re: dsc

Post by Brijill »

Don't ask me how I did that lol.
Attachments
2023-07-13_12-58dsc.png
2023-07-13_12-58dsc.png (184.02 KiB) Viewed 187 times
srcejon
Posts: 217
Joined: Thu Jan 19, 2023 2:30 pm
Location: London
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Re: dsc

Post by srcejon »

I don't see a signal there, but maybe you need to adjust the scale a bit.
Brijill
Posts: 10
Joined: Thu Jul 13, 2023 6:50 am

Re: dsc

Post by Brijill »

By scale Do you mean decimation. As to the dsc signal, they are quite short transmissions and few and far between. Catching one on a screenshot is a bit iffy. I've been trying to catch one to basically see if I'm off frequency. Doing my eyes in lol,,Cheers!
srcejon
Posts: 217
Joined: Thu Jan 19, 2023 2:30 pm
Location: London
Contact:

Re: dsc

Post by srcejon »

I mean y-axis scale (i.e. power). You currently have a range of 100dB, but signal will be quite a bit smaller than that.

You could also increase decimation, as your span is far wider than the narrow DSC signals, and doing so should make them more visible, as SNR increases with decimation.
Brijill
Posts: 10
Joined: Thu Jul 13, 2023 6:50 am

Re: dsc

Post by Brijill »

Should the dial frequency be as published ie 8414.5 KHz or - usb shift ie 8413 KHz. Any chance of a screenshot of your setup. Thanks
Brijill
Posts: 10
Joined: Thu Jul 13, 2023 6:50 am

Re: dsc

Post by Brijill »

It's ok chaps!. I finally got my 80 year old brain firing on all thrusters and realized I was not entering the correct frequency. I had assumed, wrongly, that the 5 Hz would be the last box in the demodulator settings. It is in fact the third from the right
I now have the correct frequency of 84145 KHz showing below the waterfall. I have 2 decodes so far, so now waiting to see if I am uploading to yaddnet.org. The last hurdle lol..Cheers all..
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