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Support for AM Shortwave Radio

Posted: Thu Feb 01, 2024 11:49 am
by HB9VQQ
I would like to see support for AM shortwave radio listeners. There is quite a large community of BC shortwave listeners with more than 600 Kiwi SDRs worldwide http://kiwisdr.com/public/ in the public domain. They would all benefit from RM Noise supporting AM.

Roland

Re: Support for AM Shortwave Radio

Posted: Fri Feb 02, 2024 2:47 pm
by RandyW
What is the bandwidth required for those signals?

(Internally, RM Noise operates with 8KHz sampling to support a bandwidth of 2.8KHz. If higher bandwidth/sampling is required, it will have an inverse relationship to the number of clients that can be supported by each server.)

Re: Support for AM Shortwave Radio

Posted: Fri Feb 02, 2024 3:43 pm
by HB9VQQ
9800 Hz

Re: Support for AM Shortwave Radio

Posted: Sun Feb 04, 2024 6:45 pm
by HB9VQQ
Try this for example - Chaine 3 on longwave broadcasting from Algeria http://kiwi.hb9vqq.ch:8073/?f=252.00amz9

Re: Support for AM Shortwave Radio

Posted: Sun Feb 04, 2024 11:56 pm
by RandyW
The lowest *normal* sample rate that will support a 9.8KHz bandwidth is 22,050Hz. To maintain the same level of filtering performance, we would need 2x-3x the server hardware to support the same number of clients. With the addition of more / faster servers, this will be possible in the future, but it is not at the moment.

I am already considering changes to reduce the DELAY by 50ms which will come at the cost of 2x the server hardware...