[Ground-station] DVB-S2 or -X bandwidth ?

[Howie DeFelice]

Amen

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________________________________
From: Ground-Station <ground-station-bounces at lists.openresearch.institute> on behalf of Wally Ritchie via Ground-Station <ground-station at lists.openresearch.institute>
Sent: Saturday, August 24, 2019 9:42:22 AM
To: KC9SGV <kc9sgv at gmail.com>
Cc: Ground Station <ground-station at lists.openresearch.institute>
Subject: Re: [Ground-station] DVB-S2 or -X bandwidth ?

A 1 MHz wide DVB-S2 signal supports a symbol rate of 800k symbols per second. This is sufficient to carry a virtually error-free transport a payload of a few megabits per second. In terms of communication quality digitized speech, we need a net payload of 1600 - 2400 bits per second per channel. So 1 megabit of net payload is equivalent to more than 400 communication quality voice channels (i.e. better than ssb) or roughly the equivalent of all of the 80,40,20, and 15 bands.

The whole idea here is that we are using state of the art digital technologies to transport all of the received uplink channels into a single downlink carrier. The purpose of the commercial testbed channel is to provide an environment for testing the digital DOWNLINK. There will be no analog signals - only digital. The transponder will be combining (or multiplexing) a large number of narrowband digital uplinks into a single downlink.

Forget analog modes. There is absolutely zero place for analog modulations. Any analog modes will be converted to digital on the ground.

WU1Y
Wally

On Sat, Aug 24, 2019 at 8:55 AM KC9SGV via Ground-Station <ground-station at lists.openresearch.institute> wrote:
Hi All,
Is 1 MHz wide enough for DVB-S2 transmissions ?
I cannot attach a picture here, but look on page 17 of this old TAPR paper.
Seems like 2 MHz is the minimum bandwidth required ?

https://www.tapr.org/pdf/DCC2009-DATV-KB6CJZ-W6HHC.pdf<https://nam02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.tapr.org%2Fpdf%2FDCC2009-DATV-KB6CJZ-W6HHC.pdf&data=02%7C01%7C%7Cf9206cb4dddf433fab0208d72899a6d7%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637022512696710320&sdata=rvaOxePa2pCMAUkbKXH6z33nMvCs3MFKUmXHt16AE0s%3D&reserved=0>

Maybe only legacy ham Linear modes will be supported by our 1 MHz Rent-a- GEO effort ?

Bernard,
KC9SGV


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