[amsat-bb] ISS ping box (now PBBS)

Dani EA4GPZ daniel at destevez.net
Fri Sep 23 13:59:54 UTC 2016

El 23/09/16 a las 14:22, Edson W. R. Pereira escribió:
> What would be required (from the point of view of paper work, logistics,
> approvals, etc.) to replace the current ISS packet radio TNC by a device
> that would implement some more efficient digital communications? The device
> could be a digipeater, but employing strong FEC and a more modern
> modulation and framing structure and perhaps some better scheme for channel
> access. Perhaps something similar to ngham.
> https://github.com/skagmo/ngham
> With FEC and higher speed, we could accommodate many more users on a single
> pass. A dedicated software application on the ground would implement the
> modem and process information -- separating different types of messages in
> different screens, providing a chat like mode for real-time communications,
> automatically forwarding APRS packets, etc.
> Am I day dreaming?

Hi Edson,

You're not daydreaming that much. The BEESAT satellites have a
digipeater using the Mobitex-NX protocol, which has some form of FEC.

Many other satellites on the Amateur bands transmit telemetry using
strong FEC. For instance, AAUSAT-4 uses an r=1/2, k=7 convolutional code
and (255,223) Reed-Solomon with CCSDS scrambling.

Support and experimentation for these and many other protocols is very
easy today using SDR.



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