[amsat-bb] ANS 321 AMSAT NEWS SERVICE SPECIAL BULLETIN - AO-85 Commissioned, Handed Over To AMSAT-NA Operations
daniel at destevez.net
Thu Nov 19 09:11:38 UTC 2015
El 18/11/15 a las 23:28, Phil Karn escribió:
> I designed the DUV telemetry system on Fox-1, with an important
> suggestion (use 8b10b coding for spectral shaping) from Tony, AA2TX.
> It's important to remember the severe design compromises imposed by the
> requirement that the satellite itself be an analog FM repeater,
> confining the telemetry to modulating frequencies below 300 Hz.
> These design compromises would have been unnecessary with a fully
> digital communications payload, like those on every non-amateur
> satellite launched in at least the past decade or two. I've made it
> clear that this is my last telemetry design for an analog spacecraft.
> It's past time for AMSAT to move into the all-digital era.
I'm wondering if it would be reasonable for future satellites to use an
SDR transmitter, to allow to use an analog FM downlink and digital
telemetry on two different frequencies (spaced about 20KHz apart or so).
As others have said, analog FM is quite desirable because it allows for
a very simple groundstation. Also, the current state of amateur digital
voice is not so stable with all these competing standards that have
closed implementations or use patented codecs.
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