[amsat-bb] Has anyone played with the TNC-Pi9K6 for decode of Fox birds

[Burns Fisher]

Kevin,

The data coming down from the current Fox sateliltes is not in AFSK/packet
form, which I think is what the TNC board you are looking at does.  It is
data-under-voice, something invented by AMSAT.  You can think of it as
either a 200bps square (ish) wave modulated in with the audio (i.e. you
filter out the audio above 300Hz or so and get a serial data stream) or
else you can also think of it as FSK (carrier frequency shift keying) mixed
in with the carrier frequency shift that the voice downlink causes.

So KG2C has the right idea:  Use FoxTelem to decode the audio.  I did not
see Milen's video, so I don't know how he gets the audio out.  The big
problem is that most transceiver audio output filters out audio below
200Hz.  This is sometimes true even of the data output from the transceiver
and they almost NEVER tell you the low frequency spec.  You have to get
around that.

Good luck and 73,
Burns WB1FJ
AMSAT Flight Software

On Wed, Oct 3, 2018 at 10:28 PM, Kevin Zari <kk4yel at gmail.com> wrote:

> I'm interested in connecting a TNC-Pi9k6 https://tnc-x.com/TNCPi9k6.htm
> up to my IC-910 data port, and seeing if I can decode some FoxTelem data.
> Has anyone played with this, and if not, what TNCs are you using ?
> Thanks
> -Kevin (KK4YEL)
>
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