[amsat-bb] QIKcom Satellite Modes?
Stefan Wagener
wageners at gmail.com
Tue Feb 24 01:39:03 UTC 2015
Wow Douglas,
sounds impressive and honestly I am glad you understand that. I am clueless
:-)
Tx,
Stefan, VE4NSA
On Sat, Feb 21, 2015 at 7:03 PM, Douglas Quagliana <dquagliana at aol.com>
wrote:
> Bob asks:
>
> >I just cannot think of any neat must-do ideas for how to use
> >the other bank settings.
> >The settings in bank 0 are now:
> >
> >BTEXT: USNA-W3ADO APRS Satellite every 2 minutes
> >
> >I just cannot think of any use for a separate bank settings?
> >If you have ideas of how to use the A/B settings let me know.
>
> If you don't have any other ideas:
>
> Set BTEXT to a short beacon message that includes a
> few sync bytes, your preferred text message and a few
> bytes of forward error correction. You would have to
> pre-compute these and manually enter the FEC bytes
> at the end of the BTEXT. All of this would be sent
> INSIDE the AX.25 packet as the BTEXT. That way
> standard TNCs would still see the BTEXT message
> and a few binary bytes (if they get a valid CRC)
> but we could write DSP software to ignore the HDLC
> flags, look for the sync bytes, and process the FEC
> too. Depending on your message you might want to
> 8b10b encode it to avoid HDLC zero bit stuffing which
> could complicate the ground software.
>
> At four watts RF output, you don't need the FEC, but
> it would be an interesting experiment, and easy to
> do as you only need to pre-calculate the FEC once
> and hardcode the BTEXT message.
>
> 73,
> Douglas KA2UPW/5
>
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