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[aprssig] Re: APRS for a near-Arctic hot-air balloon flight -- TinyTralk and OpenTrak 300 baud mode

Ryan Butler rbutler at tsss.org
Wed Dec 7 02:03:13 UTC 2005


Yes and No, Manchester encodede FSK is sent up to AO-16 on FM, and the 
downlink is 1200 baud PSK SSB, so for the opentracker, we're only 
interested in Manchester encoded FSK on FM, it's sounds just like 
normal 1200 baud AFSK, it just is self syncing.  MIXW will decode the 
1200 baud PSK, but the only Manchester FSK software I'm aware of is UPW

Relevant Links:

http://members.aol.com/dquagliana/upw/

http://en.wikipedia.org/wiki/Manchester_encoding

Ryan


Quoting scott at opentrac.org:

> I don't see why not.  This is for SSB operation, right?  I'd need a
> reference with the relevant specs, and most importantly something to test it
> with.  Does AGWPE handle this mode, or do any of the other soundcard modem
> programs?
>
> Scott
> N1VG
>
>> -----Original Message-----
>> From: Ryan Butler [mailto:rbutler at tsss.org]
>> Sent: Tuesday, December 06, 2005 5:43 PM
>> To: TAPR APRS Mailing List; scott at opentrac.org
>> Cc: 'TAPR APRS Mailing List'
>> Subject: RE: [aprssig] Re: APRS for a near-Arctic hot-air
>> balloon flight -- TinyTralk and OpenTrak 300 baud mode
>>
>> Scott,
>>
>> Is there a possibility of a Manchester encoded FSK firmware for use
>> with digipeating satellites like AO-16?
>>
>> Ryan, KB0JQO
>>
>>
>> Quoting scott at opentrac.org:
>>
>> >> The OpenTrack requires downloading an entirely different set
>> >> of firmware into the processor; i.e. not something you will
>> >> do in the field.
>> >
>> > That's true.  If there's sufficient interest, I could
>> change that.  It's
>> > just a few constants that get changed, but the loop that
>> references them is
>> > very timing critical and I didn't feel like messing with it
>> and using up
>> > more config space.
>> >
>> > I actually cranked it up to 2400 baud once, but couldn't
>> get AGWPE to copy
>> > it.  Not sure if that was because it wasn't modulating
>> properly, or if I
>> > didn't have the right tones - I think George wasn't even
>> sure what tones it
>> > needed, or if it had been tested.
>> >
>> > I'm thinking about trying out 600 baud, with convolutional
>> coding and a
>> > non-AX.25 frame format... just curious how much the
>> performance can be
>> > improved for a noisy channel.
>> >
>> > Scott
>> > N1VG
>> >
>> >
>> >
>> >
>> > _______________________________________________
>> > aprssig mailing list
>> > aprssig at lists.tapr.org
>> > https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
>> >
>>
>>
>>
>>
>
>
>
>






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